Abstract
Similar to most West Antarctic ice shelves, those in the Bellingshausen
Sea have rapidly thinned by hundreds of cubic kilometers over the last
decades yet they remain under-studied compared to other regions. The
increased melting rates in the West Antarctic Peninsula (WAP) have been
linked to warm Circumpolar Deep Water (CDW) that is able to access the
continental shelf due to the absence of the Antarctic Slope Current. The
exact pathways of CDW flowing on to the shelf and of meltwater flowing
away from the ice shelves are essential to understanding the dynamics in
this region and how it will change in the future. Here, we propose that
the Bellingshausen Sea plays an important role in connecting circulation
between the Amundsen Sea and the WAP and may influence water properties
that circulate under floating ice shelves throughout the West
Antarctica. Using a combination of hydrographic and isotopic data from a
recent cruise to the Bellingshausen Sea (December 2018 to January 2019),
multiple methods are applied to identify circulation pathways and to
quantify glacial meltwater fractions. The meltwater measurements show
that the Belgica and Latady Troughs are important pathways for CDW to
reach the ice shelves, though almost twice as much meltwater is
transported off the shelf via the Belgica Trough. CDW enters the shelf
at the deepest part of the Belgica Trough, moving towards the coast
along the trough’s eastern side. The largest meltwater fractions are
found along the western flank of the Belgica and Latady Troughs. The
meltwater signature can be tracked to the western edge of the
Bellingshausen Sea, where it is then entrained into a boundary current
system that flows over the continental slope towards the Amundsen Sea.