Southern Ocean bioproductivity during the last glacial cycle – new detection method and decadal-scale insight from the Scotia Sea
Southern Ocean bioproductivity during the last glacial cycle – new detection method and decadal-scale insight from the Scotia Sea
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DOI：
10.1144/sp381.17
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发表时间：
2013-07
影响因子：
3
通讯作者：
D. Sprenk;Michael E Weber;Gerhard Kuhn;Peter Rosén;Martin Frank;Mario Molina-Kescher;Volker Liebetrau;Heinz-Gerd Röhling
中科院分区：
文献类型：
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作者：
D. Sprenk;Michael E Weber;Gerhard Kuhn;Peter Rosén;Martin Frank;Mario Molina-Kescher;Volker Liebetrau;Heinz-Gerd Röhling
摘要我们提出了生物蛋白石通量记录从两个深海站点在斯科舍海（MD 07 -3133和MD 07 -3134）在十年尺度的分辨率，覆盖末次冰期循环。除了传统的和耗时的生物蛋白石测量方法，我们介绍了新的生物蛋白石估计方法来自沉积物颜色B*，湿容重，硅/钛计数比和傅立叶变换红外光谱（FTIRS）。所有的方法捕捉生物蛋白石振幅，然而，傅里叶变换红外光谱-一种新的方法，海洋沉积物-产生最可靠的结果。230 Th标准化数据显示，在沉积物集中与加强沉积物集中在冰期有很大的差异。在MD 07 -3134，230 Th的标准化生物蛋白石通量在0.2和2.5 g cm−2 kyr−1之间变化。我们的生物蛋白石通量记录表明南大洋的生物生产力变化，海冰分布和夏季海面温度变化的强烈影响。南南极极锋，最低的生物生产力发生在末次冰期最大时，中深层水的涌升减少，海冰覆盖加剧。大约17 ka，生物生产力突然增加，对应于大气CO2上升和季节性海冰覆盖率下降。
Abstract We present biogenic opal flux records from two deep-sea sites in the Scotia Sea (MD07-3133 and MD07-3134) at decadal-scale resolution, covering the last glacial cycle. In addition to conventional and time-consuming biogenic opal measuring methods, we introduce new biogenic opal estimation methods derived from sediment colour b*, wet bulk density, Si/Ti-count ratio and Fourier transform infrared spectroscopy (FTIRS). All methods capture the biogenic opal amplitude; however, FTIRS–a novel method for marine sediment – yields the most reliable results. 230Th normalization data show strong differences in sediment focusing with intensified sediment focusing during glacial times. At MD07-3134 230Th normalized biogenic opal fluxes vary between 0.2 and 2.5 g cm−2 kyr−1. Our biogenic opal flux records indicate bioproductivity changes in the Southern Ocean, strongly influenced by sea ice distribution and also summer sea surface temperature changes. South of the Antarctic Polar Front, lowest bioproductivity occurred during the Last Glacial Maximum when upwelling of mid-depth water was reduced and sea ice cover intensified. Around 17 ka, bioproductivity increased abruptly, corresponding to rising atmospheric CO2 and decreasing seasonal sea ice coverage.