Structural variation of coloured dissolved organic matter during summer and winter seasons in a tropical estuary: A case study

N V H K Chari; Sudarsana Rao Pandi; Vishnu Vardhan Kanuri; Charan Kumar Basuri

doi:10.1016/j.marpolbul.2019.110563

Structural variation of coloured dissolved organic matter during summer and winter seasons in a tropical estuary: A case study

Mar Pollut Bull. 2019 Dec:149:110563. doi: 10.1016/j.marpolbul.2019.110563. Epub 2019 Sep 7.

Authors

N V H K Chari¹, Sudarsana Rao Pandi², Vishnu Vardhan Kanuri³, Charan Kumar Basuri⁴

Affiliations

¹ Marine Chemistry Laboratory, Andhra University, Visakhapatnam 530003, India; Centre for Marine Living Resource and Ecology, Kochi 682037, India. Electronic address: harikrishnachari@gmail.com.
² National Centre for Polar and Ocean Research, Ministry of Earth Sciences, Goa, Government of India.
³ National Ganga River Basin Authority, Central Pollution Control Board, Kolkata 700107, India. Electronic address: vishnuchemistry@gmail.com.
⁴ Marine Biological Laboratory, Andhra University, Visakhapatnam 530003, India.

PMID: 31542604
DOI: 10.1016/j.marpolbul.2019.110563

Abstract

The diurnal variations in water quality and optical properties of organic matter were studied in the Gautami-Godavari estuary during two contrasting seasons. Dissolved inorganic nitrogen (DIN) and silicate showed similar patterns with the tide during summer, whereas in winter contrasting trends were noticed. Three-folds higher N to P ratio was recorded in winter than in summer. The spectral slope ratio (S_R) and specific ultra violet absorption coefficient (SUVA) peaked during summer (1.28 ± 0.09 and 3.95 ± 0.2) followed by winter (1.10 ± 0.18 and 1.91 ± 0.35). The parallel factor (PARAFAC) analysis of excitation emission matrix (EEM) fluorescence spectra was extracted three humic (C1, C2, C3) and one protein-like (tryptophan (C4)) fluorophore components. Humic like fluorophores inversely correlated with the tide in both the seasons, due to influence of seawater. In summer, the Chlorophyll a (Chl a) and dissolved organic carbon (DOC) showed positive correlations with humic like and C4 fluorophores, suggesting the insitu organic matter production.

Keywords: Coloured dissolved organic matter; Excitation emission matrix spectra; Parallel factor analysis; Spectral slope.

MeSH terms

Chlorophyll A / analysis
Environmental Monitoring
Estuaries*
Fluorescence
Humic Substances / analysis*
Nitrogen / analysis
Organic Chemicals / analysis*
Phosphorus / analysis
Seasons*
Seawater / chemistry
Tropical Climate

Substances

Humic Substances
Organic Chemicals
Phosphorus
Nitrogen
Chlorophyll A