Publication Date:
2021-01-13
Description:
Basal melt of ice shelves is not only an important part of Antarctica’s ice-sheet mass budget, but it is
also the origin of one of the most peculiar types of sea ice found in the polar oceans: platelet ice. In
many regions around coastal Antarctica, tiny ice crystals form and grow in supercooled plumes of
Ice Shelf Water, releasing heat into the surrounding ocean. They usually rise towards the surface,
eventually becoming trapped under an ice shelf as marine ice. Frequently, masses of those crystals
are advected out of the ice-shelf cavity, and accumulate below a solid sea-ice cover to form a semiconsolidated
layer. When the overlying sea ice grows into this so-called sub-ice platelet layer, the
loose crystals are consolidated, adding additional thickness to the sea ice. These phenomena are
generally referred to as platelet ice, although confusion about the terminology is widespread in
the literature. The presence of platelet ice has a profound impact on sea-ice properties and processes
in several regions of Antarctica, with numerous implications for the local polar marine biosphere.
Most notably, sub-ice platelet layers provide a stable, sheltered, nutrient- and food-rich habitat
which usually results in a highly productive and uniquely adapted ecosystem. It has also been
hypothesised that platelet ice may be an indicator of the state of an ice shelf, although comprehensive
time series are limited to the Ross Sea. This paper clears up the terminology by providing exact
definitions of the relevant terms.We review platelet-ice formation, observational methods as well as
geographical and seasonal occurrence. The physical properties and ecological implications are
merged in a way understandable for physicists and biologists alike, to lay the foundation for the
interdisciplinary research that is necessary to tackle the current knowledge gaps.
Repository Name:
EPIC Alfred Wegener Institut
Type:
Article
,
peerRev
Format:
application/pdf
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