Abstract
The Gulf of Mannar (GoM), located between India and Sri Lanka, has
astonishing faunal richness and diversity1. Two oceanographic data sets
are discussed here to show the unique ecological setting in the GoM
sustaining a rich and diverse fauna. We tested the hypothesis that a
specific stretch of a large marine environment behaves differently from
the rest of the region due to its peculiar geographical positioning.
Primarily, unlike the adjacent Indian southwestern shelf, coastal
upwelling and the associated seasonal oxygen deficiency, potentially
imparting physiological stress to marine fauna2-7, does not occur in the
GoM. Secondly, the GoM along the Indian coastline receives adequate
amount of primary (plankton) food from the Arabian Sea and the Bay of
Bengal through the seasonally reversing coastal currents8-12. Thirdly,
the GoM water has high transparency, aerated and sandy seafloor
conducive for the growth of diverse corals and many sensitive fauna1,4.
Our studies show that oxygen deficiency sheltered geography has a
significant role in facilitating significantly high faunal diversity and
richness in the GoM. We suggest that other similar coastal environments
worldwide, protected from the extended oxygen-deficient region, might be
functioning as a refuge for marine life and thereby increased faunal
diversity6,7.