Influence of water quality and sediment nature on macrobenthic community structure along Paradeep, an industrial and port influenced tropical coastal stretch of North East coast of India, Bay of Bengal

Abstract

Macrobenthic community plays a major link between primary producers, decomposers and higher trophic levels in the marine environment. To assess these ecologically important groups, water and sediment samples were collected from 17 GPS fixed locations along a stretch of 42 km on the north east coast of India during the period 2017–2019. Faunal assemblage comprises of total 12 groups; belonging to 4 phyla (Annelida, Arthropoda, Mollusca and Echinodermata) and one minor phylum (Brachiopoda), represented by 25 families. Mean abundance varies from 80 to 2640 ind. m−2 and out of these more than 90% of the population is contributed by 7 groups namely Polychaeta (37.88%), Gastropoda (20.75%), Scaphopoda (9.82%), Bivalvia (9.41%), Amphipoda (9.26%), Sipuncula (2.72%) and Isopoda (2.45%). Seasonally abundance was highest in pre monsoon (1162 ind. m−2) and lowest in monsoon (682 ind. m−2). The similarity and group average clustering (Bray Curtis) of macrobenthic community divided the area into 2 major groups (50% similarity), Group-I with stations of estuary and port and Group-II is the shoreline locations. The SIMPROF test used for further division of the stations revealed that the regions could be subdivided into four groups namely estuary, port, outfall and shoreline. Occurrence of the pollution indicator species such as Capitella capitata, Paraprionospio pinnata, Cossura longocirrata and Cossura coasta in the estuarine and port area. A positive correlation (P ≤ 0.01) between sand vs macrobenthic abundance and negative correlation between silt vs macrobenthic abundance (P≤0.01) and organic matter vs macrobenthic abundance (P ≤ 0.01) was observed as the loose texture of sediment provides higher interstitial space to harbour more number of benthos. Salinity varied in wide range from 1.10 to 30.02 PSU as, the study area include different environment such as estuary, port, outfall and open sea and besides this, river Mahanadi which discharge large quantity of fresh water during monsoon season.