Characterization of Porteresia coarctata beds along the Goa coast, India

Abstract

Porteresia coarctata, forms an important constituent in the plant succession leading to formation of mangrove communities along the estuaries in India. Major beds along the Mandovi estuary of Goa were monitored for their various ecological and environmental parameters. Nitrate and nitrite values in the over lying waters of beds varied from 0.12 to 1 Mu g at NO2 -N L sup(-1) and 1.2 to 6.7 Mu g at NO3-N L sup(-1), while salinity values were in the range of 0-36%, and gradually increased from August to September reaching its maximum during the month of April-May. The biomass values ranged from 39.3 plus or minus 5.6 to 145.2 plus or minus 32.2 g dry weight m sup(-2). Biomass and growth were negatively correlated (r = 0.53-0.80) with salinity while the same were positively correlated with nitrite (r = 0.73-0.87) and nitrate (r = 0.63-0.80) from the surface water. The growth of P. coarctata mainly continued by tiller formation. The density of seed producing shoots varied from 1 to 3 m sup(-2). The major vegetative characters of Porteresia indicated significant spatial and temporal variations. Sediments from the beds were rich in organic carbon (1.5-7.9%) and organic nitrogen (0.1-2.3%).