Nannoplankton malformation during the Paleocene-Eocene Thermal Maximum and its paleoecological and paleoceanographic significance
Nannoplankton malformation during the Paleocene-Eocene Thermal Maximum and its paleoecological and paleoceanographic significance
复制标题
DOI：
10.1002/2016pa002980
复制
发表时间：
2016-10-01
期刊：
影响因子：
--
通讯作者：
Self-Trail, Jean M.
中科院分区：
文献类型：
--
作者：
Bralower, Timothy J.;Self-Trail, Jean M.
古新世-始新世极热期（PETM）以瞬变的纳米浮游生物群为特征。我们对扩展的陆架剖面的调查提供了PETM期间短暂灾难的形态和系统发育及其与环境变化的关系的前所未有的细节。我们观察到的形态变异范围比以前文献记载的要大得多，这表明该分类群属于高度渐变的形态型丛，而不是单个物种。我们认为，该丛代表了在PETM增温和富营养化高峰期间迁移到深光区避难的单一物种的畸形生态表型。异常的是，在事件发生期间，这些深度的有机质再矿化率高，导致饱和度较低，从而导致畸形。提出的机制解释了畸形灾害与生长在上光带的原始物种共同发生的原因；此外，它阐明了为什么畸形在古生物记录中是一种罕见的现象。
The Paleocene-Eocene Thermal Maximum (PETM) is characterized by a transient group of nannoplankton, belonging to the genus Discoaster. Our investigation of expanded shelf sections provides unprecedented detail of the morphology and phylogeny of the transient Discoaster during the PETM and their relationship with environmental change. We observe a much larger range of morphological variation than previously documented suggesting that the taxa belonged to a plexus of highly gradational morphotypes rather than individual species. We propose that the plexus represents malformed ecophenotypes of a single species that migrated to a deep photic zone refuge during the height of PETM warming and eutrophication. Anomalously, high rates of organic matter remineralization characterized these depths during the event and led to lower saturation levels, which caused malformation. The proposed mechanism explains the co-occurrence of malformed Discoaster with pristine species that grew in the upper photic zone; moreover, it illuminates why malformation is a rare phenomenon in the paleontological record.