Abstract Human activities are placing escalating pressures on estuaries, with rising carbon and nitrogen inputs. However, their impact on macrobenthic fauna remains poorly understood. This study explores the Cochin Estuary (CE), assessing how variations in carbon–nitrogen levels in bottom waters and sediments shape macrobenthic faunal distribution and abundance. The results indicate that the estuary is experiencing severe carbon–nitrogen pollution. Terrestrial C3 plants, marine phytoplankton, and estuarine productivity serve as the primary sources of carbon, while nitrogen pollution is largely attributed to inputs from the fertilizer industry and sewage discharge. Ecological indices such as AMBI and BENTIX indicate moderate to heavy pollution, signaling ecological deterioration. Statistical analyses, including Pearson correlation and BIO-ENV, establish a strong connection between carbon–nitrogen loading, declining water quality, and reduced macrobenthic faunal abundance. Areas with severe carbon–nitrogen imbalances exhibited a sharp decline or complete loss of macrobenthic fauna. These findings highlight the detrimental effects of anthropogenic carbon–nitrogen pollution on macrobenthic fauna, ultimately impacting estuarine productivity. Given growing human-induced pressures, this study underscores the urgent need for continuous monitoring and sustainable estuarine management. Furthermore, it reinforces the role of macrobenthic fauna as key bioindicators, advocating for targeted conservation strategies to mitigate carbon–nitrogen pollution and habitat degradation in CE. Research highlights <UnorderedList Mark="Bullet"> <ItemContent> Cochin Estuary is heavily polluted with anthropogenic nitrogen and intense organic matter loading. </ItemContent> <ItemContent> Estuary turned to be a hub of opportunistic species, with polychaetes and oligochaetes dominating. </ItemContent> <ItemContent> Severe declines or absence of macrobenthic fauna observed in areas with high carbon–nitrogen imbalance. </ItemContent> <ItemContent> Findings stress the urgency of continuous monitoring and sustainable estuarine management. </ItemContent> </UnorderedList>

Impact of carbon–nitrogen pollution on macrobenthic fauna: insights from the Cochin Estuary, India

期刊论文
发表日期：

2026年3月6日

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N Regina Hershey

摘要

Abstract

Human activities are placing escalating pressures on estuaries, with rising carbon and nitrogen inputs. However, their impact on macrobenthic fauna remains poorly understood. This study explores the Cochin Estuary (CE), assessing how variations in carbon–nitrogen levels in bottom waters and sediments shape macrobenthic faunal distribution and abundance. The results indicate that the estuary is experiencing severe carbon–nitrogen pollution. Terrestrial C₃ plants, marine phytoplankton, and estuarine productivity serve as the primary sources of carbon, while nitrogen pollution is largely attributed to inputs from the fertilizer industry and sewage discharge. Ecological indices such as AMBI and BENTIX indicate moderate to heavy pollution, signaling ecological deterioration. Statistical analyses, including Pearson correlation and BIO-ENV, establish a strong connection between carbon–nitrogen loading, declining water quality, and reduced macrobenthic faunal abundance. Areas with severe carbon–nitrogen imbalances exhibited a sharp decline or complete loss of macrobenthic fauna. These findings highlight the detrimental effects of anthropogenic carbon–nitrogen pollution on macrobenthic fauna, ultimately impacting estuarine productivity. Given growing human-induced pressures, this study underscores the urgent need for continuous monitoring and sustainable estuarine management. Furthermore, it reinforces the role of macrobenthic fauna as key bioindicators, advocating for targeted conservation strategies to mitigate carbon–nitrogen pollution and habitat degradation in CE.

Research highlights

Cochin Estuary is heavily polluted with anthropogenic nitrogen and intense organic matter loading.

Estuary turned to be a hub of opportunistic species, with polychaetes and oligochaetes dominating.

Severe declines or absence of macrobenthic fauna observed in areas with high carbon–nitrogen imbalance.

Findings stress the urgency of continuous monitoring and sustainable estuarine management.