SEE WHY ALL ALASKA'S PONDS ARE DISAPPEARING
across Alaska’s coastal plain, providing nesting
and feeding grounds for waterfowl. The bodies of
water, each less than a hectare in area, fill
depressions in the hummocky tundra landscape
with meltwater from thawing permafrost. How the
surface hydrology of Arctic permafrost regions—a
key part of the Arctic carbon cycle—will transform
in a changing climate isn’t well understood, but
tundra ponds may be a powerful guide, because
they are closely tied to changes in precipitation
and temperature, scientists report in a study
published online before print in the Journal of
Geophysical Research: Biogeosciences. To gauge
how the ponds have changed in the past 65
years, the researchers put high-resolution aerial
photos taken across Alaska’s Barrow Peninsula in
1948 (at left) side-by-side with modern satellite
images from 2002, 2008, and 2010 (at right).
They also used pond data collected during the
International Biological Program in the 1970s,
including areal extent estimates, water depths,
and pond depths, and compared those with field
data collected from 2011 to 2013. In all, they
found, the number of ponds had shrunk by at
least 17% since 1948 and had overall shrunk in
size by about 30% . Several factors influenced the
change—as temperatures rise, evaporation
increases, and rainfall isn’t keeping pace. But
warmer temperatures, longer growing seasons,
and thawing permafrost (which supplies
nutrients) are also promoting the growth of
aquatic plants in the ponds, shrinking the size of
the basins.
Comments
Post a Comment