2005
21 April 2005. NASA RELEASE: 05-100. NASA
Study Finds Snow Melt Causes Large Ocean Plant
Blooms. A NASA
funded study has found a decline in winter
and spring snow cover over Southwest Asia
and the Himalayan mountain range is creating
conditions for more widespread blooms of ocean
plants in the Arabian Sea. The decrease in
snow cover has led to greater differences
in both temperature and pressure systems between
the Indian subcontinent and the Arabian Sea.
The pressure differences generate monsoon
winds that mix the ocean water in the Western
Arabian Sea. This mixing leads to better growing
conditions for tiny, free-floating ocean plants
called phytoplankton. ...When winter and spring
snow cover is low over Eurasia, the amount
of solar energy reflected back into the atmosphere
is less. A decline in the amount of snow cover
means less of the sun's energy goes towards
melting of snow and evaporation of wet soil.
As a result the land mass heats up more in
summer creating a larger temperature difference
between the water of the Arabian Sea and the
Indian subcontinent landmass. The temperature
difference is responsible for a disparity
in pressure over land and sea, creating a
low pressure system over the Indian subcontinent
and a high pressure system over the Arabian
Sea. This difference in pressure causes winds
to blow from the Southwest Arabian Sea bringing
annual rainfall to the subcontinent from June
to September. In the Western Arabian Sea,
these winds also cause upwelling of cooler
nutrient-rich water, creating ideal conditions
for phytoplankton to bloom every year during
summer. ... while large blooms of phytoplankton
can enhance fisheries, exceptionally large
blooms could be detrimental to the ecosystem.
Increases in phytoplankton amounts can lead
to oxygen depletion in the water column and
eventually to a decline in fish populations. More
info.
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