A biomarker perspective on dust, productivity, and sea surface temperature in the Pacific sector of the Southern Ocean
A biomarker perspective on dust, productivity, and sea surface temperature in the Pacific sector of the Southern Ocean
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DOI：
10.1016/j.gca.2017.01.045
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发表时间：
2017-05
影响因子：
5
通讯作者：
A. Jaeschke;M. Wengler;J. Hefter;T. Ronge;W. Geibert;G. Mollenhauer;R. Gersonde;F. Lamy
中科院分区：
文献类型：
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作者：
A. Jaeschke;M. Wengler;J. Hefter;T. Ronge;W. Geibert;G. Mollenhauer;R. Gersonde;F. Lamy
在这项研究中，我们提出了一个新的多代理数据集的陆源输入，海洋生产力和海表温度（SST）从52个表层沉积物样品收集沿着东西断面在南大洋太平洋部门。外来陆源输入的特点是分布的植物蜡正构烷烃和土壤衍生的支链甘油二烷基甘油四醚（brGDGTs）。230 Th归一化埋藏的两个化合物组最接近的潜在来源在澳大利亚和新西兰，并强烈相关的成岩含量（232 Th），表明共同的来源和运输。长链正构烷烃和brGDGT的检测在最偏远的网站在公海强烈建议一个主要的风成运输机制，至少110° W，即盛行西风。使用了两个独立的有机SST代用品，基于烯酮的U 37 K′和基于类异戊二烯GDGT的TEX 86。U 37 K′和TEX 86指数在0.5至20° C之间的温度范围内与温度表现出稳健的关系，可能意味着温度信号上的不同季节和区域印记。当使用Sikes等人的极地校准时，基于烯酮的温度估计最好地反映了研究区域的现代夏季SST。（1997年）。相比之下，TEX 86导出的温度可能反映地下信号而不是表面。230 Th标准化埋藏的烯酮是最高的接近副热带锋，并在整个研究区的成岩物质的沉积呈正相关。与此相反，最高的isoGDGT埋葬南部的南极极锋可能在很大程度上控制硅藻水华，从而在南方夏季高蛋白石通量。
In this study, we present a new multiproxy data set of terrigenous input, marine productivity and sea surface temperature (SST) from 52 surface sediment samples collected along E–W transects in the Pacific sector of the Southern Ocean. Allochthonous terrigenous input was characterized by the distribution of plant wax n-alkanes and soil-derived branched glycerol dialkyl glycerol tetraethers (brGDGTs). 230 Th-normalized burial of both compound groups were highest close to the potential sources in Australia and New Zealand and are strongly related to lithogenic contents (232 Th), indicating common sources and transport. Detection of both long-chain n-alkanes and brGDGTs at the most remote sites in the open ocean strongly suggests a primarily eolian transport mechanism to at least 110° W, ie by prevailing westerly winds. Two independent organic SST proxies were used, the U 37 K′ based on alkenones, and the TEX 86 based on isoprenoid GDGTs. Both, U 37 K′ and TEX 86 indices show robust relationships with temperature over a temperature range between 0.5 and 20° C, likely implying different seasonal and regional imprints on the temperature signal. Alkenone-based temperature estimates best reflect modern summer SST in the study area when using the polar calibration of Sikes et al.(1997). In contrast, TEX 86-derived temperatures may reflect a subsurface signal rather than surface. 230 Th-normalized burial of alkenones is highest close to the Subtropical Front and is positively related to the deposition of lithogenic material throughout the study area. In contrast, highest isoGDGT burial south of the Antarctic Polar Front may be largely controlled by diatom blooms, and thus high opal fluxes during austral summer.