Researchers
have found
56 more lakes
under the
Greenland Ice Sheet,
bringing the island's
number of subglacial
lakes to 60.
Subglacial lakes form when
meltwater becomes trapped,
and pools at the bottom
of an ice sheet.
Ice melted by the pressure
of thick, heavy icy above,
Earth's geothermal heat,
or heat produced by the ice
flowing, can supply the lakes
with water.
Surface meltwater can drain
to the base of the ice sheets
through crevices.
A more detailed understanding
of the ice sheet's drainage
dynamics is important.
It can help can predict how the
Greenland Ice Sheet will respond
to future climate change.
Scientists found
54 of the lakes
by analyzing airborne
radio echo
sounding data,
to map
the ice sheet bed.
Two others
were identified
by studying
ice-surface
elevation
changes.
Until now
little was known
about subglacial lakes.
The new research
was published
in June 2019,
in the journal
Nature Communications.
Most of the lakes
were found beneath
slow moving ice
on the periphery
of the ice sheet's
thicker, more stable
interior.
Researchers think
future climate change
could trigger melting
at higher elevations,
forming subglacial lakes
under the heart of the
Greenland Ice Sheet.
The lakes tend to cluster
in eastern Greenland,
where the bed is rough,
and can trap meltwater.
Sediments deposited
in the lakes
may preserve a record
of environmental change.