Micropaleontology Laboratory, Geological Oceanography Division, National Institute of Oceanography, Goa, India.
School of Earth, Ocean and Atmospheric Sciences, Goa University, Goa, India.
Environ Sci Pollut Res Int. 2024 Apr;31(17):24961-24985. doi: 10.1007/s11356-024-32685-4. Epub 2024 Mar 9.
The unicellular calcareous planktic foraminifera sequester a significant portion of the carbon dioxide dissolved in the ocean, thus burying the carbon in sediments for millions of years. The global warming and associated processes are likely to affect the planktic foraminiferal abundance and diversity. Therefore, their baseline distribution has to be documented and correlated with ambient parameters to assess its fate under different climate change scenarios. Here, we report an exceptionally high abundance of planktic foraminifera and thus large carbon burial in the southwestern Bay of Bengal. The very high absolute abundance of planktic foraminifera in the Cauvery River basin is attributed to biannual productivity, warmer and saline waters. Globigerinita glutinata is the highest abundant species followed by Globigerinoides ruber and Globigerina bulloides. Globigerina bulloides is abundant on the shelf, where the upwelling is more frequent. The relative abundance of Globorotalia menardii is positively correlated with thermocline salinity and negatively correlated with thermocline temperature. Similarly, Neogloboquadrina dutertrei and Globoquadrina conglomerata are negatively correlated with mixed layer as well as thermocline temperature and mixed layer salinity. Both these species are positively correlated with thermocline salinity. Globigerina falconensis is more abundant in the southernmost transect influenced by intense winter monsoon precipitation. We report that G. ruber prefers high saline and warmer waters with the highest abundance in the southernmost transect. From the foraminiferal distribution, it is evident that the temperature and salinity of the mixed layer as well as thermocline, food availability, and monsoon-associated processes affect the planktic foraminiferal abundance and thus carbon burial in the southwestern Bay of Bengal. The changes in influx of southeastern Arabian Sea water will affect the planktic foraminiferal population and subsequent carbon burial in the southwestern Bay of Bengal.
单细胞钙质浮游有孔虫会隔离海洋中溶解的大量二氧化碳，从而将碳埋藏在沉积物中长达数百万年。全球变暖及相关过程可能会影响浮游有孔虫的丰度和多样性。因此，必须记录其基线分布，并将其与环境参数相关联，以评估其在不同气候变化情景下的命运。在这里，我们报告了孟加拉湾西南部浮游有孔虫异常高的丰度和大量的碳埋藏。考维里河流域浮游有孔虫的绝对丰度非常高，这归因于其两年一次的生产力、温暖和咸水。Globigerinita glutinata 是最丰富的物种，其次是 Globigerinoides ruber 和 Globigerina bulloides。Globigerina bulloides 在陆架上更为丰富，那里上升流更为频繁。Globorotalia menardii 的相对丰度与温跃层盐度呈正相关，与温跃层温度呈负相关。同样，Neogloboquadrina dutertrei 和 Globoquadrina conglomerata 与混合层以及温跃层温度和混合层盐度呈负相关，与温跃层盐度呈正相关。Globigerina falconensis 在受强烈冬季季风降水影响的最南端横截面上更为丰富。我们报告称，G. ruber 更喜欢高盐度和温暖的水域，在最南端的横截面上丰度最高。从有孔虫的分布来看，很明显，混合层和温跃层的温度和盐度、食物供应以及季风相关过程都会影响浮游有孔虫的丰度，从而影响孟加拉湾西南部的碳埋藏。来自东南阿拉伯海的水的流入变化将影响浮游有孔虫的种群及其在孟加拉湾西南部的后续碳埋藏。
