Planktic foraminifera are amongst the most widely used paleoclimatic proxies. The application of foraminifera for paleoclimatic reconstruction requires knowledge of the ecological preference of species. Here, we report the surface distribution and ecology of planktic foraminifera from 99 core top samples collected from the riverine influx dominated western Bay of Bengal. The riverine influx reduces the planktic population on the shelf, in its immediate vicinity. Incidentally, the population increases on the slope in front of the major river mouths. A total 30 species belonging to 14 genera were found. Globigerinita glutinata is the most abundant species in the western Bay of Bengal, followed by Globigerina bulloides. Globigerina bulloides is abundant on the outer shelf, a region influenced by upwelling during southwest monsoon. The negative correlation of Neogloboquadrina dutertrei with sea surface salinity is attributed to the chlorophyll maximum due to the density gradient created by the hyposaline surface water. Globigerinoides ruber were abundant (>10%) at stations with higher salinity (>32 psμ). The mixed layer dwelling Trilobatus sacculifer are abundant on the slope. The increased relative abundance of Globigerinella siphonifera in shallow waters is attributed to the low salinity freshwater plume. The negative correlation of Globorotalia menardii with thermocline temperature and positive correlation with thermocline salinity suggests its cold water, high salinity habitat. We conclude that the freshwater and sediment influx and associated changes strongly modulate planktic foraminiferal distribution. The findings will help in better application of temporal changes in planktic foraminiferal population to reconstruct past environmental conditions from the Bay of Bengal.

浮游有孔虫是最广泛使用的古气候代理之一。有孔虫在古气候重建中的应用需要了解物种的生态偏好。在这里，我们从从孟加拉河西湾支流的河流涌入采集的99个核心顶部样品中报告了有孔有孔虫的表面分布和生态。河水的涌入减少了紧邻其的陆架上的浮游生物数量。顺便说一句，人口在主要河口前的斜坡上增加。共发现14个属的30种。Globigerinita glutinata是孟加拉湾西部最丰富的物种，其次是Globigerina bulloides。Globigerina Bulloides西南季风期间上涌影响了该地区的外陆架。Neogloboquadrina dutertrei与海表盐度的负相关归因于次盐碱地表水产生的密度梯度导致的叶绿素最大值。在盐度较高（> 32psμ）的测站中，大球藻（Globigerinoides ruber）含量丰富（> 10％）。斜坡上杂种Trilobatus sacculifer的居住地丰富。浅水域中虹吸球藻的相对丰度增加归因于盐度低的淡水羽流。Menardii球果的负相关与温跃层温度成正相关且与温跃层盐度呈正相关，说明其冷水，高盐度生境。我们得出的结论是，淡水和沉积物的涌入及相关变化强烈地调节了板状有孔虫的分布。这些发现将有助于更好地应用有孔有孔虫种群的时间变化，以重建孟加拉湾过去的环境条件。