The Chlorophyll a concentration in the seawaters of Vietnam coastal zone and its information significance in ecological monitoring

Abstract

In the Vietnamese waters, the value of Chlorophyll a concentration ranged from 0.29 to 2.58mg.m-3, average value of 1.20  0.76mg.m-3 for the shallow waters and from 0.05 to 1.24mg.m-3, average value of 0.37  0.37mg.m-3 for the continental shelf waters. In the offshore, the Chlorophyll a concentration is relatively lower, ranged from 0.13 to 0.24 mg.m-3. The assimilated carbon index in the waters of Vietnamese continental shelf ranged from 0.84 to 4.25 mgC.mgChl-a-1.day-1, average value is 1.66  0.95 mgC.mgChl-a-1.day-1. In the culture pools, bay and coastal waters, the assimilated carbon index is highest, average value of 121.59  25.99mgC.mgChl-a-1.day-1. Using the Chlorophyll a concentration to assess primary production with the experimental equation showed that primary production ranged from 100 - 500mg.m-3.day-1 in coastal waters. In the offshore, primary production value is lower, ranged from 0.07 to 30 mgC.m-3. day-1. The studied results argued that ecological conditions in the coastal zone give facility for the process of primary production and phytoplankton development.