A new model for biomineralization and trace-element signatures of Foraminifera tests

Biogeosciences - Tập 10 Số 10 - Trang 6759-6767
Gernot Nehrke1, Nina Keul2, Gerald Langer3, Lennart de Nooijer4, Jelle Bijma1, Anders Meibom5
1Alfred Wegener Institute, Bremerhaven, Germany
2Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York, USA
3Department of Earth Sciences, Cambridge University, Cambridge, UK
4Department of Marine Geology, Royal Netherlands Institute of Sea Research, Horntje, the Netherlands
5Laboratory for Biological Geochemistry, School of Architecture, Civil and Environmental Engineering (ENAC), Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland

Tóm tắt

Abstract. The Mg/Ca ratio of Foraminifera calcium carbonate tests is used as proxy for seawater temperature and widely applied to reconstruct global paleo-climatic changes. However, the mechanisms involved in the carbonate biomineralization process are poorly understood. The current paradigm holds that calcium ions for the test are supplied primarily by endocytosis of seawater. Here, we combine confocal-laser scanning-microscopy observations of a membrane-impermeable fluorescent marker in the extant benthic species Ammonia aomoriensis with dynamic 44Ca-labeling and NanoSIMS isotopic imaging of its test. We infer that Ca for the test in A. aomoriensis is supplied primarily via trans-membrane transport, but that a small component of passively transported (e.g., by endocytosis) seawater to the site of calcification plays a key role in defining the trace-element composition of the test. Our model accounts for the full range of Mg/Ca and Sr/Ca observed for benthic Foraminifera tests and predicts the effect of changing seawater Mg/Ca ratio. This places foram-based paleoclimatology into a strong conceptual framework.

Từ khóa


Tài liệu tham khảo

Allen, G. J. and Sanders, D.: Two Voltage-Gated, Calcium Release Channels Coreside in the Vacuolar Membrane of Broad Bean Guard Cells, The Plant Cell Online, 6, 685–694, 1994.

Bentov, S. and Erez, J.: Impact of biomineralization processes on the Mg content of foraminiferal shells: A biological perspective, Geochem. Geophys. Geosys., 7, 1–11, https://doi.org/10.1029/2005GC001015, 2006.

Bentov, S., Brownlee, C., and Erez, J.: The role of seawater endocytosis in the biomineralization process in calcareous foraminifera, Proc. Natl. Acad. Sci., 106, 21500–21504, 2009.

Blanco-Ameijeiras, S., Lebrato, M., Stoll, H. M., Iglesias-Rodriguez, M. D., Méndez-Vicente, A., Sett, S., Müller, M. N., Oschlies, A., and Schulz, K. G.: Removal of organic magnesium in coccolithophore calcite, Geochimica et Cosmochimica Acta, 89, 226–239, https://doi.org/10.1016/j.gca.2012.04.043, 2012.

de Nooijer, L. J., Langer, G., Nehrke, G., and Bijma, J.: Physiological controls on seawater uptake and calcification in the benthic foraminifer Ammonia tepida, Biogeosciences, 6, 2669–2675, https://doi.org/10.5194/bg-6-2669-2009, 2009.

Dissard, D., Nehrke, G., Reichart, G. J., and Bijma, J.: The impact of salinity on the Mg / Ca and Sr / Ca ratio in the benthic foraminifera Ammonia tepida: Results from culture experiments, Geochim. Cosmochim. Acta, 74, 928–940, 2010.

Elderfield, H., Bertram, C. J., and Erez, J.: A biomineralization model for the incorporation of trace elements into foraminiferal calcium carbonate, Earth. Planet. Sci. Lett., 142, 409–423, 1996.

Elderfield, H. and Ganssen, G.: Past temperature and [delta]18O of surface ocean waters inferred from foraminiferal Mg / Ca ratios, Nature, 405, 442–445, 2000.

Erez, J.: The Source of Ions for Biomineralization in Foraminifera and Their Implications for Paleoceanographic Proxies, Rev. Mineral. Geochem., 54, 115–149, 2003.

Gussone, N., Langer, G., Thoms, S., Nehrke, G., Eisenhauer, A., Riebesell, U., and Wefer, G.: Cellular calcium pathways and isotope fractionation in Emiliania huxleyi, Geology, 34, 625–628, 2006.

Hayward, B. W., Holzmann, M., Grenfell, H. R., Pawlowski, J., and Triggs, C. M.: Morphological distinction of molecular types in Ammonia – towards a taxonomic revision of the world's most commonly misidentified foraminifera, Mar. Micropaleontol., 50, 237–271, 2004.

Kiessling, W., Aberhan, M., and Villier, L.: Phanerozoic trends in skeletal mineralogy driven by mass extinctions, Nature Geosci., 1, 527–530, 2008.

Langer, G., Gussone, N., Nehrke, G., Riebesell, U., Eisenhauer, A., Kuhnert, H., Rost, B., Trimborn, S., and Thoms, S.: Coccolith strontium to calcium ratios in Emiliania huxleyi: The dependence on seawater strontium and calcium concentrations, Limno. Oceanogr., 51, 310–320, 2006.

Langer, G., Nehrke, G., Thoms, S., and Stoll, H.: Barium partitioning in coccoliths of Emiliania huxleyi, Geochim. Cosmochim. Acta, 73, 2899–2906, 2009.

Martin, R. E.: Cyclic and secular variation in microfossil biomineralization: clues to the biogeochemical evolution of Phanerozoic oceans, Glob. Planet. Change, 11, 1–23, https://doi.org/10.1016/0921-8181(94)00011-2, 1995.

Pilson, M. E. Q.: An introduction to the chemistry of the sea, Prentice-Hall, New Jersey, 431 pp., 1998.

Raja, R., Saraswati, P. K., Rogers, K., and Iwao, K.: Magnesium and strontium compositions of recent symbiont-bearing benthic foraminifera, Mar. Micropal., 58, 31–44, https://doi.org/10.1016/j.marmicro.2005.08.001, 2005.

Schallreuter, R. E. L.: Calcareous foraminifera from the Ordovician of Baltoscandia, J. Micropal., 2, 1–6, 1983.

Schweizer, M., Polovodova, I., Nikulina, A., and Schönfeld, J.: Molecular identification of Ammonia and Elphidium species (Foraminifera, Rotaliida) from the Kiel Fjord (SW Baltic Sea) with rDNA sequences, Helgol. Mar. Res., 65, 1–10, https://doi.org/10.1007/s10152-010-0194-3, 2011.

Segev, E. and Erez, J.: Effect of Mg / Ca ratio in seawater on shell composition in shallow benthic foraminifera, Geochem. Geophys. Geosyst., 7, Q02P09, https://doi.org/10.1029/2005gc000969, 2006.

Urey, H. C., Lowenstam, H. A., Eppstein, S., and McKinney, C. R.: Measurement of paleotemperatures and temperatures of the Upper Cretaceous of England, Denmark and the Southeastern United States, Geol. Soc. America, 62, 399–416, 1951.

Thông tin
Thông tin xuất bản

Biogeosciences

Tập 10 Số 10

6759-6767

Thông tin tác giả