Diatom assemblages in surface sediments of the northwestern Weddell Sea, Antarctic Peninsula
Diatom assemblages in surface sediments of the northwestern Weddell Sea, Antarctic Peninsula
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DOI：
10.1016/j.marmicro.2006.07.002
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发表时间：
2007-01-10
影响因子：
1.9
通讯作者：
Hutchins, Trisha
中科院分区：
文献类型：
--
作者：
Buffen, Aron;Leventer, Amy;Hutchins, Trisha
对威德尔海西北部42个表层沉积物样品的研究表明，该地区硅藻组合的现代分布与现代海洋学条件之间的关系。通过R型主成分分析和聚类分析，确定了3个硅藻组合，而Q型聚类分析用于区分两个地理上不同的生物相。基于硅藻物种的相对丰度，前拉森A冰架（莱什）的生物相与海冰硅藻组合更密切相关，而古斯塔夫王子海峡/北部半岛（PGC/NP）的生物相与两个开放的沿海硅藻组合。这种划分与当前海洋环境中观察到的变化是一致的，即莱什的特点是海冰覆盖的季节性持续时间较长，初级生产力较低，而PGC/NP的特点是海冰覆盖的季节性持续时间较短，地表水生产力较高。这种关系进一步反映在分布的古环境重要的硅藻物种Fragilariopsis curta，海链藻anarctica，和角毛藻subg。透明毛菌属以及绝对丰度数据。具体而言，E curta和形态形式T antaretica T1是海冰覆盖和生产力较低的季节性持续时间较长的代表。角毛藻亚属透明毛菌属和形态形式T anaerotica T2与海冰覆盖的季节性持续时间减少和更大的地表水生产力有关，这种情况进一步反映在硅藻绝对丰度高。这些发现为该地区未来的古海洋学工作提供了基础，特别是因为表面沉积物硅藻组合的研究对于建立底层硅藻组合与目前在水柱中发现的硅藻组合之间的联系至关重要。(c)2006 Elsevier B. V.保留所有权利。
A study of 42 surface sediment samples from the northwestern Weddell Sea documents the relationship between the modem distribution of diatom assemblages and present oceanographic conditions in the region. Three diatom assemblages were identified using R-mode principal components analysis and cluster analysis, while Q-mode cluster analysis was used to distinguish two geographically distinct biofacies. Based on the relative abundance of diatom species, the biofacies of the former Larsen A Ice Shelf (LAIS) is more closely associated with a sea ice diatom assemblage, while the biofacies of the Prince Gustav Channel/Northem Peninsula (PGC/NP) is associated with two open coastal diatom assemblages. This division is consistent with variance observed in the current oceanographic setting, whereby the LAIS is generally characterized by a longer seasonal duration of sea ice coverage and lower primary productivity relative to the PGC/NP which is marked by a shorter seasonal duration of sea ice coverage and greater surface water productivity. This relationship is further reflected in the distribution of the paleoenvironmentally significant diatom species Fragilariopsis curta, Thalassiosira antarctica, and Chaetoceros subg. Hyalochaete spp. as well as in absolute abundance data. Specifically, E curta and the morphological form T antaretica T1 are representative of greater seasonal duration of sea ice coverage and lower productivity. Chaetoceros subg. Hyalochaete spp. and the morphological form T antarctica T2 are associated with decreased seasonal duration of sea ice cover and greater surface water productivity, a setting that is further reflected in high absolute diatom abundances. These findings provide a basis for future paleoceanographic work in the region, especially as studies of surface sediment diatom assemblages are vital to establishing a link between downcore diatom assemblages and those presently found in the water column. (c) 2006 Elsevier B.V. All rights reserved.