BIOGEOCHEMISTRY OF SOFT AND BLACK CORALS, AND IMPLICATIONS FOR PALEOCEANOGRAPHY IN THE WESTERN TROPICAL PACIFIC

DISSERTATION

Presented in Partial Fulfillment of the Requirements for the degree of Doctor of

Philosophy in the Graduate School of The Ohio State University

By

Branwen Williams, M.S.

* * * *

The Ohio State University 2009

Dissertation Committee: Approved by: Professor Andrea G. Grottoli, Adviser

Professor Larry Krissek

Professor Matt Saltzman Adviser Earth Sciences Graduate Program Professor Lonnie Thompson

Copyright by

Branwen Williams

2009

ABSTRACT

Changes in the chemical and biological oceanography accompanying shifts in

ENSO conditions in the western tropical Pacific are not well understood and this

understanding would be enhanced by high resolution, century-scale proxy records

spanning the euphotic zone. Soft corals and black corals are abundant in the western

tropical Pacific from the near surface to thousands of meters deep, deposit organic

skeleton in concentric bands, and live for hundreds to thousands of years. Geochemical

measurements across colony growth axes can serve as proxies for the biogeochemistry of

particulate organic matter (POM). Yet, proxy records from these corals in the

climatically-sensitive western tropical Pacific have not yet been developed. Here,

quantifying the natural variability in organic skeletal δ13C and δ15N values facilitated comparisons of skeletal records from multiple taxa across a depth transect within the euphotic zone. Similar δ15N values between black corals and soft corals collected from a

reef offshore of Palau suggest these orders feed at the same trophic level while lower

δ13C values in black corals than soft corals indicate a correction of +1.5‰ is needed to

compare δ13C values between orders. In addition, due to chemical alteration of their food,

suspended POM, with depth, a +0.25 ‰/10 m correction needs to be applied to δ13C

values and -0.15 ‰/10 m correction needs to be applied to δ15N values to compare

records from multiple depths. Stable isotopes (δ13C and δ15N) and trace elements (Br, I,

Pb, Mn, Cd, Zn, and B) were measured in one Antipathes black colony from 5 m

ii and two Muricella soft coral colonies from 85 and 105m, all collected offshore of Palau.

Records were dated with a radiocarbon (14C)-derived chronology. The δ13C records

decreased at rates consistent with the oceanic 13C-Suess effect, indicating anthropogenic

carbon was a primary control on the δ13C of suspended POM through the top 105 m of the water. Very different δ15N records were derived from the shallow Antipathes colony

than the deeper Muricella colonies. Since all three colonies fed on suspended POM in the

water column, the dissimilar records indicated different controls on δ15N values of

suspended POM within and below the mixed layer. While changes in the source of POM

to the 5 m Antipathes colony with shifts in the relative strength of currents bathing Palau

within the mixed layer may drive increases and decreases in shallow δ15N record,

gradually decreasing δ15N values in both of the deeper Muricella records indicated a shoaling of the mean nutricline depth in recent decades. Three radial transects measured by LA-ICP-MS were only reproducible in the Antipathes colony, supporting these corals

for trace element reconstructions. This research is the first to develop soft corals and

black corals in the western Pacific as proxies of seawater chemistry across the euphotic

zone. Together, these corals provide paleoceanographic information on annual to centennial timescale changes in seawater chemistry across the depth range from near surface to thousands of meters deep

iii

ACKNOWLEDGMENTS

I sincerely thank my adviser, Andréa Grottoli. In addition to invaluable assistance in completing this dissertation, she showed by example how to run a lab, succeed as a professor, and perhaps most importantly, taught me to think critically. I thank my committee members. Larry Krissek provided endless into academic life, discussions on

ENSO, and many opportunities to immerse myself in oceanography, in Ohio. Lonnie

Thompson changed my way of viewing the world when he introduced me to the world of paleoclimatology, and somehow always found the time to talk science with me. Matt

Saltzman very graciously joined the game halfway through. I also thank the School of

Earth Sciences at OSU in general, who took in a biologist and turned me into a geologist.

The support of a Canadian abroad by the Natural Science and Engineering

Research Council of Canada provided invaluable freedom to devote my energy to my dissertation research. I also received financial support from Geological Society of

American, PADI Foundation, American Women in Science, and Friends of Orton Hall.

Funding included the National Science Foundation to Andrea Grottoli.

I could not have completed this research without the field, laboratory, and general assistance of many people. Pat and Lori Colin at the Research Foundation,

Palau, were incredibly supportive of my work. I thank Yohei Matsui and all the members of the Grottoli lab, including those who came before me, for their assistance during my research. John Olesik and Anthony Lutton of the Trace Element Research Laboratory

iv ensured I obtained quality elemental data. Tom Lippmann provided insight into data

analyses. Ghaleb Bassam at GEOTOP-UQAM-McGill ran 210Pb analyses for me. A graduate internship at the National Ocean Sciences Accelerator Mass Spectrometry facility at WHOI facilated radiocarbon analyses and I thank everyone at NOSAMS, and especially Ann McNichol.

Liz Birkos, Aron Buffen, Kelly Carroll, Sarah Fortner, Steve Goldsmith, Natalie

Kehrwald, Stephen Levas, Ryan Moyer, Becki Witherow, and many other students in

SES made Columbus my home, and SES a fun place to be. Anabelle’s company during early morning walks and bottomless cups of coffee at the Cornerstone Café increased my quality of life as a graduate student.

Special thanks to the Canadians. My parents, David and Christine Williams have always encouraged me in my eccentric pursuits, including my dream of studying the ocean since my first visit to Florida when I was nine years old. I also thank my American in-laws who frequently checked in to see how I was doing. My grandparents, John and

Evelyn Williams and Chuck and Joan Manley followed my progress along. Aaron, Liz and Bekah have always welcomed me home, and the Teeuwsens continue to be part of my family. Nina Klemm and Kate Sims kept in touch even when I was slow to respond,

Benoit Thibodeau insightfully commented on my writing, usually with a few jokes thrown in, and Randy McNobb made sure I kept school in perspective. I also thank my academic mentors, and my friends, Mike Risk, Owen Sherwood, and Daniel Sinclair

(really a Kiwi) all of whom introduced me to world of corals.

This dissertation is dedicated to Erik, who showed unending patience and support.

Thank you.

v VITA

16 May 1980 ……………….Toronto, Ontario

2003 ..………………………B.S. Marine and Freshwater Biology, University of Guelph

2005 ..………………………M.S. Biology, University of Quebec at Montreal

2005-2006 …………………. Graduate Research Assistant, School of Earth Sciences, The Ohio State University

2006-2009 .…………………NSERC Graduate Research Fellow with foreign tenure in the School of Earth Sciences, The Ohio State University

PUBLICATIONS

1. Williams, B., Risk, M.J., Ross, S.W., and Sulak, K.J. (2007) Stable isotope records from deep-water antipatharians: 400-year records from the south-eastern coast of the United States of America. Bulletin of Marine Science 81(3):437 – 447. 2. Williams, B., Risk, M.J., Stone, R., Sinclair, D.J. and Ghaleb, B. (2007) Oceanographic changes in the Gulf of Alaska over the past century recorded in deep-water gorgonian corals. Marine Ecology Progress Series 335: 85 – 94. 3. Williams, B., Risk, M.J., Ross, S.W., and Sulak, K.J. (2006) Deep-water Antipatharians: proxies of environmental change? Geology 34(9): 773 – 776, doi: 10.1130/G22685.1 4. Sinclair, D.J., Williams, B., and Risk, M. (2006) Trace element "Vital Effects" - a ubiquitous feature of Scleractinian coral skeletons. Geophysical Research Letters 33, L17707, doi:10-102932006GL027183. 5. Risk, M.J., Hall-Spencer, J., and Williams, B. (2005). Climate records from the Faroe-Shetland Trough using Lophelia pertusa (Linneaus, 1758). In: Freiwald, A., Robert, M. (eds) Cold-water Corals and Ecosystems, Erlangen, p 1097 – 1108. FIELDS OF STUDY

Major Field: Earth Sciences Area of Emphasis: Marine geochemistry

vi

TABLE OF CONTENTS

Pages

Abstract ...... ii Acknowledgements ...... iv Vita ...... v List of Tables ...... x List of Figures ...... xi

Chapters:

1. Introduction ...... 1

Significance ...... 1 Background ...... 4 and Antipatharia corals ...... 4 Radiocarbon ...... 8 Stable isotopes ...... 9 Trace elements ...... 13 Research Proposal ...... 16 Field Site: Climatology and oceanography ...... 17 Coral colony collection ...... 18 Chapter 2. Stable nitrogen and carbon isotopic variability (δ15N and δ13C) in shallow tropical Pacific soft coral and taxa and implications for paleoceanographic reconstructions ...... 19 Chapter 3. Soft coral and black coral skeletal Δ14C, δ13C and δ15N records from the Western Pacific Warm Pool and relationship to ENSO ...... 20 Chapter 4: Reproducibility and calibration of trace elements in soft coral and black coral corals ...... 22 Broader impacts ...... 24 Literature cited ...... 24

2. Stable nitrogen and carbon isotopic variability (δ15N and δ13C) in shallow tropical Pacific soft coral and black coral taxa and implications for paleoceanographic reconstructions ...... 43 Abstract ...... 44 Introduction ...... 46 Methods ...... 48 vii Study Site ...... 48 Colony identification ...... 49 Laboratory analyses ...... 49 Statistical analyses ...... 51 Results ...... 52 Coral colony collection and identification ...... 52 Isotopic analyses ...... 53 Discussion ...... 54 Variability in stable isotopes with depth ...... 54 Variability in stable isotopes between orders ...... 57 Variability in stable isotopes within and between genera ...... 58 Implications ...... 60 Acknowledgements ...... 61 Literature cited ...... 62

3. Organic skeletal stable isotope records from soft corals and black corals record water mass movement on ENSO and decadal timescales in the western tropical Pacific Ocean ...... 75 Abstract ...... 76 Introduction ...... 78 Methods ...... 80 Study area ...... 80 Colony collection and identification ...... 81 Laboratory analyses ...... 82 Chronology construction ...... 85 Statistical analyses ...... 86 Results ...... 88 Growth rates and age estimates ...... 88 Skeletal δ13C records ...... 88 Skeletal δ15N records ...... 90 Discussion ...... 90 Skeletal bomb 14C records ...... 90 Skeletal δ13C records ...... 92 Skeletal δ15N records ...... 93 Shallow Antipathes black coral records variability in source water within the mixed layer ...... 94 Deeper Muricella soft coral record shoaling of mean nutricline depth ……………………………………………………………… 96 Summary and implications ...... 97 Acknowledgements ...... 98 Literature cited ...... 99

4. Solution and laser ablation inductively coupled plasma mass spectrometry (ICP-MS) measurement of Br, I, Pb, Mn, Cd, Zn, and B in the organic skeleton of soft corals and black corals ……………...... 113

viii Abstract ...... 114 Introduction ...... 116 Methods ...... 118 Specimen collection ...... 118 Sample preparation ...... 119 Skeletal imaging ...... 120 Solution ICP-MS ...... 121 LA-ICP-MS ...... 122 Data analysis ...... 123 Results ...... 125 Coral imaging ...... 125 Coral solution ICP-MS measurements ...... 126 Coral LA-ICP-MS measurements ...... 127 Discussion ...... 128 Solution ICP-MS element concentrations ...... 130 Laser ablation ICP-MS radial profiles of element intensities ...... 131 Implications for LA-ICP-MS paleoceanographic reconstructions .. 134 Acknowledgements ...... 135 Literature cited ...... 135

5. Summary ...... 148 Natural variability in organic skeletal δ13C and δ15N values ……. 150 δ13C and δ15N records from three colonies across a depth transect . 151 Solution-derived elemental composition and reproducibility of laser ablation radial profiles …………….……...... ……………… 152 Future work ……………………………….……………………………… 153 Literature cited ……………………………….…………………………... 155

6. References ...... 156

7. Appendix A: Coral colony stable isotope data ...... 174

8. Appendix B: Test of acid treatment on stable isotope values ...... 177

9. Appendix C: Coral time series stable isotope data ...... 179

10. Appendix D: Six-monthly smoothed coral elemental time series data ...... 184

ix LIST OF TABLES

Table Page

1.1. Current higher taxonomic classification of select according to Fabricius and Alderslade (2001) with defining characteristics of relevant taxa ...... 36

1.2. Possible application of minor and trace elements measured in the organic skeleton ……………………………………………………………………. 37

1.3. of collected colonies in shallow (5-45m) and deeper (85m) water ……………………………………………………………….……… 38

2.1. Taxonomy of collected colonies in shallow (5-45m) and deeper (85m) water ………………………………………………………………………. 66

2.2. Results of ANOVA testing differences in organic skeletal δ15N and δ13C values between orders (black coral and soft coral) and depths (shallow and deeper water) …………………………………………………………….... 67

2.3. Results of ANOVA testing differences in organic skeletal δ15N and δ13C values among genera with more than one colony (, Acanthogorgia, Muricella, Paracis, , Astrogorgia, and Rhipidipathes) and depths (shallow and deeper water) ………………………………………... 68

3.1. Summary of colony, growth rates, ages, and sub-sampling resolution for black coral and soft coral colonies used in this study ...... 105

4.1. Elements analyzed by solution ICP-MS ………………...………………… 139

4.2. LA-ICP-MS instrument operating parameters ……………………………. 140

A.1. Colony identification, collection location, nitrogen stable isotope (δ15N), carbon stable isotope (δ13C), percent nitrogen, and percent carbon data ..... 175

B.1. The effect of treatment on nitrogen stable isotope (δ15N) and carbon stable isotope (δ13C) values ...... 178

x C.1. Raw stable isotope (δ13C and δ15N) data for the Antipathes colony A5m and the Muricella colonies M85m and M105m with radiocarbon (14C)- derived growth chronologies ...... 180

D.1. LA-ICP-MS elemental data for Antipathes A5m ...... 185

D.2. LA-ICP-MS elemental data for Muricella M85m ...... 187

D.3. LA-ICP-MS elemental data for Muricella M105m ...... 192

xi

LIST OF FIGURES

Figure Page

1.1. Cartoon showing drivers of carbon isotope variability in the ocean ……… 39

1.2. Cartoon showing sources and controls on nitrogen stable isotopes of organic matter in the western tropical Pacific ...... ………………….…...... 40

1.3. Map of western tropical Pacific, showing location of Palau and field sites Short Drop Off and Ulong Rock ...... 41

1.4. Photograph of a soft coral colony showing colony gross morphology and branching pattern ...... 42

2.1. Skeletal organic stable nitrogen isotopic (δ15N) values versus stable carbon isotopic (δ13C) values from all colonies in (A) shallow (5-45 m) and (B) deeper (85 m) water ……………………………………………………….. 69

2.2. Average organic skeletal (A) stable nitrogen isotopic (δ15N) value and (B) stable carbon isotopic (δ13C) value for all black coral and soft coral colonies in shallow (5- 45 m; open circles) and deeper (85 m; closed circles) water …...... 70

2.3. Average organic skeletal δ15N values for all soft coral colonies collected from shallow (5-45 m; open circles) and deeper (85 m; closed circles) water ...... 71

2.4. Average organic skeletal δ13C values for all soft coral colonies collected from shallow (5-45 m; open circles) and deeper (85 m; closed circles) water ...... 72

2.5. average organic skeletal δ15N values for colonies in (A) shallow (5- 45 m) and (B) deeper (85 m) water ……………………………………...... 73

2.6. Genus average organic skeletal δ13C values for colonies in (A) shallow (5- 45 m) and (B) deeper (85 m) water ……………………….………………. 74

3.1. Map of the western tropical Pacific showing the location of the Short Drop Off field site 2 km offshore of Palau ……………………………………… 106

xii 3.2. Cartoon showing representative basal slice with sampling tracks at 100 μm increments for δ13C and δ15N analyses …………………………………… 107

3.3. Radiocarbon values (Δ14C) for colonies Antipathes A5m, Muricella M85m, and Muricella M105m measured across a radial transect and compared to published radiocarbon records from a tropical Pacific Porites stony corals {Guilderson et al., 1998] and a Palauan Ancanthocheatetes wellsi sclerosponges [Grottoli 2006] …………………….………………... 108

3.4. Stable carbon isotope (δ13C) values for the Antipathes A5m, Muricella M85m, and Muricella M105m colonies collected from 5 m, 85 m, and 105 m, respectively, from Short Drop Off reef wall in Palau ………..…….….. 109

3.5. Coherence from cross-spectral analysis between the δ13C and Southern Oscillation Index (SOI) of records of A) Antipathes A5m, B) Muricella M85m, and C) Muricella M105m, and between the δ15N and SOI records for D) Antipathes A5m, E) Muricella M85m, and F) Muricella M105m ..... 110

3.6. Stable nitrogen isotope (δ15N) values for the Antipathes A5m, Muricella M85m, and Muricella M105m colonies collected from 5 m, 85 m, and 105 m, respectively, fromShort Drop Off reef wall in Palau …….……………. 111

3.7. Outer skeletal layer δ15N values for the Antipathes A5m, Muricella M85m, and Muricella M105m colonies plotted with the average δ15N values for the outer layer of 65 additional colonies from Chapter 2 of this dissertation over the same depth range ……………………...……………………...….. 112

4.1. Photographs showing concentric growth bands in: (A) the Antipathes colony A5m viewed under scanning electron microscope and (B) the Muricella colony M85m viewed under light microscope ………………… 141

4.2. Average concentration of the elements: A) Br, B) I, C) Pb, D) Mn, E) Cd, F) Zn, and G) B for the Antipathes colony A5m (n=10), the Muricella colony M85m (n=5), and the Muricella colony M105 (n=7) ……………... 142

4.3. Examples of the high reproducibility of the five replicate scans for one radial transect. A) 11B/13C in the Antipathes colony A5m. B) 114Cd/13C in the Muricella colony M85m …………………….………………………… 143

4.4. Three radial transects in the Antipathes colony A5m for the isotopes: A) 79Br/13C, B) 127I/13C, C) 208Pb/13C, D) 55Mn/13C, E) 114Cd/13C, F) 64Zn/13C, and G) 11B/13C …………………………………………………………….. 144

xiii 4.5. Three radial transects in the Muricella colony M85m for the isotopes: A) 79Br/13C, B) 127I/13C, C) 208Pb/13C, D) 55Mn/13C, E) 114Cd/13C, F) 64Zn/13C, and G) 11B/13C …………………………………………………………….. 145

4.6. Three radial transects in the Muricella colony M105m for the isotopes: A) 79Br/13C, B) 127I/13C, C) 208Pb/13C, D) 55Mn/13C, E) 114Cd/13C, F) 64Zn/13C, and G) 11B/13C …………………………………………………………….. 146

4.7. High-resolution δ15N values, 11B/13C intensities in the A5m Antipathes colony, and estimated sea surface salinities (SSS) reconstructed from a scleractinian coral ……………………...…………………………………. 147

xiv

CHAPTER ONE

INTRODUCTION

SIGNIFICANCE

In view of current and future climate change, as described in the recent IPCC report (Alley et al. 2007), the importance of understanding past changes in the ocean and climate are apparent. In particular, the uncertainty in the relationship between climate change and El Niño-Southern Oscillation (ENSO) currently limits the reliability of climate forecasting models (Fedorov and Philander 2000). A detailed understanding of the effect of ENSO variability on tropical Pacific circulation and water mass movement is imperative for comprehensively modelling changes in chemical and biological oceanography accompanying El Niño and La Niña events. El Niño and La Niña are opposite extremes of ENSO, such that El Niño reflects a strong and/or prolonged warming and La Niña reflects a strong and/or prolonged cooling of sea surface temperatures (SSTs) in the eastern tropical Pacific. During El Niño events, the trade winds slacken, upwelling in the eastern Pacific is suppressed, and surface waters warm.

Without strong trade winds, water is no longer pushed from east to west in the tropical

Pacific. This causes the western Pacific warm pool (WPWP) to expand eastward into the central Pacific and the thermocline in the western Pacific to shoal. During La Niña

1 events, the trade winds increase in strength, upwelling off the western South American coast is enhanced, and the SSTs in this region cool more than usual. In the western tropical Pacific, the thermocline is depressed, and the WPWP constricts by the movement of the surface waters west.

Fluctuations in productivity resulting from shifts in ENSO have been well- documented in the eastern tropical Pacific (Barber and Chavez 1983); however, less is known about changes in productivity and water mass chemistry in the western tropical

Pacific. Typically, tropical waters are oligotrophic. However, productivity increases during La Niña events in the western tropical Pacific as a result of the shoaling thermocline and nutricline, which bring nutrient-rich waters into the euphotic zone

(Kawahata and Gupta 2004; Kawahata et al. 2000; Radenac and Rodier 1996; Yoshikawa et al. 2006). Primary production in the ocean can act as a carbon sink, and increases in productivity during La Niña events may shift the tropical Pacific from a source of carbon dioxide to the atmosphere to a sink out of the atmosphere (Gupta and Kawahata 2002;

Murray et al. 1994), as carbon dioxide used during photosynthesis is sequestered to the deep ocean by particulate organic matter exported out of the euphotic zone. However, these studies have focused on datasets obtained over short periods of time, and records spanning several ENSO events are needed to put these temporally-limited datasets into a longer-term context.

To date, high resolution paleoceanographic reconstructions in the tropical Pacific have been largely derived from scleractinian corals (i.e., Cobb et al. 2003; Cole 2003;

Gagan et al. 2000). These corals provide faithful reconstructions of sea surface temperature (SST) and sea surface salinity (SSS) in the tropical Pacific (Stephans et al.

2 2004). Yet, these records are limited to near-surface, sunlit waters and do not provide

information about fluctuations in nutrient concentrations and productivity, or across a depth range. Since upwelled water does not break the surface in many areas of the western tropical Pacific (Delcroix et al. 1992), records of productivity are particularly

important from within and below the mixed layer (Enfield 1989). Sediment records can

provide information about past nutrient levels (Kienast et al. 2008) but are limited in resolution and do not provide records of recent conditions. Alyconaceans (soft corals) and antipatharians (black corals), two separate orders of non-scleractinian corals, are both

widely distributed throughout the world’s oceans and across a large range in depths from

near surface to thousands of meters deep (Moore et al. 1956). Some have a

protein-rich internal skeleton that grows in concentric rings providing chronological

control, similar to tree rings (Sherwood et al. 2005b). The geochemistry of the organic

skeleton is driven to a large extent by the coral’s food source, organic matter, in the water

column (Roark et al. 2005; Sherwood et al. 2005a; Williams et al. 2007a). In the western

tropical Pacific, these corals have the potential to provide paleoceanographic

reconstructions of seawater nutrient chemistry spanning the water column on sub-annual

to centennial timescales.

Here, I examine the geochemistry of soft coral and black coral colonies collected

across the top 105 m of the water column in the western tropical Pacific. The two goals of

this research are: 1- to quantitatively explore the variability in organic skeletal stable

isotopes from multiple taxa, sites, and depths, and 2- to test the feasibility of

reconstructing changes in seawater chemistry through radial profiles of organic skeletal

stable isotopes, radioisotopes, and trace element measurements. This research will

3 produce recommendations for extracting paleoceanographic records from soft corals and

black corals from shallow water in the western tropical Pacific, and will produce a first-

order reconstruction of changes in vertical fluctuations of water masses in the western

tropical Pacific on decadal timescales.

BACKGROUND

Past oceanic conditions such as temperature, salinity, and nutrient concentrations

can be reconstructed over time from the skeletons of marine organisms. Skeletal bands in

these organisms, such as corals, can provide chronological control. Used in conjunction

with skeletal measurements including banding characteristics and skeletal geochemical

analyses, proxy records can be developed. Recent studies have supported using soft

corals and black corals as recorders of surface water nutrient source and biological

processes (Sherwood et al. 2005a; Williams et al. 2006). Here, soft corals, black corals

and potential skeletal geochemical measurements providing oceanographic information

are discussed.

Alcyonacea and Antipatharia corals

Alcyonaceans (soft corals) are an order of marine organism belonging in the

Cnidaria, subclass , class (Table 1.1). Genera within the

suborders and Calcaxonia, commonly called the Gorgonians, are best suited

for paleoceanographic reconstructions as they are formed of an internal skeletal core covered externally by a continuous tissue layer. These corals grow their skeleton

outwards in concentric rings such that the outer layer of skeleton is the most recently

4 formed. The skeleton is formed of or gorgonin, an organic proteinaceous substance, or some combination of the two (Grasshoff and Zibrowius 1983; Lewis et al.

1992). In some taxa, the inorganic and organic skeleton form alternating annual growth bands that provide tight chronological control (Sherwood et al. 2005b). In others, the inorganic component is minimal, and skeletal rings largely reflect layers of collagen fibers (Lewis et al. 1992). Calcite sclerites, which provide skeletal support and protection, are present in the tissue and are one of the primary taxonomic identifiers.

Deep-water soft corals have been dated with varying success using growth band counts, 210Pb, U/Th, and Δ14C (Andrews et al. 2002; Druffel et al. 1990; Roark et al.

2006; Roark et al. 2005; Sherwood et al. 2005b; Thresher et al. 2004; Williams et al.

2006; Wilson et al. 2002). Annual periodicity in some genera of Holaxonians and

Calcaxonians likely results from environmental conditions with strong annual

fluctuations rather than a characteristic inherent to a specific genus itself (Andrews et al.

2002; Goldberg 1976; Noe et al. 2007; Sherwood et al. 2005b; Williams et al. 2007b).

Primnoa sp., a deep-sea soft coral in the Primoidae family within the suborder

Calcaxonia (Table 1.1), forms a skeleton comprised of couplets of calcite-gorgonin bands

that are easily viewed under ultraviolet (UV) light ( Sherwood et al. 2005b). A couplet of

one inorganic and one organic skeletal band forms annually in specimens from the north

Atlantic Ocean (Sherwood et al. 2005b). The gorgonin (organic) fraction of the skeleton

is formed concurrent to the spring nutrient flux and may result from increased food

levels; this suggests food abundance is likely a primary control on skeletal growth rates in

deep-water species (Sherwood et al. 2005a). Additional factors may drive growth band

formation in colonies from the western tropical Pacific since strong annual fluctuations in

5 nutrient fluxes are absent. Here, water temperature and/or seasonal reproduction may

control growth rates and banding patterns in addition to food abundance in colonies in

shallow water (Grigg 1974; Matsumoto 2004).

Research on skeletal geochemistry of Holaxonians and Calcaxonians has

primarily focused on cold-water taxa (i.e., commonly found in water temperatures of 4 to

12ºC) from depths >50m (Roberts et al. 2006). Food web studies using nitrogen stable

isotopes (δ15N) of the organic skeleton indicate that the diet of deep-water northern

Atlantic Calcaxonia, the Primnoids, is composed primarily of sinking particulate organic

matter (POM) and with little contribution of dissolved inorganic carbon

(DIC), dissolved organic carbon (DOC), or suspended POM (Sherwood et al. 2005a).

Since the isotopic composition of POM sinking out of the euphotic zone is preserved with

depth, colonies hundreds of meters deep in the water column act as recorders of surface

biophysical processes. For example, δ15N values in these specimens negatively correlate with surface apparent oxygen utilization, an indicator of surface productivity (Sherwood

et al. 2005a). Sinking POM as a driver of skeletal isotopic values is supported by carbon

isotope values in the organic skeleton. Stable carbon isotopes (δ13C) show decreasing

values over the past century that reflect the “δ13C-Suess effect” (Sherwood 2006;

Williams et al. 2007a), a gradual depletion of oceanic δ13C values due to burning of

isotopically-light fossil fuels (Keeling 1979). Radiocarbon (14C) measurements in the

families and Isididae, both Calcaxonians, clearly show the radiocarbon

“bomb-curve” in the skeleton (Roark et al. 2005; Sherwood et al. 2005b). The bomb-

curve reflects a near doubling of atmospheric 14C during the 1950s and 1960s due to the

testing of thermonuclear bombs in the Pacific. In contrast, carbon isotopes of the

6 inorganic skeleton of Isididae do not show either the δ13C-Suess effect or the bomb-

curve, indicating that these corals obtain carbon for the inorganic fraction of their

skeleton from the ambient carbon pool at depth (Roark et al. 2005).

Shallow-water soft corals (i.e. taxa predominately found in warm, sunlit waters)

feed on a variety of foods including mucus, microplankton, phytoplankton, and

zooplankton both as passive suspension feeders and active captors of zooplankton

(Coffroth 1984; Coma et al. 1994; Fabricius et al. 1995; Grigg 1965; Lewis 1982; Lewis

1978; Patterson 1984; Ribes et al. 1998; Sebens and Koehl 1984; Spongaule and

Labarbera 1991; Tazioli et al. 2007). Each of these fractions of marine organic matter

may have a unique δ15N and δ13C signature (Benner et al. 1997; Guo et al. 2004) since

δ15N values increase with each level in the food web (Deniro and Epstein 1981;

Minagawa and Wada 1984) while δ13C values increase with both trophic level (Deniro and Epstein 1978; Mcconnaughey and Mcroy 1979) and feeding type (i.e. benthic vs pelagic) (Nadon and Himmelman 2006). In addition, species that contain endosymbiotic algae also obtain a portion of their fixed carbon photosynthetically (Ribes et al. 2003).

However, measurements of organic skeletal stable isotopes in shallow-water taxa are limited. Ward-Paige et al. (2005) showed correlation of δ15N values to total nitrogen

content in shallow-water soft corals from the Florida Reef Tract. δ13C values in the same

colonies indicated their mode of feeding to be autotrophic in some cases and

heterotrophic in others. Thus the influence of diet, environment, and physiology on the

skeletal isotopic and trace element composition of these corals is unknown. Less is

known about the drivers of skeletal geochemistry in shallow-water tropical Pacific soft

corals, limiting their use for paleoceanographic reconstructions.

7 Antipatharians (black corals) are members of the same phylum (Cnidaria) and

class (Anthozoa) as the soft corals, but belong to the subclass Hexacorallia, and order

Antipatharia (Table 1.1). Black corals are formed of an organic skeleton composed of

chitin complexed with proteins (Ellis et al. 1980; Goldberg 1976; Goldberg 1991;

Goldberg et al. 1994). The skeleton is semi-rigid, and similar to soft corals forms

concentric coeval bands. Dating studies suggest banding is annual, and dating using 210Pb and 14C indicate that deep-water species live for thousands of years (Goldberg et al. 1994;

Holmes et al. 2006; Roark et al. 2006; Williams et al. 2006).

Stable carbon and nitrogen isotopes of deep-water black corals collected from the

Gulf of Mexico and western Atlantic appear to record changes in the source of nutrients used by the organisms (Williams et al. 2006). Similar to soft corals, black coral skeletal isotopic composition is likely also driven by the signature of their food source, organic matter (Grigg 1965), and thus should record similar processes influencing the composition and source of POM. Research on shallow-water black corals has focused on ecological studies of Hawaiian and New Zealand corals for conservation applications

(Goldberg 1991; Grange 1985; Grange and Goldberg 1994; Grigg 1965); however, little is known about shallow-water taxa from other locations, particularly the western tropical

Pacific.

Radiocarbon

Radiocarbon (14C) is produced naturally in the atmosphere as nitrogen is

bombarded by cosmic rays. Excess 14C was also produced by thermonuclear weapons testing in the mid-1950’s resulting in a pronounced bomb signal in the atmosphere and

8 ocean carbon pools. In the western Pacific, bomb carbon is present in marine organisms

starting in ~1955 and peaking in approximately 1973 (i.e., Druffel 1981; Grottoli and

Eakin 2007; Guilderson and Schrag 1998). Prior to the 14C-bomb signal,14C

concentrations in the ocean were also driven by the “14C-Suess Effect”, a dilution of

14 14 natural C by the addition of C-free fossil fuel-derived CO2 to the atmosphere (Druffel and Griffin 1993; Suess 1953). In addition, the formation of deep water isolates water

14 masses from direct CO2 exchange with the atmosphere, resulting in decreasing C content as the 14C decays. Thus, measurements of radiocarbon (reported as Δ14C) can also provide information about vertical mixing and ocean circulation (Broecker et al. 1985).

All three of these signals, the bomb-curve, the Suess effect, and water mass mixing, can be detected in the 14C signature of corals.

Stable isotopes

The distribution and isotopic composition of inorganic carbon is an important

control on the carbon isotopic ratio (δ13C = permil deviation of 13C/12C relative to VPDB)

13 13 of organic matter in marine environments. δ C of DIC (δ CDIC) shows strong temporal

and spatial variability. Carbon isotopes are fractionated by the transfer between the

atmosphere and surface waters resulting in DIC in seawater being enriched

approximately 8‰ relative to atmospheric carbon dioxide (Deniro and Epstein 1978;

Siegenthaler and Munnich 1981). This fractionation is temperature-dependent with a

13 relationship of approximately -0.1‰ per K (Mook 1986) causing lower δ CDIC values in

the tropics versus higher latitudes. The tropics are also characterized by little seasonal

13 variation which results in less temporal variability in δ CDIC than in the mid-latitude

9 regions (Gruber et al. 1999; Kroopnick 1985). Globally, the “13C Suess effect”, a gradual

depletion of δ13C values of atmospheric carbon over the past decade resulting from the

burning of 13C-light fossil fuels (Keeling et al. 2005; Keeling et al. 1995), is a dominant

control on marine δ13C values. This isotopically-depleted carbon has entered the marine

13 carbon cycle causing a depletion of δ CDIC values (Quay et al. 2003), and a resulting

13 13 depletion in δ C of POC (δ C POC) values of 2 to 5‰ since preindustrial times (Bentaleb

13 and Fontugne 1996). In addition to thermodynamic drivers, δ CDIC is controlled by

biological processes which will preferentially use isotopically-light 12C, leaving the

remaining DIC reservoir enriched in the heavier 13C. Consequently, marine organic

carbon is characterized by light δ13C values, ranging from -20 to -30‰ (Fig. 1.1)

(Goericke and Fry 1994). Remineralization and oxidation of organic matter as it sinks out

of the euphotic zone in turn releases the isotopically-light carbon back into the inorganic

reservoir. This process creates a “biological pump” creating a gradient from 13C-enriched

DIC to 13C-depleted DIC with increasing depth (Fig. 1.1).

13 Stable carbon isotope values of δ CPOC vary widely throughout the global ocean

from -16‰ in the tropics to -35‰ in the Southern Ocean (Goericke and Fry 1994)

13 indicating δ CPOC shows spatial variation greater than that solely resulting from

13 variations in δ CDIC. Isotopic fractionation during organic matter production is largely

13 responsible for the observed range in δ CPOC (Hofmann et al. 2000). Variability in

fractionation of 13C/12C during cell growth responds to physiology, including

cell geometry and membrane permeability of molecular CO2 diffusion, and

environmental factors, including temperature and light (Burkhardt et al. 1999; Fry and

Wainright 1991; Popp et al. 1998; Rau et al. 1996; Rost et al. 2002; Sackett et al. 1965).

10 13 Differences in plankton species composition also affect the δ CPOC signal, since

fractionation factors may vary predictably among different species of phytoplankton and

since δ13C is fractionated such that with each level in the food chain δ13C is depleted by

approximately 1‰ (Kukert and Riebesell 1998; Rau et al. 1992).

- Nitrate (NO3 ) is the most abundant biologically-available form of nitrogen in

marine environments. In the western tropical Pacific, the mixed layer is nitrate limited, so

nitrogen entering the system is consumed by plankton during primary production. In

nitrate limited systems, the nitrogen isotopic ratio (δ15N = permil deviation of 15N/14N relative to atmospheric N2) of organic matter in marine environments reflects the source

of nitrogen to plankton (i.e., δ15N of the substrate), which is usually nitrate. The primary

sources of nitrogen to marine environments are atmospheric deposition (Duce et al. 2008;

Prospero et al. 1996), riverine inputs of terrestrially-derived nitrogen (Walsh 1991), and

biological nitrogen fixation (Capone 2001) (Fig. 1.2).

- 14 Biologically-mediated processes converting NO3 into NH3 are faster for N than

for 15N (Owens 1987). Over time, the degree of fractionation occurring during these

reactions varies with the degree of surface nutrient utilization (Altabet and Francois

- 15 1994). Transient increases in NO3 cause the δ NNO3- to become progressively lighter as

14 - more N is initially available, and then heavier as the NO3 is used up. As the

- 15 phytoplankton draw down NO3 to very low levels, the accumulated δ NNO3- will start to

15 - 15 resemble the initial δ NNO3- in the now NO3 -limited system. Consequently, δ NNO3- has

been shown to vary on seasonal to glacial-to-interglacial timescales with the input of

- NO3 -rich water fuelling bloom productivity (Altabet et al. 1995; Wu et al. 1997).

11 Within the ocean, new nitrate can be transported into the sunlit euphotic zone

from the nitrate-rich deep ocean by convection (Williams et al. 2000), advective fluxes

during upwelling and vertical mixing (Williams and Follows 1998), and diffusion across

the thermocline (Lewis et al. 1986; Planas et al. 1999).

In addition to temporal changes, δ15N of organic matter varies vertically and

horizontally. δ15N values of suspended PON show a subsurface minima coinciding with a subsurface maximum in concentration of PON at the top of the nutricline (Altabet and

Mccarthy 1985; Montoya et al. 1992). δ15N values of suspended PON increase by up to

10‰ with depth below the nutricline (Altabet 1988; Altabet and Mccarthy 1985; Altabet

and Mccarthy 1986; Saino and Hattori 1980; Saino and Hattori 1987). This results from

remineralization (Altabet and Mccarthy 1985; Checkley and Miller 1989; Saino and

Hattori 1987), oxidative degradation (Saino and Hattori 1980), ammonification

(Minagawa and Wada 1984) and addition of organic debris from higher trophic levels

(Nakatsuka et al. 1997). In contrast to suspended PON, δ15N of PON sinking out of the

euphotic zone decreases with depth (Altabet et al. 1991; Nakatsuka et al. 1997). This may result from preferential degradation of amino acids, which are heavier (δ15N ~ 3‰) than

bulk POM (Macko et al. 1987), and/or zooplankton excretion at depth and subsequent

bacterial incorporation of depleted δ15N ammonium (Checkley and Miller 1989).

In the western Pacific warm pool (WPWP), a barrier layer between the warm

(SSTs of ≥ 28ºC) and fresh (SSS of ≤ 35) mixed layer and the thermocline (defined as the

20ºC isotherm) causes stratification inhibiting transport of nutrients from deeper water

into the euphotic zone, and leaves the surface water depleted of nitrate (Ando and

Mcphaden 1997; Borgne et al. 2002; Kawahata et al. 2000; Mackey et al. 1995;

12 Yoshikawa et al. 2006). The South Equatorial Current (SEC), and likely the North

Equatorial Current as well, transfer δ15N-enriched nitrate from the eastern equatorial

15 Pacific to the WPWP (Pena et al. 1994). However, WPWP δ NNO3- values of 5‰ at

100m depth are markedly lower than values of 10‰ at the same depth in the central and

eastern tropical Pacific (Yoshikawa et al. 2006). Lower values have been attributed to

nitrogen fixation (Capone et al. 1997; Liu et al. 1996; Minagawa and Wada 1986) and/or

inputs of terrestrial nitrogenous nutrients through river water discharge and atmospheric deposition due to heavy rainfall (Kawahata et al. 2000; Yoshikawa et al. 2005), in addition to nitrate supplied from the SEC (Fig. 1.2).

Trace Elements

In scleractinian corals, trace elements are incorporated into the lattice by

substitution during formation of calcium carbonate in response to environmental conditions (Shen et al. 1991). Similarly, studies show that trace elements are incorporated

by substitution into the inorganic skeleton of some soft corals, although extraction of

climate records has proven difficult (Bond et al. 2005; Weinbauer and Vellmirov 1995).

Trace elements are expected to be incorporated heterotrophically into the organic

skeleton of soft corals and black corals. However, if the element is taken into the skeleton

in proportion to ambient environmental concentrations, then skeletal measurements could

vary in response to changes in seawater conditions. Below, the characteristics of Br, I, B,

Cd, Zn, Pb, and Mn in the ocean are discussed as these elements are likely to be useful

proxies (Table 1.2).

13 Bromine, present as the bromide ion Br-, is abundant in seawater. It has a

conservative distribution and varies only due to differences in evaporation or precipitation in seawater. High concentrations of bromine are present in the skeleton of soft corals and black corals, and particularly in older parts of the skeleton in soft corals and in younger parts of the skeleton in black corals (Goldberg 1978).

- Dissolved iodine is mostly present as iodate (IO3 ) in seawater, although in the

- - - euphotic zone some iodate is reduced to iodide (I ) as phytoplankton reduce NO3 to NO2

(Wong and Hung 2001). Therefore, iodide is slightly depleted at the surface, similar to nitrate, while iodate has a surface maximum. Iodate and nitrate concentrations have been used to distinguish between water masses with similar temperatures and salinities (Wong and Zhang 2003). High concentrations of iodine are present in both soft corals and black corals, and are higher in the older parts of the skeleton in both soft corals and black corals than in younger parts of the skeleton (Goldberg 1978). Thus skeletal bromine and iodine concentrations may be used to track changes in the biology of a coral over time, rather than ambient environmental conditions.

- Boron is present in seawater as the borate ion (B(OH)4 ) and undissociated boric

0 acid (B(OH)3 ), and has nearly constant concentrations with depth in seawater. On a large

scale, boron is generally more concentrated in marine than freshwater sediments, and

boron is absorbed by clays in direct proportion to the boron concentration in solution

(Couch 1971; Harriss 1969). Concentrations of boron in sediments do not appear to be a

strong indicator of paleosalinity (Harriss 1972), possibly as a consequence of post-

depositional alterations (Cook 1977; Perry Jr 1972). Boron concentrations in bivalves

14 reflect that of the surrounding water (Roopnarine et al. 1998) suggesting that it may be a

useful proxy for paleosalinities.

The majority of dissolved Zn (99%) in seawater is bound to organic ligands

where it is transported to depth (Bruland 1980; Bruland 1989; Zirino and Healy 1971). In

surface waters, this reduces the bioavailable fraction of Zn to concentrations limiting to

some phytoplankton (Brand et al., 1983; De La Rocha et al., 2000; Sunda and Huntsman,

1992, 1995). Therefore although zinc enters the oceans from aerosol deposition, and to

lesser extent from rivers, it is often in very low concentrations in surface waters and

maximum at mid-depths (Bruland 1980; Jickells 1995; Shiller and Boyle 1985).

Dissolved manganese is primarily present in seawater as the Mn2+ ion, although it

is also stable as Mn(IV) in the form MnO2 in the presence of oxygen (Johnson et al.

1996). Concentrations of dissolved manganese are high in the surface waters and decrease with depth as dissolved Mn2+ is sorbed onto sinking particles and removed to

the sediment (Bender et al. 1977). Concentrations also increase within the oxygen

minimum (Klinkhammer and Bender 1980). Dust deposition is the primary source of Mn

to the open ocean (Klinkhammer and Bender 1980), while in coastal zones, waters are

generally enriched owing to large fluxes of dissolved and particulate Mn from rivers, shelf sediments, and the atmosphere (Bender et al. 1977; Kremling 1985; Landing and

Bruland 1980).

Dissolved cadmium is present in seawater primarily as CdCl+. Cd is a trace

element, and it is classified as a recycled element since it is biodepleted and potentially

biolimiting. It is depleted in surface waters due to the uptake by planktonic biological

activity and is subsequently released at depth by the dissolution of organic matter (Abe

15 2004; Abe 2005; Boyle 1992; Broecker and Peng 1982; Lea and Martin 1996; Rosenthal

- et al. 1997). Cadmium concentrations also closely relate to [NO3 ] but vary inversely to

Zn and Mn (Bruland 1980; Sunda and Huntsman 1998). Therefore, if Cd, Zn, and Mn

levels in a coral skeleton are driven by environmental concentrations, then we can expect

δ15N and Cd concentrations to vary inversely with Zn and Mn concentrations across a

depth transect (Table 1.2).

0 Dissolved lead is present as PbCO3 , with high concentrations at the surface due

to atmospheric input and decreasing concentrations with depth as dissolved Pb is sorbed

onto sinking particles and removed to the sediment. Atmospheric lead is dominated by

lead from industrial activities. Records of lead concentrations in the North Atlantic have

reconstructed anthropogenic lead use, particularly of leaded gasoline (Shen and Boyle

1987), and show declining concentrations in the since the 1980s (Wu and

Boyle 1997). The predominant source of anthropogenic lead to the western tropical

Pacific is East and Southeast Asia. These regions have only recently introduced unleaded

gasoline, and consequently lead concentrations peak much later in the tropical Pacific than the North Atlantic (Inoue et al. 2006; Inoue and Tanimizu 2008).

RESEARCH PROPOSAL

The goals of this dissertation research were to 1) examine spatial and temporal

variability in the geochemical composition of soft corals and black corals among multiple

taxa collected across a depth range from Palau, in the western tropical Pacific, and 2) use

δ15N isotopes to track variability in water masses bathing the coral colonies within and

below the mixed layer. Variability in stable isotope (δ15N and δ13C) values from sixty-

16 five specimens was examined, and high-resolution decadal to centennial variability in

14C, δ15N, δ13C, and trace element (B11, C13, Mn55, Zn64, Br79, Cd114, I127, and Pb208)

records from 5, 85, and 105m colonies were compared to oceanographic conditions. The

results of this research are presented in three chapters: (1) natural variability in δ15N and

δ13C, (2) high-resolution 14C, δ15N and δ13C records from 3 coral colonies collected at 5,

85, and 105 m depth, and (3) high-resolution trace element records from the same three

colonies.

Field Site: Climatology and Oceanography

Palau (7°16N, 134°31E; Fig. 1.3) is located in the northwestern quadrant of the

western Pacific warm pool (WPWP), which is characterized by warm surface waters (>

28 ºC), low salinity (< 34 psu), and relatively low nutrient levels (Picaut et al. 1996;

Yoshikawa et al. 2006). The average depth of the mixed layer fluctuates from

approximately 30 m to 90 m (Colin 2001; Cronin and McPhaden 1997). The north-south

movement of the Intertropical Convergence Zone (ITCZ) influences the water in which

Palau is bathed such that when the ITCZ moves south, Palau is bathed in North

Equatorial Current (NEC) waters and when in its more northern position, Palau is bathed

in North Equatorial Countercurrent (NECC) waters (Australia Government Bureau of

Meteorology 2002; Radenac and Rodier 1996). The thermocline and nutricline depths

fluctuate seasonally and on ENSO timescales from 55 m to 200 m, such that they shoal

during El Niño conditions and deepen during La Niña conditions (Colin 2001; McPhaden

and Picaut 1990; Solomon and Jin 2004; Yoshikawa et al. 2006).

17 Coral colony collection

Sixty-five live specimens were collected using SCUBA from vertical transects at

two sites, Short Drop Off (SDO) and Ulong Rock (Ulong), offshore of Palau from June

18th to 22nd in 2006 (Fig. 1.3). Both sites are 300 m vertical reef escarpments located

offshore of the island of Koror, and experience seasonal seawater temperature patterns

characteristic of the western tropical Pacific. SDO and Ulong were selected for sample

collection because of the availability of in-situ instrumental temperature records from 2 to

90 m depth from 1999 to 2006 provided by Dr. Colin at the Coral Reef Research

Foundation (CRRF). In addition, both reef escarpments are located well-offshore,

experience good open ocean flushing, and are minimally affected by local lagoonal or

riverine influence.

Colonies were collected from a wide range of taxonomic groups within the orders

alcyonacea and antipatharia (Table 1.3). Most colonies were growing outward into the

water column, perpendicular to the wall. Photos showing gross colony morphology and

branching patterns were taken of each colony after collection (Fig. 1.4). A basal section

from each colony was removed from directly above the holdfast to the lower branches,

and transported frozen to the laboratory to prevent decomposition and isotopic

fractionation. All specimens were analyzed for work described in chapter 2. In addition,

two large specimens (one black coral from 5 m deep and one soft coral from 85 m deep)

were selected for analyses for chapters 3 and 4. An additional specimen was collected by

submersible in 2008 from SDO for analyses for chapters 3 and 4.

Taxonomic identification was made in the laboratory based on photos and

sclerites. Soft corals were identified to the genus level according to Fabricius &

18 Aldersade (2001) and with the assistance of Gary Williams of the California Academy of

Sciences. Black corals were identified to the genus level by Dennis Opresko of the Oak

Ridge National Laboratory. Identification below genera was not feasible as many species have not been described for both soft corals (G. Williams, private communication) and black corals (D. Opresko, private communication).

Chapter 2: Stable nitrogen and carbon isotopic variability (δ15N and δ13C) in shallow tropical Pacific soft coral and black coral taxa and implications for paleoceanographic reconstructions

Forty-six soft coral and eight black coral colonies were collected live from two vertical reef walls offshore of Palau in 2006. Colonies were collected from the top 85 m of the water column. The outermost ring of the skeleton at the base of each colony was removed for stable isotopic analyses (δ13C and δ15N) by Elemental Analyzer Stable

Isotope Ratio Mass Spectrometry (EA-SIRMS). The inherent variability in stable isotopes in between taxa of soft corals and black corals from the western tropical Pacific was quantitatively determined.

The data were statistically analyzed to determine what, if any, corrections need to be applied when comparing the isotopic records from specimens collected from different depths or from different taxa. This is a critical exercise if multiple soft coral and black coral proxy records are to be reliably compared and used for paleoceanographic reconstructions. Therefore, the skeletal δ15N and δ13C values of multiple coral colonies from different taxa, depths and sites in the western tropical Pacific were examined to test

19 the following hypotheses (stated in the form of alternate hypotheses where the null

hypothesis is the hypothesis of no difference):

13 15 H1: δ C and δ N values differ between orders (soft corals and black

corals) and genera at a given depth and site.

13 15 H2: δ C values decrease with depth while δ N increases with depth.

The δ13C and δ15N in soft corals and black corals are expected to vary between taxa due

to taxa-specific variations in either biological fractionation and/or their food source

preferences (i.e., sinking vs suspended POM), and with depth due to depth-dependent

variations in either biological fractionation and/or food source preferences or availability.

Thus, skeletal δ13C and δ15N values should be more similar within a taxonomic group

than between taxonomic groups and within a depth than between depths. Because of

potential differences in food sources and biology, δ13C and δ15N are expected to differ

15 between taxonomic groups at genera, family, and order levels (accept H1). If δ N values of suspended POM increase and δ13C values decrease with depth, then deep-collected

specimens where POM is the dominant food source are expected to have enriched δ15N

13 values and depleted δ C values relative to shallow-collected specimens (accept H2).

However, suspended POM may not be the dominant food source to the specimens or may

15 13 show no variation of δ N and δ C with depth (accept H2 null). If the colonies obtain

their food from a combination of sinking and suspended POM, or some other source, then

isotopic composition may be related to depth in some other manner than hypothesized

here.

20

Chapter 3: Soft coral and black coral skeletal Δ14C, δ13C and δ15N records from the

Western Pacific Warm Pool and relationship to ENSO.

This study will assess the relationship between skeletal Δ14C, δ13C, and δ15N values measured across a radial transect of three specimens collected from Palau: one black coral from 5 m depth, one soft coral from 85 m depth, and one soft coral from 105 m depth. Together, these records will be used to reconstruct changes in particulate organic matter over time in the upper 105 m of the water column in the western tropical

Pacific. 14C measurements of sub-samples selected across a radial transect were analyzed

by Accelerator Mass Spectrometry at National Ocean Sciences Accelerator Mass

Spectrometry Facility at WHOI, and used to construct a growth chronology. Along the

same radial transect, high resolution sub-samples were measured for δ13C and δ15N values by Elemental Analyzer Stable Isotope Ratio Mass Spectrometry (EA-SIRMS) in the Stable Isotope Biogeochemistry Lab at OSU. The following hypotheses were specifically tested (stated in the form of alternate hypotheses where the null hypothesis is the hypothesis of no difference):

14 H1: Radial time series of organic skeletal Δ C measurements will show

the 14C bomb-curve.

13 13 H2: δ C values will decrease over time corresponding to the δ C-Suess

effect.

15 H3: δ N values will fluctuate on ENSO time scales.

21 To test these hypotheses, δ13C and δ15N were measured at 100 μm increments across a

radial transect of the skeleton. Δ14C was measured in 300 μm increments at select

intervals along the same radial transect. Δ14C measurements were compared to

reconstructed bomb-curves from sclerosponges and scleractinian corals at the same and

nearby sites, respectively, and used to develop a growth chronology for each colony.

Using regression analysis, the rate of decrease in δ13C values was compared among

colonies and to other records from scleractinian corals. Cross-spectral analysess of the

δ15N record from each coral with the Southern Oscillation Index (SOI) were used to test

15 H3. Long-term trends in the δ N records are also investigated with regression analysis.

Variability in the deeper records (85 m and 105 m), but not the shallow record (5 m), is

expected if the depth of the thermocline and nutricline is changing.

Chapter 4: Reproducibility and calibration of trace elements in soft coral and black coral

corals.

Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS)

techniques have been well-developed to study tropical scleractinian corals. To date, these

techniques have not been applied to the organic skeleton in soft corals and black corals.

This study evaluated, as a first order approach, which minor and trace elements may yield

useful high resolution paleoceanographic data from these corals. Elements were selected

based on the likelihood that concentrations in the skeleton would vary between colonies

with either depth or over time in response to environmental conditions (i.e., variability in

sea surface salinity, changes in concentration with depth, etc.), and/or known changes in

element concentration in the skeleton. The following hypotheses were tested (stated in

22 the form of alternate hypotheses where the null hypothesis is the hypothesis of no

difference):

H1: Average concentrations for each element will vary by colony.

H2: Three parallel laser tracks for each element will provide reproducible

results within a colony.

From each colony analyzed for Chapter 3, at least five skeletal sub-samples from the

period of 1965-2006 were dissolved in HNO3 and the concentrations of I, Br, B, Mn, Zn,

Cd, and Pb were determined using solution ICP-MS in the Trace Element Research

Laboratory. Average concentrations for each element were compared between the

colonies using an analysis of variance (ANOVA) to test H1. Adjacent to the transects

sampled for Chapter 3, three approximately parallel radial transects were analyzed for I,

Br, B, Mn, Zn, Cd, Pb, and C intensities by laser ablation ICP-MS. Each transect was

analyzed six times, with the first scan considered a cleaning scan and its data discarded.

Averaging the five remaining scans produced a robust average for each transect.

Reproducibility of these three transects for each coral will test H2. Finally, the LA-ICP-

MS data with the best reproducibility among parallel laser tracks is compared to known

changes in environmental conditions to construct first order paleoceanographic records.

These are the first reported laser measurements of the organic skeleton of soft coral and

black coral corals and help define the elements that should be developed as proxies in these corals from the tropical Pacific Ocean.

23 BROADER IMPACTS

This research examines the natural isotopic variability in shallow water soft corals

and black corals from the western tropical Pacific. This step is critical before interpreting

proxy-based records from the skeletal geochemistry of these corals. Secondly, this

research reconstructed of seawater organic geochemistry using radiocarbon, stable

isotopes, and trace elements. By combining several of the proxies, the generated data has

the potential to identify shifts in the water masses that bathe Palau, and to determine the

frequency of such shifts on ENSO and longer timescales. In particular, vertical

fluctuations of the nutricline depth reconstructed from these data may yield information

important to understanding mechanisms causing productivity and nutricline depth

variability in the western tropical Pacific. With potential alterations of ENSO

accompanying current and future global change, this may assist in predicting changes in

productivity related to ENSO and the Pacific carbon sink.

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35 TABLES

Phylum Cnidaria: Radial symmetry Class Anthozoa: Marine, polypoid, polyps solitary or colonial Subclass Hexacorallia: Polyps bear six, or multiple of six, tentacles without pinnules Order (hard corals) Order Actinaria (sea anemones) Order Zoanthiniaria (zoanthids) Order Corallimorpharia (mushroom anemones) Subclass Ceriantipatharia Order Antipatharia (black corals): polyps are arranged around an axial skeleton of black horny material bearing thorns Order Ceriantharia (tube anemones) Subclass Octocorallia: polyps bears eight hollow tentacles, fringed on both sides by one to several rows of pinnules Order Pennatulacea (sea pens) Order Helioporacea (blue corals) Order Alcyonacea (soft corals and sea fans): skeletal components composed of calcite and gorgonin Group : Unconsolidated axis consisting predominantly of CaCO3 sclerites Suborder Holaxonia: Axis with continuous solid axial structure composed of scleroproteinous gorgonin and commonly with small amounts of embedded non- scleritic CaCO3 and with hollow cross-chambered central core Suborder Calcaxonia: Continuous solid axial structure of scleroproteinous gorgonin with large amounts of non-scleritic CaCO3 as internodes or embedded in the gorgonin, and without hollow cross-chambered central core

Table 1.1. Current higher taxonomic classification of select Cnidaria according to Fabricius and Alderslade (2001) with defining characteristics of relevant taxa.

36

Element Application as proxy Br High skeletal concentrations, increases in soft corals and decreases in black corals with age I High skeletal concentrations, increases with age in both corals B Concentration proportional to seawater salinity Zn Low concentrations in surface waters Mn High in surface waters, maximum at oxygen minimum, low in deeper waters Cd Low in surface waters, high in deeper waters Pb High concentrations in surface waters, reflects anthropogenic use

Table 1.2. Possible application of minor and trace elements measured in the organic skeleton.

37

Taxonomy No of colonies No of colonies Shallow (5-45m) Deeper (85m) Class Anthozoa Subclass Hexacorallia Order Antipatharia (Black corals) Family Antipathidae Genus Antipathes 1 Family Aphanipathidae Genus Rhipidipathes 7 Subclass Octocorallia Order Alcyonacea (Soft corals) Scleraxonia Group Family Genus Annella 5 Suborder Holaxonia Family Keroeididae Genus Keroeides 1 Family Genus Muricella 1 Genus Acanthogorgia 2 3 Family Genus Astrogorgia 21 Genus Villogorgia 3 2 Genus Paracis 4 Genus 1 Genus Echinogorgia 1 Suborder Calcaxonia Family Genus Viminella 1 Genus Ellisella 1

Table 1.3. Taxonomy of collected colonies in shallow (5-45m) and deeper (85m) water.

38 FIGURES

Figure 1.1. Cartoon showing drivers of carbon isotope variability in the ocean. δ13C values from Druffel et al. (2003), Gruber et al. (1999), Keeling et al. (1995), Nakatsuka et al. (1997), and Rau et al. (1997).

39

Figure 1.2. Cartoon showing sources and controls on nitrogen stable isotopes of organic matter in the western tropical Pacific. δ15N values from Benner et al. (1997) and Yoshikawa et al. (2006).

40

Figure 1.3. Map of western tropical Pacific, showing location of Palau and field sites Short Drop Off and Ulong Rock. Figure courtesy of J. Watson.

41

Figure 1.4. Photograph of a soft coral colony showing colony gross morphology and branching pattern.

42 CHAPTER 2

15 13 STABLE NITROGEN AND CARBON ISOTOPIC (δ N AND δ C) VARIABILITY IN SHALLOW TROPICAL PACIFIC SOFT CORAL AND BLACK CORAL TAXA AND IMPLICATIONS FOR PALEOCEANOGRAPHIC RECONSTRUCTIONS

Branwen Williams and Andréa G. Grottoli

The Ohio State University, School of Earth Sciences,

125 South Oval Mall, Columbus, OH 43210 USA

For submission to Geochimica et Cosmochimica Acta

43 ABSTRACT

Soft corals and black corals are useful tools for paleoceanographic

reconstructions, yet most work has focused on deep-water taxa and few studies have used

these corals as proxy organisms in shallow water (<200 m). To facilitate the use of stable

nitrogen (δ15N) and carbon (δ13C) isotope records from shallow-water soft coral and

black coral taxa for paleoceanographic reconstructions, quantification of the inherent

variability in skeletal isotope values between taxa is needed. Here, skeletal δ15N and δ13C

values were measured in multiple colonies from eleven genera of soft corals and two

genera of black corals from shallow (5-45 m) and deeper (85 m) water at two sites in the

tropical western Pacific. Overall, skeletal δ15N values were significantly higher and δ13C values were significantly lower in deeper colonies than shallow colonies. This is consistent with changes in isotope values of suspended particulate organic matter (POM) through the upper 100 m of the water column and supports the hypothesis that suspended

POM is the primary food source and control on skeletal isotopic composition of these corals. To reliably compare stable isotope-based proxy records from soft corals collected across a depth range in the photic zone, a +0.15 ‰/10 m correction needs to be applied to

δ15N records and a -0.25 ‰/10 m correction needs to be applied to δ13C records. Average

δ15N values were similar between black corals and soft corals in shallow water, indicating

feeding at a similar trophic level for the two orders. In contrast, average δ13C values of

black corals were significantly lower than those for soft corals, potentially resulting from

metabolic processes relating to differing skeletal compositions among orders. Thus, a

+1.5 ‰ correction should be applied when comparing δ13C-based proxy records from

44 shallow-water soft and black corals. In shallow water, average δ15N values did not vary

significantly between Rhipidipathes, Annella, Astrogorgia, and Villogorgia, and low variability in δ15N values among multiple colonies of each species suggests that one

colony can be representative of each genus when constructing δ15N-based

paleoceanographic records. In deeper water, δ15N values in multiple colonies of

Acanthogorgia were highly variable, suggesting caution should be exercised when

interpreting paleoceanographic records from this genus. Average δ13C values did not differ significantly between soft coral genera in shallow water or in deeper water, and low variability in δ13C within these genera, with the exception of Villogorgia in shallow water, indicates that all these genera are well suited for δ13C-based paleoceanographic

reconstructions.

45 INTRODUCTION

A vast array of proxy tools exists for reconstructing past ocean conditions. Yet few of these yield information at both high temporal resolution (i.e., sub annual) and across a wide depth range. Soft corals and black corals are a relatively new tool for paleoceanographic reconstruction (Sherwood and Risk, 2007). They have a global distribution, grow from the surface to several kilometers deep (Cimberg, 1981; Moore et al., 1956), and have a banded skeleton providing chronological control with the potential

for sub-annual resolution (Sherwood et al., 2005a). While attention has mostly focused

on deep-water taxa in mid-to-high latitudes, paleoceanographic reconstructions from

shallow-water soft coral and black coral taxa in the tropics could prove essential to

understanding past behavior of tropical oceanographic systems. Since large and old

colonies are rare, reconstructions from multiple soft coral and black coral taxa from a variety of sites and depths are needed. However, the natural variability that exists among taxa and depths needs to be assessed so that corrections can be made when comparing records.

Measurements of the stable nitrogen (δ15N) and stable carbon (δ13C) isotopic

composition of the organic skeleton are primary methods of obtaining paleoceanographic

information from the skeleton of these types of corals (see review in Sherwood and Risk,

2007). In deep-water taxa (i.e., commonly found greater than 200m), δ15N and δ13C values reflect the composition of sinking particulate organic matter (POM) (Heikoop et al., 2002; Roark et al., 2005; Sherwood et al., 2005b; Williams et al., 2007). Since δ15N and δ13C values of sinking POM undergo minimal alteration with depth, the isotopic

values of sinking POM, and therefore coral colonies at depth, record surface processes or

46 sources of nutrients influencing the isotopic composition of surface organic matter.

However, such reconstructions assume that corals do not differ in diet or metabolic

fractionation within or between species, across depth, or in geographically distant

locations in the ocean. In fact, in deep-water temperate taxa these factors may be

important as δ15N values may vary up to 2.5 ‰ among colonies from the same location

and up to 1.5 ‰ from a single skeletal ring within a colony (Sherwood et al., 2005b;

Williams et al., 2007). By quantifying and understanding this variability, the organic skeletal δ15N and δ13C records of deep-water colonies have been shown to be

reproducible among colonies from the same site on at least decadal scales, supporting

their use for decadal and longer paleoceanographic reconstructions.

Less is known about the natural isotopic variability and the source(s) of that

variability in tropical shallow-water taxa (<200 m). Similar to deep-water taxa,

differences in diet (Benner et al., 1997; Coffroth, 1984; Coma et al., 1994; Fabricius et

al., 1995; Grigg, 1965; Guo et al., 2004; Lewis, 1978; Ribes et al., 1998; Tazioli et al.,

2007), metabolic fractionation rates, or growth rates among shallow-water taxa could

influence their skeletal isotopic signatures independent of oceanographic conditions,

making their derived proxy records difficult to compare. In addition, variable skeletal

composition between taxa may override any environmental signal recorded in these

corals since inherently different isotopic signatures may characterize unique skeletal

compositions. This may be particularly evident between orders, as the soft corals with internal skeletons (groups Scleraxonia, Holaxonia and Calcaxonia, formerly in the order

Gorgonacea) suitable for paleoceanographic reconstructions are composed of gorgonin

(an organic proteinaceous substance), sometimes in combination with calcite (Grasshoff

47 and Zibrowius, 1983; Lewis et al., 1992). Black corals in contrast form a skeleton

composed predominantly of chitin complexed with proteins (Ellis et al., 1980; Goldberg,

1976).

δ15N and δ13C values of tropical shallow-water black and soft coral taxa could

differ across depth and sites, among colonies within a taxa, or between taxa if 1- the

source of nitrogen and carbon differed among these parameters, and/or 2- if biological

fractionation of acquired nitrogen and carbon was taxa-specific. A detailed study is

needed to quantify the baseline isotopic variability among genera in soft corals and black

corals to facilitate comparison of isotope-based paleoceanographic proxy reconstructions

from multiple taxa. This is particularly important when comparing colonies from multiple

taxa, depths, and sites. Therefore, with the intent to quantify the inherent variability in the

skeletal stable isotopic composition among soft corals and black corals and to identify

strategies to use these corals for paleoceanographic reconstructions, we examined the

organic skeletal δ15N and δ13C values of multiple coral colonies from different taxa,

depths and sites in the western tropical Pacific.

METHODS

Study Site

Soft coral and black coral colonies were collected from Short Drop Off (7º16 N,

134º31 W) and Ulong Rock (7º17 N, 134º14 W) offshore of Palau in June 2006. Both

sites are 300m vertical reef walls located offshore the island of Koror and experience similar seasonal seawater temperature patterns in the upper 85 m of the water column

(Colin, 2001). The temperature of the mixed layer is greater than 28ºC and the average

48 temperature below the mixed layer is 23ºC. The base of the mixed layer fluctuates in depth on seasonal and El Niño-Southern Oscillation timescales from less than 35 m to greater than 85 m, with an average depth of 55 m (Zhang et al., 2007).

Colony identification

Colonies from a wide range of taxonomic groups were collected along a vertical wall from 5, 15, 25, 35, 45, and 85 m deep by SCUBA. Most colonies were growing outward into the water column, perpendicular to the wall. Photos showing gross colony morphology and branching pattern were taken of each colony after collection. A basal section from each colony was removed from directly above the holdfast to the lower branches, and transported frozen to the laboratory for isotopic analyses. Taxonomic identification was made in the laboratory based on photos and sclerites. Soft corals were identified to the genus level according to Fabricius & Aldersade (2001) and with the assistance of Gary Williams of the California Academy of Sciences. Black corals were identified to the genus level by Dennis Opresko of the Oak Ridge National Laboratory.

Identification below genus was not feasible as many species have not been described for both soft corals and black corals.

Laboratory analyses

The bottom three centimetres of the basal section from each colony were cut using a Dremel drill for small specimens and a rock saw for larger specimens. Working under a dissecting microscope, an area of approximately 2 mm x 2 mm of the external layer of tissue was removed with forceps from the outside of each basal section. At the

49 same location, a 2 mm x 2 mm area of the outer layer of skeleton was gently cut off with

a scalpel to a depth of 0.1 to 0.5 mm. The depth of sampled skeleton varied according to the thickness of the outer growth ring such that the sample was deeper (up to 0.5 mm) from bases with thicker growth rings and shallower (at least 0.1 mm) from bases with thinner growth rings. This strategy assumed that growth rings represented the same time

interval and represented the most recently formed skeletal material from each colony.

Sufficient skeletal material was removed to obtain approximately 1 mg of dried skeleton.

Each skeletal sample was individually soaked in 10% HCl solution in a glass beaker for

four hours to remove any calcium carbonate and isolate the organic fraction of the

skeleton, rinsed three times in 18 mΩ Milli-Q®, and dried over night at 60ºC. The carbon-

to-nitrogen (C:N) ratio and the stable isotope (δ15N and δ13C) ratios of each sample were

measured by combusting the organic fraction in a Costech Elemental Analyzer where the

resulting N2 and CO2 gases were analyzed with a Finnigan Delta IV Plus isotope ratio

mass spectrometer via a Finnigan ConFlow III open split interface. The standard

Acetanilide was used for calibration of percent C and N, and the C:N ratios. δ15N values

were reported relative to air (δ15N = per mil deviation of the ratio of stable nitrogen

isotopes 15N:14N relative to air). δ13C values were reported relative to Vienna Peedee

Belemnite Limestone Standard (V-PDB) (δ13C = permil deviation of the ratio of stable

carbon isotopes 13C:12C relative to V-PDB). The standard deviation of the mean of

repeated measurements of internal standards (n = 85) was ± 0.15 ‰ for δ15N and ± 0.06

‰ for δ13C. At least 10% of all samples were run in duplicate and the standard deviation of the mean repeated measurements was ± 0.37 ‰ for δ15N and ± 0.43 ‰ for δ13C.

50 Statistical analyses

Differences in δ15N, δ13C values, and C:N ratios between the two sites were not significant based on a students t-test. Therefore, data from both sites was pooled to

increase statistical power in subsequent statistical analyses. δ15N values of pooled data

were normally distributed based on the Shapiro-Wilk test. δ13C values of pooled data

were not normally distributed and logarithmic, square root, and inverse transformations

did not produce normal data. Since lipid content can influence δ13C values (DeNiro and

Epstein, 1977; McConnaughey and McRoy, 1979), C:N ratios were used a proxy for lipid

content (Post, 2007) to assess if lipid content differed significantly between orders, and

to determine if the δ13C values needed to be “lipid-corrected” for organisms in each

order. Visual examination of C:N ratios of each order showed a bimodal distribution.

Therefore, a non-parametric signed rank was used to test for differences in C:N ratios of

pooled data between orders.

To test for differences between colonies within (<55 m) and below the mixed

layer (>55 m), shallow colonies from 5-45 m were grouped together and compared to

deeper colonies from 85 m. Since ANOVA is robust to non-normal data, a fully factorial

model III ANOVA of all colonies was used to test for differences in skeletal δ15N and

δ13C values between orders (black corals vs. soft corals) and between the two depth

categories (shallow 5-45 m vs. deeper 85 m). A second fully factorial model III ANOVA

tested for differences in skeletal δ15N and δ13C values between genera (Antipathes,

Rhipidipathes, Annella, Keroeides, Muricella, Acanthogorgia, Astrogorgia, Villogorgia,

Paracis, Bebryce, Echinogorgia, Viminella, and Ellisella) and between two depth categories (shallow 5-45 m vs. deeper 85 m). Only genera present in more than one

51 colony were included in this ANOVA, although genera represented by a single colony

were also plotted for comparison purposes. A posteriori Tukey-Kramer tests were used to

explore significant effects in all cases. Correlations between average soft coral skeletal

δ15N and δ13C and depth were assessed by linear regression analyses. Black corals were

not collected from 85 m and hence were excluded from this analysis. Statistical analyses

were performed using SAS software, Version 8.02 of the SAS System for Windows.

[Copyright C 1999-2001 SAS Institute Inc. SAS and all other SAS Institute Inc. products

and service names are registered trademarks or trademarks of SAS Institute Ind., Cary,

NC, USA.]. All averages are reported ± 1 standard deviation (SD). P-levels ≤ 0.05 were

considered significant.

RESULTS

Colony collection and identification

Thirty-two soft corals and eight black corals were collected from within the mixed

layer (5-45 m) and are referred to from hereon as shallow colonies (Table 2.1). Fourteen

soft corals and no black corals were collected from mostly below the mixed layer (85 m)

and are henceforth referred to as deeper colonies (Table 2.1). The diameters of the

skeletal bases from collected colonies ranged from approximately 0.5 - 7 cm with heights

of approximately 10 - 150 cm. The majority of colonies collected were small (less than

50 cm in height).

Soft coral colonies were collected from the Scleraxonia group, and the suborders

Holaxonia and Calcaxonia (Table 2.1). The highest abundance and diversity of collected

colonies were Holaxonians, represented by 39 colonies in three families. Five colonies

52 from a single genus were Scleraxonians, and two colonies from two separate genera but

one family were Calcaxonians. Colonies from the genus Astrogorgia was abundant in

shallow water and a large number were collected. This, in addition to the logistical

difficulties in collecting by SCUBA from deeper depths resulted in a larger number of

colonies collected from <45m depth than from below that depth. Colonies from two

genera and two separate families of black corals were collected, all from shallow water

(Table 2.1).

Isotopic analyses

Skeletal δ15N values ranged from 5.5 to 7.5‰ and from 6.7 to 8.7‰ for colonies in shallow and deeper water, respectively (Fig. 2.1A, B). Although skeletal carbon to

nitrogen (C:N) ratios varied significantly between orders (p>0.05), the C:N ratios were

<3.5 for both orders. Thus corrections for lipid content would have no significant impact

on δ13C values (Post et al., 2007) and none was applied. Skeletal δ13C values ranged from

-17.1 to -19.3‰ and from -18.9 to -19.9‰ for colonies in shallow and deeper water, respectively (Fig. 2.1A, B). In addition, δ13C values for shallow colonies had a bimodal

distribution, with one cluster primarily composed of black corals centered at -17.5‰ and

a second cluster primarily composed of soft corals centered at -19.0‰ (Fig. 2.1A).

Average δ15N values were significantly lower in shallow soft corals than in deeper

soft corals, by 0.9 ‰, but shallow soft corals did not differ from shallow black corals

(Table 2.2, Fig. 2.2A). Average δ13C values of deeper soft corals did not differ from those

of shallow black corals but both were significantly lower than average δ13C values of

shallow soft corals by approximately 1.5 ‰ (Table 2.2, Fig. 2.2B).

53 Average δ15N and δ13C values significantly differed between genera and depths

(Table 2.3). The interaction of depth by genus was not significant for either δ15N or δ13C values indicating that the influence of depth on average isotope values was generally consistent among genera. Closer examination of the soft corals across depth revealed a significant increase in δ15N values and a significant decrease in δ13C values with depth

(Figs. 2.3, 2.4). Significant differences in both δ15N and δ13C values were detected among

genera in shallow water (Fig. 2.5A, 2.6A) but not among genera in deeper water (Fig.

2.5B, 2.6B). In shallow water colonies, average δ15N values for Acanthogorgia were

significantly lower than values for Astrogorgia and Villogorgia (Fig. 2.5A). By

comparison, shallow water average δ13C values for the black coral Rhipidipathes were significantly lower than δ13C values for the soft corals Annella, Acanthogorga, and

Astrogorgia (Fig. 2.6A). No difference in average genus values among deeper colonies was present for either δ15N or δ13C values (Fig. 2.5B, 2.6B). Acanthogorgia colonies in deeper water showed a markedly larger range in δ15N values than any other genera (Fig.

2.5), while both Rhipidipathes and Villogorgia colonies in shallow water had markedly

larger ranges in δ13C values than other genera (Fig. 2.6). While it is not possible to

statistically evaluate the δ15N or δ13C values for genera represented by a single colony, general observations suggest that these singly-represented δ15N and δ13C values fall

within the range of the genera represented by multiple colonies at both shallow and

deeper depths (Fig. 2.5, 2.6).

DISCUSSION

Variability in stable isotopes with depth

54 δ15N increases by approximately 3.4 ‰ with each trophic level in the food web as

a result of trophic fractionation (i.e., the preferential use of lighter isotopes during

metabolism leaving predators enriched in heavier isotopes than their prey) (DeNiro and

Epstein, 1981; Minagawa and Wada, 1984). Feeding higher in the food web could drive

enriched δ15N values in deeper relative to shallow soft coral colonies (Fig. 2.2A, 2.4).

However, a systematic shift in coral diet within the top 100m of the water column is

improbable.

A more likely explanation is that soft corals feed on suspended POM which

becomes increasingly enriched in δ15N values with depth in the top 100m of the water

column (Benner et al., 1997). Since 14N is preferentially used during bacterial

degradation, suspended POM becomes increasingly enriched in 15N over time as it very

slowly sinks in the water column (Macko and Estep, 1984; Macko et al., 1986; Saino and

Hattori, 1980; Wada, 1980). The present study shows an average increase of nearly 1 ‰

between shallow and deeper coral colonies, consistent with the reported increase in δ15N

values of suspended POM across a similar depth range. Therefore, suspended POM is the

likely food of soft corals and thus a dominant control on the isotopic composition of these

corals within the photic zone. Similarly, Mintenbeck et al. (2007) predict a 1-2.5 ‰

increase in tissue δ15N values in suspension feeders across the top 100 m of the water column as a result of the increase in δ15N values of suspended POM across a similar

depth range. Thus, to reliably compare δ15N-based proxy records from soft corals

collected at different depths in the photic zone, a +0.15 ‰/10 m correction needs to be

applied. Although black corals were not collected in deeper water, a comparable increase

in δ15N values with depth would be expected for this taxonomic order, with a similar

55 correction factor needed when comparing isotopic records from specimens collected at

different depths.

However, corals at several hundred meters deep are known to feed primarily on

sinking POM rapidly exported out of the euphotic zone (Roark et al., 2006; Roark et al.,

2005; Sherwood et al., 2005b; Williams et al., 2007). The diet of soft corals and black corals must at some point shift from a diet predominantly composed of smaller particles suspended in the water column (i.e., suspended POM) to one of sinking POM. This could either reflect an inherently different diet between colonies in shallow and deep water, or be a consequence of changes in food availability with depth. Regardless, caution is needed in comparing colonies from this study to typical deep-water taxa as their skeletal isotopic composition may reflect different food sources.

δ13C values of suspended POM decrease by up to 2.4 ‰ with depth within the

euphotic zone (~100 m) as a result of changes in physical and biological parameters

(O'Leary et al., 2001) and/or due to preferential remineralisation of labile carbon

molecules with high δ13C values at the base of the pycnocline (e.g. amino acids and

sugars (Druffel et al., 2003; Jeffrey et al., 1983)). Therefore, a diet of suspended POM is

consistent with lower δ13C values in deeper soft corals compared to shallow soft corals

(Fig. 2.2B, 2.4). Thus, to reliably compare δ13C-based proxy records from soft corals collected from across a depth range in the photic zone, a -0.25 ‰/10 m correction needs to be applied. It is hypothesized that a comparable decrease in δ13C values with depth

would be expected for black corals and that a similar correction factor would be needed

when comparing isotopic records from specimens collected across depth.

56 Variability in stable isotopes between orders

Based on similar average δ15N values, shallow soft coral and black coral colonies are feeding at the same trophic level (Fig. 2.2A). Both δ15N and δ13C values indicate that

suspended POM is the primary food source to soft corals, and this is most likely true for

black corals as well. Therefore, the higher average δ13C value for soft corals than black

corals is unlikely to result from differences in diet (Fig. 2.2B, 2.5), but may be due to different lipid or amino acid compositions of their gorgonin and chitin skeletons, respectively.

Since δ13C values of lipids are depleted relative to carbohydrates and proteins

(DeNiro and Epstein, 1977; McConnaughey and McRoy, 1979), a higher proportion of

lipids relative to carbohydrates and proteins in soft corals would cause correspondingly

lower skeletal δ13C values in soft corals than black corals. C:N ratios as a proxy for lipid

content reveal that any differences in lipid composition are not large enough to account

for the variation in δ13C values (Post et al., 2007) between the orders. Amino acid

concentrations differ between black coral and soft coral skeletons (Goldberg, 1991;

Sherwood et al., 2006), and δ13C values of amino acids vary based on fractionation

during metabolic processes incorporating carbon (Hayes, 2001). Since these corals have a

protein-rich skeleton, differences in skeletal amino acid δ13C values resulting from order-

specific metabolic processes may cause the differing carbon signatures observed here.

Compound-specific analyses of the skeletal amino acids would be needed to test this

hypothesis.

Regardless of the source of variability, a +1.5 ‰ correction must be applied to

compare δ13C-based proxy records from soft corals to records from black corals in

57 shallow water. No black coral colonies were collected from deeper waters so data is not

available to test for differences in δ13C values between deeper black coral and soft coral

colonies in the western tropical Pacific. However, δ13C values for the black coral

Bathypathes were not significantly different from the values of the other deep-sea soft

corals collected from the Newfoundland and Labrador continental slope in the northern

Atlantic (Sherwood et al., 2008) indicating differing δ13C values are not universally

characteristic of these orders. Further research is needed to determine if lower skeletal

δ13C values in black corals relative to soft corals is characteristic of colonies in shallow

water or is unique to the western tropical Pacific.

Variability in stable isotopes within and between genera

δ15N values did not vary widely among colonies within a genus (SD for genera

averages <±0.5 ‰), with the exception of Acanthogorgia in deeper water (SD ± 1.0‰)

(Fig. 2.5). Thus, one colony within Rhipidipathes, Annella, Astrogorgia, Villogorgia, and

Paracis should be sufficiently representative of each genus when constructing δ15N-based paleoceanographic records. These data also suggest that reproducibility of δ15N records

should be very good within these genera. The wide range in δ15N values among

Acanthogorgia colonies in deeper water (Fig. 2.5B) indicates that stable isotope analyses

from several colonies are needed to obtain a representative record for this genus.

In shallow water, average δ15N values for Acanthogorgia colonies differed from

the values of all other genera (Fig. 2.5A). To account for this difference, a +1.0 ‰ correction needs to be applied to Acanthogorgia colonies in shallow water before comparison among δ15N-based proxy records can be made. This, in addition to the wide

58 range in δ15N values present in deeper colonies of Acanthogorgia, suggests that caution

should be exercised when interpreting δ15N paleoceanographic records from this genus in

general. Average δ15N values did not significantly differ between genera in deeper water

though the average Villogorgia value was +0.9 ‰ compared to average Acanthogorgia

and Paracis values (Fig. 2.5B). In addition, genera represented by a single colony show a

wide range in δ15N values from 6.7 ‰ to 8.5 ‰, similar to the range demonstrated by

Acanthogorgia (Fig. 2.5B). This wide variability in δ15N values among genera in deeper

water suggests that δ15N values in each genus should be adjusted to the average soft coral

δ15N value in deeper water of 7.8 ‰ before records are compared.

In deep-water taxa, differences in δ15N values reflect feeding along a spectrum of

trophic levels, driven by either substrate heterogeneity or colony/ morphology (Dai and Lin, 1993; Lewis, 1982; Sherwood et al., 2008). In shallow water, a diet supplemented with smaller size fractions of organic matter would drive lower δ15N values

in Acanthogorgia relative to Astrogorgia and Villogorgia. Since colonies analyzed here were collected from the same site, differences in feeding resulting from varying substrate within that site are unlikely. Colony morphology and polyp size also do not dramatically vary within Acanthogorgia colonies collected here, or between Acanthogorgia and

Astrogorgia and Villogorgia, and therefore are also unlikely to drive variability in the size class of consumed food particles.

The standard deviations of the mean δ13C values for Annella, Astrogorgia, and

Acanthogorgia in shallow water (Fig 7A), and for Villogorgia, Acanthogorgia, and

Paracis in deeper water, were small (Fig. 2.6B). Therefore, a single colony should be

sufficiently representative of each genus for paleoceanographic records, and comparison

59 of δ13C records from colonies among these genera within a depth can be made without corrections. However, higher variability in δ13C values in shallow-water Rhipidipathes

and Villogorgia (Fig. 2.6A) suggests an inherent variability in these genera. Therefore,

several stable isotope values from multiple colonies would be needed to obtain a

representative isotope record from these genera.

Carbon isotope values can be interpreted as recording a spectrum of feeding

types, from pelagic (low δ13C) to benthic (high δ13C) (McConnaughey and McRoy, 1979;

Nadon and Himmelman, 2006). Thus similar to δ15N, variability in δ13C values could

reflect differences in feeding preferences resulting from variable substrate/habitat, colony

or polyp morphology. If true, then we would expect variability within genera and

between genera to show similar patterns for both δ15N and δ13C values. Since this is not

true (Figs. 2.5, 2.6), different processes must be influencing δ13C values; this conclusion

does not support variations in diet as the primary cause in variability in δ13C values.

Instead, an inherent difference in metabolic fractionation, potentially relating to amino

acid concentrations as discussed, above seems likely.

Implications

No variability in skeletal δ15N and δ13C values was measured between the two sites. This is consistent with both sites experiencing open ocean conditions and suggests that comparisons among colonies with a wide spatial distribution but influenced by similar oceanographic conditions are valid. Higher δ15N values and lower δ13C values in

deeper corals likely reflect the isotopic enrichment of their food source, suspended POM, with depth. A +0.15 ‰/10 m correction for δ15N values and a -0.25 ‰/10 m correction

60 for δ13C values needs to be applied when comparing isotope records from colonies at

different depths. An order-specific difference in physiology and/or carbon fractionation

in black corals compared to soft corals is present, resulting in order-specific carbon

isotopic offsets. This may relate to differences in skeletal composition. To compare δ13C values of colonies from different orders, a +1.5 ‰ correction needs to be applied to soft corals. Variability in δ15N values among corals within the genera Rhipidipathes, Annella,

Astrogorgia, Villogorgia, and Paracis is low and only one colony in needed to obtain a representative δ15N values of each genus. These genera are suggested for δ15N-based

paleoceanographic reconstructions. Variability in δ13C values among corals within the

genera Annella, Astrogorgia, Acanthogorgia Villogorgia, and Paracis is also low and

only one colony is needed to obtain a representative δ13C value from each genus. These

genera are suggested for δ13C-based paleoceanographic reconstructions.

Acknowledgements: The authors thank for P. Colin and L. Colin for support of this research, Y. Matsui for laboratory assistance, and R. Moyer, S. Levas, A. Hughes and B.

Thibodeau for helpful discussion. Funding for this research was awarded to B.W. through a Natural Sciences and Engineering Research Council of Canada (NSERC) postgraduate scholarship, PADI Foundation Award, and GSA Award. Funding was provided to A.G.G. by National Science Foundation program in Chemical Oceanography (OCE-0610487 &

0426022), the American Society for Mass Spectrometry, and the Andrew Mellon

Foundation.

61 LITERATURE CITED

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65 TABLES

No of colonies No of colonies Taxonomy Shallow (5-45m) Deeper (85m) Class Anthozoa Subclass Hexacorallia Order Antipatharia (Black corals) Family Antipathidae Genus Antipathes 1 Family Aphanipathidae Genus Rhipidipathes 7 Subclass Octocorallia Order Alcyonacea (Soft corals) Scleraxonia Group Family Subergorgiidae Genus Annella 5 Suborder Holaxonia Family Keroeididae Genus Keroeides 1 Family Acanthogorgiidae Genus Muricella 1 Genus Acanthogorgia 2 3 Family Plexauridae Genus Astrogorgia 21 Genus Villogorgia 3 2 Genus Paracis 4 Genus Bebryce 1 Genus Echinogorgia 1 Suborder Calcaxonia Family Ellisellidae Genus Viminella 1 Genus Ellisella 1

Table 2.1. Taxonomy of collected colonies in shallow (5-45m) and deeper (85m) water.

66

δ15N δ13C

F- Source df F-value P df p value Model 2 13.46 <0.01 2 41.74 <0.01 Depth 1 22.65 <0.01 1 71.76 <0.01 Order 1 1.11 0.30 1 25.78 <0.01

Table 2.2. Results of ANOVA testing differences in organic skeletal δ15N and δ13C values between orders (black coral and soft coral) and depths (shallow and deeper water). An interaction term is not possible since black corals were collected only at the shallow depth. All colonies were included in statistical analysis. df=degrees of freedom.

67

δ15N δ13C

Source df F-value p df F-value p Model 7 8.61 <0.01 7 15.10 <0.01 Depth 1 27.12 <0.01 1 12.73 <0.01 Genus 5 4.55 <0.01 5 7.95 <0.01 Depth*Genus 1 1.31 0.26 1 0.43 0.52

Table 2.3. Results of ANOVA testing differences in organic skeletal δ15N and δ13C values among genera with more than one colony (Annella, Acanthogorgia, Muricella, Paracis, Villogorgia, Astrogorgia, and Rhipidipathes) and depths (shallow and deeper water). df=degrees of freedom.

68 FIGURES

9 (A)

8

7 N (‰)air 15 δ Antipathes Rhipidipathes 6 Annella Acanthogorgia Villogorgia Astrogorgia Keroides 5 -21 -20 -19 -18 -17

δ13C (‰)v-pdb

9 (B)

8

7 N (‰)air N 15

δ Acanthogorgia Muricella 6 Villogorgia Bebryce Echinogorgia Ellisella Villogorgia 5 -21 -20 -19 -18 -17

13 δ C (‰)v-pdb

Figure 2.1. Skeletal organic stable nitrogen isotopic (δ15N) values versus stable carbon isotopic (δ13C) values from all colonies in (A) shallow (5-45 m) and (B) deeper (85 m) water. Ellipses highlight bimodal distribution of δ13C values. See Table 2.1 for detailed taxonomic information. 69 (A) 9 * (12) 8

7 N (‰, air) (± 1SD) 15 δ (32) 6 (8)

Shallow 5 Average Deep

Black coral Soft coral

(B) -16

-17 *

-18 C (‰, v-pdb) (± 1SD) 13

δ -19

-20 Average

Black coral Soft coral

Figure 2.2. Average organic skeletal (A) stable nitrogen isotopic (δ15N) values and (B) stable carbon isotopic (δ13C) values for all black coral and soft coral colonies in shallow (5- 45 m; open circles) and deeper (85 m; closed circles) water. All averages are ± 1 standard deviation. Symbols (*) indicate significant differences at p ≤ 0.05 between order and depths by a posteriori Tukey-Kramer tests. Number of colonies for each average provided in parentheses. See Table 2.2 for statistical results.

70 8.5

8.0

7.5

7.0 N (‰, air) (± 1SD) 15 δ 15 6.5 δ N = 0.013 (depth) + 6.43 r2 = 0.84, p = 0.01

Average Average 6.0

5.5 0 20406080100 Depth (m)

Figure 2.3. Average organic skeletal δ15N values for all soft coral colonies collected from shallow (5-45 m; open circles) and deeper (85 m; closed circles) water. All averages are ± 1 standard deviation. Regression line is described by equation shown.

71 -16.5

-17.0 13 δ C = -0.022 (depth) -17.11 -17.5 r2 = 0.86, p = 0.007

-18.0

C (‰,vpdb) (± 1SD) -18.5 13 δ

-19.0

Average Average -19.5

-20.0 0 20406080100

Depth (m)

Figure 2.4. Average organic skeletal δ13C values for all soft coral colonies collected from shallow (5-45 m; open circles) and deeper (85 m; closed circles) water. All averages are ± 1 standard deviation. Regression line is described by equation shown.

72 (A) 9

8 † † † *† 7 * (3) N (‰, air)(± 1SD)

15 (21) * δ 6 (7) (5) (2) 5 Average Average Shallow water colonies (5-45m) colonies water Shallow

(B) Genus 9 * *

8 * (2)

7 (4) N (‰, air) (± 1SD) 15

δ (3) 6

5 Deeper water colonies (85m) colonies water Deeper Average Average

s la ia a a ia e gi ll th rg r thes ryce rg a o o a ise b o p g g ll e g Annel Paracis tip E B o idi tho n Muricella Viminellain ip stro Villogorgian A Keroeides A a ch E Rh Ac Genus

Figure 2.5. Genus average organic skeletal δ15N values for colonies in (A) shallow (5-45 m) and (B) deeper (85 m) water. Averages are plotted to the left of the dashed line for genera with more than one colony within a depth. Number of colonies for genera averages at both depths provided in parentheses. All averages are ± 1 standard deviation. Genera represented by a single colony at a given depth are plotted to the right of the dashed line, do not have error bars, and were not included in the statistical analyses. Genera averages with similar symbols (*, †) do not significantly differ from each other within each depth. See Table 2.1 for detailed taxonomic information and Table 2.3 for statistical results.

73 (A) -16

† † -17 *† *† * -18 C (‰, vpdb) (± 1SD) vpdb) C(‰, 13

δ -19

-20 Shallow water colonies (5-45m) colonies water Shallow Average Average

(B) -16

-17

-18

C (‰, vpdb) (± 1SD) (± vpdb) (‰, C * * * 13

δ -19

-20 Deeper water colonies (85m) colonies water Deeper Average Average

ia is lla e a ella gia gia ac e yc or or ic nn gorg ar r br inell A o og P roeides Ellisella m l hog Mu Be Ke Vi Astr Vil Antipathes Echinogorgia Rhipidipathes Acant Genus

Figure 2.6. Genus average organic skeletal δ13C values for colonies in (A) shallow (5-45 m) and (B) deeper (85 m) water. Averages are plotted to the left of the dashed line for genera with more than one colony within a depth. Number of colonies for genera averages at both depths provided in parentheses. All averages are ± 1 standard deviation. Genera represented by a single colony at a given depth are plotted to the right of the dashed line, do not have error bars, and were not included in the statistical analyses. Genera averages with similar symbols (*, †) do not significantly differ from each other within each depth. See Table 2.1 for detailed taxonomic information and Table 2.3 for statistical results.

74

CHAPTER 3

ORGANIC SKELETAL STABLE ISOTOPE RECORDS FROM SOFT CORALS AND BLACK CORALS RECORD WATER MASS MOVEMENT ON ENSO AND DECADAL TIMESCALES IN THE WESTERN TROPICAL PACIFIC OCEAN

Branwen Williams and Andréa G. Grottoli

School of Earth Sciences, Ohio State University,

Columbus, Ohio, USA

For submission to Paleoceanography

75 ABSTRACT

High resolution stable carbon (δ13C) and nitrogen (δ15N) isotopic records in soft corals

and black corals provide a new means of paleoceanographic reconstruction in the western

tropical Pacific. Radiocarbon-derived growth chronologies were applied to the carbon

(δ13C) and nitrogen (δ15N) stable isotope records from one Antipathes black coral from 5

m depth and two Muricella soft corals from 85 and 105 m depth collected offshore of

Palau (7°16N, 134°31E). δ13C values of the Antipathes black coral colony decreased

~0.8‰ over the 41-year record while the two Muricella soft coral δ13C records decreased

at a rate of 0.14‰ for the 1970’s, 0.20‰ for the 1980’s, 0.26‰ for the 1990’s and

0.29‰ for the 2000’s. This is consistent with the 13C-Suess effect measured in tropical

Pacific seawater dissolved inorganic carbon and is similar to rates measured in a

sclerosponge skeletal 13C record from the same site. Stratification of the water column by

the barrier layer prevented the upward flux of nutrients into the nitrate-poor mixed layer.

Since nutrients drive POM δ15N values and thus skeletal δ15N values, different factors

drive variability in the δ15N record of the Antipathes colony within the mixed layer than

the δ15N records from the deeper Muricella colonies. The 5 m Antipathes δ15N record

contains major increases and decreases of 0.8‰, suggesting shifts in the relative strengths of currents bathing Palau in the top tens of meters of the water column. The 85 and 105 m Muricella δ15N records decreased by 1‰ from the late 1970’s through 2000, then

increased by 0.3‰ by 2006. These records indicate a shoaling of the mean nutricline

depth in the western tropical Pacific throughout the positive Pacific Decadal Oscillation

phase that began in the mid-1970’s. Together, paleoceanographic records from black

76 coral and soft coral skeletons record variability in the horizontal and vertical movements of water masses around Palau on ENSO and longer timescales.

77 INTRODUCTION

New and export production from the equatorial Pacific upwelling zone are

important components of the global ocean carbon cycle, as the eastern tropical Pacific is

one of the largest sources of carbon dioxide (CO2) to the atmosphere [Chavez and

Barber, 1987; Chavez and Toggweiler, 1995; Murray et al., 1994]. This is particularly

evident during strong El Niño conditions when the deepening thermocline prevents upwelled water from reaching the surface and decreases the CO2 flux out of the ocean

[Chavez et al., 1999]. Although most studies in the western tropical Pacific focus on

changes in physical oceanography on El Niño-Southern Oscillation (ENSO) timescales,

there is some evidence that a shoaling thermocline during El Niño conditions brings

deeper nutrient-rich water to the bottom of the euphotic zone and increases primary

productivity [Barber and Kogelschatz, 1990; Radenac and Rodier, 1996]. Therefore

changes in productivity occur in the western tropical Pacific that may also be important to

carbon cycling. A better understanding of the controls on carbon cycling in this region

are needed, particularly with potential changes in ENSO dynamics and/or the mean state

of the tropical Pacific under current global change [Cane and Evans, 2000; Collins, 2005;

Lea et al., 2000].

Since nutrient concentrations and productivity are a primary control on carbon

cycling in the western tropical Pacific [Behrenfeld et al., 2006; Chavez and Barber, 1987;

Turk et al., 2001], it is important to understand factors driving these variables. In the

western tropical Pacific the thermohaline structure of the water column determines

nutricline depth. The barrier layer formed by salinity and temperature gradients prevents

the upward flux of nutrients from nutrient-rich waters below the nutricline and maintains

78 nitrate-limited surface waters [Yoshikawa et al., 2006]. During El Niño conditions the

nutricline shoals bringing increased concentrations of nutrients to the bottom of the

euphotic zone. This fuels productivity and leads to a cessation of oligotrophy, and recent

studies support the interpretation of changes in productivity on ENSO timescales in the

western tropical Pacific [Dandonneau, 1992; Le Bouteiller et al., 1992; Kawahata and

Gupta, 2004]. However, our understanding of the relationship between ENSO, nutrients,

and thermocline depth in the western Pacific is based only on sparse instrumental data

collected in snapshots of time over the past several decades. How these relationships

vary on finer spatial scales and on longer timescales (i.e., over the past 50-100 years) is

completely unknown. Our understanding of these relationships would benefit from

reconstructions of nutrient concentrations and thermocline depth in the western tropical

Pacific.

High resolution reconstructions of paleoceanographic conditions in the tropical

Pacific are largely derived from scleractinian corals [i.e., Cole, 2003; Druffel, 1997;

Fairbanks et al., 1997; Gagan et al., 2000; Grottoli and Eakin, 2007]. These organisms

provide faithful proxy records of sea surface temperature (SST) and sea surface salinity

(SSS) in the tropical Pacific [Stephans et al., 2004]. Yet such records are largely limited

to near-surface waters and do not yield data about past changes in nutrient concentrations

or thermocline depth. Sediment records can provide information about past nutrient levels

[Kienast et al., 2008] but are limited in temporal resolution and do not provide records on recent timescales. Skeletal records from alyconaceans (soft corals) and antipatharians

(black corals), two separate orders of corals within the class Anthozoa, may provide such reconstructions of nutrient concentrations and/or thermocline depth. These corals are

79 widely distributed in the tropical Pacific from near surface to thousands of meters deep,

and can grow for several hundred years [Fabricius and Alderslade, 2001; Moore et al.,

1956]. Some species have a protein-rich internal skeleton that grows in concentric rings

providing chronological control, similar to tree rings [Grange and Goldberg, 1994;

Grigg, 1974; Sherwood et al., 2005a; Williams et al., 2006]. The geochemistry of the

organic skeleton is driven to a large extent by particulate organic matter in the water

column that the coral eat [Roark et al., 2005; Sherwood et al., 2005b; Williams et al.,

2007a; Williams and Grottoli, Submitted]. Therefore these corals have the potential to

yield paleoceanographic records of organic matter geochemistry spanning the water

column on sub-annual to centennial timescales. Here, high-resolution nitrogen (δ15N) and carbon (δ13C) stable isotope records from the organic skeleton of one Antipathes black

coral from 5m and two Muricella soft corals from 85m and 105m depth were developed.

The records were then used to reconstruct recent changes in organic matter geochemistry

in the western tropical Pacific, and to make a first order interpretation of the related

changes in horizontal water mass movement and nutricline depth variability. This is the first application of proxy records derived from soft corals and black corals in the western tropical Pacific.

METHODS

Study area

The island of Palau (N 07° 16’, E 134° 31’) is located in the northwestern quadrant of the western Pacific warm pool (WPWP), which is characterized by surface water with warm temperatures (>28º C) [Yan et al., 1992], low salinity (< 34) [Picaut et

80 al., 1996], and relatively low nutrient levels [Yoshikawa et al., 2006]. Palau is bathed in a mixture of waters from both the cold North Equatorial Current (NEC) and the warm, low- salinity North Equatorial Counter Current (NECC). The relative strength of the currents

bathing Palau is closely linked to the Intertropical Convergence Zone (ITCZ) [Donguy

and Meyers, 1996], which moves north over Palau during the fall and south during the spring. The westward-flowing NEC, north of the ITCZ, is driven by the NE trade winds.

As the ITCZ moves north during the fall, the NE trade winds weaken, resulting in a stronger NECC presence in Palau. Conversely, as the ITCZ moves south during the spring, the NE trade winds strengthen, resulting in a stronger NEC presence in Palau

[Wang et al., 2002].

The mixed layer depth offshore of Palau ranges from 30 to 90 m, with an average depth of 55 m [Colin, 2001; Cronin and McPhaden, 1997]. The thermocline depth ranges

from 55 to 200 m, with an average depth of 150 m. Salinity and temperature gradients

form a barrier layer between the bottom of the mixed layer and the top of the thermocline

[Lukas and Lindstrom, 1991]. Local wind forcing, resulting from easterly trade winds, controls the mixed layer and thermocline depths, such that they shoal during El Niño

conditions and deepen during La Niña conditions [McPhaden and Picaut, 1990; Solomon

and Jin, 2005; Zhang et al., 2007]. The depth of the nutricline and chlorophyll maximum

correspond to the thermocline and thus also fluctuate both seasonally and on ENSO timescales [Radenac and Rodier, 1996].

Colony Collection and Identification

Colonies were collected from Short Drop Off (SDO, 7º 16.4’N, 134º31.4’E), a

81 300 m vertical escarpment located 2 km offshore of Palau (Fig. 3.1). The site is

well-flushed by a dominant local current traveling the length of the wall and is subject to

minimal terrestrial influence. One Antipathes sp. black coral was collected from 5 m

(named A5m) and one Muricella sp. soft coral was collected from 85 m (named M85m)

using SCUBA in June 2006. One Muricella sp. soft coral was collected from 105 m

(named M105m) by submersible in November 2008. All colonies were alive and in

growth position when collected. A basal section, approximately 10 cm long, was

removed from each colony from directly above the holdfast to just below the lowest

branches using large garden shears. Colonies A5m and M85m were transported to the

laboratory frozen. Colony M105m was transported dried. The Muricella colonies were

identified according to Fabricius & Aldersade [2001] based on photos showing gross

colony morphology and morphology of sclerites under light microscope, and with the

assistance of L. Colin at the Coral Reef Research Foundation, Palau. The Antipathes

colony was identified by D. Opresko of the Oak Ridge National Laboratory.

Laboratory Analyses

An approximately one-centimeter thick cross-sectional slice was cut using a rock saw from the basal section of each colony. The location of the slice along the basal section was selected based on the absence of branches around the holdfast and where the base had the largest basal diameter. This served to cover the longest period of growth of the coral with minimal interference to the cross-section by branches. Tissue from the thawed basal slices of colonies A5m and M85m was removed using forceps. Since colony M105m was shipped to the laboratory dried, tissue could not be removed.

82 Skeletal δ15N values in Muricella were lower (F = 3.06, n = 22, p = 0.07) in HCl-

treated samples than non-treated samples indicating mobilization of the nitrogen with

acid treatments (Appendix B, Table 6.1). In contrast, skeletal δ13C values did not differ

between HCl-treated and non-treated samples indicating that the contribution of

carbonate to δ13C values was minimal (F = 0.47, n = 22, p = 0.63) (Appendix B, Table

6.1). Based on this test, skeletal samples were not pre-treated with acid prior to analysis.

Using 18 mΩ Milli-Q® water, each skeletal cross-sectional slice was cleaned in an

ultrasonic bath for three ten-minute periods, rinsed one additional time, and dried

overnight in an oven at 40º C. A radial track for sub-sampling was selected based on clear

banding patterns and the maximal radial distance across the cross-sectional slice. Across

the selected radial track in each colony, the skeleton was sub-sampled by milling at 0.2

mm increments in the Antipathes colony A5m and at 0.1 mm increments in the Muricella colonies M85m and M105m (Fig. 3.2) using a high-precision, computer-driven

Merchantek microdrill attached to an x, y, z controlled stage. The sampling interval was selected to maximize resolution of the resulting record and still obtain sufficient skeletal material for analysis. The width of skeletal bands was not consistent among all of the bands, and variations in width within a single band were present. In addition, growth of the skeleton was not perfectly linear across the radial axis of the slice. Therefore, the depth (3 mm) and width (varied with location along transect, 0.5 mm to 1 cm) of the drilling path were set to minimize temporal aliasing. At least 0.8 mg of skeletal material was removed for analytical measurement. Half of the sample (at least 0.4 mg) of material from each drill path was analyzed for δ13C (δ13C = permil deviation of the ratio of stable

carbon isotopes 13C:12C relative to Vienna Peedee Belemnite Limestone Standard

83 (VPDB)) and δ15N (δ15N = per mil deviation of the ratio of stable nitrogen isotopes

15N:14N relative to air) isotopic composition. At selected locations across the radial

transect of each colony, the remaining 0.4 mg of sub-sampled material from each of three

adjacent drill paths was combinted to obtain 1.2 mg of skeletal material for radiocarbon

(14C) analysis.

14C was measured at the National Ocean Sciences Accelerator Mass Spectrometry

(NOSAMS) Facility at the Woods Hole Oceanographic Institution using standard

NOSAMS methods [Osborne et al., 1994]. Briefly, weighed portions of the organic

skeleton were combusted by Fisons Carlo Erba NA1500 elemental analyzer. A split of

13 the resulting CO2 gas was analyzed for δ C, and the remainder was cryogenically purified and reduced to graphite under hydrogen gas using an iron catalyst to produce a graphite target. The radiocarbon content of the graphite was measured by accelerator mass spectrometry (AMS). Values were reported as Δ14C (the per mil deviation of

14C/12C of the sample relative to that of 95% Oxalic Acid-1 standard) [Stuiver and

Polach, 1977] and were blank corrected. The reported uncertainty of duplicate analyses

of a known standard was typically ± 5-8‰.

Carbon-to-nitrogen (C:N) ratio by mass and the δ13C and δ15N values of each sample were measured by combusting the organic fraction in a Costech Elemental

Analyzer where the resulting N2 and CO2 gases were analyzed with a Finnigan Delta IV

Plus isotope ratio mass spectrometer via a Finnigan ConFlow III open split interface. The

standard Acetanilide was used for calibration of percent C and N, and the carbon-to- nitrogen (C:N) ratios. δ13C values were reported relative to Vienna Peedee Belemnite

Limestone Standard (VPDB) [Coplen, 1994]. δ15N values were reported relative to air

84 [Mariotti, 1984]. The standard deviation of the mean of repeated measurements of internal standards was ± 0.06‰ for δ13C and ± 0.15‰ for δ15N. At least 10% of all samples were run in duplicate.

Chronology Construction

Bombardment of 14N atoms by cosmic rays produces 14C in the stratosphere.

Excess 14C was produced by atmospheric thermonuclear weapons testing in the 1950’s and early 1960’s over the Pacific Ocean. This anthropogenic ‘bomb’ 14C caused an increase in 14C activity in the atmosphere and subsequently in the oceanic carbon pools.

Incorporation of bomb 14C into marine organisms started in the mid-1950’s, peaked in the

1970’s and has been decreasing since that time [Grottoli and Eakin, 2007]. Since marine organisms including corals and sclerosponges incorporate carbon from their ambient environment without fractionation, measurements of bomb 14C in marine organisms can be used to identity specific points in time (i.e. the onset and peak of bomb 14C) in the skeleton [Druffel and Linick, 1978; Grottoli and Eakin, 2007]. Here, measurements of bomb 14C (reported as Δ14C) across a radial transect of the organic coral skeleton were used in addition to the known date of collection to develop a growth chronology for each colony. First, the known collection date was adjusted to account for the tissue removed in the Antipathes colony A5m and the Muricella colony M85m. Since tissue turnover likely occurs on seasonal to sub-annual timescales [Sherwood et al., 2005b] and may be age and taxa dependent, the chronologies for colonies A5m and M85m were started six months prior to collection date. The tissue was not removed in the Muricella colony M105m so the chronology was started from the outside edge of the basal slice in 2008. Next, the

85 base of the bomb-curve was identified in the 14C records for the Muricella colonies

M85m and M105m, and was anchored at ~1955. The growth rate in mm/yr was then

calculated for both Muricella colonies using the anchored base of the bomb-curve and the

year of collection, which was 2006 for M85m and 2008 for M105m. Assuming constant

growth rates, the remainder of the skeletal 14C values were plotted against time and were

compared to known 14C bomb-curve reconstructions from the tropical Pacific from

scleractinian corals and sclerosponges [Grottoli 2006; Guilderson et al., 1998]. The

timing of the peak of the bomb-curve in colonies M85m and M105m was then used to

test the assumption of constant growth rates. Skeletal 14C values from the Antipathes

colony A5m indicated the colony was <50 years old. Growth rates were estimated and

adjusted so that the 14C values plotted against time had the best fit to known 14C bomb-

curve reconstructions. The 14C-derived chronologies for each colony were then applied to

the stable isotope records.

Statistical Analysis

An order-specific correction of +1.5‰ was applied to the black coral δ13C values prior to comparing it with the soft coral records (Williams and Grottoli, submitted). In addition, a depth correction of +0.25‰/10 m was applied to the δ13C records of the

colonies prior to comparing them (Williams and Grottoli, submitted). Here, the order-

specific correction was offset by the depth correction within error, thus the δ13C records

from all three colonies were directly compared. No order-specific correction was needed

for δ15N-based proxy records (Williams and Grottoli, submitted). A depth correction of -

0.15‰/10 m was applied to compare colonies collected from 5 m, 85 m and 105 m

86 (Williams and Grottoli, submitted). While this isotopic correction was applied prior to

interpretation of the data, the original data were plotted here so that the different records

could be viewed more easily.

Best fit quadratic curves were fit to each δ13C and δ15N record (p<0.0001 for all

curves) using SigmaPlot (Systat Software Inc., San Jose, CA). To directly compare the

rates of decreasing δ13C values in all three records, the change in δ13C for each decade

post-1970 was calculated from the best fit curve equations of each record. The data sets

were detrended by subtracting each data point from the best fit curves. δ13C and δ15N detrended datasets were tested for the presence of outliers using Boxplot statistics.

Outliers were identified as data points that were more than 1.5 interquartile ranges above or below the first and third quartile (equivalent to the 1st and 99th percentile) and were

removed.

Based on growth rates calculated from the 14C-derived chronology, colonies A5m,

M85m, and M105m were milled at 6.6 month, 6.1 month, and 8 month intervals,

respectively (Table 1.1). The Timer program from the Arand software package (courtesy

of Philip Howell, Brown University, ftp://pixie.geo.brown.edu/pub) was applied to the detrended δ13C and δ15N records for each colony to produce evenly-spaced annual values

for the entire record of each colony through interpolation. The spectral energy was

evaluated on the detrended and interpolated datasets. The coherency and correlation analyses were conducted between δ13C and δ15N records from each colony and the annual

averaged Southern Oscillation Index (SOI)

(http://www.bom.gov.au/climate/current/soi2.shtml). The SOI served as a measure of

ENSO. Spectral and cross-spectral analyses were performed using the Spectral and

87 Cross-spectral programs from the Arand software package. Spectral energy and

coherence greater than 95% were considered statistically significant.

Using the detrended and interpolated datasets, a Pearson correlation coefficient

was used to calculate the correlation between the δ13C and δ15N records for each colony

and the SOI. These analyses were generated using SAS software, Version 8.02 of the

SAS System for Windows. [Copyright C 1999-2001 SAS Institute Inc. SAS and all other

SAS Institute Inc. products and service names are registered trademarks or trademarks of

SAS Institute Ind., Cary, NC, USA.]. P-levels ≤ 0.05 were considered significant for all

statistical analyses.

RESULTS

Growth rates and age estimates

Δ14C measurements clearly showed the onset and peak of the 14C bomb curve in

all three colonies (Fig. 3.3). The shapes of the bomb-curves are consistent with those

published for a sclerosponge and a scleractinian coral also from the western tropical

Pacific (Fig. 3.3) [Grottoli, 2006; Guilderson et al., 1998]. Growth rates were an order of

magnitude lower in Muricella than Antipathes (Table 3.1). Using the calculated growth rates and radial distances, colony ages of 41, 106, and 63 years were determined for the

A5m, M85m, and M105m colonies, respectively, and each high-resolution sample

spanned 6 to 8 months of growth.

Skeletal δ13C records

One δ13C value from the Antipathes colony A5m and one from the Muricella

88 colony M85m were determined to be outliers, were removed, and were replaced with an average of the preceding and following δ13C values in the chronology. These anomalous

values likely reflect contamination of the sample. To directly compare records derived

from all three colonies, the outer δ13C values of colony M105m associated with the tissue were removed and the growth chronology for colony M105m was adjusted to start in

2007.

In the Antipathes colony A5m, δ13C values decreased by ~0.8‰ over the duration

of the 41-year record (Fig. 3.4). In addition, a decade-long large negative anomaly of up

to 0.8‰ with strong interannual variability was observed from 1981-1991. Other

pronounced negative anomalies were also present in 1967, 1973, and 1997. In the

Muricella colony M85m, mean δ13C values decreased by ~1.7‰ over the duration of the

106-year record. Most of this decrease (~1.3‰) occurred after 1975. This record also

contained a prolonged ~0.6‰ negative anomaly from 1919 through 1936 (Fig. 3.4). In

the Muricella colony M105m, mean δ13C values decreased by ~1.3‰ from 1944 to 2007.

In addition, δ13C variability about the mean curve was higher prior to the mid-1970’s than

after the mid-1970’s (Fig. 3.4). Starting in the 1970’s, δ13C values in both Muricella

colonies, M85m and M105m, decreased at similar average decadal rates of 0.14‰ for the

1970’s, 0.20‰ for the 1980’s, 0.26‰ for the 1990’s and of 0.29‰ for 2000’s as

calculated from the best fit curves (Fig. 3.4).

Single spectrum analysis of the detrended and interpolated yearly δ13C records

revealed no significant spectrum in any of the colonies. Cross-spectral analysis of these

skeletal δ13C records with SOI revealed that they were coherent in the A5m Antipathes

colony at a frequency centered at 4 years, in the M85m Muricella colony at a frequency

89 centered at 9 years, and no coherence was detected in the M105m Muricella colony (Fig

3.5A, B, C).

Skeletal δ15N records

No outliers were identified in the δ15N records for colonies A5m and M85m. To directly

compare records derived from all three colonies, the outer δ15N values of colony M105m

associated with the tissue were removed and the growth chronology was adjusted to start

in 2007.

In the Antipathes colony A5m, δ15N values increased 0.8‰ starting in 1976,

peaked in the mid-1980’s, and decreased 0.8‰ by 1997 (Fig. 3.6). δ15N values then

increased and decreased again ~0.8‰ from 1997 to 2004. In the Muricella colony M85m,

mean δ15N values decreased by ~1‰ from the early 1900’s to the late 1990’s and then

increased by 0.3‰ through to the end of the record (Fig. 3.6). In the Muricella colony

M105m, mean δ15N values decreased by ~0.8‰ from the mid-1940’s to the mid-1990’s and then increased by 0.3‰ by the end of the record (Fig. 3.6).

Single spectrum analysis of the detrended and interpolated yearly δ15N records

revealed no significant spectrum in any of the colonies. Cross-spectral analysis of these

skeletal δ15N records with SOI revealed that they were coherent in the Antipathes colony

A5m at a frequency centered at 3.5 years, in the Muricella colony M85m at 5 years, and

no coherence was detected in the Muricella colony M105m (Fig 3.5D, E, F).

DISCUSSION

Skeletal bomb 14C records

90 The Δ14C values across a growth transect in the organic skeleton of each colony

all reflect a 14C bomb-curve (Fig. 3.3). The peak 14C values in the colonies A5m and

M85m are similar to those measured in a shallow water sclerosponge specimen from the

same site in Palau [Grottoli, 2006] and to those measured in scleractinian corals from

Nauru (Fig. 3.3) [Guilderson et al., 1998]. Since soft corals and black corals from Short

Drop Off (SDO) feed on suspended particulate organic matter (POM) [Williams and

Grottoli, submitted], these results indicate that bomb 14C has fully permeated the

suspended POM pool to a depth of 85 m at this site. The lower peak Δ14C values for the

deepest Muricella colony M105m (Fig. 3.3) are most likely due the contribution of

deeper and thus older seawater to the site, which diluted the bomb-14C signal.

Growth rates calculated from the 14C bomb-curve were constant across the radial

transects of all the colonies, and were an order of magnitude higher in the shallow

Antipathes colony than the deeper Muricella colonies (Table 3.1). The radial growth rate

of 0.18 mm yr-1 for the Antipathes coral A5m is similar to the ranges reported for

Antipathes dendrochristos (0.10-0.14 mm yr-1 ) and Antipathes dichotoma (0.18-1.14 mm

yr-1) collected from depths ranging from 50-106 m [Love et al., 2007; Roark et al., 2006].

In addition, radial growth rates of 0.02 mm yr-1 for the Muricella corals M85m and

M105m are within the range reported for Primnoa spp. (0.01-0.04 mm yr-1) collected

from several hundred meters deep but are less than those for Plexaurella dichotoma (0.12

mm yr-1) from 6 m deep [Risk et al., 2002; Bond et al., 2005; Williams et al., 2007b].

Therefore higher growth rates in the Antipathes black coral than the Muricella colonies results from taxonomic variability and not slower growth rates with depth.

91 13 Coral δ C records

δ13C values of atmospheric carbon are decreasing due to the burning of 13C-light fossil fuels (i.e., the 13C-Suess effect), and subsequently δ13C values of dissolved

inorganic carbon (DIC) in the ocean are also decreasing [Keeling, 1979; Bacastow et al.,

1996; Sonnerup et al., 1999; Sonnerup et al., 2000]. Decreasing DIC δ13C values are

incorporated into the marine carbon cycle, including the suspended POM pool, and

eventually into the coral colonies. In this study, the average rate of δ13C decline per

decade jumped from 0.14‰ in the 1970’s to 0.29‰ for 2000’s in the Muricella colonies

M85m and M105m (Fig. 3.4). These decadal rate changes are virtually identical to those

observed in a sclerosponge from the same site [Grottoli, in prep.] and they correspond

well to those recorded in oceanic DIC-13C over the past several decades [Quay et al.,

2003; Quay et al., 2007]. Therefore, the time lag in uptake and assimilation of DIC

during primary production and incorporation of that carbon into POM is negligible on

decadal time scales.

Consistency between the decadal rates of decrease in δ13C values from the corals

and the sclerosponge further supports the 14C-derived growth chronologies developed for

these corals. In addition, with a high enough sampling resolution in the Muricella

colonies, the calculation of growth rates is feasible by correlating measured decreases in

δ13C values with those reported elsewhere in the tropical Pacific over the past 40 years. In

contrast to the Muricella colonies, decadal rates of decrease cannot be calculated for the

δ13C record from the Antipathes colony A5m as this record was characterized by large

negative anomalies that override decreasing δ13C values (Fig. 3.4). However, the overall

92 average decrease of 0.8‰ over the entire 41 year period is consistent with the average

decrease in δ13C for the two Muricella colonies over the same period of time.

Additional variability was present in the δ13C records. Since the δ13C of POM

drives the δ13C values of the coral organic skeleton in Palau [Williams and Grottoli,

submitted], then the coherence of δ13C values in the Antipathes colony A5m with the SOI

at 4 years (Fig. 3.5A) was likely caused by ENSO timescale variability in the δ13C of

POM within the mixed layer. The amount of primary productivity and the plankton species composition both differ between El Niño and La Niña conditions in the western tropical Pacific, which could drive the changes in POM δ13C values [Falkowski, 1991; Le

Bouteiller et al., 1992; Mackey et al., 1997; Turk et al., 2001]. However, most of the

changes in productivity are expected to occur toward the bottom of the photic zone due to

the periodic presence of nutrients as the nutricline shoals during El Niño conditions. This

was not consistent with the absence of δ13C variability on ENSO timescales in the deeper

Muricella records from closer to the bottom of the photic zone. Therefore the cause of

interannual variability in all the coral skeletal δ13C values is unclear.

Coral δ15N records

As a result of the degradation of suspended POM with depth [Saino and Hattori,

1980; Macko and Estep, 1984], organic skeletal δ15N values increase by 0.15‰ for every

10 m of depth increase in the euphotic zone (Fig. 3.7) [Williams and Grottoli, Submitted].

This increase in δ15N values with depth explains the 1.5‰ and 1.9‰ higher values in the

Muricella soft coral colonies M85m and M105m, respectively, than in the Antipathes

93 colony A5m (Fig. 3.7). Therefore none of the variability in δ15N values among these three

colonies was related to taxa.

Despite a similar nitrogen source of suspended POM and the absence of

taxonomic influences on δ15N values between the species, the δ15N record from the

Antipathes black coral from 5 m dramatically differed from the Muricella soft coral

records from 85 and 105 m for the same time period (Fig. 3.6). This difference most

- likely reflects the strong separation of the warm, fresh, and NO3 -limited surface waters

- from colder, more saline, and more NO3 -rich deeper water below the mixed layer

[Kawahata et al., 2000; Le Borgne et al., 2002; Mackey et al., 1995; Zhang et al., 2007].

The separation is a consequence of the barrier layer characteristic of the western tropical

Pacific [Lukas and Lindstrom, 1991], which prevents the upward flux of nitrate into

surface waters [Turk et al., 2001]. The end result is that the controls on δ15N values of

suspended POM within the mixed layer differ from those below the mixed layer.

Therefore, the δ15N record from the 5 m Antipathes record will be discussed separately

from the 85 m and 105 m Muricella records.

Shallow Antipathes black coral records variability in source water within the mixed layer

Denitrification has not been reported in the western tropical Pacific [Deutsch et

al., 2001] and atmospheric input and vertical mixing are unimportant sources of nitrogen

to surface waters in the region [Mackey et al., 1995]. Therefore the large 15 year- and 5

year-long positive anomalies present in the shallow Antipathes A5m colony δ15N record

must result from either fluctuations in the fractionation of 15N/14N during primary

- production due to transient increases in NO3 concentrations fueling productivity, and/or

94 from changes in the source of POM to Palau. Since the mixed layer in the western

tropical Pacific is very nutrient limited [Turk et al., 2001; Yoshikawa et al., 2006],

- transient increases in NO3 to the mixed layer would be completely used up by primary

productivity, probably on seasonal timescales. Therefore, the influence of fractionation

on nitrogen isotopes during primary production would be negligible at greater than

15 - 15 seasonal timescales. Instead δ N values of the ambient NO3 would drive the δ N values of the resulting organic matter. Thus, since the skeletal δ15N values here are

reported on annual timescales (i.e, minimizing the impact of a single seasonal event), the

most likely cause of the skeletal δ15N anomalies in the Antipathes black coral record from

within the mixed layer are changes in the source of POM bathing the colony on

interannual timescales.

15 - Surface currents originating west of Palau have low δ N-NO3 due to the

influence of terrestrial sources (i.e., river water input or atmospheric deposition due to heavy rainfall), and/or fractionation during nitrogen fixation [Kawahata et al., 2000;

Yoshikawa et al., 2005]. In contrast, surface currents originating east of Palau have high

15 - δ N-NO3 values from denitrification occurring in the eastern tropical Pacific [Sigman et

15 - al., 2005]. High δ N-NO3 values in the western tropical Pacific have previously been

- attributed to NO3 advected into the region from the eastern tropical Pacific via the North

Equatorial Current [Kienast et al., 2008; Pena et al., 1994; Yoshikawa et al., 2006].

Therefore we hypothesize that a shift in the relative strength of the currents bathing Palau

15 - drive δ N-NO3 variation within the mixed layer, and hence the suspended POM and coral skeletal δ15N, on interannual to decadal timescales.

95 During El Niño warm phases, weakened trade winds enhance the NECC, bringing

15 - water with low δ N-NO3 from the western-portion of the WPWP to Palau. During La

Niña cool phases, the trade winds are enhanced, strengthening the NEC supplying water

15 - with high δ N-NO3 from the eastern equatorial Pacific. Since the strength of the trade

winds vary with the north/south movement of the ITCZ on ENSO timescales, the

coherence in the Antipathes δ15N record with the SOI on ENSO timescales supports a relationship between the relative strengths of the NEC and NECC bathing Palau and

ENSO (Fig. 3.6). Therefore, an enhancement of the trade winds and NEC during the late

1980’s to early 1990’s and again in the early 2000’s could account for the relative

increase in Antipathes δ15N values in the 1980’s and mid-2000’s (Fig. 3.6). However, this

is not consistent with wind anomaly measurements from 1980-2000 (i.e., trade wind

index anomaly from NOAA: http://www.cpc.noaa.gov/data/indices). Additional data on

the relative strength and position of the NEC and NECC in the western tropical Pacific

are needed to further test the hypothesis. Alternatively, the biology of the Antipathes coral could drive the variability, so that additional records from the same region are needed to verify if the changes in the record are colony-specific or environmentally- driven.

Deeper Muricella soft coral record shoaling of mean nutricline depth

In the western tropical Pacific, the barrier layer prevents the transport of nutrients

- - from the NO3 -rich deeper water into the NO3 -poor surface waters and as a consequence,

the nutricline generally corresponds to the top of the thermocline [Mackey et al., 1995;

Yoshikawa et al., 2006]. The average depth of the thermocline/nutricline is approximately

96 150 m [Yoshikawa et al., 2006] although it shoals as shallow as 75 m seasonally and on

- ENSO timescales [Colin, 2001]. The NO3 below the nutricline is characterized by low

15 - δ N values in comparison to the NO3 above the nutricline [Yoshikawa et al., 2006], and this δ15N signal is expected to be transferred to the organic matter in the water column.

Therefore when the nutricline is deep, the Muricella soft coral colonies are bathed in

water with high δ15N values. When the nutricline shoals, they are bathed in water with

low δ15N values. The consistent decline in the δ15N values over the last several decades in

the records from both colonies (Fig. 3.6) likely indicates a shoaling of the mean nutricline

depth such that both colonies are more frequently bathed in water characterized by low

δ15N values. This is consistent with a general shoaling of the thermocline recorded in

Indonesian Seaway sclerosponges [Moore et al., 2000], temperature data-sets [Zhang et

al., 2007] and supports a shift to more El Niño-like conditions as predicted by some

global climate models over the past ~50 years [Knutson and Manabe, 1995; Meehl and

Washington, 1996; Vecchi et al., 2006]. Fluctuations in the depth of the nutricline on

ENSO timescales driving productivity also explain the coherence of the Muricella soft

coral M85m record with SOI (Fig. 3.5E). The absence of such a relationship in the

Muricella soft coral M105 record was surprising, but could reflect the reduced influence

of the nutricline fluctuations on the δ15N record since this colony was located closer to

the average depth of the nutricline.

Summary and Implications

This research supports the control of ambient suspended POM on the isotopic

composition of Antipathes and Muricella corals in the top 105 m of the water column.

97 Decreasing δ13C values in all three colonies since the 1970’s were consistent with the

13C-Suess effect, indicating that atmospheric carbon has penetrated the upper 105m of the

water column in step with atmospheric CO2 concentration increases. Variability in coral

15 - δ N values from within the NO3 -limited mixed layer appear to be driven by shifts in the

- local surface currents entraining NO3 to the region on ENSO and longer timescales. In

contrast, gradually decreasing δ15N values in two deeper colonies indicate a shoaling of

mean nutricline depth over the past 30 years in the western tropical Pacific. Such a

15 - shoaling enhances the entrainment of low δ N, nutrient-rich water into the NO3 -limited euphotic zone stimulating primary productivity. Thus, these coral records suggest that primary productivity has increased over the past 30 years, enhancing the biological pump, and thus the amount of carbon dioxide removed from the atmosphere in the western tropical Pacific.

Acknowledgements: We thank P Colin and L Colin at the Coral Reef Research

Foundation in Palau for their support of this research assistance in coral colony collection. A McNichol and NOSAMS at WHOI and Y Matsui and SIB Lab at OSU provided laboratory assistance. B Thibodeau and R Moyer provided insightful comments to improve this manuscript. P Howell of Brown University maintains and distributes the

ARAND software package used for statistical analysis. BW was supported by an Natural

Science and Engineering Research Council of Canada postgraduate fellowship. This work was supported by the PADI Foundation, Geological Society of America Award,

Friends of Orton Hall travel award, and a NOSAMS Internship to BW, as well as

National Science Foundation Chemical Oceanography (0610487 and 0426022), National

98 Science Foundation Biological Oceanography (0542415), and the Andrew Mellon

Foundation to AGG.

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104 TABLE

Collectio Colony Genera Average Age δ13C and δ15N sub- n year ID radial growth (years) sample resolution rate (mm/yr) (months) 2006 A5m Antipathes 0.18 41 6.6 2006 M85m Muricella 0.02 106 8.0 2008 M105m Muricella 0.02 63 6.1

Table 3.1. Summary of colony, growth rates, ages, and sub-sampling resolution for black coral and soft coral colonies used in this study.

105 FIGURES

Figure 3.1. Map of the western tropical Pacific showing the location of the Short Drop Off field site 2 km offshore of Palau. Figure courtesy of J. Watson.

106

Figure 3.2. Cartoon showing representative basal slice with continuous sampling tracks at 100 μm increments for δ13C and δ15N analyses. At select locations across the radial axis, additional samples were collected for 14C analysis.

107

Figure 3.3. Radiocarbon values (Δ14C) for colonies Antipathes A5m (●), Muricella M85m (●), and Muricella M105m (●) measured across a radial transect and compared to published radiocarbon records from tropical Pacific Porites stony corals {Guilderson et al., 1998] and a Palauan Ancanthocheatetes wellsi sclerosponge [Grottoli 2006].

108 -16.5

-17.0

-17.5

-18.0

-18.5 C (‰, v-pdb) 13 δ -19.0

2 -19.5 A5m, r =0.54 M85m, r2=0.78 M105m, r2=0.73 -20.0 1900 1920 1940 1960 1980 2000 2020

Years

Figure 3.4. Stable carbon isotope (δ13C) values for the Antipathes A5m (●), Muricella M85m (●), and Muricella M105m (●) colonies collected from 5 m, 85 m, and 105 m, respectively, from Short Drop Off reef wall in Palau. Best fit curves for each δ13C record (r2 = 0.54-0.78, p<0.0001 for all curves) are shown.

109 1.0 13 A) A5m δ C vs SOI D) A5m δ15N vs SOI 95% 95% 0.8

0.6

0.4 Coherency

0.2

0.0 1.0 B) M85m δ13C vs SOI E) M85m δ15N vs SOI

0.8 95% 95%

0.6

0.4 Coherency

0.2

0.0 1.0 C) M105m δ13C vs SOI F) M105m δ15N vs SOI

0.8

0.6

0.4 Coherency

0.2

0.0 0.0 0.1 0.2 0.3 0.4 0.00.10.20.30.4 Frequency Frequency

10 5 3.3 2.5 10 5 3.3 2.5 Period (years) Period (years)

Figure 3.5. Coherence from cross-spectral analysis between the δ13C and Southern Oscillation Index (SOI) of records of A) Antipathes A5m, B) Muricella M85m, and C) Muricella M105m, and between the δ15N and SOI records for D) Antipathes A5m, E) Muricella M85m, and F) Muricella M105m.

110 9.5

9.0

8.5

8.0

7.5 N (‰, air) 15

δ 7.0

6.5

A5m, r2=0.37 6.0 M85m, r2=0.65 M105m, r2=0.41 5.5 1880 1900 1920 1940 1960 1980 2000 2020

Years

Figure 3.6. Stable nitrogen isotope (δ15N) values for the Antipathes A5m (●), Muricella M85m (●), and Muricella M105m (●) colonies collected from 5 m, 85 m, and 105 m, respectively, fromShort Drop Off reef wall in Palau. Best fit curves for each δ15N record (r2 = 0.37-0.65, p<0.0001 for all curves) are shown.

111 8.5

8.0

7.5

7.0 N (‰, air) (± 1SD) air) N (‰, 15 δ 6.5

Ave ± SD Average Average 6.0 A5m M85m M105m 5.5 0 20 40 60 80 100 120

Depth (m)

Figure 3.7. Outer skeletal layer δ15N values for the Antipathes A5m (●), Muricella M85m (●), and Muricella M105m (●) colonies plotted with the average δ15N values for the outer layer of 65 additional colonies (○) from Chapter 2 of this dissertation over the same depth range. The outer skeletal ring represents approximately the same point in time for all colonies.

112

CHAPTER 4

SOLUTION AND LASER ABLATION INDUCTIVELY COUPLED PLASMA MASS SPECTROMETRY (ICP-MS) MEASUREMENTS OF BR, I, PB, MN, CD, ZN, AND B IN THE ORGANIC SKELETON OF SOFT CORALS AND BLACK CORALS

B Williams and AG Grottoli

The Ohio State University

125 South Oval Mall, Columbus, OH 43210

Prepared for Journal of Geophysical Research – Biogeosciences

113 ABSTRACT

Proxy records can be derived from soft corals and black corals using minor and

trace elements measurements of the organic skeleton of these corals. Here, concentrations

of the elements Br, I, Pb, Mn, Cd, Zn, and B in the organic skeleton were determined

using solution inductively coupled plasma mass spectrometry (ICP-MS) in one

Antipathes black coral from 5 m water depth and two Muricella soft corals from 85 m and 105 m water depth from Palau in the western tropical Pacific. In the same colonies, the intensities of 79Br, 127I, 208Pb, 55Mn, 114Cd, 64Zn, and 11B normalized to 13C were

measured at high resolution along radial transects covering the lifespan of the colonies

using laser ablation ICP-MS (LA-ICP-MS). Solution ICP-MS analyses of the three

colonies revealed overall high Br and I concentrations, and higher I in the Antipathes

black coral than the Muricella soft corals which is similar to qualitative measurements

from previous studies. In addition, average Pb and Cd concentrations increased and Mn

concentrations decreased with increasing depth, consistent with the changes in these

elements in seawater with depth, and suggesting that these corals are recording ambient

concentrations of these elements. In contrast, trends in Br, B, and Zn concentrations with

depth were not consistent with ambient concentrations of these elements with depth or

with taxa, and instead may reflect colony-specific variability. At high resolution, parallel

laser transects by LA-ICP-MS within a colony were highly reproducible for all elements

measured in the Antipathes black coral. In addition, the 127I/13C intensity and 79Br/13C

intensity varied with age as expected from previous literature, and possibly in response to

changes in skeletal morphology. Most interestingly, the 11B/13C intensity varied on

approximately decadal timescales, though the cause of the variability is unknown. Thus,

114 high-resolution LA-ICP-MS elemental records in black corals could be more fully developed for paleoceanographic reconstructions. In contrast, results of the laser transects from the two Muricella soft corals were not reproducible for any of the elements, and no discernable patterns were detected that could be developed into reliable proxy records using the current LA-ICP-MS method.

115 INTRODUCTION

Trace element measurements in the calcium carbonate skeleton of scleractinian

corals have been used to reconstruct seawater temperature ( Sr/Ca [i.e., Beck et al., 1992;

Smith et al., 1979]), upwelling (Ba/Ca [i.e., Lea et al., 1989]; Cd/Ca [i.e., Matthews et al.,

2008; Shen et al., 1987], terrestrial runoff at coastal sites (Ba/Ca [Tudhope et al., 1997]),

and soil erosion (Y/Ca [Lewis et al., 2007]). Such elemental proxy records have not been

developed for soft and black corals as a result of perceived difficulties in sub-sampling

trace elements at high resolution.

Stable isotopes records from soft and black corals have been successfully used as

proxy records of nutrient sources and biophysical processes in surface waters [Chapter 3

of this dissertation, Sherwood and Risk, 2007; Williams et al., 2007]. These corals form a

proteinaceous skeleton with growth bands useful for chronological control [Grange and

Goldberg, 1994; Sherwood et al., 2005b] similar to scleractinian corals. However, soft corals and black corals are widely distributed in the tropical Pacific from near surface to thousands of meters deep [Fabricius and Alderslade, 2001; Moore et al., 1956] and can provide proxy records from locations where scleractinian corals are absent. Unlike scleractinian corals, in which trace elements are incorporated into the lattice by

substitution during formation of calcium carbonate in response to their concentration in the seawater [Shen and Sanford, 1990] or temperature-dependent fractionation [Beck et al., 1992], the method of trace element incorporation into the organic skeleton of soft corals and black corals is unknown. To date, research has focused on Sr/Ca and Mg/Ca ratios in the calcite skeleton that is present in some soft coral species [Bond et al., 2005;

Sherwood et al., 2005a; Sinclair et al., 2005; Weinbauer and Velimirovm, 1995]. The

116 study of elemental abundances in the organic skeleton of soft corals and black skeletons

has focused on understanding their morphology and possible application as biomaterials

[Goldberg, 1976; Nowak et al., 2005]. For example, a recent study used electron and proton microprobes to qualitatively explore the spatial distribution of Br, I, Zn, Mg, Ca,

Sr, C, P, and S in the skeleton of three black coral specimens from different locations to assess skeletal morphological features, but not to reconstruct environmental conditions

[Nowak et al., 2008].

To date, no high resolution elemental analyses of the organic skeleton of soft corals, or quantitative comparisons of trace elements concentrations between the organic skeletons of soft corals and black corals, have been performed. If trace elements are incorporated into the skeleton in response to ambient seawater concentrations or environmental conditions, then these corals may provide an opportunity to reconstruct paleoceanographic conditions across a larger depth and latitudinal range then is possible

with scleractinian corals. Therefore, the goal of this paper is to: 1) quantitatively establish

concentrations of minor (Br, I) and trace elements (Pb, Mn, Cd, Zn, and B) in the organic

skeleton of western tropical Pacific soft corals and black corals collected along a 105 m

depth transect, and 2) evaluate the use of high-resolution LA-ICP-MS measurements of

Pb, Mn, Cd, Zn, and B for possible paleoceanographic proxy records. As a first order

approach, Pb and Cd were selected because concentrations of these elements increase

with depth in the ocean, and Mn and Zn were selected because concentrations of these

elements decrease with depth [Abe, 2004; Bruland, 1983; Klinkhammer and Bender,

1980]. B was selected because of its linear relationship with salinity [Barth, 1998; Couch,

1971]. Br and I were selected because preliminary analyses revealed high concentrations

117 of these elements in the soft coral and the black coral skeletons, and because reported

differences in these concentrations appear to be linked to the coral age [Goldberg, 1976;

1978].

To achieve these goals, the selected elements were measured by solution ICP-MS to accurately determine concentrations of the elements in the skeleton of one Antipathes black coral from 5 m water depth and two Muricella soft corals from 85 and 105 m water depth collected from Short Drop Off Reef offshore of Palau in the western tropical

Pacific. Depth-controlled and order-controlled (i.e., black coral versus soft coral)

variations in element concentrations were evaluated. Next, three adjacent radial transects

from a basal section of each of the three coral colonies were measured using LA-ICP-MS

to test for reproducibility of each elemental measurement, and to evaluate the potential

proxy applications of each element.

METHODS

Specimen collection

Two coral colonies, one Antipathes black coral from 5 m (A5m) and one

Muricella soft coral from 85 m (M85m) were collected in 2006 by a diver using SCUBA.

One additional Muricella soft coral from 105 m (M105m) was collected in 2008 by submersible. Colonies were collected from Short Drop Off (SDO, 7º16.4’N, 134º31.4’E)

– a 300 m vertical escarpment located 2 km offshore of Palau. The site is well-flushed by a dominant local current traveling the length of the wall and is subject to minimal terrestrial influence. SDO is subject to the open ocean conditions surrounding Palau: warm surface waters (>28ºC), low salinity (< 34 psu), and relatively low nutrient levels

118 within the mixed layer [Picaut et al., 1996; Yoshikawa et al., 2006]. At 5 m depth, the

Antipathes colony A5m was located within the warm mixed layer, while the Muricella

colonies M85m and M105m were located within the range of vertical fluctuations of the

thermocline (55 to 200 m) [Colin, 2001; Delcroix et al., 1996; Iijima et al., 2005; Zhang

et al., 2007].

All colonies were alive and in growth position when collected. An approximately

10 cm basal section was removed from each colony, from directly above the holdfast to

just below the lowest branches, using large garden shears. Colonies A5m and M85m

were transported to the laboratory frozen. Colony M105m was transported dried. The

Antipathes colony was identified by D. Opresko of the Oak Ridge National Laboratory.

The Muricella colonies were identified according to Fabricius and Aldersade [2001]

based on photos showing gross colony morphology, the morphology of sclerites under

light microscope, and with the assistance of L. Colin at the Coral Reef Research

Foundation, Palau.

Sample preparation

Two one-centimetre thick cross-sectional slices were cut from the bases of the

Antipathes colony A5m and the Muricella colony M85m from the base of the Antipathes

colony A5m and the Muricella colony M85m using a rock saw lubricated with water.

One one-centimetre thick cross-sectional slice was cut from the Muricella colony

M105m. The location of each slice along the basal section was selected based on the absence of branches around the holdfast and the position with the largest diameter. This optimized the chances of getting the longest period of growth by the coral with minimal

119 interference to the cross-section by branches. One cross-sectional slice from each of the

colonies A5m and M85m was sent to Calgary Rock and Mineral Services Inc. for thin

sectioning to 30 μm and polishing. The remaining cross-sectional slices were prepared for

elemental analysis. The outer tissue layer from colonies A5m and M85m was removed

using forceps. Since colony M105m was dried, tissue was not removed from the basal

cross-sectional slice. The cut surface of each cross-sectional slice was then smoothed

using sandpaper attached to a Dremel drill. Loose skeletal material was removed with

pressurized air. Using 18 mΩ Milli-Q water, each cross-sectional skeletal slice was rinsed

three times, cleaned in an ultrasonic bath for three ten-minute periods, rinsed one

additional time, and dried overnight at 40ºC. A radial track for sub-sampling was selected to optimize both the clearest banding patterns and the maximal radial distance across the cross-sectional slice.

Skeletal imaging

Thin sections from the Antipathes colony A5m and the Muricella colony M85m were viewed under light microscope and photographed with an attached Nikon D80

Digital single-lens reflex camera with 10.2 Megapixel image size and 7.5 times optical zoom. The thin sections were also viewed and photographed using a Quanta200 Scanning

Electron Microscope under high vacuum with a secondary electron detector in the

Campus Electron Optics Facility at the Ohio State University (OSU). Photos of each thin section were spliced together using Adobe Photoshop CS2 software to create a single

mosaic image for both of the colonies.

120 Solution ICP-MS

To account for potential variation in trace element concentrations across growth

rings within a basal cross-sectional slice multiple skeletal samples were collected across a

radial transect, analyzed by ICP-MS, and averaged to generate a representative

concentration of each element for each colony. To do this, a radial transect across the

basal cross-sectional slice of each colony was sampled at high-resolution by milling at

0.1 mm increments using a high-precision, computer-driven Merchantek microdrill attached to an x, y, z controlled stage. The depth (~5 mm) and length (which varied along

the transect from 0.5 cm to 1 cm) of the drilling path were set to minimize aliasing across

time. Ten samples from the Antipathes colony A5m, five samples from the Muricella colony M85m, and seven samples from the Muricella colony M105m were selected for solution ICP-MS analysis. These samples were all selected from the 1966-2006 period of each colony (see Ch3 for details of the chronologies of each colony).

Approximately 0.5 mg of each skeletal sample was dissolved into 0.1 mL of double-distilled HNO3 in an ultrasonic bath heated to 40ºC for six hours at which point the skeletal material was fully dissolved. Dissolved samples were spiked with 45Sc, 103Rh, and 81Tl as internal standards, and the resulting solution was diluted to 1 mL with 18 mΩ

Milli-Q water. A stock standard solution was made from single element standards and

used to make five calibration standards spanning the expected range of element

concentrations in the coral skeletons. All solutions were made in a Class 100 laminar

flow hood. Two method blanks were collected by opening vials in the lab while at the

microdrill station, capping them and then treated them the same as samples. These

121 method blanks tested for laboratory contamination and the measured values were

subtracted from the sample’s values.

All solution ICP-MS analyses were made on a Perkin-Elmer Sciex ELAN 6000

ICP-MS in the Trace Element Research Laboratory at OSU. 79Br, 81Br, and 127I were

measured in analog mode. 206Pb, 207Pb, and 208Pb, 55Mn, 111Cd, 113Cd, 114Cd, 66Zn, 68Zn, and 11B were measured in pulse mode. Calibration curves using the five stock solutions

- were created at the start, middle, and end of the analyses. HNO3 blanks (n=9) and external check standards (n=9) were run every 3 to 5 samples. Precision of the check standards as indicated by the relative standard deviations (RSD) for each element varied by element and was <5% for Pb, Mn, Cd, and Zn, around 15% for Br and B, and was

140% for I (Table 4.1). Accuracy was better than 1% for Pb, Mn, Cd, and Zn as determined by comparing the measured check standard value with the nominal value of the stock solution. Accuracy was poor for Br and I (Table 4.1). Internal standards 45Sc,

103Rh, and 81Tl accounted for instrumental drift over the duration of the analyses.

LA-ICP-MS

The isotopes 79Br, 81Br, 127I, 208Pb, 55Mn, 114Cd, 64Zn, 11B, and 13C were measured

across the radius of the cross-sectional basal skeletal slice of each coral colony by LA-

ICP-MS in the Trace Element Research Laboratory at OSU. Each skeletal slice was

mounted into an ablation cell with a motorized stage and scanned beneath a 193 nm ArF

excimer laser with homogenizing beam (New Wave UP-193-HE) (Table 4.2). Three

radial transects were selected from the center of the slice to the outer edge. At the sample

surface, the laser beam had a 50μm spot diameter. The laser was pulsed at 10 Hz and

122 ~0.5 mJ cm-2. Ablated material was carried to the plasma of a ThermoFinnigan Element 2

Inductively Coupled Plasma Sector Field Mass Spectrometer (ICP-SFMS) with fast

magnet scan and high abundant sensitivity options via a continuous 0.8 L min-1 He

stream that was mixed with 1.0 L min-1 Ar after the ablation cell. Plasma power was

~1150 watts. Measurements were preceded and succeeded by ~20 s of background acquisitions. The ICP-SFMS was operated in medium mass spectral resolution (R=300).

Each section was scanned at a rate of ~10 μm/s. Autolock mass was used to minimize mass drift.

Each radial transect was scanned six times. The first scan was considered a cleaning scan and the resulting data were discarded. Instrument drift as determined from measurements of background before and after each transect was less than <10% for all scans. Drift in relative sensitivities was below 15% except for Br in all the colonies and I in the Antipathes colony A5m. This resulted from slow washout times of these elements.

Since suitable external standards have not been established for organic coral skeleton, isotopes in the synthetic glass standard reference material NIST 612 and the calcium carbonate standard MACS-1 were measured. The external standards were mounted in the ablation cell along with the Antipathes colony A5m skeletal slice. Due to the size of the basal slices for the Muricella colonies M85m and M105, the external standards were mounted into the ablation cell separate from the skeletal slice, and were analyzed before and after each radial transect.

Data Analysis

Elemental concentrations determined by solution ICP-MS were automatically

123 scaled by the instrument software to account for the natural abundance of the specific

isotope measured. For elements in which multiple isotopes were measured, i.e., Br, Pb,

Cd, and Zn, concentrations were determined by averaging the values from each of the

isotopes measured for that element. A fully factorial model III ANOVA was used to test

for differences between colonies for each element measured. The ANOVA was generated using SAS software, Version 8.02 of the SAS System for Windows. [Copyright C 1999-

2001 SAS Institute Inc. SAS and all other SAS Institute Inc. products and service names are registered trademarks or trademarks of SAS Institute Ind., Cary, NC, USA.]. All averages are reported ± 1 standard error (SE). p-levels ≤ 0.05 were considered significant.

LA-ICP-MS data for each element were converted to an ASCII file using the instrument software and then imported into an Excel spreadsheet. The cross-sectional slices for the Muricella colonies M85m and M105m had visible skeletal cracks parallel to some growth bands. The location of cracks were noted during the ablation scans and data from these locations were subsequently removed from the laser ablation data so that the resulting dataset only included measurements of background before and after the sample, and of the sample itself. Data were smoothed using a four point moving average to reduce the effect of peak hopping during analysis on the resulting data. An average of the background signal obtained before each standard and sample measurement was subtracted from the signals for each standard and sample. The resulting smoothed and background-corrected data for each element were then normalized to 13C and multiplied

by 1000. 13C was used in this study as an internal standard to account for variability in the amount of material ablated by the laser. 13C was chosen because the carbon content of

black corals was presumed to be constant throughout the skeleton, and because 13C has

124 been successfully used as an internal standard in other studies of materials comprised of organic matter [Rege et al., 2005].

The “cleaning” scan for each transect was discarded and the subsequent five scans were averaged together to yield one record per radial transect. For each specimen, three radial transects were generated so that the intra-colony variability could be assessed.

Linear correlation analysis examined the relationship between the three radial transects in each colony for each element using SAS software. Since suitable standards were not present that matrix-match the skeleton of soft corals and black corals, calibration of the

LA-ICP-MS data to determine the skeletal concentration was not feasible. Therefore only intensity profiles are presented for each element. The 14C-derived growth chronology developed in Chapter 3 of this dissertation was applied to the intensity profiles for each element of each colony. Best fit quadratic curves were fit to intensity profiles that were reproducible within a colony and that significantly varied over the lifespan of a colony. In

addition, the same intensity profiles were also interpolated to produce evenly-spaced

annual values using the Timer program from the Arand Software package (courtesy of

Philip Howell, Brown University, ftp://pixie.geo.brown.edu/pub).The spectral energy was evaluated on the interpolated datasets with the mean value subtracted using the Spectral program from the Arand Software package.

RESULTS

Coral imaging

Growth banding was observable in the cross-sectional slices of all colonies by visual inspection and in photographs of the Antipathes colony A5m (Fig 4.1A) and the

125 Muricella colony M85m (Fig. 4.1B). Banding in the Antipathes colony A5m was best viewed using SEM while banding in the Muricella colony M85m was best viewed under light microscope. Preparation of the thin sections caused visible cracks between the skeletal growth bands that were tens of microns wide in A5m and millimeters wide in

M85m (Fig. 4.1). Clarity of skeleton bands varied greatly in both colonies. In the

Antipathes colony A5m, bands were clearly delineated at the center of the basal cross- sectional slice, could be easily counted, and were generally brighter than bands in the rest of the slice. Bands were darker and less clear in the middle part of the skeleton between the center and the outer edge of the basal slice, and the delineation of bands in this region was subjective. Bands toward the outer edge of the basal slice were also brighter, similar to the center of the slice, although bands were not always easily viewed or counted (Fig.

4.1A). Radial growth was approximately symmetrical in this colony, with the largest source of variation resulting from skeletal cracks. In the Muricella colony M85m, clear banding patterns were visible in some areas of the basal slice with band widths ranging from tens of microns to greater than one mm. In some regions of the skeleton delineation between bands was subjective and a single band could not be clearly followed around hte circumference of the slice (Fig. 4.1B). Radial growth was asymmetrical in this colony resulting in an oblong shape.

Coral solution ICP-MS measurements

Overall, Br and I concentrations were highest while the minor elements Pb and

Mn were lowest (Fig. 4.2A-D) in all of the colonies. The skeletal I concentration was an order of magnitude higher in the Antipathes colony A5m than in the two Muricella

126 colonies (Fig. 4.2B). Skeletal Br and Pb concentrations increased with depth, such that

both elements differed significantly between the shallowest (A5m) and deepest (M105m)

colonies (Fig 4.2A, C). Although not statistically significant, skeletal Mn concentrations

decreased with depth (Fig. 4.3D). Skeletal Cd and Zn concentrations increased with depth

such that [Cd] was significantly higher in the both of the Muricella colonies M85m and

M105m than in the shallow Antipathes colony A5m (Fig. 4.2E), and skeletal Zn

concentrations were an order of magnitude higher in the colony M105m than the other

two colonies (Fig. 4.2F). Finally, [B] in the Muricella colony M85m was less than half as

abundant as in the other two colonies (Fig. 4.2G).

Coral laser ablation ICP-MS measurements

The intensities of the five replicate scans within each radial transect were highly

reproducible in all three transects within each colony (Fig. 4.3). Therefore, in each colony

the 5 replicate scans of each transect were averaged to produce three approximately

parallel radial transect profiles per colony.

Within the Antipathes colony A5m, the three radial transects were significantly

correlated with each other for all elements (Pearson correlation coefficients of r =0.46 to r

=0.98, p <0.0001), confirming that they were very reproducible within the coral (Fig 4.4).

Overall, the following patterns were observed: 1- 79Br/13C intensities increased from the

1990’s to the mid-2000’s (Fig. 4.4A), 2- 127I/13C, 208Pb/13C, and 114Cd/13C intensities were greatly elevated in the 1960’s portion of the record (Fig. 4.4B, C, E), 3- large peak in intensities of short duration in ~1983 was observed in a single transect for each of

55Mn/13C, 114Cd/13C, and 64Zn/13C (Fig. 4.4D-F), and 4- 11B/13C intensities varied on

127 decadal-scales over the lifespan of the coral (Fig. 4.4G). Therefore, only the 11B/13C

intensities were fit with a best fit curve and evaluated for spectral energy, which revealed

no significant spectrum.

The intensities of three radial transects in the Muricella colonies M85m and

M105m were not always reproducible (Fig.4.5, 4.6) and transects for many elements were not statistically correlated. In the Muricella colony M85m, large negative anomalies in 79Br/13C, 208Pb/13C, 114Cd/13C, and 11B/13C intensities were observed in one of the three

transects in the 1970’s (Fig 4.5A, C, E, G). In two of the three transects, large positive departures of short duration in 127I/13C and 55Mn/13C intensities were present in the early

1990’s (Fig. 4.5B, D). In general, a gradual increase in 208Pb/13C was observed from the

1940’s to the present (Fig. 4.5C) while 55Mn/13C, 64Zn/13C, and 11B/13C intensities all

increased in the youngest portion of the record (Fig. 4.5D, F, G). In the Muricella colony

M105m, 127I/13C and 55Mn/13C intensities were anomalously high in the mid-1950’s and

from 2000 to the end of the record (Fig. 4.6B, D). In addition, 208Pb/13C, 114Cd/13C, and

64Zn/13C intensities were also anomalously high in the mid-1950’s (Fig. 4.6C, E, F).

Large fluctuations in 208Pb/13C and 114Cd/13C intensities started in the mid-1950’s and slowly decreased in intensity until the 1990’s (Fig. 4.6C, E) while 11B/13C intensities

doubled in magnitude in the last five years of the record (Fig. 4.6G).

DISCUSSION

The source of trace elements and their method of incorporation into the skeletons

of soft corals and black corals are unknown. The major elements carbon and nitrogen are

obtained heterotrophically from ambient suspended particulate organic matter (POM) in

128 colonies within the euphotic zone from the western tropical Pacific [Williams & Grottoli,

submitted], and this is likely the primarily source of trace elements to these corals as

well. However, trace element measurements of suspended POM through the euphotic

zone in the western tropical Pacific are rare. POM elemental composition largely depends

on the elemental concentrations in the plankton and/or elemental adsorption onto POM –

both of which occur partly as a function of the concentrations of each element in seawater

[Boyle et al., 1976; Fisher et al., 1987; Hardstedt-Romeo, 1982]. Therefore, if the

concentrations of trace elements in POM reflect those of seawater, and if the corals

incorporate trace elements directly from POM, then the concentrations of trace elements

in the organic skeleton should reflect those of seawater. As a first order approach, the

trace element concentrations in the coral skeletons collected at various depths were

compared to known changes in the concentrations of thosese trace elements in seawater

with depth.

Of the three corals analyzed here, the Antipathes coral A5m was collected from

within the mixed layer while the two Muricella corals M85m and M105m were collected

from depths that primarily sit below the mixed layer in the western tropical Pacific

[Colin, 2001]. Therefore differences in the average elemental concentrations of the

Antipathes coral and the Muricella corals could reflect either order-specific variability in

skeletal geochemistry, offsets in concentration related to changes in seawater

concentrations with depth and/or differences in source water above and below the mixed

layer. Differences between the Muricella colonies from M85m and M105m could reflect either colony-specific variability or changes in the concentration in an element in

seawater with depth in the water column. In addition, changes in element concentrations

129 within a single colony over time (i.e., across a radial transect) could reflect either variability in the biology of the coral colony itself or variability in response to ambient environmental conditions.

Solution ICP-MS element concentrations

The high halogen contents (Br and I) measured here (Fig. 4.2A, B) are consistent with the results of previous studies on soft corals and black corals using analytical methods other than ICP-MS [Cook, 1904; Goldberg, 1978; Goldberg et al., 1994; Nowak et al., 2008; Roche, 1952; Sugimoto, 1928]. However, Goldberg [1978] reported similar concentrations of I and Br in soft corals while our data show that [Br] are higher than [I] in the Muricella colonies (Fig. 4.2A, B). In addition, the [Br] increases with depth in these colonies although seawater [Br] does not change with depth [Morris and Riley,

1966]. Therefore, although high [Br] and [I] are characteristic these corals, concentrations of these halogens could be also order-specific (i.e., I, Fig. 4.2B) and colony-specific (i.e.,

Br, Fig. 4.2A).

Order-specific variability does not drive skeletal [Pb] since it varies significantly between all three colonies (Fig. 4.2C). Therefore skeletal [Pb] could reflect either colony- specific variability or ambient concentrations of Pb in seawater. Low [Pb] in the

Antipathes colony A5m and high [Pb] in the deepest Muricella colony M105m (Fig 4.2C) is not consistent with higher [Pb] in surface water supplied by atmospheric input.

However, subsurface maxima in [Pb] are present at several hundreds of meters deep in the central Pacific [Flegal and Patterson, 1983], and could explain the increasing skeletal

[Pb] with depth. Lower skeletal [Cd] in the Antipathes colony A5m compared to the two

130 deeper Muricella corals M85m and M105m (Fig. 4.2E) could also be an order-specific

effect or a depth effect. Ambient [Cd] in seawater is depleted at the surface due to

biological activity [Xu et al., 2008], while the remineralisation of sinking organic

material increases [Cd] at depth [Boyle et al., 1976], so a depth effect is likely. Similarly,

high skeletal [Mn] in the Antipathes colony A5m and low [Mn] in the deepest Muricella

colony M105m is consistent with higher [Mn] in surface waters, supplied by atmospheric

dust deposition (Fig. 4.2D) [Klinkhammer and Bender, 1980]. Therefore, while colony-

specific and order-specific effects cannot be ruled out for [Pb] and [Cd], respectively, increasing concentrations of Pb and Cd, and decreasing [Mn] with depth appear to reflect ambient concentrations in seawater.

Order-specific variability does not drive skeletal [Zn] and [B], as concentrations of these elements significantly differ in one Muricella colony relative to the other

Muricella colony and the Antipathes colony (Fig. 4.2F, G). For Zn, significantly higher concentrations in the deepest Muricella colony M105m could reflect ambient seawater concentrations as [Zn] is higher at mid-depths than in near-surface waters [Bruland,

1980]. This is unlikely, however, since the two Muricella colonies are only separated by

20 m in depth. For B, significantly lower concentrations in the Muricella colony M85m are not consistent with known changes in [B] in seawater with depth. Therefore, higher

[Zn] in the Muricella colony M105m and lower [B] in the Muricella colony M85m here are likely to be colony-specific responses.

Laser ablation ICP-MS radial profiles of element intensities

In the Antipathes colony A5m, lower laser ablation-derived 79Br/13C intensities

131 and higher 127I/13C intensities in the oldest part of the skeleton (Fig. 4.4A, B) are

consistent with higher [I] and lower [Br] in the older parts of an Antipathes skeleton

reported by Goldberg [1978]. This agreement, in addition to the high degree of

reproducibility of the radial transects in the Antipathes colony for all elements measured

(Fig. 4.4), supports the interpretation that measured LA-ICP-MS intensities vary in

response to skeletal elemental concentrations in black corals. Therefore extracting

reliable trace element records from the skeleton of Antipathes corals should be feasible;

so that the LA-ICP-MS data for the Antipathes colony A5m is discussed further. In contrast to the Antipathes colony, no changes in intensities of either 79Br/13C or 127I/13C

were measured by laser ablation in the Muricella colonies (Fig 4.5A, B; 4.6A, B). This,

in addition to the low degree of reproducibility of the radial transects in the Muricella

colonies for nearly all of the elements measured (Fig. 4.5; 4.6) suggests that it is not

possible to extract reliable paleoceanographic records from the skeleton of Muricella

corals by LA-ICP-MS at this time.

In black corals, higher concentrations of I are associated with gluing regions

between cells in the skeleton [Nowak et al., 2008]. Thus, the high I concentrations in the

oldest parts of the skeleton (Fig. 4.4B; Goldberg [1978]) indicate elevated percentage of

gluing regions related to the early stages of growth. The similarities in the intensity

profiles of 208Pb/13C, 55Mn/13C, and 114Cd/13C with 127I/13C indicate that these elements

may also be concentrated in the gluing zones in the early part of the record (Fig. 4.4A, C-

E). Therefore, the distribution of many elements in the skeleton may reflect skeletal morphology and not be related to changes in ambient concentrations or environmental conditions at all. This interpretation contrasts with the interpretation of the solution ICP-

132 MS measurements, where [Pb], [Mn], and [Cd] vary between the colonies in a manner

consistent with ambient concentrations of the elements. Together, these data suggests that

ambient environmental concentrations may determine the average concentrations of these

elements in a colony while biology may drive compositioal variability within that colony

over time.

Nowark et al. [2008] also report high [Zn] in the gluing zones. This is not

supported here where 64Zn/13C intensities were not elevated in the oldest portion of the

record (Fig. 4.4E). Thus, either skeletal [Zn] varies with black coral taxa or

concentrations in the skeleton are environmentally-driven. Since solution ICP-MS

measurements suggested that [Zn] were colony-specific, this supports either colony-

specific or taxa-specific effects. However, if environmental concentrations drive

variability in Zn within a colony over time, then the Zn record here suggests that little

change in the aerial deposition of Zn has occurred over the past several decades.

11B/13C intensities fluctuated dramatically on interannual to decadal timescales

throughout the Antipathes record (Fig 4.4G) making it the most promising possibility for

trace element reconstructions of all of the elements in this study. On a large scale, [B] in

seawater varies directly with salinity [Barth, 1998]. If skeletal 11B/13C intensities reflect

[B] in the seawater, then skeletal 11B/13C should fluctuate in response to changes in the

ambient seawater salinity. Salinity in the western Pacific warm pool varies predominantly

on ENSO timescales [Delcroix et al., 1996]. However, surface seawater salinities reconstructed by Iijima et al. [2005] from 1993 to 1998 in a nearby lagoonal scleratinian coral were not correlated with 11B/13C intensities from the Antipathes colony A5m (Fig.

133 4.7). Although lagoonal and open ocean salinities may not be directly comparable, this

does suggest that salinity likely does not drive the large-scale variability in the record.

Interestingly, the best fit quadratic curve of the 11B/13C intensities highly

correlates with the best fit quadratic curve of the δ15N record from the same Antipathes coral A5m as presented in Chapter 3 of this dissertation (r=0.999, p<0.0001) (Fig. 4.7).

This suggests a common cause of the long-term trends in both the 11B/13C and δ15N

records. Although variability in these records cannot currently be explained by known

changes in local or regional environmental conditions, the relationship between these

records and absence of a relationship with other skeletal measurements (i.e. δ13C, and

trace elements measured here) suggests additional changes in environmental conditions

may drive 11B/13C variability.

Implications for LA-ICP-MS paleoceanographic reconstructions

Symmetrical growth and high reproducibility among radial transects in the

Antipathes colony indicate that these corals are well suited for high resolution trace

element paleoceanographic reconstructions by LA-ICP-MS. Asymmetrical growth bands and high skeletal heterogeneity in the Muricella colonies are a limiting factor in developing LA-ICP-MS proxies from the skeleton of this genus. Average solution ICP-

MS derived concentrations for Pb, Mn, and Cd across the three colonies were consistent with known changes in the concentration of these elements in seawater with depth.

However, these same elements measured by LA-ICP-MS vary across a radial profile in the Antipathes colony in a manner similar to I, which is known to vary in response to skeletal morphology in these corals. In addition, 11B/13C intensities in the A5m

134 Antipathes colony varied on interannual and decadal timescales possibly in conjunction

with salinity of ambient water masses, although this is not supported by reconstructed salinity measurements from a nearby lagoonal scleractinian coral. Therefore, although difficulties in interpreting data are present, this work supports development of proxy records using high resolution trace element measurements by ICP-MS.

Acknowledgements. We thank P. Colin and L. Colin at the Coral Reef Research

Foundation for collecting colonies M85m and M105m, and assistance with collecting colony A5m. J. Olesik and A. Lutton from the Trace Element Research Lab, C. Begg from the Campus Electron Optics Facility and C. Millan provided laboratory support. S.

Levas, R. Moyer, and B. Thibodeau offered insightful comments on this research. B.

Williams was supported by an NSERC postgraduate scholarship and received additional funding from PADI Foundation, the Geological Society of America, Friends of Orton

Hall, and American Women in Science. Laboratory analyses were funded by National

Science Foundation Chemical Oceanography (0610487 and 0426022), National Science

Foundation Biological Oceanography (0542415) to A.G.Grottoli.

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137 Shen, G., and C. Sanford. 1990. Trace element indicators of climate variability in reef- building corals. Elsevier Oceanography Series 52(5): 255-283. Sherwood, O., J.M. Heikoop, D.J. Sinclair, D.B. Scott, M.J. Risk, and C.K. Shearer. 2005a. Skeletal Mg/Ca in Primnoa resedaeformis: relationship to temperature? In Cold Water Corals and Ecosystems, edited by A. Freiwald and M. Roberts, Springer Verlag, Berlin Heidelberg. Sherwood, O., D. Scott, M. Risk, and T. Guilderson. 2005b. Radiocarbon evidence for annual growth rings in a deep sea octocoral (Primnoa resedaeformis). Marine Ecology Progress Series 301: 129-134. Sherwood, O. and Risk, M., 2007. Deep-Sea Corals: New insights to paleoceanography, In: Late Cenozoic Paleoceanography (eds. C. Hillaire-Marcel and A. de Vernal), Elsevier, 1: 491-517. Sinclair, D., D.J. Sinclair, O.A. Sherwood, M.J. Risk, C. Hillaire-Marcel, M. Tubrett, P. Sylvester, M. McCulloch, and L. Kinsley. 2005. Testing the reproducibility of Mg/Ca profiles in the deep-water coral Primnoa resedaeformis: putting the proxy through its paces. In Cold-water Corals and Ecosystems, edited by A. Freiwald and J. Roberts, Springer-Verlag, Berlin Heidelberg, p. 1039-1060. Smith, S., R.W. Buddemeier, R.C. Redalje, and J.E. Houck. 1979. Strontium-calcium thermometry in coral skeletons. Science 204(4391): 404-407. Sugimoto, K. 1928. Iodine in gorgonian corals. The Journal of Biological Chemistry 76(3): 723-728. Tudhope, A., D.W. Lea, G.B. Shimmield, C.P. Chilcott, T.P. Scoffin, A.E. Fallick, and M. Jebb. 1997. Climate records from massive Porites corals in Papua New Guinea: a comparison of skeletal Ba/Ca, skeletal δ18O and coastal rainfall. Proceedings of the 8th International Coral Reef Symposium 2: 1719-1724. Weinbauer, M.G. and B. Vellmirov. 1995. Calcium, magnesium and strontium concentrations in the calcite sclerites of Meditteranean gorgonians (Coelenterata: Octocorallia). Estuarine, Coastal and Shelf Science 40: 87-104. Williams, B., M.J. Risk, S.W. Ross, and K.J. Sulak. 2007. Stable isotope records from deep-water Antipatharians: 400-year records from the south-eastern coast of the United States of America. Bulletin of Marine Science 81(3): 437-447. Xu, Y., L. Feng, P. Jeffrey, Y. Shi, and F.M. Morel. 2008. Structure and metal exchange in the cadmium carbonic anhydrase of marine . Nature 452: 56-61. Yoshikawa, C., Y. Yamanaka, and T. Nakatsuka. 2006. Nitrate-Nitrogen Isotopic Patterns in Surface Waters of the Western and Central Equatorial Pacific. Journal of Oceanography 62: 511-525. Zhang, R.-H., A.J. Busalacchi, and Y. Xue. 2007. Decadal change in the relationship between the oceanic entrainment temperature and thermocline depth in the far western tropical Pacific. Geophysical Research Letters 34: L23612, doi:23610.21029/22007GL032119.

138 TABLES

Element Known Measured ±SE RSD Detection Method (Isotope) value value Limits Blank B (11) Pulse 0.6 0.76 0.04 16 0.09 0.53 Mn (55) Pulse 0.6 0.60 0.01 2.80 0.12 0.12 Zn (66, 68) Pulse 12.0 11.90 0.15 3.91 0.30 1.92 Br (79, 81) Analog 13333 9801 461 14 7046 1379 Cd (111, 112, Pulse 0.2 0.20 0.00 3.97 0.39 0.00 114) I (127) Analog 100 568 272 144 9829 662 Pb (206, 207, Pulse 0.3 0.31 0.01 5.66 0.02 0.06 208)

Table 4.1. Elements analyzed by solution ICP-MS. Detection limits (DL) are calculated as 3 times the standard deviation of the instrument response to HNO3. Method blanks of HNO3 were subtracted from coral samples. Data are presented in parts per million (ppm).

139

Parameter Setting Laser New Wave UP 193-HE laser system with homogenized beam Pulse energy ~0.5 mJ Repetition rate 10 Hz Spot diameter at sample 50 μm surface Scan rate 10 μm s-1 Center gas 0.8 L min-1 through ablation cell mixed with 1 L min Ar before injection into center of plasma Plasma power 1150 Watts ICP-MS Thermofinnigan Element 2 Isotopes 11B, 13C, 55Mn, 64Zn, 79Br, 114Cd, 127I, and 208Pb Resolution 300

Table 4.2. LA-ICP-MS instrument operating parameters.

140 FIGURES

Figure 4.1. Photographs showing concentric growth bands in: (A) the Antipathes colony A5m viewed under scanning electron microscope and (B) the Muricella colony M85m viewed under light microscope. 141 A 36000 ^ 30000 *^

24000 *

[Br] (ppm) [Br] 18000

12000 300000 B A5m* M85m M105m 225000

150000 [I] (ppm) [I] 75000

0.8 0 C 0.6 ^

0.4 *

[Pb] (ppm) [Pb] 0.2

0.0 1.0 D 0.8

0.6

0.4 [Mn] (ppm) [Mn] 0.2 12 E A5m M85m M105m 9

6

[Cd] (ppb) 3 * 0 600 F * 450

300

150 (ppm) [Zn]

60 0 G 50 40 30 * [B] (ppm) [B] 20 10 A5m M85m M105m

Figure 4.2. Average concentration of the elements: A) Br, B) I, C) Pb, D) Mn, E) Cd, F) Zn, and G) B for the Antipathes colony A5m (n=10), the Muricella colony M85m (n=5), and the Muricella colony M105 (n=7).All averages are ± 1 standard error. Colony averages with similar symbols (*, †) do not significantly differ from each other.

142 50 A

40

30 C 13 B/ 11 20

10

0 1970 1980 1990 2000 2010 Year 14 B

12

10

C 8 13 Cd/ 6 114

4

2

0 1900 1920 1940 1960 1980 2000

Year

Figure 4.3. Examples of the high reproducibility of the five replicate scans for one radial transect. A) 11B/13C in the Antipathes colony A5m. B) 114Cd/13C in the Muricella colony M85m. All radial scans were smoothed with a 4-point running mean, blank-corrected, normalized to 13C, and multiplied by 1000. 143

Figure 4.4. Three radial transects in the Antipathes colony A5m for the isotopes: A) 79Br/13C, B) 127I/13C, C) 208Pb/13C, D) 55Mn/13C, E) 114Cd/13C, F) 64Zn/13C, and G) 11B/13C. Each isotope was smoothed with a 4-point running mean, blank-corrected, normalized to 13C, and multiplied by 1000. Each radial transect is the average of five replicate scans. 144

Figure 4.5. Three radial transects in the Muricella colony M85m for the isotopes: A) 79Br/13C, B) 127I/13C, C) 208Pb/13C, D) 55Mn/13C, E) 114Cd/13C, F) 64Zn/13C, and G) 11B/13C. Each isotope was smoothed with a 4-point running mean, blank-corrected, normalized to 13C, and multiplied by 1000. Each radial transect is the average of five replicate scans. 145

Figure 4.6. Three radial transects in the Muricella colony M105m for the isotopes: A) 79Br/13C, B) 127I/13C, C) 208Pb/13C, D) 55Mn/13C, E) 114Cd/13C, F) 64Zn/13C, and G) 11B/13C. Each isotope was smoothed with a 4-point running mean, blank-corrected, normalized to 13C, and multiplied by 1000. Each radial transect is the average of five replicate scans. 146

7.5 34.0 δ15N 11B/13C 40 SSS 33.5 7.0

33.0 30 C 13 6.5 32.5 B/ N (‰, air) 11 15

δ 20 32.0 Estimated SSS 6.0

31.5 10

5.5 31.0 1960 1970 1980 1990 2000 2010 Year

Figure 4.7. High-resolution δ15N values, 11B/13C intensities in the A5m Antipathes colony, and estimated sea surface salinities (SSS) reconstructed from a scleractinian coral. δ15N values were measured at 0.2 mm increments across a radial transect and interpolated to annual values (from Ch3). 11B/13C intensities were smoothed with a 4- point running mean, blank corrected 11B intensities normalized to 13C and multiplied by 1000. Monthly SSS data from Iijima et al. [2005] and Wu and Grottoli [Submitted].

147

CHAPTER 5

SUMMARY

The goals of this dissertation research were to: 1) examine natural variability in δ13C and

δ15N values of soft corals and black corals among multiple taxa collected across a depth range from Palau, in the western tropical Pacific, 2) use δ13C and δ15N values to track variability in ambient particulate organic matter bathing the coral colonies across a 105 m depth transect, and 3) evaluate the use of minor and trace element measurements of the organic skeleton to develop proxy records. The major findings of this dissertation were:

(1) δ13C values differed between black corals and soft corals, and δ13C values and δ15N

values varied with water depth. Thus, a +1.5‰ correction should be applied to black

coral δ13C values when comparing δ13C-based proxy records from shallow-water

black corals to soft corals. Similarly, a +0.25 ‰/10 m correction needs to be applied

to δ13C records and -0.15 ‰/10 m correction needs to be applied to δ15N records to

compare records from multiple depths within the euphotic zone.

148 (2) The δ13C values recorded over time by the one Antipathes black coral and two

Muricella soft coral decreased at rates consistent with the oceanic 13C-Suess effect.

This supports the hypothesis that anthropogenic carbon was a primary control on the

δ13C composition of suspended particulate organic matter throughout the upper 105 m

of the water column. Very different δ15N records were derived from the shallow

Antipathes colony and the deeper Muricella colonies. Since all three colonies fed on

suspended particulate organic matter in the water column, the dissimilar records

indicated different controls on δ15N values of suspended particulate organic matter

within versus below the mixed layer. Variability in the Antipathes δ15N record from 5

m could reflect changes in the source of nitrogen to the colony resulting from

variability in the strength of the North Equatorial Current versus the North Equatorial

Countercurrent bathing Palau in the top tens of meters of the water column. Gradually

decreasing δ15N values in both Muricella records indicate a shoaling of the mean

nutricline depth, particularly over the past 30 years.

(3) Average Pb, Mn, and Cd concentrations in the one Antipathes and two Muricella

corals varied with depth, consistent with ambient changes in the distribution of these

elements in seawater. Higher I in the Antipathes colony indicated that I

concentrations were taxa-specific, and variability in Br, Zn, and B concentrations

between the colonies indicated that concentrations of these elements were colony-

specific. For closely spaced measurements, reproducibility among parallel radial

transects was high for all the isotopes measured in the Antipathes coral, suggesting

that laser ablation measurements from these corals could be more fully developed for

149 trace element reconstructions. In contrast, measurements made along parallel radial

transects were not reproducible in either of the two Muricella colonies analyzed and

no discernable patterns were detected that could be developed into reliable proxy

records.

Natural variability in organic skeletal δ13C and δ15N values

Most research on black corals and soft corals has focused on deep-water taxa

[Sherwood et al., 2005; Sherwood and Risk, 2007; Williams et al., 2006] and few studies

have evaluated the feasibility of extracting climatically-driven paleoceanographic records

from the organic skeletons of shallow-water taxa. Here, δ13C and δ15N values were

measured in skeleton formed contemporaneously in 65 colonies from multiple taxa and

across the top 85 m of the water column from the western tropical Pacific.

Within a given depth interval, isotope values varied between taxa. Average δ13C

values of black corals were lower than those of soft corals and require a +1.5 ‰

13 13 correction to compare black coral δ C values to soft coral δ C values (accept H1 for

δ13C values, Ch 2). Average δ15N values did not vary between black corals and soft corals

15 13 (reject H1 for δ N values, Ch 2). Low δ C variability in all genera with the exception of

Villogorgia in shallow water, and low δ15N variability among Rhipidipathes, Annella,

Astrogorgia, and Villogorgia indicate that one colony is sufficiently representative of

each genus for δ13C- and δ15N-based paleoceanographic reconstructions.

For all of the colonies, δ13C values decreased and δ15N values increased with

13 water depth (accept H2, Ch 2). This most likely reflects decreases in δ C and increases in

δ15N of the suspended particulate organic matter (POM) upon which these corals feed, as

150 it becomes degraded in the water column with depth (Ch 2). Therefore, stable isotopes in

these corals record the isotopic composition of ambient suspended POM and not

biophysical processes occurring in surface waters and then transported to depth, as is

recorded in deep-water taxa [Roark et al., 2005; Sherwood et al., 2005; Williams et al.,

2007]. In addition, since the isotopic composition of suspended POM changes with

depth, a reliable comparison of stable isotope-based proxy records from corals collected

from a range in depths in the euphotic zone requires a +0.25 ‰/10 m correction to δ13C

records and a -0.15 ‰/10 m correction to δ15N records.

δ13C and δ15N records from three colonies across a depth transect

High-resolution δ13C and δ15N records were generated from one Antipathes black coral collected from 5 m and two Muricella soft corals from 85 m and 105 m (Ch 3). 14C was measured at selected intervals across a radial transect of each colony. The bomb-14C

curve was readily identified (accept H1, Ch 3) and used, in conjunction with the year of collection, to establish the chronology for the δ13C and δ15N records for each colony (Ch

3).

The taxa-specific δ13C offset between the Antipathes black coral and the

Muricella soft corals was opposed by the depth-dependent offset (offset calculations

developed in Ch 2). Thus the δ13C records from all three colonies were similar (Ch 3).

The δ13C records from the Muricella soft corals decreased by 0.14‰ for the 1970’s,

0.20‰ for the 1980’s, 0.26‰ for the 1990’s and a predicted rate of 0.29‰ for the 2000’s

(accept H2, Ch 3). These records indicate that anthropogenic carbon had permeated the water column to below 105 m.

151 After applying the δ15N depth-dependent correction (corrections developed in Ch

2), the δ15N records for all three colonies were similar (Ch 3). The δ15N records from the

Antipathes colony from 5 m and Muricella colony from 85 m were coherent with the SOI on El Niño-Southern Oscillation timescales (accept H3, Ch 3). The source of POM to the

5 m Antipathes colony appears to change with shifts in the dominance of currents within the mixed layer and may drive additional increases and decreases in δ15N values. The

δ15N records from the Muricella colonies at 85 and 105 m both decreased ~1‰ from the late 1970’s through 2000 suggesting a shoaling of the mean nutricline depth in the western tropical Pacific since the Pacific Decadal Oscillation shift in the late 1970’s.

Since productivity in the western tropical Pacific is generally nitrate-limited, a shoaling of the mean nutricline depth will bring more nutrients into the euphotic zone, increasing productivity. A gradual rise in productivity would increase the biological pump, and thus the amount of carbon dioxide removed from the atmosphere, in the western tropical

Pacific.

Solution-derived elemental composition and reproducibility of laser ablation radial profiles

Using the same Antipathes black coral from 5 m and Muricella soft corals from

85 m and 105 m as in Ch 3, the feasibility of developing proxy records from minor and trace element measurements of the organic skeleton was tested. Average skeletal concentrations of the elements Br, I, Pb, Mn, Cd, Zn, and B measured by solution ICP-

MS varied among the Antipathes and the two Muricella corals (accept H1, Ch 4). The skeletal concentrations of Pb, Mn, and Cd varied with depth as expected if driven by

152 ambient seawater concentrations. In contrast, higher I concentrations in the Antipathes

colony than the Muricella colonies indicate that order-specific variability drove I

concentrations, and Br, Zn, and B varied in a manner not consistent with depth or taxa thus displaying colony-specific variability.

High resolution parallel laser transects measured by LA-ICP-MS from the two

Muricella soft corals were not reproducible for any of the elements (reject H2, Ch 4 for

Muricella), and no discernable patterns were present among the records. Thus Muricella

corals cannot be developed into reliable proxy records using the current LA-ICP-MS

method. However, parallel laser transects by LA-ICP-MS were highly reproducible for

all elements measured in the Antipathes black coral (accept H2, Ch 4 for Antipathes). In addition, the 127I/13C intensities increased and the 79Br/13C intensities decreased as

expected with colony age, and the 11B/13C intensities varied in a similar pattern to δ15N, suggesting that 11B/13C may be recording variability in the source of water masses

bathing the colony on interannual to decadal scales. Thus high-resolution LA-ICP-MS

elemental records in black corals could be more fully developed for paleoceanographic

reconstructions.

FUTURE WORK

The research presented here demonstrated that climatically-driven paleoceanographic records can be successfully extracted from shallow-water soft coral and black coral colonies. However continued research would overcome limitations present in the current research.

153 (1) All three skeletal records were sampled at sub-annual resolution. Since banding

patterns were difficult to discern in both Antipathes and Muricella, growth bands

could not be used to further refine the 14C-derived growth chronology. By

constraining growth rates and periodicity of bands, or identifying additional time

points in the skeleton, we could gain confidence in the chronology, and hence the

interpretation of the skeletal records at higher resolution.

(2) The minor and trace element measurements presented here represent the first step in

developing proxy records derived from element concentrations in the organic skeleton

of shallow-water soft corals and black corals. Skeletal heterogeneity makes it difficult

to obtain reliable records from the Muricella colonies. However, the Antipathes

profiles were very reproducible and could provide high resolution proxy records over

hundreds to thousands of years. To accurately interpret these records, calibration of

the ICP-MS data with environmental conditions is needed. Measuring elemental

abundances in corals grown under known conditions could further constrain controls

on skeletal element concentrations. Future research would also include the

development of a suitable standard for laser ablation to permit calibration of the laser

intensities to elemental concentrations.

The research presented here illustrates the use of soft corals and black corals for paleoceanographic reconstructions in the western tropical Pacific. In particular, δ15N records in colonies from below the mixed layer reconstruct nutricline variability in a climatically-sensitive region. Records of nutricline variability throughout the tropical

154 Pacific would greatly enhance our understanding of recent changes in the Pacific Ocean and distinguish climate change-induced variation from natural ENSO and decadal-scale variability.

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173

APPENDIX A

CORAL COLONY STABLE ISOTOPE DATA

174 Family Genera Depth Site δ15N δ13C N C (m) (‰) (‰) [%] [%] Acanthogorgiidae Acanthogorgia 5 SDO 5.60 -17.79 13.55 43.11 Acanthogorgiidae Acanthogorgia 5 SDO 6.00 -17.63 14.25 44.99 Acanthogorgiidae Acanthogorgia 85 SDO 8.65 -18.75 14.89 45.47 Acanthogorgiidae Acanthogorgia 85 Ulong 6.65 -19.21 14.57 46.73 Acanthogorgiidae Acanthogorgia 85 Ulong 7.31 -19.16 14.45 44.92 Acanthogorgiidae Muricella 85 SDO 7.97 -18.72 15.27 43.68 Antipatharidae Antipathes 5 SDO 6.40 -19.05 15.53 45.39 Aphanipathidae Rhipidipathes 25 SDO 6.27 -18.10 18.21 47.12 Aphanipathidae Rhipidipathes 25 SDO 5.83 -19.20 18.48 51.52 Aphanipathidae Rhipidipathes 25 SDO 6.60 -19.18 19.08 51.34 Aphanipathidae Rhipidipathes 25 Ulong 6.72 -18.62 18.87 49.32 Aphanipathidae Rhipidipathes 25 Ulong 6.97 -19.32 18.62 50.56 Aphanipathidae Rhipidipathes 25 Ulong 6.78 -19.06 18.46 50.43 Aphanipathidae Rhipidipathes 25 Ulong 6.83 -17.26 12.81 42.55 Ellisella Ellisella 85 SDO 8.34 -19.02 15.58 46.90 Ellisella Viminella 85 SDO 7.22 -18.99 14.19 45.69 Keroeididae Keroeides 35 SDO 6.29 -17.95 13.46 43.87 Plexauridae Astrogorgia 5 SDO 7.09 -17.07 14.54 43.82 Plexauridae Astrogorgia 5 SDO 7.10 -17.66 16.25 48.58 Plexauridae Astrogorgia 15 SDO 7.40 -17.50 14.57 45.96 Plexauridae Astrogorgia 15 SDO 6.63 -17.53 15.21 46.66 Plexauridae Astrogorgia 15 SDO 6.59 -17.68 13.52 41.47 Plexauridae Astrogorgia 15 SDO 7.15 -17.66 15.37 46.77 Plexauridae Astrogorgia 15 SDO 7.22 -17.58 15.78 49.82 Plexauridae Astrogorgia 15 SDO 6.80 -17.53 14.74 44.94 Plexauridae Astrogorgia 15 SDO 6.75 -17.26 14.85 45.09 Plexauridae Astrogorgia 15 SDO 6.40 -17.34 15.17 46.69 Plexauridae Astrogorgia 15 SDO 6.37 -17.58 14.76 45.37 Plexauridae Astrogorgia 15 SDO 6.55 -17.87 16.34 50.17 Plexauridae Astrogorgia 15 SDO 7.03 -17.77 16.57 52.46 Plexauridae Astrogorgia 25 SDO 6.43 -17.34 13.68 41.63 Plexauridae Astrogorgia 25 SDO 6.13 -17.54 13.63 42.74 Plexauridae Astrogorgia 25 SDO 6.87 -17.63 15.27 47.26 Plexauridae Astrogorgia 25 Ulong 7.11 -17.20 14.23 43.59 Plexauridae Astrogorgia 25 Ulong 7.17 -17.33 12.91 40.65 Plexauridae Astrogorgia 25 Ulong 7.17 -17.05 14.12 43.97 Plexauridae Astrogorgia 25 Ulong 7.08 -16.85 14.37 43.85 Plexauridae Astrogorgia 45 Ulong 7.40 -18.76 15.06 45.37 Plexauridae Bebryce 85 SDO 7.35 -19.49 14.47 43.91 Plexauridae Echinogorgia 85 Ulong 6.60 -18.97 15.54 45.11 Plexauridae Paracis 85 SDO 7.37 -18.72 14.51 45.69 Plexauridae Paracis 85 SDO 7.21 -19.20 14.70 47.18

Table A.1. Colony identification, collection location, nitrogen stable isotope (δ15N), carbon stable isotope (δ13C), percent nitrogen, and percent carbon data discussed in Chapter 2. 175 Table A.1 Continued

Plexauridae Paracis 85 SDO 7.64 -19.82 13.88 45.15 Plexauridae Paracis 85 SDO 7.74 -19.72 13.90 44.80 Plexauridae Villogorgia 25 SDO 7.09 -18.68 13.22 47.13 Plexauridae Villogorgia 25 SDO 7.46 -19.02 12.38 48.38 Plexauridae Villogorgia 35 Ulong 7.15 -17.42 15.10 46.55 Plexauridae Villogorgia 85 SDO 8.19 -19.64 15.18 47.06 Plexauridae Villogorgia 85 Ulong 8.50 -18.94 13.76 43.03 Subergorgiidae Annella 5 SDO 6.19 -17.02 14.67 44.57 Subergorgiidae Annella 25 Ulong 6.88 -17.64 15.54 45.74 Subergorgiidae Annella 35 SDO 6.01 -17.21 14.45 44.36 Subergorgiidae Annella 35 Ulong 7.21 -17.07 15.06 44.76 Subergorgiidae Annella 45 SDO 6.53 -17.55 14.26 42.33

176

APPENDIX B

TEST OF ACID TREATMENT ON STABLE ISOTOPES VALUES

177

Treatment δ15N δ13C Nitrogen Carbon (‰) (‰) [%] [%]

None 8.06 -17.87 16.70 47.70 8.06 -17.90 16.60 47.50 8.05 -17.81 16.60 47.30 8.19 -17.78 16.20 46.60 8.31 -17.71 16.40 47.10 8.19 -17.92 16.30 46.90 7.90 -17.83 16.00 46.20

HCl vapour 8.03 -17.85 14.10 40.80 7.99 -17.84 14.20 41.10 8.26 -17.72 14.20 41.00 8.02 -17.86 13.90 40.10 7.96 -17.89 13.90 39.80 7.95 -17.92 14.00 40.50 8.03 -17.82 13.90 40.20 8.07 -17.97 13.80 39.60

HCl soak 7.90 -17.90 16.80 48.30 8.01 -17.83 16.60 48.30 7.90 -17.76 16.80 48.20 8.26 -17.79 16.10 46.60 7.91 -17.90 16.60 47.60 7.97 -17.80 16.50 47.60 7.84 -17.78 16.30 47.40 7.81 -17.87 16.70 48.30

Table B.1. The effect of treatment on nitrogen stable isotope (δ15N) and carbon stable isotope (δ13C) values was tested. 40 mg of homogenized skeletal material was divided into 23 sub-samples and randomly assigned to a treatment. Seven sub-samples were not treated. Eight sub-samples were bathed in HCl fumes for four days. Eight sub-samples were soaked in a 5% HCl bath until no reaction occurred when acid was refreshed. Although not significant (p = 0.07), δ15N values were lower in the treated sub-samples than the non-treated sub-samples. No significant differences in δ13C values were present among the treatment groups. Percent nitrogen was significantly lower in the HCl vapour- treated sub-samples and percent carbon significantly varied among all the treatments. All differences were tested with a fully factorial model III analysis of variance (ANOVA) using SAS software, Version 8.02 of the SAS System for Windows. [Copyright C 1999- 2001 SAS Institute Inc. SAS and all other SAS Institute Inc. products and service names are registered trademarks or trademarks of SAS Institute Ind., Cary, NC, USA.].

178

APPENDIX C

CORAL TIME SERIES STABLE ISOTOPE DATA

179

Antipathes A5m Muricella M85m Muricella M105m

δ15N δ13C δ15N δ13C δ15N δ13C Year (‰) (‰) Year (‰) (‰) Year (‰) (‰) 2006.00 6.19 -18.81 2006.00 7.67 -19.05 2007.00 8.07 -19.05 2005.45 6.15 -18.83 2005.33 7.64 -18.96 2006.49 8.03 -19.10 2004.90 ------2004.67 7.63 -19.04 2005.98 8.19 -19.03 2004.35 ------2004.00 7.45 -18.92 2005.47 8.01 -18.87 2003.80 5.87 -18.65 2003.33 7.73 -18.78 2004.96 8.25 -18.95 2003.25 6.03 -18.61 2002.67 7.40 -18.86 2004.45 7.84 -18.98 2002.70 6.01 -18.68 2002.00 7.46 -18.80 2003.94 8.01 -18.85 2002.15 6.51 -18.58 2001.33 7.61 -18.45 2003.43 7.97 -18.91 2001.60 6.42 -18.60 2000.67 7.51 -18.53 2002.92 8.03 -18.86 2001.05 6.66 -18.58 2000.00 7.67 -18.44 2002.41 8.29 -18.78 2000.50 6.79 -18.60 1999.33 7.29 -18.45 2001.90 8.08 -18.92 1999.95 6.52 -18.85 1998.67 7.34 -18.60 2001.39 8.37 -18.88 1999.40 6.33 -18.67 1998.00 7.59 -18.61 2000.88 7.97 -18.48 1998.85 6.33 -18.89 1997.33 7.14 -18.69 2000.37 8.05 -18.77 1998.30 6.23 -18.95 1996.67 7.44 -18.65 1999.86 8.22 -18.79 1997.75 6.17 -19.24 1996.00 7.34 -18.50 1999.35 8.27 -18.65 1997.20 5.90 -18.60 1995.33 7.33 -18.47 1998.84 8.01 -18.64 1996.65 6.25 -18.75 1994.67 7.34 -18.48 1998.33 7.87 -18.39 1996.10 6.50 -18.66 1994.00 7.48 -18.34 1997.82 8.06 -18.50 1995.55 6.31 -18.80 1993.33 7.77 -18.19 1997.31 8.04 -18.40 1995.00 6.18 -18.76 1992.67 7.63 -18.16 1996.80 7.81 -18.38 1994.45 6.38 -18.68 1992.00 7.62 -18.16 1996.29 7.87 -18.38 1993.90 6.33 -18.68 1991.33 7.59 -18.16 1995.78 8.02 -18.41 1993.35 6.56 -18.62 1990.67 7.53 -18.18 1995.27 8.02 -18.25 1992.80 6.21 -18.82 1990.00 7.73 -18.14 1994.76 7.88 -18.36 1992.25 6.37 -18.59 1989.33 7.80 -18.06 1994.25 7.84 -18.44 1991.70 6.36 -18.75 1988.67 7.85 -18.02 1993.74 7.84 -18.36 1991.15 6.54 -18.58 1988.00 7.84 -18.07 1993.23 7.48 -18.51 1990.60 6.49 -18.87 1987.33 7.78 -18.15 1992.72 7.59 -18.40 1990.05 6.40 -19.15 1986.67 7.82 -18.08 1992.21 7.76 -18.41 1989.50 6.68 -18.95 1986.00 7.95 -17.94 1991.70 7.87 -18.29 1988.95 6.53 -19.18 1985.33 7.85 -17.94 1991.19 7.88 -18.37 1988.40 6.54 -19.07 1984.67 7.83 -17.90 1990.68 7.88 -18.44 1987.85 6.50 -19.59 1984.00 7.89 -17.94 1990.17 8.37 -18.06 1987.30 6.63 -19.09 1983.33 8.12 -17.96 1989.66 7.97 -18.38 1986.75 6.71 -18.64 1982.67 8.07 -17.96 1989.15 8.10 -18.32 1986.20 6.69 -19.21 1982.00 8.02 -17.96 1988.64 8.22 -18.11 1985.65 6.77 -18.88 1981.33 8.03 -17.94 1988.13 8.18 -18.26 1985.10 6.65 -18.70 1980.67 8.03 -17.93 1987.62 8.06 -18.31 1984.55 6.67 -19.25 1980.00 8.19 -17.87 1987.11 8.27 -18.37

Table C.1. Raw stable isotope (δ13C and δ15N) data for the Antipathes colony A5m and the Muricella colonies M85m and M105m with radiocarbon (14C)- derived growth chronologies presented and discussed in Chapter 3. 180 Table C.1. Continued

1984.00 6.66 -19.25 1979.33 8.24 -17.97 1986.60 8.67 -18.27 1983.45 6.39 -18.71 1978.67 7.99 -17.84 1986.09 8.43 -18.15 1982.90 6.39 -19.00 1978.00 8.03 -17.79 1985.58 8.14 -18.18 1982.35 6.35 -18.76 1977.33 8.02 -17.83 1985.07 8.36 -18.23 1981.80 6.24 -18.53 1976.67 8.07 -17.81 1984.56 8.15 -18.04 1981.25 6.17 -18.18 1976.00 8.01 -17.60 1984.05 8.24 -18.14 1980.70 6.20 -18.21 1975.33 7.77 -17.69 1983.54 8.12 -18.04 1980.15 6.35 -18.12 1974.67 7.98 -17.63 1983.03 8.72 -17.85 1979.60 6.33 -18.31 1974.00 8.03 -17.75 1982.52 8.30 -17.93 1979.05 6.24 -18.28 1973.33 8.02 -17.61 1982.01 8.39 -17.91 1978.50 6.29 -18.14 1972.67 7.82 -17.73 1981.50 8.49 -18.07 1977.95 6.11 -18.16 1972.00 7.93 -17.65 1980.99 8.32 -18.03 1977.40 6.13 -18.30 1971.33 8.01 -17.59 1980.48 8.32 -18.19 1976.85 6.13 -18.20 1970.67 8.24 -17.62 1979.97 8.62 -17.96 1976.30 5.97 -18.15 1970.00 8.02 -17.75 1979.46 8.26 -17.70 1975.75 6.00 -18.11 1969.33 8.16 -17.67 1978.95 8.62 -18.01 1975.20 6.03 -18.10 1968.67 8.18 -17.66 1978.44 8.37 -18.12 1974.65 5.90 -18.05 1968.00 8.30 -17.72 1977.93 8.62 -18.14 1974.10 6.28 -18.42 1967.33 8.26 -17.70 1977.42 8.80 -18.11 1973.55 6.19 -18.84 1966.67 8.27 -17.59 1976.91 8.53 -18.16 1973.00 6.15 -17.96 1966.00 8.20 -17.73 1976.40 8.69 -18.04 1972.45 6.25 -18.35 1965.33 7.94 -17.68 1975.89 8.68 -18.01 1971.90 6.08 -18.17 1964.67 8.09 -17.78 1975.38 8.56 -18.02 1971.35 6.09 -17.90 1964.00 8.36 -17.70 1974.87 8.57 -18.18 1970.80 6.11 -17.88 1963.33 8.04 -17.71 1974.36 8.40 -18.06 1970.25 5.97 -17.98 1962.67 7.81 -17.60 1973.85 8.52 -18.07 1969.70 6.10 -17.92 1962.00 7.85 -17.76 1973.34 8.56 -17.92 1969.15 6.14 -17.92 1961.33 7.94 -17.70 1972.83 8.57 -17.76 1968.60 6.04 -18.04 1960.67 7.95 -17.54 1972.32 8.66 -17.68 1968.05 6.41 -17.85 1960.00 7.77 -17.79 1971.81 8.43 -17.53 1967.50 5.99 -17.94 1959.33 8.05 -17.73 1971.30 8.43 -17.81 1966.95 5.95 -18.67 1958.67 8.11 -17.65 1970.79 8.45 -17.90 1966.40 5.98 -18.06 1958.00 8.05 -17.66 1970.28 8.45 -18.03 1957.33 8.07 -17.73 1969.77 8.62 -17.79 1956.67 7.81 -17.69 1969.26 8.36 -17.90 1956.00 8.20 -17.67 1968.75 8.71 -17.90 1955.33 8.04 -17.67 1968.24 8.46 -17.92 1954.67 8.16 -17.74 1967.73 8.08 -18.27 1954.00 8.14 -17.52 1967.22 8.56 -18.08 1953.33 8.17 -17.80 1966.71 8.41 -18.28 1952.67 8.54 -17.90 1966.20 8.72 -18.22 1952.00 8.40 -17.67 1965.69 8.71 -18.09 1951.33 8.42 -17.73 1965.18 8.56 -17.96 1950.67 8.43 -17.41 1964.67 8.73 -18.18 1950.00 8.40 -17.55 1964.16 8.59 -18.20 1949.33 8.56 -17.45 1963.65 8.35 -18.33 1948.67 8.18 -17.53 1963.14 8.80 -18.29 181 Table C.1 Continued

1948.00 8.19 -17.38 1962.63 8.40 -18.36 1947.33 8.25 -17.36 1962.12 8.61 -18.26 1946.67 8.11 -17.49 1961.61 8.38 -18.17 1946.00 8.12 -17.41 1961.10 8.13 -17.72 1945.33 8.35 -17.42 1960.59 8.09 -18.06 1944.67 8.11 -17.41 1960.08 8.17 -18.26 1944.00 8.30 -17.43 1959.57 8.16 -18.12 1943.33 8.17 -17.39 1959.06 8.33 -18.02 1942.67 8.24 -17.46 1958.55 8.35 -17.95 1942.00 8.11 -17.37 1958.04 8.14 -18.11 1941.33 8.21 -17.32 1957.53 7.99 -18.22 1940.67 8.30 -17.30 1957.02 8.70 -18.20 1940.00 7.97 -17.35 1956.51 8.21 -17.99 1939.33 8.02 -17.23 1956.00 8.49 -18.08 1938.67 8.11 -17.38 1955.49 8.66 -18.08 1938.00 7.95 -17.10 1954.98 8.86 -18.03 1937.33 8.20 -17.38 1954.47 8.61 -17.98 1936.67 8.24 -17.34 1953.96 9.13 -17.92 1936.00 8.21 -17.31 1953.45 8.54 -17.92 1935.33 8.07 -17.46 1952.94 8.46 -17.90 1934.67 7.95 -17.57 1952.43 8.60 -17.82 1934.00 8.23 -17.47 1951.92 8.23 -17.73 1933.33 8.18 -17.76 1951.41 8.32 -17.99 1932.67 8.04 -17.63 1950.90 8.47 -18.12 1932.00 8.16 -17.47 1950.39 8.29 -18.11 1931.33 8.10 -17.89 1949.88 8.64 -18.13 1930.67 7.94 -17.72 1949.37 8.35 -17.99 1930.00 8.07 -17.80 1948.86 8.88 -17.94 1929.33 8.16 -17.87 1948.35 8.72 -17.95 1928.67 8.13 -17.89 1947.84 8.69 -17.93 1928.00 8.03 -17.82 1947.33 8.62 -17.80 1927.33 8.07 -17.95 1946.82 8.51 -17.76 1926.67 8.16 -17.92 1946.31 8.82 -17.75 1926.00 8.06 -17.89 1945.80 8.25 -17.81 1925.33 8.19 -17.76 1945.29 8.30 -17.79 1924.67 8.05 -17.75 1944.78 8.85 -17.87 1924.00 8.37 -17.74 1944.27 8.16 -17.65 1923.33 8.25 -17.80 1922.67 8.31 -17.59 1922.00 8.43 -17.67 1921.33 8.45 -17.65 1920.67 8.44 -17.51 1920.00 8.60 -17.44 1919.33 8.40 -17.25 1918.67 8.65 -17.29 1918.00 8.34 -17.33 1917.33 8.52 -17.26 182 Table C.1 Continued

1916.67 8.24 -17.28 1916.00 8.52 -17.29 1915.33 8.55 -17.25 1914.67 8.34 -17.09 1914.00 8.21 -17.50 1913.33 8.15 -17.15 1912.67 8.54 -17.42 1912.00 8.26 -17.32 1911.33 8.20 -17.12 1910.67 8.35 -17.33 1910.00 8.23 -17.37 1909.33 8.19 -17.44 1908.67 8.38 -17.35 1908.00 8.24 -17.72 1907.33 8.36 -17.37 1906.67 8.43 -17.32 1906.00 8.14 -17.29 1905.33 8.14 -17.13 1904.67 8.20 -17.35 1904.00 8.03 -17.60 1903.33 8.09 -17.35 1902.67 7.94 -17.18 1902.00 8.12 -17.28 1901.33 7.76 -17.08 1900.67 8.05 -17.33 1900.00 8.19 -17.47

183

APPENDIX D

SIX-MONTHLY SMOOTHED CORAL ELEMENTAL TIME SERIES DATA

184 Year Br I Pb Mn Cd Zn B 1965.6 1543.7966 140964.4195 0.9362 6.1717 6.8185 5.0920 12.3020 1966.1 1448.6115 136672.2913 0.8667 5.7485 6.3697 4.6884 11.3897 1966.6 1107.5858 130098.1322 0.9373 5.2219 8.3185 5.8972 9.3143 1967.1 919.1249 132190.2172 0.9093 4.5498 7.8927 6.5873 8.9696 1967.6 801.2585 119670.7831 0.7528 3.7527 4.1806 6.5814 8.8216 1968.1 654.9905 85544.3354 0.5001 2.9096 1.3238 5.2470 7.7948 1968.6 577.7485 63127.4711 0.4333 3.1893 0.4977 5.4743 8.9558 1969.1 639.5176 49989.1126 0.3819 3.3062 0.2992 5.0407 10.7161 1969.6 678.2388 47769.3860 0.3835 3.2694 0.3004 5.4935 12.7521 1970.1 703.4142 38492.9657 0.3445 2.7582 0.1936 5.0576 14.0722 1970.6 635.4178 33391.2518 0.3460 2.0285 0.1908 4.5809 11.0710 1971.1 572.1225 32982.6798 0.3631 1.9028 0.1851 5.0322 9.9551 1971.6 747.5092 37007.1192 0.3973 2.7571 0.1892 6.7194 14.5045 1972.1 1020.1175 30208.6947 0.3019 2.7723 0.1704 5.5848 18.1777 1972.6 1462.5776 20644.1659 0.1967 2.5985 0.1636 4.4669 20.4859 1973.1 2026.4769 18118.0519 0.1798 2.7257 0.1862 4.2262 22.5306 1973.6 2263.6899 19306.7175 0.1997 2.5872 0.1949 4.0018 23.1924 1974.1 2099.5160 19183.3958 0.1768 2.0927 0.1798 3.8032 18.7794 1974.6 2476.7029 18529.6610 0.1852 2.1888 0.1738 4.3378 18.1875 1975.1 2283.0294 20099.1412 0.2108 2.2036 0.1483 4.5893 16.9553 1975.6 1542.1791 20734.2359 0.2219 2.0621 0.1528 4.2122 16.2902 1976.1 1418.1319 19797.3377 0.2439 2.3315 0.1975 4.5029 16.3409 1976.6 1125.3895 22069.2629 0.2459 2.3479 0.1668 4.4857 15.8505 1977.1 959.1191 21656.5125 0.2480 2.1497 0.1484 4.3727 16.7695 1977.6 1273.1938 22500.5749 0.2797 2.0924 0.1608 4.8793 16.8717 1978.1 1837.6435 20210.9031 0.2452 2.0943 0.1806 4.6936 17.1505 1978.6 1884.8205 17682.8898 0.2384 2.1512 0.1105 4.4720 15.3097 1979.1 1293.8182 13746.8081 0.2058 1.9011 0.0719 3.3896 8.8904 1979.5 1101.3365 12999.5583 0.1910 2.3846 0.1353 3.0985 7.9552 1980.0 1609.3182 15543.5178 0.2218 2.2399 0.1198 4.2293 15.5589 1980.5 1994.9914 16923.4652 0.2338 2.1930 0.1255 4.5243 20.0415 1981.0 2049.8447 17766.5053 0.2359 2.1589 0.1255 4.9858 20.5161 1981.5 2618.7910 18311.8123 0.2371 2.2098 0.1526 5.2685 20.3226 1982.0 2600.4692 17910.7322 0.2417 2.6338 0.1460 5.3672 19.7501 1982.5 2288.1280 20910.6447 0.2714 3.9270 0.3843 7.4455 18.2633 1983.0 2053.9550 18780.2107 0.2685 2.1351 0.1233 5.2972 18.0113 1983.5 2096.6852 18805.2860 0.2789 2.2453 0.1222 5.2800 18.9978 1984.0 1632.2723 18050.5268 0.2490 1.9625 0.1296 4.8064 18.0707 1984.5 1871.9306 16539.2841 0.2351 2.0254 0.1446 5.0106 21.2366 1985.0 2250.4157 15841.0622 0.2516 2.6379 0.1581 5.4302 24.2015 1985.5 2405.2712 14579.6239 0.2209 2.8156 0.1158 5.3645 25.8094 1986.0 2763.2460 14522.1476 0.2339 2.7168 0.1168 4.9743 24.1470 1986.5 2749.5398 16530.4613 0.2498 2.6840 0.1547 5.5501 23.4017

Table D.1. LA-ICP-MS elemental data for Antipathes A5m presented and discussed in Chapter 4. For each element, three radial transects were smoothed to six-month intervals and then averaged. Growth chronologies developed in Chapter 3. 185 Table D.1 Continued

1987.0 2538.5855 14663.9717 0.2377 2.4442 0.1696 5.6416 23.1924 1987.5 2541.1217 14059.1442 0.2192 2.3412 0.1423 5.1222 23.1223 1988.0 2366.1264 14165.2197 0.2164 2.3274 0.1554 4.8686 23.8430 1988.5 2187.6660 14570.9763 0.2220 2.3371 0.1879 5.0373 24.2907 1989.0 2334.1512 14711.8699 0.2098 2.2046 0.1591 5.3329 24.1796 1989.5 2362.1295 14590.4458 0.2127 2.1502 0.1592 5.4196 22.8757 1990.0 2362.2974 16087.2035 0.2269 2.0244 0.1909 5.5546 20.9872 1990.5 2041.7990 17481.4091 0.2395 2.3145 0.1793 5.5834 21.5087 1991.0 1873.2657 15099.9442 0.2088 2.1526 0.1556 5.5554 22.6174 1991.5 2065.9578 14571.7942 0.2058 2.3341 0.1793 5.4084 23.8928 1992.0 2167.7143 15921.7566 0.2525 2.4650 0.1860 5.8991 24.4540 1992.5 2431.5975 16020.8120 0.2640 2.1532 0.2101 6.0742 22.4367 1993.0 2927.5272 15536.9844 0.2433 2.0513 0.1891 6.4019 22.7657 1993.5 4101.3248 15772.6630 0.2626 2.4233 0.1946 7.1658 25.8163 1994.0 4780.7396 15654.4151 0.2678 2.5690 0.1955 7.8557 28.4593 1994.5 5226.0555 14793.2312 0.2562 2.8160 0.2132 8.1176 26.7259 1995.0 5745.9347 14387.1972 0.4058 6.2319 0.2347 8.8369 22.0451 1995.5 6799.2412 14054.4988 0.4681 8.4379 0.2450 9.9058 21.7047 1996.0 7064.3034 13026.5744 0.2422 4.2688 0.1775 6.9580 24.8513 1996.5 7638.1895 13773.8976 0.2219 3.3446 0.2124 6.6077 25.0479 1997.0 7824.2684 14729.5130 0.2305 3.5198 0.2167 6.8358 24.3998 1997.5 6369.0692 13530.9184 0.2510 2.7754 0.2002 5.7814 18.5148 1998.0 5267.7531 12145.7868 0.2275 2.2405 0.1408 4.5761 14.8968 1998.5 5572.4484 12271.5052 0.4499 2.5786 0.1665 4.8808 15.0956 1999.0 6672.8832 13635.9523 0.6271 4.6772 0.2072 6.5802 18.4742 1999.5 6865.7265 14094.4190 0.2854 3.4870 0.1686 6.1270 20.7136 2000.0 7647.2454 13925.0228 0.2242 3.2304 0.2266 5.9816 20.9324 2000.5 7862.8402 15539.6932 0.2244 2.8237 0.2567 6.6335 19.4443 2001.0 7826.3759 16389.6691 0.2242 2.8793 0.2092 7.1405 18.3046 2001.5 8487.9579 19012.9494 0.2477 3.0372 0.2601 7.4839 16.6423 2002.0 8721.2884 25053.3382 0.3100 3.3019 0.2713 7.9121 15.6861 2002.5 9057.6414 26214.2456 0.3186 3.3304 0.2427 7.9122 15.4326 2003.0 9422.0537 27229.9015 0.3403 3.2376 0.2773 8.1154 15.3212 2003.5 6120.9961 40598.1157 0.4264 3.1866 0.2781 8.5317 15.0213 2004.0 3973.2317 32358.3129 0.4000 3.2101 0.3043 8.5042 18.0329 2004.5 3685.9342 29006.0843 0.3708 3.0467 0.2374 8.1145 19.5801 2005.0 3340.4904 26110.1829 0.3598 2.5431 0.2305 6.9335 18.6343 2005.5 2765.6557 26832.0863 0.8894 3.6570 0.2662 17.4818 18.2862 2006.0 3244.4280 34298.0216 1.3749 4.5614 0.2969 31.7652 21.8929

186 Year Br I Pb Mn Cd Zn B 1900.2 7192.8035 501.4190 2.3590 0.9340 6.2779 13.6324 10.7344 1900.7 6625.6321 458.1499 2.1363 0.8133 5.3776 10.8854 10.1337 1901.2 7531.5938 472.3486 2.4627 1.0280 5.3165 12.4816 12.6811 1901.7 7860.1017 470.5973 2.5664 1.0387 5.5722 13.3982 13.3993 1902.2 7898.1138 478.3696 2.4702 0.9339 5.9810 13.8492 13.1843 1902.7 8022.3172 487.3349 2.4599 0.9706 6.2070 13.7051 13.5041 1903.2 8270.7950 489.8384 2.4822 0.9774 6.2089 13.2550 13.7407 1903.7 8573.3233 505.0496 2.4715 0.9731 6.1048 12.4480 13.8851 1904.2 8770.6790 500.0196 2.4126 0.9668 5.6894 11.5436 13.5191 1904.7 8584.6085 519.6286 2.2884 0.8917 5.5135 10.9793 13.1080 1905.2 8236.8469 539.5580 2.2906 0.9224 5.5915 11.4102 13.4297 1905.7 8049.4014 546.1669 2.2699 0.9003 5.6169 11.7069 13.2858 1906.2 8036.8015 538.5806 2.2698 0.9249 5.6343 11.9070 13.3030 1906.7 8117.4837 538.9657 2.3503 0.9352 5.3356 12.3728 13.6901 1907.2 8132.0647 537.2797 2.3242 0.9187 5.2000 12.3814 13.4946 1907.7 8065.9251 526.2742 2.3750 0.9743 5.2586 12.0279 13.4961 1908.2 7867.6420 508.9878 2.2629 0.9013 5.0890 11.3080 13.2784 1908.7 7700.4417 516.2952 2.2580 0.9144 5.0095 10.9584 12.9618 1909.2 7285.5524 509.1476 2.0989 1.1405 4.3987 9.7967 11.9385 1909.7 7179.9087 521.9422 2.0755 0.9965 4.3419 9.6911 11.3327 1910.2 7514.6172 537.4470 2.1538 1.2072 4.6146 10.2711 11.9489 1910.7 7829.7626 546.6072 2.2367 1.3374 4.4932 11.0250 12.6612 1911.2 8060.2714 532.1290 2.2275 0.9802 4.4375 11.3532 12.3885 1911.7 8181.1490 529.6337 2.3742 0.9355 4.8746 12.4343 13.3565 1912.2 7790.3903 524.5475 2.3375 1.0575 4.9909 13.3709 13.5838 1912.7 7588.7048 531.8198 2.2293 0.9080 4.6139 13.6603 12.8984 1913.2 7674.1674 538.3645 2.2299 0.9087 4.6501 14.4495 12.5553 1913.7 7821.4725 522.4233 2.3091 0.9199 4.9414 15.1076 12.7342 1914.2 7738.0526 515.8792 2.3718 1.0506 4.9820 16.4847 13.3765 1914.7 7723.3605 523.3572 2.3431 0.9588 4.9365 16.3895 13.3418 1915.2 7847.3286 537.2585 2.3271 0.9614 4.9374 16.2802 13.2165 1915.7 7915.0499 551.5972 2.3042 0.9043 4.8144 16.4919 12.6714 1916.2 8161.9842 550.5292 2.3389 0.9322 4.9277 15.3396 12.9447 1916.7 8055.4511 544.2070 2.3009 0.9429 5.0691 14.7961 12.9409 1917.2 8296.0580 555.1976 2.4413 0.9289 4.8615 14.0005 13.2968 1917.7 8097.9815 539.5094 2.4064 0.9709 4.9796 11.9499 12.9896 1918.2 7538.7171 546.3601 2.3722 0.8963 5.5069 10.6529 12.9116 1918.7 7274.1122 561.3471 2.3689 0.9319 5.5279 10.6264 13.1022 1919.2 7222.2615 580.0364 2.3135 1.1326 5.8387 10.8501 13.4461 1919.7 7618.4639 607.6227 2.4499 1.0740 5.8795 10.2470 13.9947 1920.2 7653.6342 600.3038 2.4174 0.9571 5.2234 10.7201 13.3851 1920.7 7634.5107 615.8629 2.5501 1.0011 5.4306 11.3440 13.6801 1921.2 7245.4700 605.8589 2.3182 0.8967 5.0284 10.7671 13.1632

Table D.2. LA-ICP-MS elemental data for Muricella M85m presented and discussed in Chapter 4. For each element, three radial transects were smoothed to six month intervals and then averaged. Growth chronologies developed in Chapter 3. 187 Table D.2 Continued

1921.7 7331.2079 605.3100 2.2967 0.8963 4.8886 11.3501 12.5178 1922.2 7764.3653 601.2536 2.4762 0.9364 5.0894 12.7540 13.0292 1922.7 7305.9766 576.3275 2.3714 0.8686 4.9307 12.1772 12.6555 1923.2 7133.7392 573.9948 2.1803 0.8497 4.6396 12.7399 11.5864 1923.7 7537.1871 595.9132 2.3122 0.8968 4.7899 12.5592 12.2980 1924.2 7378.4285 588.0789 2.3186 0.8938 4.8866 11.3534 12.2470 1924.7 7228.9502 590.9529 2.2977 0.9282 4.7334 10.7431 12.5165 1925.2 6413.7104 565.8158 1.9560 1.6970 4.0547 9.8957 10.8351 1925.8 5917.2982 549.4585 1.7820 1.6128 3.9211 9.3837 9.7175 1926.3 6602.5767 573.4691 2.0330 0.8802 4.4699 10.3587 10.3315 1926.8 6985.8945 579.0568 2.1493 0.8646 4.8926 10.5640 11.1091 1927.3 6924.7889 568.7657 2.1941 0.8686 5.0614 11.1240 11.3747 1927.8 6648.2043 558.0348 2.1730 0.9027 5.0727 10.8556 11.4420 1928.3 6413.8219 543.6634 2.0887 0.8346 5.0203 10.3781 10.7872 1928.8 6256.8987 544.2729 2.0551 0.7980 5.4451 11.7073 10.5797 1929.3 6174.7765 536.2436 2.0166 0.7935 5.1700 13.4905 10.0231 1929.8 6089.4327 531.5188 1.9464 0.7633 4.9933 14.4108 9.5393 1930.3 6523.1858 533.6818 2.1023 0.7849 5.1740 16.7605 9.6188 1930.8 6456.6851 522.5297 1.9675 0.6793 4.9584 17.7541 8.7369 1931.3 6378.5035 535.5976 1.9261 0.6799 4.8627 19.7041 7.9727 1931.8 6261.1462 543.2754 1.9314 0.7672 5.1599 23.2947 7.4234 1932.3 6064.7807 528.9200 1.8814 0.7462 4.9911 25.3571 6.6774 1932.8 5520.9337 500.6420 1.6693 0.6680 4.7001 25.9761 5.5934 1933.3 6258.0250 517.2010 1.8051 0.7845 5.3781 35.4871 7.9047 1933.8 6547.8059 492.6565 1.8616 0.7484 5.6952 35.5590 10.9782 1934.3 6508.7795 516.1855 1.7724 0.7206 5.0561 28.8240 10.4509 1934.8 6849.4758 539.5094 1.8884 0.7832 5.2121 27.4836 10.9865 1935.3 7098.2839 546.0341 1.9556 0.8000 5.5301 25.3336 11.6265 1935.8 7098.4756 539.8865 1.9342 0.7864 5.2689 22.3240 11.0781 1936.3 7098.4988 554.8542 2.0500 0.7528 5.7235 20.4612 11.5906 1936.8 6864.6153 541.0750 1.9564 0.7703 5.6364 18.5266 11.2743 1937.3 6757.0552 545.4738 1.8762 0.7592 5.0839 15.8450 10.4589 1937.8 6937.3463 573.8054 2.0032 0.7765 5.4628 13.2541 10.7458 1938.3 6293.9639 564.6125 1.8845 0.8374 5.1578 9.9787 10.4211 1938.8 5830.1872 540.2944 1.6829 0.7057 4.7029 8.4417 8.6565 1939.3 6681.8326 577.0800 2.0478 0.7822 5.2256 8.3608 9.9814 1939.8 7157.0580 574.4296 2.2549 0.7969 5.4435 8.5198 11.4426 1940.3 7101.6067 577.7628 2.2327 0.8448 5.7428 8.8306 11.3017 1940.8 7097.1679 594.7047 2.3655 0.8628 6.2623 9.0265 11.8609 1941.3 7557.9357 608.1599 2.5748 0.9133 6.7217 8.9613 12.5321 1941.8 7273.6359 584.9676 2.3663 0.8052 5.6699 8.2614 11.5391 1942.3 7617.7848 602.8966 2.6092 0.8668 6.0332 8.3028 12.2681 1942.8 7708.6508 616.7387 2.6180 0.8795 6.2201 7.8151 12.7789 1943.3 7547.0688 621.7234 2.6178 0.9329 6.2963 7.3153 12.7044 1943.8 7108.8834 600.7473 2.4574 0.7965 5.8531 7.1959 11.9598 1944.3 6955.8886 607.6690 2.4275 0.8022 5.6517 7.2938 11.2092 1944.8 7093.3904 608.2933 2.5206 0.8272 5.7683 6.7937 11.2717 188 Table D.2 Continued

1945.3 7080.4757 592.0108 2.5353 0.7944 5.5163 6.7223 11.4717 1945.8 6848.2561 577.6968 2.6294 0.8313 5.4476 7.3915 11.5940 1946.3 7269.7796 587.6185 2.8194 0.8929 5.7261 8.1119 12.4128 1946.8 7333.0167 575.2134 2.8247 0.8940 5.6656 9.1261 12.3430 1947.3 7319.0207 572.6096 2.8082 0.8380 5.8284 9.4804 12.5148 1947.8 7026.5750 570.3068 2.6593 0.8293 5.7654 10.0194 11.7853 1948.3 7596.2585 622.6382 2.9126 0.8836 5.7911 10.9644 12.7108 1948.8 7874.5880 617.9950 3.1227 0.9006 5.8067 11.7436 13.1511 1949.3 7974.9424 609.6322 3.0664 0.9125 5.8973 12.4069 13.7202 1949.8 7692.4323 604.8144 2.9811 0.8564 5.4799 13.1004 12.7694 1950.3 7972.1200 591.6722 3.2968 0.9217 5.7356 14.7164 13.7614 1950.8 7477.4024 557.6625 3.0850 0.8533 5.6805 14.9942 13.0565 1951.3 7367.3120 555.2219 3.0972 0.8960 5.7868 15.2582 13.3577 1951.8 7279.8352 552.4830 3.0244 0.8399 5.1357 12.9086 12.5365 1952.3 7460.3278 553.7456 3.1492 0.8794 5.1267 12.8145 12.7607 1952.8 7692.1902 553.8724 3.2684 0.9145 5.4926 12.0483 12.9721 1953.3 7757.9602 553.4690 3.3683 0.9007 5.4683 11.7148 13.5921 1953.8 7596.2451 525.6514 3.4118 0.8509 5.5041 11.4564 13.2051 1954.3 7352.1346 501.6816 3.2407 0.8517 4.9674 11.2794 12.6750 1954.8 7140.4776 503.6244 3.1456 0.7989 5.0169 10.9412 11.8525 1955.3 7547.1555 513.3608 3.5393 0.8985 5.7069 12.1040 13.4626 1955.8 7299.5980 505.7262 3.1492 0.8488 5.1020 11.4250 12.0940 1956.3 7321.1203 512.4454 3.3155 0.8272 5.1544 12.0554 12.0626 1956.8 7376.3957 502.3404 3.4193 0.8099 5.3537 11.9981 11.7719 1957.3 7146.5683 478.0903 3.3253 0.7994 5.5140 12.1013 11.5826 1957.9 6961.5964 489.5919 3.1898 0.7705 5.0938 11.6619 10.6927 1958.4 6639.7823 497.9149 3.1392 0.7540 5.2221 11.9351 9.7671 1958.9 6488.4663 499.2876 2.9616 0.7161 4.7832 11.8991 8.9782 1959.4 7162.5425 550.6497 3.2241 0.7927 5.5310 15.3631 9.9586 1959.9 7556.2733 557.8096 3.6008 0.9134 6.5573 17.8685 10.4913 1960.4 7635.9842 570.9970 3.5161 0.8977 6.4088 16.3372 10.3387 1960.9 8589.8402 614.3397 3.8910 0.9788 8.0389 18.9457 11.5666 1961.4 7871.4250 603.6979 3.2637 0.8570 6.7949 16.3605 10.8161 1961.9 7776.3478 619.8960 3.1937 0.8423 6.4087 17.8097 9.8879 1962.4 8891.9851 669.6619 3.6931 1.0206 6.8952 20.7652 11.7661 1962.9 8485.7437 645.1346 3.6823 0.9858 6.9130 19.3532 11.2902 1963.4 8167.1134 613.5492 3.6772 0.9812 6.8521 18.2312 11.5895 1963.9 7834.7399 581.7168 3.6209 0.9757 6.4970 17.6744 11.5408 1964.4 7803.3124 583.8183 3.6093 0.9776 6.4853 18.8930 11.7158 1964.9 8451.5698 613.4236 4.0234 1.0838 7.3426 22.6499 13.0758 1965.4 7896.7972 575.8769 3.7914 0.9984 6.1579 21.6119 12.5122 1965.9 7611.6968 546.4504 3.7132 0.9449 5.4614 21.6112 12.1134 1966.4 7786.6009 534.5370 3.8525 0.9382 5.3919 23.2339 12.3747 1966.9 7577.7680 539.7243 3.6684 0.9428 5.4683 21.8527 12.2396 1967.4 7227.0403 525.3269 3.4931 0.9129 5.5430 19.2543 12.0963 1967.9 7435.5194 530.2884 3.7418 0.9146 5.4117 18.8970 12.0720 1968.4 7718.1616 548.2646 3.7502 0.8754 4.9110 17.9110 11.4806 189 Table D.2 Continued

1968.9 7745.1387 543.6247 3.6264 0.8285 4.3017 17.7908 10.8145 1969.4 7074.4905 506.8939 3.1886 0.6843 3.4550 15.4973 9.3720 1969.9 6887.6510 492.3895 3.1244 0.7035 3.5107 14.7239 9.0899 1970.4 7385.8102 514.8357 3.3880 0.7504 4.1196 16.1227 9.7267 1970.9 7818.6127 542.1528 3.7323 0.8927 4.8394 17.8777 10.7019 1971.4 7747.4110 542.4048 3.6977 0.9376 4.9554 17.4132 11.4731 1971.9 7953.0906 563.5549 3.8797 0.8979 4.6872 17.4585 11.4783 1972.4 7919.8477 585.4583 3.7828 0.9039 4.5428 17.1472 10.8931 1972.9 7345.8995 562.6579 3.5036 0.8298 4.6478 18.6336 10.1264 1973.4 6959.3048 511.7327 3.2613 0.7565 3.6626 19.0966 9.3699 1973.9 6662.2311 466.8712 3.0495 0.6807 3.2328 20.0145 8.8669 1974.4 6737.7264 479.3147 3.0928 0.7098 3.2591 19.1260 9.3045 1974.9 6957.7211 499.2281 3.2732 0.7723 3.5276 17.6424 9.7308 1975.4 7038.8507 506.3088 3.5553 0.8330 4.1753 18.6114 9.9080 1975.9 7558.2465 537.4526 3.7839 0.8726 4.0346 19.3955 10.3805 1976.4 7946.0891 568.8297 4.0160 0.9766 4.6503 21.7226 11.1684 1976.9 8021.5049 573.3154 4.2874 1.0381 4.7684 21.9986 12.0484 1977.4 8168.1439 580.9234 4.2411 1.0333 4.6483 19.9706 12.0304 1977.9 8408.0911 575.0280 4.5427 1.0179 4.7747 19.1527 12.4410 1978.4 8394.7186 563.9400 4.5920 1.0587 4.7339 19.5041 12.5658 1978.9 8418.7681 578.7967 4.6682 1.0759 5.4107 18.9729 12.7994 1979.4 8334.4306 573.5175 4.4105 1.0182 5.1603 17.3335 12.5104 1979.9 8284.5691 564.5609 4.3028 1.0353 4.7222 16.6971 12.3143 1980.4 8257.8421 552.2659 4.4123 1.0013 4.4956 18.0803 11.7399 1980.9 8744.1071 562.8688 4.7340 1.1195 4.7575 21.0637 12.7783 1981.4 8640.6759 573.5149 4.5667 1.0768 4.5138 19.8452 12.7687 1981.9 8228.9651 548.9370 4.3794 1.0813 4.3452 18.6394 12.1966 1982.4 7916.0881 552.6677 4.6417 1.3673 4.5539 20.1878 11.7636 1982.9 7446.6632 559.2606 4.3444 1.2424 4.6343 21.7730 11.4509 1983.4 7247.6106 585.4731 3.8022 1.0218 4.6255 20.7644 11.0792 1983.9 7590.8382 579.0659 4.0061 1.0312 4.4444 19.6332 11.1881 1984.4 8144.2552 578.1650 4.2224 1.1074 4.4513 24.1375 12.1605 1984.9 8782.2472 589.1222 4.7921 1.1767 4.5012 28.9307 13.3513 1985.4 8563.5952 578.9204 4.3346 1.1444 4.3863 27.1885 12.8026 1985.9 8633.6130 573.9169 4.5255 1.2379 4.6311 27.0463 13.4357 1986.4 8514.3418 576.0896 4.3511 1.2759 4.9539 24.9995 13.3430 1986.9 7980.8264 561.0704 4.1775 1.2464 5.0083 20.0812 13.1349 1987.4 7847.8170 561.3570 4.2009 1.2884 4.8256 16.8810 13.0888 1987.9 7223.5790 616.7022 3.7679 1.2463 4.6735 16.0552 12.2665 1988.4 7729.9928 613.5847 3.8768 1.3243 4.2670 19.6268 12.7529 1988.9 8109.2818 567.7994 3.9231 1.3966 4.1045 26.2868 13.4052 1989.4 8481.3023 558.5931 4.0169 1.5105 4.2658 33.9098 13.7407 1990.0 8716.2903 579.2213 4.2207 1.8920 5.0357 32.2632 14.8293 1990.5 8259.5111 546.8161 3.9867 2.0310 4.9179 18.0207 14.7945 1991.0 8180.9054 585.3547 3.9657 3.4229 4.5008 21.0153 14.7421 1991.5 7355.2898 1201.7310 3.5708 18.1521 4.3142 39.7045 15.4953 1992.0 7138.3198 1262.9563 3.4194 19.4787 4.0853 48.0440 15.7397 190 Table D.2 Continued

1992.5 7408.3849 835.0945 3.3523 6.4241 4.4044 44.8196 14.4858 1993.0 7669.5480 708.3013 3.5132 3.2314 4.8363 30.3716 14.0178 1993.5 7641.0315 644.2073 3.7093 2.5501 5.2723 19.9136 14.8095 1994.0 7444.6548 603.6337 3.7527 2.2982 5.0447 20.8519 15.3214 1994.5 7446.5931 693.3055 3.9534 2.4315 5.0614 33.1368 16.9493 1995.0 6998.9660 623.4936 3.7574 2.4608 4.6810 57.9824 16.1205 1995.5 6941.6725 575.6438 3.9154 2.5278 5.5026 73.1323 17.3821 1996.0 6720.6748 567.7411 3.5954 2.4447 5.0922 64.3429 17.7163 1996.5 6884.8439 580.0447 3.8498 2.6572 4.7086 73.8606 17.1441 1997.0 7065.1977 556.9712 3.9222 2.8809 4.5962 117.5272 18.8559 1997.5 6761.7129 517.6864 3.6307 2.6248 4.3050 161.7283 18.4166 1998.0 6868.0672 551.1737 3.8413 2.5195 4.6647 188.6978 19.4089 1998.5 7169.0829 585.8542 4.0676 2.7260 4.8126 176.4516 20.3046 1999.0 6885.9479 601.4296 3.7768 2.8323 4.6493 127.2191 17.9159 1999.5 6636.0726 612.1515 3.5739 2.8076 4.6428 121.0345 16.7960 2000.0 6765.6516 650.2184 4.0317 3.0145 4.9472 159.9719 17.8697 2000.5 6700.9229 649.3405 3.9925 3.1465 4.9082 153.8037 17.9896 2001.0 6686.8579 654.6339 3.6781 3.2508 4.7010 133.3208 16.5727 2001.5 6765.8558 667.2312 3.8961 3.5644 4.6935 125.6823 15.4144 2002.0 6982.6464 696.8698 5.5603 4.2415 4.8731 152.9450 15.4490 2002.5 7206.6085 708.5690 5.4874 4.8238 5.2878 158.3109 15.7276 2003.0 6928.6574 688.8944 5.3404 4.9182 5.3802 140.7097 14.5595 2003.5 7588.8535 740.4591 4.7860 5.7777 5.7989 128.2485 14.6285 2004.0 8189.0747 719.0382 3.6905 7.3245 6.7617 115.5125 16.7532 2004.5 7864.1651 664.9528 3.4512 4.8240 5.6597 72.8440 13.4571 2005.0 7528.4085 642.6028 3.7140 5.3658 5.6647 34.9711 12.1918 2005.5 6753.9962 615.5789 5.7297 7.8216 5.4221 26.2543 10.2139 2006.0 7084.4662 660.3451 5.9378 8.3782 4.6638 43.9161 10.2522

191 Year B Mn Zn Br Cd I Pb 1944.1 24.3663 1.4102 121.4730 12383.1772 9.1928 1199.3263 4.3595 1944.6 21.2134 1.2162 107.3032 11198.0779 8.7613 1000.9661 3.7052 1945.1 18.1505 0.9574 79.1014 9733.6634 6.8089 776.4984 2.6568 1945.6 19.3864 0.9625 76.7463 10751.6823 6.2719 904.1869 2.7640 1946.1 19.0876 0.7958 71.4306 10862.3180 5.4348 1059.4128 2.6228 1946.6 19.6413 0.9155 74.0687 11379.8335 6.5571 1342.4769 3.3970 1947.1 17.7376 0.8252 58.5272 10239.5676 7.4516 1016.8293 2.9560 1947.6 20.3924 1.5406 53.3358 10377.8442 8.3282 1186.3658 2.9325 1948.1 20.0570 1.6165 48.3319 10228.4341 5.9319 1342.2682 2.8974 1948.6 19.0936 0.8437 32.4738 10238.7801 4.4202 1495.4213 2.6494 1949.1 21.2490 0.9189 23.7409 11102.1759 4.0992 1735.6833 3.0185 1949.6 20.3101 0.9225 16.3357 10584.1891 3.6174 1887.8391 2.9480 1950.1 21.0179 0.8782 15.8084 10901.6243 3.9209 1872.7456 3.1516 1950.6 21.2001 0.8406 15.6146 10664.3918 4.1919 1826.4852 3.1427 1951.1 20.2815 0.7850 17.7579 10095.2964 4.6511 1251.8043 3.1489 1951.6 19.1703 0.6725 23.4479 9723.5197 4.2091 1258.5249 2.9733 1952.1 21.0381 0.6807 36.3893 10534.8323 4.2018 1631.4257 3.2281 1952.6 19.4292 0.5136 44.7498 10230.8797 3.9335 1698.1447 2.8939 1953.1 20.2115 0.5911 64.7489 10876.6489 4.6240 1774.5036 3.2635 1953.6 19.1364 0.5957 76.9986 10817.9076 6.2031 1773.6266 3.3415 1954.2 17.7040 0.8784 85.4329 10176.2993 10.1839 2432.5748 3.6714 1954.7 17.7549 3.3011 121.3903 9959.4357 16.9597 4499.0684 5.2114 1955.2 17.1515 2.6210 189.0478 10035.2422 29.9501 4025.9024 9.4978 1955.7 19.8104 5.7894 221.9773 8826.9789 37.7363 4120.0621 13.4544 1956.2 17.8725 3.9453 219.0598 8640.3321 38.6295 3413.2216 12.1307 1956.7 14.7589 2.1433 192.6553 8064.5655 29.1660 2779.6577 8.4528 1957.2 18.5661 2.5512 266.4722 9694.4611 25.7683 1081.6787 7.9535 1957.7 21.0310 1.4864 478.7306 12874.3512 18.0739 1947.9055 6.5589 1958.2 21.2447 1.2036 454.9414 13005.9341 25.9368 1870.5768 7.5620 1958.7 20.7837 1.3041 367.9114 12428.5898 25.8879 1861.3826 7.4071 1959.2 20.4811 1.0668 276.1352 11445.3733 16.2306 1478.1428 6.0071 1959.7 19.8937 0.8007 264.4821 11045.2237 11.3555 1094.9942 5.8840 1960.2 19.7570 0.8694 251.0174 10790.3197 11.9182 1100.4099 6.0153 1960.7 21.4694 1.0592 230.9495 10987.2032 12.1995 1075.2899 6.0238 1961.2 21.7238 1.2003 256.2986 11278.5012 13.4289 1098.9719 5.8461 1961.7 20.3702 0.9624 315.6534 11586.9491 14.8141 1576.9158 6.5863 1962.2 19.6537 0.7796 337.0448 11572.4995 17.5516 1740.3602 7.4330 1962.7 19.7155 0.7911 367.3248 11815.8344 17.9368 1704.3604 6.3673 1963.2 20.1506 0.8311 280.3847 11843.5851 17.0014 1638.7479 5.5405 1963.7 19.2710 0.7094 244.3787 11248.6679 18.0111 1480.5162 6.0745 1964.2 19.1200 0.6209 194.5045 10324.5861 14.7737 1040.9993 5.6015 1964.7 18.0913 0.5385 137.9753 9704.0833 11.1765 879.0533 5.2426 1965.2 17.5128 0.3434 119.7758 9624.5611 10.3791 707.5959 5.0597

Table D.3. LA-ICP-MS elemental data for Muricella M105m presented and discussed in Chapter 4. For each element, three radial transects were smoothed to six month intervals and then averaged. Growth chronologies developed in Chapter 3. 192 Table D.3 Contined

1965.7 20.1960 0.5087 140.7316 10349.0892 9.8955 1048.3494 4.6604 1966.2 22.3090 0.4760 151.2291 11137.1089 11.8166 915.9174 5.6384 1966.7 20.9343 0.3621 150.8229 10689.0165 11.2293 832.8757 6.3044 1967.2 21.3766 0.3696 154.9133 10764.7989 8.6804 810.1202 5.5412 1967.7 19.4760 0.4686 129.1198 10103.0968 9.5577 832.8229 5.2348 1968.2 19.4276 0.3371 124.1428 10015.3149 10.3805 774.9651 4.7881 1968.7 20.5425 0.4353 126.7653 10119.9711 9.7295 1040.4565 4.7009 1969.3 21.2241 0.4692 129.6197 10820.1807 11.3772 1262.0015 5.3296 1969.8 20.0711 0.3332 123.1282 10272.3594 16.3515 1060.0897 5.7458 1970.3 22.5597 0.3916 129.4190 10436.6408 18.4831 1159.0547 7.1593 1970.8 21.5545 0.3456 127.7052 10147.8554 17.3009 1151.8237 7.4142 1971.3 21.3893 0.3400 130.0669 10400.0283 15.9966 1043.2535 7.3842 1971.8 20.8290 0.3184 131.1796 10487.4991 15.5993 1047.6207 7.2702 1972.3 20.6297 0.3204 136.4527 10740.9930 14.2925 1138.1835 6.3128 1972.8 20.8216 0.3582 153.8032 11567.4956 13.2364 796.5363 5.8799 1973.3 20.4399 0.3018 154.4263 11634.2064 12.2288 907.7623 5.8406 1973.8 21.1773 0.3317 154.0256 11251.8362 11.7982 861.2329 6.4292 1974.3 20.0278 0.2922 149.9881 10872.7693 10.6258 870.5422 6.3052 1974.8 19.9745 0.2905 151.9398 11710.7632 8.4518 839.3406 6.0615 1975.3 21.7895 0.3106 166.0473 12204.9891 10.1884 770.9459 6.4983 1975.8 19.6789 0.2770 161.2255 11401.8256 10.1402 898.4564 6.4130 1976.3 18.4210 0.2859 147.5622 10746.6348 9.9973 1306.8482 6.1862 1976.8 18.8649 0.2879 145.5880 11313.8143 7.1168 1843.8376 5.0642 1977.3 17.1465 0.2964 154.6510 10516.9756 6.3520 718.5567 4.9807 1977.8 17.9515 0.3799 154.5607 10326.0321 6.5371 895.9500 5.0574 1978.3 18.8163 0.4244 156.5276 10228.5593 7.9403 983.9139 5.7814 1978.8 20.3495 0.5072 168.7476 11051.8606 7.5225 1414.2243 5.8242 1979.3 18.4962 0.3207 171.0899 10964.6378 6.6755 1172.2245 5.9419 1979.8 16.3134 0.2666 159.5771 9703.2293 6.9020 836.0798 5.8621 1980.3 18.9609 0.2980 181.5288 11173.2694 7.6486 1139.6993 6.0897 1980.8 18.1856 0.2557 179.3769 10850.7862 7.8950 1438.2585 6.4772 1981.3 21.1985 0.5883 179.9882 11922.2419 8.9534 1913.1498 7.0836 1981.8 19.6209 0.2602 177.6236 11489.1526 9.5037 1343.7643 6.4144 1982.3 20.4620 0.2461 177.5535 11534.5667 7.2277 1132.1330 6.2730 1982.8 20.0115 0.2671 188.6050 11445.3753 5.3124 960.7541 5.5521 1983.3 21.3238 0.3254 221.3455 12199.0665 4.9544 846.7252 5.4941 1983.8 19.5417 0.4340 215.5958 11486.6657 4.7448 1039.4301 5.0438 1984.4 19.3667 0.3594 191.9745 10863.1712 4.3390 1482.3963 4.6287 1984.9 20.4764 0.3448 184.3306 11579.2511 3.7333 1337.6934 4.3834 1985.4 19.5291 0.2422 203.5889 12211.2346 3.9560 774.0535 4.2480 1985.9 19.2399 0.3322 200.4599 11949.7451 5.0571 1089.4618 4.7326 1986.4 18.3594 0.4217 169.9777 10354.2392 3.6898 1759.4981 4.2776 1986.9 17.6107 0.4210 160.1202 10629.6198 3.8904 1280.2282 3.9998 1987.4 17.4760 0.3599 160.8090 10562.6488 3.9911 809.4662 4.0510 1987.9 17.9875 0.2802 165.1754 10336.7289 3.9541 1019.2546 3.9808 1988.4 17.3822 0.2415 162.7334 9747.9175 2.9153 919.9290 3.7838 1988.9 18.6089 0.3404 174.5657 10022.9789 2.4879 1261.4934 3.9218 193 Table D.3 Continued

1989.4 20.4789 0.6263 189.6545 10894.7229 2.2308 2110.7066 4.0782 1989.9 19.3706 0.4796 177.1253 10555.5054 2.0757 2127.4308 4.2848 1990.4 19.8878 0.3436 168.3372 11026.7526 2.2542 1970.4922 4.4702 1990.9 20.5201 0.3068 171.2442 11636.7261 2.4037 1491.5528 4.5143 1991.4 20.4597 0.3177 191.5392 11872.2394 2.2369 1598.8036 4.3005 1991.9 20.3013 0.3885 195.2750 11545.6418 1.7931 1798.5544 4.3863 1992.4 19.8266 0.6538 188.5332 10631.1820 1.4967 2056.9647 4.1653 1992.9 19.8492 0.6872 180.4702 9719.1584 1.4961 2079.4136 4.1318 1993.4 22.1615 0.5405 200.6717 10461.7477 1.4830 2500.7761 4.0010 1993.9 22.3488 0.4563 214.1795 11142.6083 1.7049 2158.5684 3.9678 1994.4 22.0384 0.4793 219.8014 11685.1701 2.0322 1832.6551 4.3240 1994.9 21.1264 0.6999 215.1402 11541.0300 1.8187 1763.1108 4.2730 1995.4 21.7561 0.7858 175.4803 10180.9639 1.7274 1935.3973 3.6621 1995.9 23.9867 0.8535 192.8268 11324.2656 2.0585 2377.0962 3.8965 1996.4 22.5369 0.7325 218.6599 11789.8643 1.9552 1663.8468 4.2056 1996.9 21.7505 0.8984 199.8990 10660.1160 1.7391 2029.4221 4.2979 1997.4 20.7274 0.7736 172.4004 10027.7632 1.6045 2240.9510 3.5562 1997.9 21.0298 0.8833 172.4906 10286.5690 1.4735 2352.3893 3.2316 1998.4 23.2475 1.1129 197.5912 11368.8003 1.7893 2375.8141 4.0112 1998.9 21.9133 1.0200 231.4052 11503.8050 1.9014 1976.2680 4.2876 1999.5 20.8546 1.0486 246.0997 10902.3429 2.0861 1953.0482 4.3047 2000.0 20.6135 1.3332 232.5595 10335.3792 2.2858 3678.3089 4.1766 2000.5 19.5221 1.0376 226.5885 9808.1092 2.1718 3985.5410 4.0058 2001.0 18.6789 1.2315 217.6233 9154.8235 1.9689 3522.2724 3.5044 2001.5 17.8971 1.4851 202.0535 9040.3409 2.0677 3710.2112 3.3529 2002.0 20.2790 27.1896 248.5647 10219.2637 2.3020 3964.1024 4.2614 2002.5 23.6348 86.6475 291.4242 11236.4307 2.2925 5551.9834 5.5631 2003.0 22.5595 34.1991 254.7299 9749.0738 2.1486 3547.7628 4.5911 2003.5 20.1813 4.0592 242.4795 8337.8167 2.2173 1039.1380 4.5378 2004.0 20.3795 3.5834 219.1643 8020.3821 2.2625 1567.5433 3.6866 2004.5 23.1454 3.6344 232.1650 8880.7955 2.3834 2298.2483 3.3811 2005.0 24.6291 3.3249 237.8564 9873.8206 2.5456 977.3483 3.8110 2005.5 27.8416 5.6978 240.5751 9408.6159 2.6354 551.9274 3.5649 2006.0 36.4331 11.0123 212.6605 8696.8879 2.5934 684.0438 3.6172 2006.5 35.8873 9.0966 266.4753 9409.6609 3.4106 428.8005 4.2687 2007.0 38.6009 11.6297 280.8506 9933.8084 4.0131 404.7912 5.1420

194