Summary of Abstract Submission

Abstract Submission No. IO50-03-0021PresentationPoster


B. SRIDEVI*1, V.V.S.S. Sarma2, T.V. Ramana Murty2, Y.Sadhuram2, K.V.S.R.Prasad1

1 Depatment of Meteorology & Oceanography, Andhra University, India
2 CSIR-National Institute of Oceanography, Visakhapatnam, India


Godavari River is one of the largest rivers in India having 25 tributarieswhich made an extensive delta on the east coast of India. The fresh water discharge into estuary is controlled by a century old ┐Low Dam┐ at Dowleiswaram. The variations in the distribution of salinity in this estuary are driven by river discharge during wet season (June - November) and tides during dry period (December - May). It has been hypothesized that variations in magnitude of river discharge may have significant influence on stratification that may impact phytoplankton blooms. The river discharge during 2009 was 60% less than that of 2008 as the Indian subcontinent received less rainfall during former period. This led todecrease in flushing rates from 1.2 to 6.3 days during peak discharge period. As a result strong stratification was developed in the Godavari estuary in 2009 (> 8psu m-1) than in 2008 (~7psu m-1). It is well known that stability of water column is an important parameter that controls phytoplankton dynamics in the estuary. Higher phytoplankton biomass by 40 - 60% was observed during 2009 than 2008 associated with decrease in river discharge. This study suggest that modification of river discharge due to natural processes, weakening of monsoon due to El Nino or Indian Ocean Dipole, or artificially, due to construction of more dams and re-routing the river flow, will have significant impact on health of the estuary.