Microscopic visualization approach of foraminiferal calcification environment

Thursday, 18 December 2014
Takashi Toyofuku1, Kazuhiko Fujita2, Miki Yamamoto1, Lennart Jan de Nooijer3, Hidetaka Nomaki1, Masashi Tsuchiya1 and Hiroshi Kitazato4, (1)JAMSTEC Japan Agency for Marine-Earth Science and Technology, Kanagawa, Japan, (2)University of the Ryukyus, Okinawa, Japan, (3)Royal Netherlands Institute for Sea Research, Den Burg, Netherlands, (4)Japan Marine Sci & Tech Ctr, Yokosuka Kanagawa, Japan
Foraminifera, marine unicellular organism, have been thought as one of the major carbonate producer in ocean. Foraminiferal calcareous fossils are commonly utilized as paleo-environmental indicators in a variety of studies of earth science because these have been archived as numerous materials in sediment for long time and diverse environmental information are brought by population, morphology and geochemical fingerprints. Finally, the calcareous test itself is interested by many micropalaeontologists. The knowledge about the cytological process on carbonate precipitation has been described for couples of decade using by multi approaches. Foraminiferal regulations of calcium and carbonate ion uptake into calcareous tests from ambient seawater under different pH conditions are of great interest. Our previous studies showed the potential to understanding the biomineralization of foraminifera by the application of fluorescent indicators. Recently, we apply the method to show the spatial distributions of cytological calcium and pH in living cell. Observed results show that foraminifera severely controls intra-cellular pH variation and concentration of calcium at different environmental pH conditions. These observations results will help to consider how the geochemical compositions arranging on the foraminiferal test, sensitivity of pH proxy of boron and others.