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www.biogeosciences-discuss.net/6/7083/2009/
doi:10.5194/bgd-6-7083-2009
© Author(s) 2009. This work is distributed
under the Creative Commons Attribution 3.0 License.
Physiological controls on seawater uptake and calcification in the benthic foraminifer Ammonia tepida
1Alfred Wegener Institute for Polar- and Marine Research (AWI), Am Handelshafen 12, 27570 Bremerhaven, Germany
2Institute of Environmental Science and Technology, Universitat Autònoma de Barcelona (UAB), 08193 Bellaterra, Spain
Abstract. During the last decades conceptual models describing the calcification pathway of foraminifera and its physiological controls have been developed. These models are derived by combining data of tracer experiments and microscopic observations obtained from different species. Although vital for understanding their calcitic isotopic and trace elemental composition, direct observational evidence on e.g. seawater vacuolization and intracellular Ca-cycling is lacking for most species. To analyse the relation between seawater uptake and calcification, we incubated juveniles of the cosmopolitan benthic, intertidal foraminifer Ammonia tepida with various fluorescent probes. Visualizing the membranes of endocytosed vesicles was achieved by incubating specimens with the dye FM1-43, while Ca ions in the calcification vesicles were detected by the Ca2+-indicator Fluo3-AM. Uptake of fluorescent latex-beads (0.5 μm diameter) and subsequent transport to the site of chamber formation provided additional evidence that endocytosis is related to the calcification pathway and not merely involved in membrane cycling. Our results show for the first time that endocytosis of seawater is part of the calcification process in Ammonia tepida. Data on the intracellular calcium ion-cycling allowed for calculating a preliminary cellular Ca-budget during foraminiferal calcification.
Discussion Paper (PDF, 14066 KB) Interactive Discussion (Closed, 3 Comments) Final Revised Paper (BG)
Notice on Discussion StatusCitation: 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 Discuss., 6, 7083-7102, doi:10.5194/bgd-6-7083-2009, 2009. Bibtex EndNote Reference Manager XML
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