Influence of the upwelling events on the δ13C and δ18O of the benthic bivalve shells of the South Western Continental Margin of India
Influence of the upwelling events on the δ13C and δ18O of the benthic bivalve shells of the South Western Continental Margin of India
复制标题
上升流事件对印度西南大陆边缘底栖双壳贝δ13C和δ18O的影响
DOI：
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发表时间：
2016
影响因子：
2.8
通讯作者：
V. N. Sanjeevan
中科院分区：
文献类型：
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作者：
J. Jacob;P. Ghosh;K. U. Abdul Jaleel;B. Smitha;K. Abhilash;V. N. Sanjeevan
在这项研究中，上升流强度的时空变化和相关的生物生产力观测期间的不同阶段的夏季风沿着西南印度大陆边缘（SWCMI）的无机生物碳酸盐壳体的δ 13 C和δ 18 O的影响进行了研究。分析了2009年夏季风爆发和盛期（OSM和PSM）西南印度洋（12°N、10°N和9°N）10个表层沉积物样品中1-5 mm的多种底栖双壳类贝壳的δ 13 C和δ 18 O。沿研究区域的海表温度沿着表明在PSM比OSM突出的上升流。对双壳类贝壳中δ 18 O的分析值和预测值进行比较，证实了它们在两个取样期间的原地来源。在PSM期间，底栖双壳类贝壳的δ 13 C值比OSM期间更贫，OSM期间记录的PSM研究区域底沃茨溶解无机碳的δ 13 C值较低，这是由于上涌沃茨、高表面生产力以及与之相关的次表层和底沃茨有机物的高度降解。然而，在10°N的底栖双壳类贝壳中没有观察到δ 13 C的这种损耗，因为它受到了自季风早期以来科钦河口高输出碳通量的影响。
In this study, the influence of the spatial and temporal variability of upwelling intensity and the associated biological productivity observed during different phases of summer monsoon along the southwestern continental margin of India (SWCMI) on the δ13C and δ18O of the inorganic biogenic carbonate shells was investigated. Multispecies benthic bivalve shells (1–5 mm) separated from ten surface sediment samples of SWCMI (off 12°N, 10°N and 9°N) collected during the onset (OSM) and peak (PSM) phase of the summer monsoon of 2009 were analysed for δ13C and δ18O. Sea surface temperature along the study region indicates prominent upwelling in PSM than in OSM. A comparison of analytical and predicted values for δ18O in the bivalve shells confirmed their in situ origin during both the sampling periods. During PSM, the δ13C values in the benthic bivalve shells were more depleted in 13C than during OSM which recorded lower values of δ13C in dissolved inorganic carbon of bottom waters expected in the study region in PSM due to the upwelled waters, high surface productivity and the associated high degradation of the organic matter in the subsurface and bottom waters. However, this depletion of δ13C was not observed in benthic bivalve shells obtained from 10°N, since it is influenced by high export fluxes of carbon from the Cochin estuary since early monsoon months.