Carbon dynamics in the western Arctic Ocean: insights from full-depth carbon isotope profiles of DIC, DOC, and POC
Carbon dynamics in the western Arctic Ocean: insights from full-depth carbon isotope profiles of DIC, DOC, and POC
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DOI：
10.5194/bg-9-1217-2012
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发表时间：
2012-01-01
期刊：
影响因子：
4.9
通讯作者：
Eglinton, T. I.
中科院分区：
文献类型：
--
作者：
Griffith, D. R.;McNichol, A. P.;Eglinton, T. I.
北极变暖预计将持续到下个世纪。然而，我们目前对北冰洋碳循环的了解有限，阻碍了我们预测变化的条件将如何影响当地北极生态系统、区域碳预算和全球气候的能力。本文介绍了北冰洋加拿大海盆两个地点的溶解无机碳(DIC)、溶解有机碳(DOC)和悬浮颗粒有机碳(POCsusp)的第一套同步、全深度双同位素剖面。北极下沉和悬浮POC的碳同位素组成与大西洋和太平洋开阔海域形成强烈对比，表明北极POCsusp的输入是表层衍生有机碳(OC)、吸附/平流有机碳(OC)和原位DIC固定有机碳的组合。后一个过程在中等深度显得尤为重要，在那里质量平衡计算表明，来自原位DIC固定的OC占POCsusp的22%。与其他海洋一样，海面来源的有机碳仍然是北极POCsusp的主要来源。然而，我们认为，加拿大盆地中显著较小的垂直POC通量使得即使在主体同位素水平上也可以看到DIC固定在POCsusp池中的证据。
Arctic warming is projected to continue throughout the coming century. Yet, our currently limited understanding of the Arctic Ocean carbon cycle hinders our ability to predict how changing conditions will affect local Arctic ecosystems, regional carbon budgets, and global climate. We present here the first set of concurrent, full-depth, dual-isotope profiles for dissolved inorganic carbon (DIC), dissolved organic carbon (DOC), and suspended particulate organic carbon (POCsusp) at two sites in the Canada Basin of the Arctic Ocean. The carbon isotope composition of sinking and suspended POC in the Arctic contrasts strongly with open ocean Atlantic and Pacific sites, pointing to a combination of inputs to Arctic POCsusp at depth, including surface-derived organic carbon (OC), sorbed/advected OC, and OC derived from in situ DIC fixation. The latter process appears to be particularly important at intermediate depths, where mass balance calculations suggest that OC derived from in situ DIC fixation contributes up to 22% of POCsusp. As in other oceans, surface-derived OC is still a dominant source to Arctic POCsusp. Yet, we suggest that significantly smaller vertical POC fluxes in the Canada Basin make it possible to see evidence of DIC fixation in the POCsusp pool even at the bulk isotope level.