Chlorophyll and suspended sediment concentrations in the Bay of Bengal and the Arabian sea at the river mouths

Chlorophyll and suspended sediment concentrations and sea surface temperature are important parameters in assessing productivity of coastal regions. Numerous rivers flow into eastern (Ganges, Subarnarekha, Mahanadi, Godavari, Krishna, Penner, Kaveri) and western (Narmada, Tapti, and Indus) coasts with their contrasting feature. Using IRS P4 OCM and MODIS data, we have retrieved chlorophyll and suspended concentrations near the mouth of these rivers. The contrast differences in chlorophyll and suspended sediment concentrations have been found. The characteristics of the chlorophyll and suspended concentrations at the mouth of these rives are attributed to the nature of the geological terrains through which these rivers pass through, this is also evident from the analysis of water sample data. The chlorophyll concentrations are found to be dependent on the sea surface temperature, wind velocity, wind pattern and monsoon activities. The Indus river shows contrasting nature compared to other rivers along the east and west coasts of India. Narmada river which flows into the Arabian Sea shows relatively high Chlorophyll concentrations. The suspended sediment concentration during winter months (January - February) at the mouth of Krishna, Godavari and Kaveri rivers flow through the southern peninsular India show more or less common trend. The length of rivers, inland course in sedimentary or hard rock terrains and their flow direction towards the Bay of Bengal or into the Arabian Sea are found to control the suspended sediment concentrations at river mouth other than sea related activities. Comparison of the chlorophyll concentrations using IRS P 4 OCM and MODIS data also shows low chlorophyll concentration in the Bay of Bengal as compared to the Arabian Sea.