Delineating the food web structure in an Indian estuary during tropical winter employing stable isotope signatures and mixing model

• Published in: Environmental science and pollution research international Vol. 30; no. 17; pp. 49412 - 49434
• Main Authors: Lal, Dhanya Mohan, Sreekanth, Giri Bhavan, Soman, Chitra, Sharma, Anupam, Abidi, Zeba Jaffer
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.04.2023; Springer Nature B.V
• Subjects: Anthropogenic factors; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Carbon; Carbon Isotopes - analysis; Carbon sources; Consumer groups; Detritus; Earth and Environmental Science; Ecosystem; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Environmental science; Estuaries; Food Chain; Food chains; Food webs; Guilds; Human influences; Nitrogen; Nitrogen enrichment; Nitrogen Isotopes - analysis; Organic matter; Particulate organic matter; Phytoplankton; Plankton; Research Article; Signatures; Stable isotopes; Waste Water Technology; Water Management; Water Pollution Control; Food web; Mixing model; Trophic guild; Trophic level; Estuary; Stable isotopes
• ISSN: 1614-7499; 0944-1344; 1614-7499
• DOI: 10.1007/s11356-023-25549-w

The food and feeding links and sources in an impacted tropical estuary situated along India’s western coast, the Ulhas River Estuary (URE) was analyzed employing the stable carbon and nitrogen isotopic signatures (δ 13 C and δ 15 N). Three basal carbon sources, such as mangrove leaves, particulate organic matter (phytoplankton), and detritus, were analyzed together with eight consumer groups from various trophic guilds. The δ 13 C varied from − 19.67 to − 24.61‰, whereas δ 15 N ranged from 6.31 to 15.39‰ from the primary consumer to the top predator species. The stable isotope mixing model developed for URE revealed a phytoplankton based pelagic food chain and detritus based benthic food chain in URE. The fairly larger value of SEA (Standard Ellipse Area) in the URE suggest a much broader food web structure and high trophic diversity in the ecosystem. Higher influence of detritus on the assimilated diet of majority of consumers and evidences of nitrogen enrichment in the basal sources such as detritus and particulate organic matter by anthropogenic activities in URE point towards nitrogen pollution and subsequent trophic disturbance in this tropical estuarine ecosystem.