Stable isotopic composition of carbon (δ¹³C_POM) and nitrogen (δ¹⁵N_POM) in the particulate organic matter (POM) is used to identify sources of organic carbon and nutrients using monthly time-series observation in the coastal Bay of Bengal (BoB). The hydrographic structure indicates that the coastal BoB is influenced by coastal upwelling during March–May, advection of peninsular river discharge during June to September and glacial (Ganges) river discharge during October to December due to reversing of East India Coastal Currents (EICC). C/N ratios in POM were mostly higher values than Redfield ratio in the study region indicating possible contribution of terrestrial origin. Enriched δ¹³C_POM were found during March–May associated with coastal upwelling indicating major contribution of POM from the in situ production while lower values were noticed during June to September followed by October to December indicating influence of terrestrial sources. δ¹⁵N_POM displayed strong inverse relation with salinity and linear relation with Chl-a suggesting that anthropogenic nutrients from the land increased coastal phytoplankton biomass. δ¹⁵N_POM linearly decreased with increase in distance from the coast and reached to the typical offshore value of 6–6.5‰ indicating that terrestrial nutrients influence was spread up to a distance of 15 to 20 km from the coast in the study region. Our study suggested that coastal waters are influenced by terrestrial/anthropogenic nutrients and its impact can be noticed up to 15 to 20 km from the coast and its impact on Biodiversity Beyond National Jurisdiction may be negligible than hitherto hypothesized.

碳（δ的稳定同位素组成¹³ Ç _POM）和氮（δ ¹⁵ Ñ _POM）中的颗粒有机物质（POM）被用于识别在孟加拉沿海湾使用月时序观察有机碳源和营养物（ BoB）。水文结构表明，由于东印度洋洋流（EICC）的逆转，沿海的BoB受3月至5月的海岸上升，6月至9月的半岛河流平流以及10月至12月的冰川（恒河）流影响。在研究区域中，POM中的C / N比值大多高于Redfield比值，表明可能是地球起源的原因。富集的δ ¹³ C ^ _POM在3月至5月期间发现与沿海上升有关，表明原位生产中POM的主要贡献，而在6月至9月发现较低的POM值，随后在10月至12月发现地面来源的影响。δ ¹⁵ Ñ _POM显示具有盐度和线性关系与叶绿素a表明从土地人为营养素增加沿海浮游植物强反比关系。δ ¹⁵ Ñ _POM随着距海岸距离的增加线性减小，并达到典型的离岸值6-6.5‰，这表明在研究区域内，陆地养分的影响扩展到距海岸15至20 km的距离。我们的研究表明，沿海水域受到陆地/人为养分的影响，并且距海岸最多15至20 km都可注意到其影响，并且其对国家管辖范围以外的生物多样性的影响可能比迄今假设的微不足道。