Spatio-temporal variation in the macrobenthos of Paradip port, east coast of India

Abstract

The spatio-temporal variation in the abundance and community structure of macrobenthic invertebrates, which are useful ecological indicators, was assessed along with associated environmental settings and sediment characteristics in Paradip port, Odisha along the east coast of India. The Paradip port is a coastal port directly connected to the Bay of Bengal and is influenced by tropical monsoons. The maximum diversity and abundance of macroinvertebrates was reported during monsoon season, whereas it was minimum during post-monsoon and pre-monsoon and attributed to higher organic carbon in the sediments. The sediment characteristics (sediment composition and total organic carbon) were the major factors influencing the abundance and community composition of benthic organisms. Silty-sand was dominant throughout the port environment. The polychaetes were the dominant macrobenthos organisms followed by Pantopoda and Crustaceans. Organically rich and sandy-silt sediments have led to the dominance of pollution indicator taxa such as Tharyx sp., Prionospio sp., Cossura sp., Magelona sp. and Mediomastus sp. The multivariate index of trophic state indicated good water quality in near bottom water; however, high organic carbon load in the sediments could have resulted in a stressed environment. This study will serve as a baseline for future studies on the diversity of macro-benthic invertebrates and benthic ecology of the monsoon influenced coastal habitats, especially in a busy port subjected to rigorous physical and anthropogenic stress.