Benthic quality assessment of a hypersaline lake along the southeast coast of India

Abstract

The study describes macrobenthic community structure for assessing the benthic quality of a hypersaline lake along the southeast coast of India. Sediment and water samples were collected during November 2018 (Northeast Monsoon — NEM), April (Pre-Monsoon — PRM), and July 2019 (Southwest Monsoon — SWM). Based on salinity distribution the lake can be characterized into four regions viz., Northern inlet, Middle inlet, Southern inlet, and Central region. Seasonal analysis showed that the middle inlet and the central region of the lake experience hypersaline conditions throughout the year. Macrobenthic abundance and diversity index were high during SWM compared to other seasons. Some macrobenthic species (Cirratulus filiformis, Pagurapseudopsis gymnophobia, Apseudes chilkensis, Tanais sp.) showed a high preference for non-hypersaline regions while their presence in hypersaline regions was comparatively low/sparse. The present study identified that polychaete species such as Dendonereis aestuarina, Sigambra parva, Capitella capitata, Heteromastus similis can survive in hypersaline (> 60) conditions. The seasonal benthic quality status of the lake assessed by the AZTI Marine Biotic Index (AMBI) indicated heavily disturbed conditions during NEM and slightly disturbed during SWM.