Ecological Studies on the Distribution of Phyto Plankton Biomass, East Coast of India

During premonsoon season, the Bhavanapadu backwaters (BBW), was characterized by warm waters (av. 32.6 ± 0.6°C) with relatively high salinity (>23; except in the lower estuary). On the other hand, fresh water was found to dominate the entire area during monsoon and postmonsoon seasons. The enormous input of nutrients (nitrate, phosphate and silicate) into the estuary from various sources (industries, agriculture and domestic) was responsible for the high phytoplankton biomass (av. 10.4 ± 10.1 mg m⁻³) irrespective of seasons. Hence, it is suggested that during the periods of fresh water dominance, the trophic food web of Bhavanapadu estuarine system is characterized by substantial amount of unconsumed carbon at primary level owing to the reduction in phytoplankton grazers (zooplankton).