Community benthic paleoecology from high-resolution climate records: Mollusca and foraminifera in post-glacial environments of the California margin
Community benthic paleoecology from high-resolution climate records: Mollusca and foraminifera in post-glacial environments of the California margin
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来自高分辨率气候记录的群落底栖古生态学：加利福尼亚边缘冰期后环境中的软体动物和有孔虫
DOI：
10.1016/j.quascirev.2016.11.009
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发表时间：
2017
影响因子：
4
通讯作者：
J. Kennett
中科院分区：
文献类型：
--
作者：
S. Myhre;K. Kroeker;T. Hill;P. Roopnarine;J. Kennett
对过去气候的古生态重建通常基于一个具有一致存在的单一分类群。对多分类群群落范围变化与气候变率之间的关系知之甚少。在这里，我们重建了晚第四纪（16.1-3.4 ka）的沉积物芯从加州边缘（418米以下的海平面）的圣巴巴拉盆地（SBB），美国，使用软体动物（动物）和有孔虫（Rhizaria）微体化石。在以前的调查的基础上，我们使用多元排序和聚类分析来解释这些明显不同的分类群体在离散的气候事件中的社区规模的变化。海底生物群落之间的最强差异发生在冰川（终止IA之前，14.7万年）和间冰期气候事件。全新世群落划分良好，表明这些微体化石记录了亚千年的海洋学变化。我们记录了强有力的证据，化能合成的营养网和硫化物环境（从腹足类Alia permodesta和bivalveLucinoma aequizonata），其特征是以前解释为含氧（如前Bølling变暖）的限制间隔。软体动物的记录表明，一阶营养碎屑和化学合成固定碳之间的能量转移。与广泛不同的生理偏好的软体动物发生在这里的单一，十年的沉积物的间隔，并作为这样的软体动物组合可能反映显着的年代际海洋学的变化。有孔虫组合提供了特殊的记录的顺序，按时间顺序进行的冰消期的气候和海洋事件，而软体动物组合反映了非时序的相似性，在重复发生的社区。这里驱动群落相似性的有孔虫类群也被独立地认为是海底缺氧制度的标志物种，这为氧合变化是海底环境变化的主要驱动因素的想法提供了支持。
Paleoecological reconstructions of past climate are often based on a single taxonomic group with a consistent presence. Less is known about the relationship between multi-taxon community-wide change and climate variability. Here we reconstruct paleoecological change in a Late Quaternary (16.1–3.4 ka) sediment core from the California margin (418 m below sea level) of Santa Barbara Basin (SBB), USA, using Mollusca (Animalia) and Foraminifera (Rhizaria) microfossils. Building upon previous investigations, we use multivariate ordination and cluster analyses to interpret community-scale changes in these distinctly different taxonomic groups across discrete climate episodes. The strongest differences between seafloor biological communities occurred between glacial (prior to Termination IA, 14.7 ka) and interglacial climate episodes. Holocene communities were well partitioned, indicating that sub-millennial oceanographic variability was recorded by these microfossils. We document strong evidence of chemosynthetic trophic webs and sulfidic environments (from gastropodAlia permodestaand bivalveLucinoma aequizonata), which characterized restricted intervals previously interpreted as well oxygenated (such as the Pre-Bølling Warming). Mollusc records indicate first-order trophic energetic shifts between detrital and chemosynthetically-fixed carbon. Molluscs associated with widely different physiological preferences occur here within single, decadal intervals of sediment, and as such mollusc assemblages may reflect significant inter-decadal oceanographic variability. Foraminifera assemblages provide exceptional records of the sequential, chronological progression of the deglacial climatic and oceanographic events, whereas mollusc assemblages reflect non-chronological similarities in reoccurring communities. Foraminifera taxa that drive community similarity here are also independently recognized as marker species for seafloor hypoxia regimes, which provides support for the idea that oxygenation change is a principal driver of seafloor environmental variability.