Contrasting Productivity and Redox Potential in Arabian Sea and Bay of Bengal  

作　　者：Suhas S Shetye Maruthadu Sudhakar Rahul Mohan Babula Jena 

机构地区：[1]National Centre for Antarctic & Ocean Research [2]Ministry of Earth Sciences

出　　处：《Journal of Earth Science》2014年第2期366-370,共5页地球科学学刊（英文版）

基　　金：the Ministry of Earth Sciences of India for funding the study

摘　　要：Understanding the past and present changes is critical for evaluating the future climatic changes. In order to understand the paleoproductivity and depositional environments of Northern In- dian Ocean, two sediment cores were collected, one each from the Arabian Sea （lat. 16°51.40′N and long. 71°54.37′E, water depth 803 m） and the Bay of Bengal （lat. 13°05.35′N and long. 91°28.21′E, wa- ter depth 3 054 m）. The surface seawater samples indicate higherpCO2 values in Arabian Sea as com- pared to the Bay of Bengal. The sediment organic carbon variations along with sedimentological and other geochemical parameters were studied. Sediment organic carbon varied from 0.5%--4.7% and 0.3%-1.22% in Arabian Sea and the Bay of Bengal, respectively. In Arabian Sea, low productivity, oxic conditions and less intense southwest monsoon prevailed during the deglacial period, whereas productivity has increased from last 16 kyr to the modern age. In the Bay of Bengal, organic carbon decreased from the Last Glacial Maxima （LGM） to the modern age, indicating higher productivity in the past as compared to modern age. Fe was associated with organic carbon in the Bay of Bengal and increased during LGM, showing similar trend to that of organic carbon, indicating that Fe may be the limiting factor for the growth of phytoplankton in the Bay of Bengal in the modern age. In the Bay of Bengal, Mn is enriched during modern age and is depleted during LGM, whereas chromium showed the opposite trend indicating anoxic conditions during the LGM, whereas in Arabian Sea the trends are opposite to the Bay of Bengal.Understanding the past and present changes is critical for evaluating the future climatic changes. In order to understand the paleoproductivity and depositional environments of Northern In- dian Ocean, two sediment cores were collected, one each from the Arabian Sea （lat. 16°51.40′N and long. 71°54.37′E, water depth 803 m） and the Bay of Bengal （lat. 13°05.35′N and long. 91°28.21′E, wa- ter depth 3 054 m）. The surface seawater samples indicate higherpCO2 values in Arabian Sea as com- pared to the Bay of Bengal. The sediment organic carbon variations along with sedimentological and other geochemical parameters were studied. Sediment organic carbon varied from 0.5%--4.7% and 0.3%-1.22% in Arabian Sea and the Bay of Bengal, respectively. In Arabian Sea, low productivity, oxic conditions and less intense southwest monsoon prevailed during the deglacial period, whereas productivity has increased from last 16 kyr to the modern age. In the Bay of Bengal, organic carbon decreased from the Last Glacial Maxima （LGM） to the modern age, indicating higher productivity in the past as compared to modern age. Fe was associated with organic carbon in the Bay of Bengal and increased during LGM, showing similar trend to that of organic carbon, indicating that Fe may be the limiting factor for the growth of phytoplankton in the Bay of Bengal in the modern age. In the Bay of Bengal, Mn is enriched during modern age and is depleted during LGM, whereas chromium showed the opposite trend indicating anoxic conditions during the LGM, whereas in Arabian Sea the trends are opposite to the Bay of Bengal.

关 键 词：PALEOPRODUCTIVITY GEOCHEMICAL DEGLACIAL organic carbon. 

分 类 号：P736[天文地球—海洋地质]