Spatiotemporal dynamics of carbon isotope ratios and phytoplankton composition in the eastern Arabian Sea.

Autor: Marathe P; Centre for Marine Living Resources and Ecology (CMLRE), Kochi, Kerala, India; Kerala University of Fisheries and Ocean Studies (KUFOS), Kochi, Kerala, India., Vijayan AK; Centre for Marine Living Resources and Ecology (CMLRE), Kochi, Kerala, India; Ministry of Earth Sciences (MoES), Government of India, Prithvi Bhawan, New Delhi, India. Electronic address: anilkumar.v@gov.in., Reddy BB; Centre for Marine Living Resources and Ecology (CMLRE), Kochi, Kerala, India; Kerala University of Fisheries and Ocean Studies (KUFOS), Kochi, Kerala, India., Sudheesh V; Centre for Marine Living Resources and Ecology (CMLRE), Kochi, Kerala, India; Central University of Kerala (CUK), Kasargod, Kerala, India.
Jazyk: angličtina
Zdroj: Marine pollution bulletin [Mar Pollut Bull] 2024 Dec 26; Vol. 212, pp. 117474. Date of Electronic Publication: 2024 Dec 26.
DOI: 10.1016/j.marpolbul.2024.117474
Abstrakt: This study investigated major contributors of the particulate organic matter (POM) using stable isotope ratios of particulate organic carbon (δ 13 C POC ) and its relationship with phytoplankton composition during three seasons across six coast-offshore transects in the eastern Arabian Sea (EAS). Results revealed significant spatiotemporal variations, with elevated δ 13 C POC in coastal waters during the winter and summer monsoon (-22.40 ± 1.76‰), linked to increased phytoplankton biomass (2.26 ± 2.21 μg l -1 ) and dominance of diatoms (micro-phytoplankton) (65.35 ± 30.98%). In contrast, lower δ 13 C POC during the spring inter monsoon (SIM) and in offshore waters during WM and SM (-23.31 ± 1.32‰) were associated with cyanobacteria (pico-phytoplankton) dominance (78.27 ± 22.75%). Positive correlations of POC with Chlorophyll a (Chla) and particulate nitrogen (PN) (r > 0.5, p < 0.05), along with their ratios (POC:Chla < 200 and POC:PN < 12), indicated the autochthonous nature of POM. Distinct δ 13 C POC ranges were identified based on phytoplankton composition; diatoms (micro-phytoplankton) dominated waters exhibited δ 13 C POC values between -23.83 and -19.19‰, while nano and/or pico-phytoplankton dominated showed values ranging from -26.00 to -22.15‰. This study highlights spatiotemporal variability in the POM composition and emphasises the importance of δ 13 C POC in understanding its relationship with phytoplankton composition. Baseline information on δ 13 C POC will aid in developing stable isotope isoscapes of the EAS, enhancing our understanding of trophodynamics and animal migratory patterns.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2024. Published by Elsevier Ltd.)
Databáze: MEDLINE
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