サンゴ骨格の微小領域における化学組成の不均質性 : 石灰化プロセスの解明とサンゴ古水温計への応用(<特集>サンゴ年輪と低緯度の海洋環境)

概要

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Massive corals have been widely used as proxies for past changes in sea surface temperature (SST) of the tropical and subtropical oceans because the oxygen isotopic (δ^<18>O) and strontium/calcium (Sr/Ca) ratios of their aragonitic skeletons are believed to vary quantitatively as a function of the temperature of the ambient sea water. However, recent microanalytical studies using secondary ion mass spectrometry (SIMS) have revealed large chemical heterogeneities for Sr/Ca and oxygen isotopic ratios in coral skeleton, which cannot be explained by temperature variation. The newly developed NanoSIMS has a potential to determine chemical variations within the two basic building blocks of the coral skeleton; centres of calcification and fibers. Such data can provide important new information about the biomineralization process and help constrain the degree to which temperature and/or biological processes affect the composition of skeleton in corals, as well as in biogenetic carbonates formed by other marine organisms.
日本地球化学会の論文
2004-12-27