Exploring photosymbiotic ecology of planktic foraminifers from chamber-by-chamber isotopic history of individual foraminifers
Exploring photosymbiotic ecology of planktic foraminifers from chamber-by-chamber isotopic history of individual foraminifers
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从单个有孔虫的逐室同位素历史探索浮游有孔虫的光共生生态
DOI：
10.1017/pab.2014.7
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发表时间：
2015
期刊：
影响因子：
2.7
通讯作者：
Hiromichi Hirano
中科院分区：
文献类型：
--
作者：
Haruka Takagi;Kazuyoshi Moriya;Toyoho Ishimura;Atsushi Suzuki;Hodaka Kawahata;Hiromichi Hirano
光共生生态学的进化是浮游有孔虫在贫营养海洋中生存的重要适应方式。因此，了解化石物种的光共生生态是了解浮游有孔虫古生物多样性动态的关键。由于有孔虫测试记录了地球化学特征中生态信息的个体发育历史，因此分析具有生长的单个地球化学剖面可以揭示物种的生态。本研究通过对有孔虫个体的稳定同位素（δ 13 C和δ 18 O）进行逐室检测，以识别光共生信号。我们观察到共生物种Globigerinoides acylobatus和Globigerinoides sacculifer的个体发育δ 13 C增加高达2.4‰，伴随着相对稳定的负δ 18 O。而在非共生物种Globorotalia truncatulinoides中，δ 13 C和δ 18 O在个体发育过程中表现出显著的正相关。这两个生态组产生对比的同位素配置文件，从而使我们能够使用我们的个体发育的同位素分析的个别标本，以确定藻类光合共生化石有孔虫。个体发育的逐室同位素分析在稀有物种分析中具有很大的优势，因为只需要一个个体来描述个体发育的同位素历史。除了光共生识别，我们的方法具有很大的潜力，提供新的见解物种古生态学研究，如钙化深度的个体发育史。
Evolution of photosymbiotic ecology is an important adaptation for planktic foraminifers that enhances the ecological advantage of living in oligotrophic oceans. Therefore, detecting photosymbiotic ecology in fossil species is one of the keys to understanding the paleobiodiversity dynamics of planktic foraminifers. Because foraminiferal tests record the ontogenetic history of ecological information in geochemical signatures, analyzing individual geochemical profiles with growth can reveal a species’ ecology. This study examined chamber-by-chamber stable isotopes (δ13C and δ18O) of foraminiferal individuals to identify photosymbiotic signals. We observed an ontogenetic δ13C increase of up to 2.4‰, accompanied by relatively stable, negative δ18O, in the symbiotic species Globigerinoides conglobatus and Globigerinoides sacculifer. In contrast, δ13C and δ18O showed significant positive correlation during ontogeny in the asymbiotic species Globorotalia truncatulinoides. These two ecological groups produce contrasting isotopic profiles, thereby allowing us to use our ontogenetic isotopic analyses of individual specimens to identify algal photosymbiosis in fossil foraminifers. The chamber-by-chamber isotope analyses with individual ontogeny have great advantages in analyzing rare species because only one individual is required to describe ontogenetic isotopic history. In addition to photosymbiotic identification, our methods hold great potential to provide new insight into species paleoecological studies such as the ontogenetic history of calcification depth.