Organic carbon production, mineralisation and preservation on the Peruvian margin
Organic carbon production, mineralisation and preservation on the Peruvian margin
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DOI：
10.5194/bg-12-1537-2015
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发表时间：
2015-01-01
期刊：
影响因子：
4.9
通讯作者：
Wallmann, K.
中科院分区：
文献类型：
--
作者：
Dale, A. W.;Sommer, S.;Wallmann, K.
通过原位通量测量、沉积地球化学和建模相结合的方法，对秘鲁边缘（南纬11度和12度）16个站点的碳循环进行了研究，这些站点从陆架中部74米水深处一直到1024米深处。底层水的含氧量在约400米深处低于检测极限，在最深的站点增加到53微摩尔。沉积物堆积速率在陆架中部向海一侧急剧下降，随后在深海站点又有所增加。在富氧的深海站点，陆架中部的有机碳埋藏效率（CBE）异常低（60%）。与其他研究一致，在中层水最低含氧带的缺氧水体下，CBE升高。根据海底通量计算的有机碳沉降速率表明，与其他缺氧环境相比，水柱中有机物的矿化效率较高。秘鲁边缘的观测结果表明，缺氧对水柱中有机物的降解影响不大，但促进了沉积物中有机物的保存。
Carbon cycling in Peruvian margin sediments (11 and 12 degrees S) was examined at 16 stations, from 74 m water depth on the middle shelf down to 1024 m, using a combination of in situ flux measurements, sedimentary geochemistry and modelling. Bottom water oxygen was below detection limit down to ca. 400 m and increased to 53 mu M at the deepest station. Sediment accumulation rates decreased sharply seaward of the middle shelf and subsequently increased at the deep stations. The organic carbon burial efficiency (CBE) was unusually low on the middle shelf (60%) at the deep oxygenated sites. In line with other studies, CBE was elevated under oxygen-deficient waters in the mid-water oxygen minimum zone. Organic carbon rain rates calculated from the benthic fluxes alluded to efficient mineralisation of organic matter in the water column compared to other oxygen-deficient environments. The observations at the Peruvian margin suggest that a lack of oxygen does not greatly affect the degradation of organic matter in the water column but promotes the preservation of organic matter in sediments.