Observation of Spatial and Temporal Distribution of Dissolved Oxygen and Detection of Oxygen Minimum Zones in the Bay of Bengal

The decrease in oxygen content (deoxygenation) of coastal and oceanic waters worldwide has found to be worsened in recent decades. Recent findings indicate that the Peru-Chile margins, West African coast, the northern Indian Ocean and Bay of Bengal are increasingly vulnerable to deoxygenation events. This study observed the distribution of dissolved oxygen (DO) and found the Oxygen Minimum Zones (OMZ) in the Bay of Bengal spatially and temporally. DO data was collected from the World Ocean Database for all the years the inventory has available. A permanent hypoxic condition at the mid-layer depths (200m -900m) was observed in the shallower area. During monsoon season, due to meteorological turmoil of cyclone genesis and heavy rainfall, the area get enough oxygen. The vertical distribution is found to be as decreasing at first few hundred depths and then increasing from 1,000m to the bed. The sections show OMZs more in summer and winter; less in monsoon. The OMZs lie mostly at 200-500m depth along the continental slope or at mid-regions of the basin.