Study on the characteristics of some oceanic factors in the coastal waters of Ben Tre and neighboring areas

Abstract

Studying the characteristics and fluctuate of oceanic factors have very important role in fisheries oceanography, help us to have a more general view about the hydrodynamic - hydrological regime in the research region sea, have great significance in the zoning sea region serving the exploitation and protection resources and marine environment. Based on oceanographic data collected from 02 survey trips in the coastal waters of Ben Tre in November 2020 (Northeast monsoon season) and May-June 2021 (Southwest monsoon season) from 30 stations, some oceanic factors such as: temperature, salinity and chlorophyll - a were analyzed. Statistical analysis results show that some oceanic factors in coastal waters of Ben Tre have strong fluctuations in the coastal area, at the sea surface layer according to the monsoon seasons of the year. In the southwest monsoon, appeared two region has thermocline: region distance to coastline less 15 nautical at a depth of 2-5m and region distance to coastline 30 - 45 nautical at a depth of 13 - 25m. In Northeast monsoon, the appearance of salinity isovalue line 33,0‰ moving from offshore to coastal waters, this salinity isoline will weaked and gradually disappear when the southwest monsoon returns. The average of chlorophyll a in the entire water blocks is approx 1,3µg/l, fluctuated strongly at the depth from 0 to 15m, the maximum value of chlorophyll - a is scattered at different depths with different values in each wind season.