UNIVERSITY OF CALIFORNIA, SAN DIEGO Climate and Food Supply Influences on Mobile Epibenthic Megafauna Populations in the Abyssal NE Pacific from 1989 to 2004 A dissertation submitted in partial satisfaction of the requirements for the degree of Doctor of Philosophy in Marine Biology by Henry A. Ruhl Committee in charge: Kenneth L. Smith Jr., Chair Daniel R. Cayan Lisa A. Levin David P. Phillips George Sugihara 2006 Copyright © Henry A. Ruhl, 2006 All Rights reserved. The dissertation of Henry A. Ruhl is approved, and it is acceptable in quality and form for publication on microfilm: Chair University of California, San Diego 2006 iii For my family, friends, and dearest love & For all those who have nurtured, supported, and inspired iv TABLE OF CONTENTS Signature Page……………………………………………………………… iii Dedication………………………………………………………….……….. iv Table of Contents…………………………………………………………… v List of Figures………………………………………………………………. vi List of Tables……………………………………………………………….. ix Acknowledgments………………………………………………….………. x Vita and Publications……………………………………………………….. xii Abstract…………………………………………………………….……….. xvi I. General Introduction.……………………………………………….. 1 II. Shifts in deep-sea community structure linked to climate and food supply…………………………………………………………. 12 III. Population dynamics of abyssal epibenthic megafauna in the NE Pacific from 1989-2004………………………………………… 27 IV. Dispersion of mobile epibenthic megafauna on the abyssal seafloor in the NE Pacific from 1989-2004………………………… 85 V. Community stability in the variable resource habitat of the abyssal NE Pacific….…………………………………….………… 108 VI. Conclusions………………………………………………………… 147 v LIST OF FIGURES II Fig. 1 A-C) Abundance estimates for dominant echinoderms, D) POC flux and Bakun upwelling estimates, E) The NOI, SOI, and MEI ENSO indices………………………………… 14 Fig. 2 Bray-Curtis similarity dendrogram for the mobile epibenthic community composition from 1989-2002……….. 14 Fig. 3 Plot of peaks in the temporal lags in the climate, POC flux and abundance cross-correlations…………………….… 24 III Fig. 4 Abundance and body size estimates for the top ten most dominant mobile epibenthic megafauna from 1989-2004…………….. 48 Fig. 5 Yearly percent frequency histograms of body size for E. minutissima………………………………………………. 50 Fig. 6 Relative similarity of monthly cumulative size distributions…………………………………………………. 51 Fig. 7 Relative similarity of yearly cumulative size distributions…………………………………………………. 52 Fig. 8 Monthly percent frequency histograms of body size for E. minutissima………………………………………………. 57 Fig. 9 Yearly percent frequency histograms of body size for P. diaphana…………………………………………………. 59 Fig. 10 Monthly percent frequency histograms of body size for P. diaphana…………………………………………………. 60 Fig. 11 Yearly percent frequency histograms of body size for P. vitrea……………………………………………………... 62 Fig. 12 Monthly percent frequency histograms of body size for P. vitrea……………………………………………………... 63 vi Fig. 13 Yearly percent frequency histograms of body size for A. abyssorum………………………………………………… 65 Fig. 14 Monthly percent frequency histograms of body size for A. abyssorum………………………………………………… 66 Fig. 15 Yearly percent frequency histograms of body size for O. bathybia………………………………………………….. 68 Fig. 16 Monthly percent frequency histograms of body size for O. bathybia …………………………………………………. 69 Fig. 17 Yearly percent frequency histograms of body size for Ec. rostrata…………………………………………………. 79 Fig. 18 Monthly percent frequency histograms of body size for Ec. rostrata…………………………………………………. 72 Fig. 19 Yearly percent frequency histograms of body size for Sy. profundi…………………………………………………. 74 Fig. 20 Yearly percent frequency histograms of body size for S. globosa ………………………………………….……….. 75 Fig. 21 Yearly percent frequency histograms of body size for O. mutabilis…………………………………………………. 76 Fig. 22 Yearly percent frequency histograms of body size for Ps. longicauda………………………………………………. 77 IV Fig. 23 Example count m-1 along a transect and resulting 3TLQV’s for uniform, random, and aggregated dispersions………………………………………………….. 98 Fig. 24 Count m-1 along a transect and resulting 3TLQV’s for example E. minutissima enumerations…………….……….. 99 Fig. 25 Count m-1 along a transect and resulting 3TLQV’s for example A. abyssorum and O. bathybia……………………. 100 vii V1 Fig. 26 Scatter plots and dendrograms of Bray-Curtis similarity for rank-abundance distributions and species compositions from 1989-2004…………………………………………….. 119 Fig. 27 Timeseries plots showing RAD similarity, evenness, species composition similarity, and POC flux……………… 121 Fig. 28 Monthly ranked abundances, dominant taxon for each corresponding rank, and monthly body size to abundance relationships………………………………………………… 122 Fig. 29 Time-series plots of measured and modeled POC flux…….. 139 Fig. 30 Possible results from a RAD shift analysis…………………. 139 viii LIST OF TABLES II Table 1 Results from time-lagged Spearman-rank cross correlations between climate indices, POC flux, and abundances………………………………………………….. 15 III Table 2 Results form Spearman-rank correlations between abundance and time, and body size and time……………….. 53 Table 3 Results from Spearman –rank correlations and ANOSIM tests to determine links between intraspecific body size and abundance…………………………………… 54 IV Table 4 Dispersion analysis results indicating uniform, random, or aggregation patterns and scales, as well as Mann-Whitney U test results evaluating any links between either POC flux or density and the observed dispersion patterns…………………………………………… 101 ix ACKNOWLEDGEMENTS I’d first like to thank my mentor Ken Smith. His vision and tenacity in deep-sea research has been paramount in making this abyssal long-term research possible. Lisa Levin, George Sugihara, Dan Cayan, and David Phillips also helped to shape the work presented here. Ron Burton, Nancy Knowlton, and Phil Hastings also helped to guide my early research at SIO. Roberta Baldwin, who is already missed, was a great oceanographer, colleague, and friend. She was always there to help not only to myself, but many other students and patrons of the Smith Lab. Long-term research is not possible without the support of many individuals over many years. The efforts of many other Smith Lab team members past and present including Fred Uhlman, Mike Kirk, Rob Glatts, Jake Ellena, Dave Bailey, Mike Vardaro, Ron Kaufmann, Stace Beaulieu, Lynn Lauerman, Waldo Wakefield, Jeff Drazen, and Angelo Carlucci have been essential to success at Station M and have all contributed to what’s presented here. Several undergraduates also assisted in the collection and analysis of specimens and data both at sea and ashore including Jake Lowenstein, Ashley Booth, Noelle Yochum, Lisa Zarubick, Rachelle Jensen, Glenn Wheeler, Molly Berkey, and Darya Pilram. Additional thanks to Bob Wilson and the SIO shipboard technical support group; Larry Lovell, Kent Trego, and the SIO Benthic Invertebrates Collection; John Helly and the San Diego Super Computer center; Mark Ohman, Mike Landry, Greg Mitchell, Mati Kahru, and the California Current Ecosystem and California Cooperative Oceanic Fisheries Investigations programs; and Mary Tyree and the Climate Research Division. The constructive and supportive atmosphere at SIO helped to not only improve my research, but also to make my graduate research experience a lifetime highlight. This x work was supported by the National Science Foundation grant numbers OCE 89-22620, OCE92-17334, OCE98-07103, OCE00-02385, OCE02-42472. Lastly my fiancé Steph, my parents Pat and Garrett, my sister Parker, and my many other friends and family members have all encouraged and supported me. This support has included a significant amount patience as I’ve traveled, worked in the lab, and communicated the results. Chapter II, in full, is a reprint of the material as it appeared in Science (Ruhl, H. A. and K. L. Smith, Jr. 2004. Shifts in deep-sea community structure linked to climate and food supply. Science 305: 513-515.). Chapter III, in full, has been submitted to the journal Ecology and Chapter V, in full, has been submitted to Science. I was the principal researcher/author on the above papers. xi VITA 1994-1999, Biological Science Technician, US Geological Survey, Reston, Virginia. 1996, B.S. in Biology, George Mason University, Fairfax, Virginia. 1998, Hydrology, Johns Hopkins University, Washington, DC. 2005, Teaching Assistant, University of California, San Diego. 2006, Ph.D. in Marine Biology, University of California, San Diego. JOURNAL PUBLICATIONS Bailey, D., H. A. Ruhl, and K. L. Smith, Jr. 2006. Long-Term Changes in Benthopelagic Fish Abundance in the Abyssal N.E. Pacific Ocean. Ecology 87: 549-555. Beaulieu, S. E., K. L. Smith Jr., H. A. Ruhl, and R. J. Baldwin. in preparation. Megafauna at the abyssal seafloor underlying the North Pacific Subtropical Gyre: composition and abundance from photographic and video surveys. Deep- Sea Research I. Cranmer, T. L., H. A. Ruhl, R. J. Baldwin, and R. S. Kaufmann. 2003. Spatial and Temporal Variation in the Abundance, Distribution and Population Structure of Epibenthic Megafauna in Port Foster, Deception Island. Deep-Sea Research II 50: 1821-1842. Kendall, K. A., H. A. Ruhl, and R. C. Wilson. 2003. Distribution and Abundance of Marine Bird and Pinniped Populations Within Port Foster, Deception Island, Antarctica. Deep-Sea Research II 50: 1873-1888. Ruhl, H. A., P. A. Hastings, L. A. Zarubick, R. M. Jensen, and K. Zdzitowiecki. 2003. Fish Populations of Port Foster, Deception Island, Antarctica and Vicinity. Deep-Sea Research II 50: 1843-1858. Ruhl, H. A. and K. L. Smith Jr.