Episodes of intensified biological productivity in the subtropical Atlantic Ocean during the termination of the Middle Eocene Climatic Optimum (MECO)
Episodes of intensified biological productivity in the subtropical Atlantic Ocean during the termination of the Middle Eocene Climatic Optimum (MECO)
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DOI：
10.1002/2014pa002673
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发表时间：
2015-08
期刊：
影响因子：
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通讯作者：
I. Moebius;O. Friedrich;K. Edgar;P. Sexton
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文献类型：
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作者：
I. Moebius;O. Friedrich;K. Edgar;P. Sexton
始新世中期气候适宜期（MECO）是一个约500 kyr的显著全球变暖间隔，气候系统在50 kyr内恢复。深海沉积记录可以提供宝贵的见解，海洋生态系统对这一长期的全球变暖事件的反应，从而在这段时间内的生态变化。在这里，我们提出了新的底栖有孔虫组合数据大洋钻探计划网站1051在亚热带北大西洋，跨越MECO和后MECO间隔（41.1至39.5马）。我们发现，在研究的时间间隔内，底栖有孔虫组合的物种组成变化不大，这表明环境变化的速度是渐进的，这些生物能够适应。然而，我们确定了两个短暂的间隔与峰值变暖（高生产力区间（HPI）-1; 40.07-39.96马）和MECO（HPI-2; 39.68-39.55马）后不久，底栖有孔虫积累率增加了一个数量级。这些HPIs在站点1051出现的时间间隔，加强生产力在特提斯，南大洋，南大西洋，我们认为，加强水文循环在气候温暖的MECO负责海洋陆架和斜坡环境的富营养化。
The Middle Eocene Climatic Optimum (MECO) is an ~500 kyr interval of pronounced global warming from which the climate system recovered in <50 kyr. The deep-sea sedimentary record can provide valuable insight on the marine ecosystem response to this protracted global warming event and consequently on the ecological changes during this time. Here we present new benthic foraminiferal assemblage data from Ocean Drilling Program Site 1051 in the subtropical North Atlantic, spanning the MECO and post-MECO interval (41.1 to 39.5 Ma). We find little change in the species composition of benthic foraminiferal assemblages during the studied interval, suggesting that the rate of environmental change was gradual enough that these organisms were able to adapt. However, we identify two transient intervals associated with peak warming (higher-productivity interval (HPI)-1; 40.07–39.96 Ma) and shortly after the MECO (HPI-2; 39.68–39.55 Ma), where benthic foraminiferal accumulation rates increase by an order of magnitude. These HPIs at Site 1051 appear to coincide with intervals of strengthened productivity in the Tethys, Southern Ocean, and South Atlantic, and we suggest that an intensified hydrological cycle during the climatic warmth of the MECO was responsible for eutrophication of marine shelf and slope environments.