Distribution, characteristics and fate of fluorescent dissolved organic matter (FDOM) in the Bay of Bengal

Nahin Mostofa Niloy; Sm Ahsan Habib; Mohammad Imrul Islam; Md Morshedul Haque; Mashura Shammi; Shafi M Tareq

doi:10.1016/j.marpolbul.2023.115467

Distribution, characteristics and fate of fluorescent dissolved organic matter (FDOM) in the Bay of Bengal

Mar Pollut Bull. 2023 Oct:195:115467. doi: 10.1016/j.marpolbul.2023.115467. Epub 2023 Aug 31.

Authors

Nahin Mostofa Niloy¹, Sm Ahsan Habib², Mohammad Imrul Islam², Md Morshedul Haque³, Mashura Shammi⁴, Shafi M Tareq⁵

Affiliations

¹ Hydrobiogeochemistry and Pollution Control Laboratory, Department of Environmental Sciences, Jahangirnagar University, Dhaka 1342, Bangladesh; Centre for Coastal Biogeochemistry, School of Environment, Science and Engineering, Southern Cross University, Lismore, New South Wales, Australia.
² Bangladesh Space Research and Remote Sensing Organization (SPARRSO), Bangladesh.
³ Hydrobiogeochemistry and Pollution Control Laboratory, Department of Environmental Sciences, Jahangirnagar University, Dhaka 1342, Bangladesh; Department of Environmental Science and Engineering, Bangladesh University of Textiles, Tejgaon, Dhaka 1208, Bangladesh.
⁴ Hydrobiogeochemistry and Pollution Control Laboratory, Department of Environmental Sciences, Jahangirnagar University, Dhaka 1342, Bangladesh.
⁵ Hydrobiogeochemistry and Pollution Control Laboratory, Department of Environmental Sciences, Jahangirnagar University, Dhaka 1342, Bangladesh. Electronic address: smtareq@juniv.edu.

PMID: 37659388
DOI: 10.1016/j.marpolbul.2023.115467

Abstract

The Bay of Bengal (BoB) is the largest sink to retain discharges from major rivers and the Sundarbans Mangrove Forest in Bangladesh and upholds significant ecological and resource diversity. This study aims to characterize, and identify sources, spatial dynamics, and the fate of the principal ecological web driver that is fluorescent dissolved organic matter (FDOM) in the BoB using advanced techniques of excitation-emission matrix (EEM) fluorescence spectroscopy and multivariate parallel factor (PARAFAC) analyses. The identified four protein-, two humic- and one detergent-like FDOM components mostly showed higher abundance in the shallow water than deep unlike a protein-like component. Such exceptional protein-like component was identified to form colloidal structure under elevated salinity in deep water. Autochthonous humic-like FDOM originated from primary production and water temperature counteracted microbial polymerization in shallow and deep water, respectively. The annual mass deposition indicated the influx of anthropogenic pollutants from both terrestrial and internal marine systems.

Keywords: Anthropogenic pollutants; Bay of Bengal; Excitation-emission matrix; Fluorescence spectroscopy; Parallel factor analysis.