Foraminifera in surface sediments of Mandovi River Estuary: Indicators for mining pollution and high sea stand in Goa, India

Abstract

Foraminiferal characteristics of 11 surface sediment samples collected from the Mandovi estuary during 2001 have been compared with similar data based on samples collected during 1994. The study reveals drastic fall in total foraminiferal number in the lower reaches of the Mandovi River estuary, from 138/g dry sediment sample in 1994 to 41/g sediment sample in 2001. The decline is also noted in diversity from 22 in 1994 to only 5 species in 2001. The ever-increasing suspended load in Mandovi estuary, probably due to mining activities in the catchment area of the Mandovi River estuary, is suggested as the plausible reason for the decline of fauna. An intriguing finding of the present study is the presence of substantial amount of reworked/older specimens, at the lower reaches of the estuary, that could be indicators of Holocene high sea stand.