from phys.org, February 17, 2015
Researchers have identified how warm Atlantic water that is flowing deep into the Arctic Ocean is mixing with colder waters above to contribute to sea-ice loss in the Arctic. The results, published this week in the journal Nature Geoscience, show that tidal flows in the Arctic are causing deep, warm water (originating from the Gulf Stream) to mix with cold, fresh water lying above, in turn contributing to melting the floating sea ice.
Past research on how warm layers of ocean water mix with cold layers lying above has focused on turbulence driven by winds and waves, rather than on tidal mixing, since tidal flows around the Arctic Ocean are generally weak. However, direct measurements of turbulence from across the seasonally ice-free Arctic Ocean show that tidal motions interacting with steep sea bed slopes are in fact a major cause of vertical mixing.