Defaunation of meiofauna in Mumbai bay (India) - A severely polluted area

Meiofauna plays an important role in the benthic food web of shallow water ecosystems. In the present study, the status of meiofauna was addressed in the intertidal and subtidal environment of Mumbai bay (West coast of India), a severely polluted area. A total of four intertidal sites were sampled monthly for a period of six months (October 2010-March 2011) and eight subtidal sites were sampled thrice (October 2010, December 2010 and March 2011). The results revealed the defaunation of meiofauna occurring in Mumbai bay. Among the intertidal sites, Elephanta was very poor in terms of density and diversity, whereas in the subtidal environment, most of the sites were almost devoid of meiofauna. Compared to an earlier study in the subtidal sediments off Mumbai (Sajan, 2003), meiofaunal density in the present study was almost 40 times less (maximum density 25.5 ind. 10 cm−2). Even, such low densities have never been recorded earlier from any other subtidal regions of the west coast of India from an equivalent depth. Loss of meiofauna is quite alarming as it could alter the biogeochemical cycles of the Mumbai coastal area, thereby affecting the ecosystem functioning.