dc.description.abstract | The Gulf of Mannar (GoM), located between India and Sri Lanka, is a biodiversity hotspot and the first Indian marine biosphere reserve. Despite its location at the confluence zone of the Southeastern Arabian Sea (SEAS) and the Bay of Bengal (BoB), the naturally sheltered physiography of GoM makes it conducive for diverse and rich biological communities, including many sensitive, threatened and endangered species. This study used�in situ�hydrography and remote sensing data to examine the characteristics of the GoM in comparison with the adjacent SEAS and the Palk Bay (PB). The study showed that the seasonal variability in major environmental variables (temperature, salinity, suspended sediments, sea level, dissolved oxygen and chlorophyll) is minimal in the GoM compared to the SEAS and PB. Seasonal changes in sea surface temperature in the GoM were�<�2��C, while SEAS and PB experienced up to 4.5��C and 3��C, respectively. Similarly, the seasonal surface salinity in the GoM exhibited a limited variance of <1, unlike the SEAS and the PB, where it fluctuated >2. The data of the water column hydrography confirmed the above trend, indicating minimal seasonal variability of major environmental variables in the GoM. Unlike the SEAS, the GoM has minimal rainfall and river discharge, resulting in lower variability in salinity over seasons. Given the basic ecological principles, higher environmental stability over seasons is shown here as the primary cause, making the GoM a biodiversity hotspot. This special feature, when complement with other conducive characteristics of the GoM, such as the availability of a large plankton stock, a lack of hypoxic stress, and a sandy and aerated sea bottom, provides a fair scientific reasoning for its high biological diversity and richness Thus, the current study provided a clear example of how special geographical settings in a region define the regional oceanography, favouring higher biodiversity and richness than the neighboring areas. | |