Local- and Large-Scale Drivers of Variability in the Coastal Freshwater Budget of the Western Antarctic Peninsula

Michael P. Meredith, Sharon E. Stammerjohn, Hugh W. Ducklow, Melanie J. Leng, Carol Arrowsmith, J. Alexander Brearley, Hugh J. Venables, Mark Barham, Jan Melchior van Wessem, Oscar Schofield, Nicole Waite

Research output: Contribution to journalArticlepeer-review

Abstract

The west Antarctic Peninsula (WAP) is a region of marked climatic variability, exhibiting strong changes in sea ice extent, retreat of most of its glaciers, and shifts in the amount and form of precipitation. These changes can have significant impacts on the oceanic freshwater budget and marine biogeochemical processes; it is thus important to ascertain the relative balance of the drivers and the spatial scales over which they operate. We present a novel 7-year summer-season (October to March; 2011 to 2018) series of oxygen isotopes in seawater (δ18O), augmented with some winter sampling, collected adjacent to Anvers Island at the WAP. These data are used to attribute oceanic freshwater changes to sea ice and meteoric sources, and to deduce information on the spatial scales over which the changes are driven. Sea ice melt shows significant seasonality (∼9% range) and marked interannual changes, with pronounced maxima in seasons 2013/14 and 2016/17. Both of these extrema are driven by anomalous winds, but reflect strongly contrasting dynamic and thermodynamic sea ice responses. Meteoric water also shows seasonality (∼7% range) with interannual variability reflecting changes in the input of accumulated precipitation and glacial melt to the ocean. Unlike sea ice melt, meteoric water extremes are especially pronounced in thin (<10 m) surface layers close to the proximate glacier, associated with enhanced ocean stratification. Isotopic tracers help to deconvolve the complex spatio-temporal scales inherent in the coastal freshwater budget, and hence improve our knowledge of the separate and cumulative physical and ecological impacts.

Original languageEnglish (US)
Article numbere2021JC017172
JournalJournal of Geophysical Research: Oceans
Volume126
Issue number6
DOIs
StatePublished - Jun 2021

All Science Journal Classification (ASJC) codes

  • Geochemistry and Petrology
  • Geophysics
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Oceanography

Keywords

  • 0740 snowmelt
  • 0750 sea ice (4540)
  • 0776 glaciology (1621, 1827, 1863)
  • 4207 Arctic and Antarctic oceanography (9310, 9315)
  • 4870 stable isotopes (0454, 1041)

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