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 and biogeochemical changes to glaciers and the marine environment. We compare sediment sources and drivers of macronutrient distributions at two bays along the WAP during austral summer 2...

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Bibliographic Details
Published in:Marine Chemistry
Main Authors: Jones, Rhiannon Laila Caitlin, Meredith, Michael, Lohan, Maeve, Woodward, E. Malcolm S., Van Landeghem, Katrien, Retallick, Kate, Flanagan, Oliver George, Vora, Mehul, Annett, Amber
Format: Article in Journal/Newspaper
Language:English
Published: 2023
Subjects:
Antarctic
Antarctic Peninsula
Austral
Marian
Ryder
Ryder Bay
Fourcade
Fourcade Glacier
Marian Cove
Sheldon Glacier
Antarc*
Online Access:https://eprints.soton.ac.uk/479421/
https://eprints.soton.ac.uk/479421/1/1_s2.0_S0304420323000269_main.pdf
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Summary:At the West Antarctic Peninsula (WAP), continued atmospheric and oceanic warming is causing significant physical and biogeochemical changes to glaciers and the marine environment. We compare sediment sources and drivers of macronutrient distributions at two bays along the WAP during austral summer 2020, using radioactive radium and stable oxygen isotopes to trace sedimentary influences and quantify different freshwater inputs. In the Ryder Bay, where the Sheldon Glacier is marine-terminating, radium activities at the sediment-water interface indicate considerable benthic mixing. Using radium isotope activity gradients to resolve radium and macronutrient fluxes, we find buoyant meltwater proximal to the glacier drives vigorous mixing of sediment and entrainment of macronutrient deep waters, on the order of 2.0 × 105 mol d−1 for nitrate. Conversely, in the Marian Cove, where the Fourcade Glacier terminates on land, low salinities and oxygen isotopes indicate a meltwater-rich surface layer <1 m thick and rich in sediment, and strong vertical mixing to the seafloor. A continued shift to land-terminating glaciers along the WAP may have a significant impact upon nutrient and sediment supply to the euphotic zone, with impacts upon primary productivity and carbon uptake efficiency. The future of primary production, carbon uptake, and food web dynamics is therefore linked to glacier retreat dynamics in the many fjords along the WAP.

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