Composition and vertical distribution of organic matter in Central Indian Ocean sediment cores

Sruthi Thalayappil; Muhammed Nayeem Mullungal; Sajna Peediyakkathodi; Ratheesh Kumar C S; Resmi Panikkaveettil; Salas P M; Sujatha C H

doi:10.1038/s41598-023-49116-y

Composition and vertical distribution of organic matter in Central Indian Ocean sediment cores

Sci Rep. 2024 Jan 25;14(1):2157. doi: 10.1038/s41598-023-49116-y.

Authors

Sruthi Thalayappil^{1

2}, Muhammed Nayeem Mullungal³, Sajna Peediyakkathodi⁴, Ratheesh Kumar C S⁴, Resmi Panikkaveettil², Salas P M¹, Sujatha C H¹

Affiliations

¹ Department of Chemical Oceanography, School of Marine Sciences, Cochin University of Science and Technology, Kochi, Kerala, 682016, India.
² Kerala University of Fisheries and Ocean Studies, Panangad, Kerala, India.
³ Environmental Sciences Program, Department of Biological and Environmental Sciences, College of Arts and Science, Qatar University, P.O. Box 2713, Doha, Qatar. mmullungal@qu.edu.qa.
⁴ School of Environmental Studies, Cochin University of Science and Technology, Kochi, Kerala, 682022, India.

Abstract

This study aimed to investigate the quality and quantity of organic matter (OM) using biochemical components (protein, carbohydrate and lipids) in the sediment cores collected from the Central Indian Ocean (CIOB) under the program Equatorial Indian Ocean Process Study Dynamics and Biogeochemistry (EIOPS). Total organic carbon (TOC) and biochemical parameters (carbohydrate, lipid, protein, Tannin and lignin) were determined in core I and core II, respectively. Total carbohydrates varied from 4.66 to 2557.32 mg/kg (average 459.31 mg/kg) and 142.23 to 821.56 mg/kg (average 380.01 mg/kg) in core I and II, respectively. In core I, PRT varied from 70.95 to 107.05 mg/kg, and the minimum and maximum content of CHO was 143.23 and 822.56 mg/kg. The maximum and minimum concentrations of BPC in core II were 786.32 and 381.07 at 0-10 cm depth, respectively, which corresponded to the concentrations of PRT, CHO, LPD, and Tannin. The results showed that PRT was statistically significant with the TOC and negatively correlated with the LPD and CHO, while LPD was highly significant with clay and silt grains. In most of the samples, the ratio of LPD to CHO ratio was > 1, which indicated higher productivity of benthic organisms inhabiting the CIOB.