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12-2010 The Role of Sulfur in Biomineralization: Argopecten Irradians and the Impact of Ocean Acidification Bryanna Joy Broadaway University of Massachusetts Boston
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Recommended Citation Broadaway, Bryanna Joy, "The Role of Sulfur in Biomineralization: Argopecten Irradians and the Impact of Ocean Acidification" (2010). Graduate Masters Theses. Paper 24.
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THE ROLE OF SULFUR IN BIOMINERALIZATION: ARGOPECTEN IRRADIANS
AND THE IMPACT OF OCEAN ACIDIFICATION
A Thesis Presented by BRYANNA JOY BROADAWAY
Submitted to the Office of Graduate Studies, University of Massachusetts Boston, in partial fulfillment of the requirements for the degree of
MASTER IN SCIENCE
December 2010
Environmental, Earth and Ocean Sciences
© 2010 by Bryanna J. Broadaway All rights reserved
THE ROLE OF SULFUR IN BIOMINERALIZATION: ARGOPECTEN IRRADIANS
AND THE IMPACT OF OCEAN ACIDIFICATION
A Thesis Presented
by
BRYANNA JOY BROADAWAY
Approved as to style and content by:
______Robyn Hannigan, Professor Chairperson of Committee
______Curtis Olsen, Professor Member
______William Robinson, Professor Member
______John Duff, Program Director Environmental, Earth and Ocean Sciences Program
______Robyn Hannigan, Chairperson Environmental, Earth and Ocean Sciences Department
ABSTRACT
THE ROLE OF SULFUR IN BIOMINERALIZATION: ARGOPECTEN IRRADIANS
AND THE IMPACT OF OCEAN ACIDIFICATION
December 2010
Bryanna Joy Broadaway, B.S., Arkansas State University M.S., University of Massachusetts Boston
Directed by Professor Robyn Hannigan
The burning of fossil fuels, and other natural processes, has led to an increase of
carbon dioxide (CO2) in the atmosphere. The equilibration of atmospheric CO2 with surface waters causes the ocean pH to decrease from the current value of 8.1. Evidence suggests that as the ocean becomes more alkaline, organisms such as the bay scallop,
Argopecten irradians¸will become more stressed due to increased energy demands to maintain shell deposition and growth. This stress, as hypothesized here, may cause the deposition of S-bearing organic macromolecules to aid in mineralization as well as the potential for sulfate substitution and the deposition of gypsum (calcium sulfate) as opposed to calcite. I hypothesize that scallops raised under pH conditions predicted for the end of the 21st century will have higher total S content which may be due to the
iv deposition of sulfate and/or deposition of high-S organic macromolecules. I will investigate this possibility as well as the possibility that the shift towards increased sulfur impacts the stable S isotopic composition of the inorganic and organic components of shells from organisms raised under high dissolved CO2 conditions as compared to
“normal” pH.
v
TABLE OF CONTENTS
LIST OF FIGURES…………………………………………………………. vii
CHAPTER Page
1. INTRODUCTION……………………………………………… 1 1.1. Marine Carbonate Cycle Through Time……………...... 9 1.2. Biomineralization and Ocean Acidification Impacts on Calcifiers……………………………………………………. 15
2. PROPOSED RESEARCH……………………………………… 26
3. MATERIALS AND METHODS………………………………. 29 3.1. Control ………………………………………………… 29 3.2. Experimental Growth Conditions……………………… 31 3.3. Measurement of Calcification………………………….. 32 3.4. Calcium Carbonate Polymorphism Identification……… 33 3.5. Metal associated with Organic Fraction……………..… 35 3.6. Measurement of Total Sulfur in Shell………………..… 39 3.7. Measurement of Sulfur Isotopes (32 and 34)…………... 40
4. RESULTS………………………………………………………. 43
REFERENCE LIST……………………………………………………... …. 45
iv
LIST OF FIGURES
Figure Page
1: Mid-Atlantic distribution of the bay scallop…………… …………………………5
2: Global biogeochemical cycling of calcium carbonate..… ……..…………………11
2- 3: [CO3 ] [(mol per kg seawater) vs. age (Ma)...... 13
- 2- - + 4: CO2, HCO3 , CO3 , OH , and H as a function of pH (Ridgwell 2005) ...... 15
5: Transverse section of a bivalve shell (Lowenstam 1989) ...... 16
6: Shell and mantle of the bivalve, Atrina rigida (red abalone)...... 18
7: Nantucket Harbor site locations visited during the summer of 2009 (July 21st – Aug 12th)...... 30
8: Absorption FT-IR spectra...... 35
9: Thin section cut from the umbo to the leading edge and example of where laser analysis will occur used to analyze juveniles (Carré, Bentaleb et al. 2006) ...... 37
10: Flow chart of sequential leaching techniques used to isolate the organic fraction in shale that will be applied to the shells (Abanda 2006) ...... 41
v
CHAPTER 1
INTRODUCTION
Several years of research performed at Mauna Loa, Hawaii by Keeling provided substantial information about carbon dioxide concentrations (CO2) and isotopic
abundances of atmospheric carbon 13 and carbon 12 (Keeling 1960). Keeling concluded
that CO2 was increasing in the atmosphere as a direct result of human activity. Recently,
the relation between increased atmospheric CO2 and ocean pH has been more clearly
established as pH of the global ocean has declined by 0.1 pH units since preindustrial
times (Orr 2005), such that current ocean water has an average pH of 8.08 (Potera 2010).
This relation is based on the fact that as carbon dioxide increases in the atmosphere, it
diffuses into the surface waters of the ocean due to partial pressure differences (Henry’s
Law). Through this air-sea gas exchange, atmospheric CO2 enters the ocean where it
either becomes dissolved or escapes, through evaporation, back into the atmosphere.
Carbon dioxide, once dissolved in the surface waters, can form carbonic acid as a first step in the series of several reversible dissociation reactions that can release free
- 2- hydrogen ions that form bicarbonate (HCO3 ) and carbonate (CO3 ) ions (Equation 1).
1
The resultant increase in the dissolved free hydrogen ion (H+) leads to a decline in pH
(pH = -log [H+]).