Seasonality and Habitat controls on benthic foraminiferal salinity proxies

1. Seasonality and Habitat controls on benthic foraminiferal salinity proxies Adriana Dueñas-Bohórquez G. J. Reichart, J. Bijma, R. da Rocha, A. Kuroyanagi, Sander Ernst, Shauna Ni Fhlaithearta, Markus Raitzsch Universiteit Utrecht

2. TOOLS TO RECONSTRUCT PALEO-ENVIRONMENTS Planktonic foraminifer Universiteit Utrecht PALEOTEMPERATURE PROXY Shell composition TRACE ELEMENTS + ISOTOPE CHEMISTRY Mg Temperature PROXIES * T = 20.6 – 4.38 (δ18Oforams -δ18Oseawater) * based on benthic foram H. elegans PALEOSALINITY Benthic foraminifer

3. Universiteit Utrecht Additional Effects on Mg incorporation 2. Chemistry of surrounding seawater 1. Vital effects Carbonate ChemistryCO2 + H2O ↔ HCO3- ↔ CO32-pH - Omega (Ω: calcite saturation state)+ Salinity Culturing experiments

4. Universiteit Utrecht Alkalinity DIC CO2 + H2O ↔ HCO3- ↔ CO32- + H+ pH - Omega (calcite saturation state) Benthic foraminifera set-up Seawater sampling INTRODUCTION Influence of the carbonate system parameters and salinity on Mg incorporation in foraminiferal calcite: Experimental set-up 6 cm Direction seawater flow

5. Universiteit Utrecht Seawater with altered carbonate chemistry Planktonic foraminifera set-up Planktonic foraminifer

6. Universiteit Utrecht Chapter I Effect of salinity and calcium carbonate saturation state on Mg incorporation in foraminiferal calcite A. Dueñas-Bohórquez (1), J. Bijma (2), R. da Rocha (2), A. Kuroyanagi (3) and G. J. Reichart (1,2) (1) Faculty of Geosciences, Utrecht University, The Netherlands, (2) Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, Germany, (3) National Institute of Advanced Industrial Science and Technology, Ibaraki, Japan. A. Dueñas-Bohórquez (1), J. Bijma (2), R. da Rocha (2), A. Kuroyanagi (3) and G. J. Reichart (1,2) Chapter II Ontogenic and Inter-individual variations of Mg/Ca ratio of planktonic foraminifera University of Puerto Rico Universiteit Utrecht

7. Universiteit Utrecht Chapter I and II OBJECTIVES • Effect of salinity, independent of the calcite saturation state of seawater (Ω), on Mg incorporation in planktonic foraminifera. Ωcalc= [Ca2+][CO32-] / Kspcalc • Inter and intra-individual variations on Mg incorporation in planktonic foraminifera.

8. Chapter I and II Universiteit Utrecht F (Sac-like chamber) F-1 chamber F-2 chamber Globigerinoides sacculifer (Brady) METHODOLOGY Vital Effect: Inter and Intra-individual variations • Southwest coast Puerto Rico • T = 26°C. • Constant light intensity Chemistry of surrounding seawater: • Salinity 2. Omega (calcite saturation state) Ωcalc= [Ca2+][CO32-] / Kspcalc Foraminiferal Mg analysis Laser ablation -ICP-MS (Utrecht University)

9. Chapter I and II Results and conclusions Universiteit Utrecht Controls (s were not modified). • Salinity overriding control on Mg incorporation (constant T = 26 °C) (+1,5 %  0.17 per salinity unit increase).

10. Chapter I and II F (sac-like chamber) F-1 chamber F-2 chamber G. sacculifer (Brady) ...results and conclusions Universiteit Utrecht Chamber formation • Important effect of inter and intra-individual variations on Mg incorporation.

11. Chapter III Effect of Salinity on Mg/Ca ratio in benthic foraminifera Universiteit Utrecht Tropical benthic Heterostegina sp. Shallow benthic Ammonia tepida Deep benthic Bulimina marginata 1st SET OF EXPERIMENTS S1 S2 S3 S4 - Different Salts - Variation in carbonate parameters - Different Mg/Ca in SW. 2ND SET OF EXPERIMENTS S1 S2 S3 S4 - Different Salts - Constant carbonate parameters - Constant Mg/Ca in SW. IN PROGRESS LA-ICP-MS OF SPECIMENS IN PROGRESS

12. Universiteit Utrecht 1ST SET OF EXPERIMENTS 2ND SET OF EXPERIMENTS Preliminary results Heterostegina sp. and Ammonia tepida IN PROGRESS Chapter IV Carbonate saturation state vs. Ca+2 and CO32- effect on foraminiferal Mg incorporation Ωcalc = [Ca2+][CO32-] / Kspcalc Tropical benthic Heterostegina sp. Shallow benthic Ammonia tepida Deep benthic Bulimina marginata

13. Chapter IV Universiteit Utrecht Sr/Ca (mmol/mol) Mg/Ca (mmol/mol) D Sr 1ST SET OF EXPERIMENTS Ωcalc = [Ca2+][CO32-] / Kspcalc Constant carbonate parameters (TA, DIC, CO32-, HCO3-, pH) Constant Mg/Ca in seawater Variable Sr/Ca in seawater Tropical benthic Heterostegina sp. D = (TE/Ca2+)foram/(TE/Ca2+)SW

14. Chapter IV Universiteit Utrecht Sr/Ca (mmol/mol) Variable Sr/Ca in seawater Mg/Ca (mmol/mol) D Sr 1ST SET OF EXPERIMENTS Ωcalc = [Ca2+][CO32-] / Kspcalc Constant carbonate parameters (TA, DIC, CO32-, HCO3-, pH) Constant Mg/Ca in seawater Shallow benthic Ammonia tepida D = (TE/Ca2+)foram/(TE/Ca2+)SW

15. Chapter V Ontogenic and Inter-individual variations of trace metal composition in deep benthic foraminiferal calcite Universiteit Utrecht Mg (ppm) M n ( µ m o l / l ) 0 4 8 1 2 1 6 2 0 8 1 7 0 2 6 9 2 5 4 3 Mn (ppm) 4 6 8 1 0 or … microhabitat effect 1 2 3 4 5 6 7 8 9 C. pachyderma 1 2 3 4 5 6 7 8 9

16. Universiteit Utrecht Publications • Copper incorporation in foraminiferal calcite: results from culturing experiments. L. J. de Nooijer, G.J. Reichart, A. Dueñas-Bohórquez, M. Wolthers, S.R. Ernst, G.J. van der Zwaan. Biogeosciences, 4, 493–504, 2007. • In prep.: The effect of salinity and seawater calcite saturation state on Mg incorporation in planktonic foraminifera.A. Dueñas-Bohórquez, G.J. Reichart, R. Da Rocha, A. Kuroyanagi, J. Bijma. • In prep.: Ontogenic and Inter-individual variations of Mg/Ca ratio of planktonic foraminifera. A. Dueñas-Bohórquez, G.J. Reichart, R. Da Rocha, A. Kuroyanagi, J. Bijma.