ANTARCTICA OVERTURNING CIRCULATION – ENVIRONMENT
News: Deep-ocean currents in Antarctica are slowing earlier than predicted
What is in the news?
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Recently, scientists have
discovered that the deep Ocean currents in Antarctica are moving slower than
predicted.
Key takeaways from the news:
Antarctica Overturning circulation:
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It is an action that
takes place beneath the surface of the ocean. Here, trillions of tons of cold,
dense, oxygen-rich water cascade off the continental shelf and sink to great
depths.
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This Antarctic “bottom
water” then spreads north along the sea floor in deep ocean currents, before
slowly rising, thousands of kilometers away.
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Antarctica overturning
circulation” that redistributes heat, carbon and nutrients around the globe.
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The overturning is
crucial to keeping the earth’s climate stable. It’s also the main way oxygen
reaches the deep ocean.
Slowing down of Overturning circulation:
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New measurements show the
overturning circulation has slowed by
almost a third (30%) and deep ocean oxygen levels are declining.
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This slowdown has the
potential to disrupt the connection between the Antarctic coasts and the deep
ocean.
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Deep
ocean water flows from the Antarctic could decline by 40% by 2050,
Reason behind the slow down:
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As temperatures rise,
freshwater from Antarctica’s melting ice enters the ocean, reducing the
salinity and density of the surface water and diminishing that downward flow to
the sea’s bottom.
Impacts:
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As the flow of bottom
water slows, the supply of oxygen to the deep ocean declines.
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It reduces the amount of
nutrients that get returned from the deep ocean back up to the surface.
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Ocean would not be able
to absorb as much carbon dioxide as its upper layers become more stratified,
leaving more CO2 in the atmosphere.
About Antarctica:
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It is the fifth-largest continent.
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The Indian Antarctic
Programme is a multi-disciplinary, multi-institutional programme under the
control of the National Centre for Antarctic and Ocean Research, Ministry of Earth Sciences.
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India officially acceded
to the Antarctic Treaty System in August 1983.
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Research stations: Maitri
and Bharathi.