Continued glacial retreat linked to changing macronutrient supply along the West Antarctic Peninsula

At the West Antarctic Peninsula (WAP), continued atmospheric and oceanic warming is causing significant physical biogeochemical changes to glaciers marine environment. We compare sediment sources drivers of macronutrient distributions at two bays along WAP during austral summer 2020, using radioactive radium stable oxygen isotopes trace sedimentary influences quantify different freshwater inputs. In Ryder Bay, where Sheldon Glacier marine-terminating, activities sediment-water interface indicate considerable benthic mixing. Using isotope activity gradients resolve fluxes, we find buoyant meltwater proximal glacier drives vigorous mixing entrainment deep waters, on order 2.0 × 105 mol d−1 for nitrate. Conversely, in Marian Cove, Fourcade terminates land, low salinities a meltwater-rich surface layer <1 m thick rich sediment, strong vertical seafloor. A shift land-terminating may have impact upon nutrient supply euphotic zone, with impacts primary productivity carbon uptake efficiency. The future production, uptake, food web dynamics therefore linked retreat many fjords WAP.