Stable isotope composition (d18O) of seawater from stations in the Palmer LTER Study Site
The west Antarctic Peninsula (WAP) is a region of marked climatic variability, exhibiting strong changes in sea ice extent, retreat of the majority of its glaciers, and shifts in the amount and form of precipitation. These changes can have significant impacts on the oceanic freshwater budget and mar...
| Main Authors: | , , |
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| Format: | Dataset |
| Language: | English |
| Published: |
Environmental Data Initiative
2021
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| Subjects: | |
| Online Access: | https://dx.doi.org/10.6073/pasta/251000bc5fdcc5f11ad975295dd38774 https://portal.edirepository.org/nis/mapbrowse?packageid=knb-lter-pal.309.1 |
| Summary: | The west Antarctic Peninsula (WAP) is a region of marked climatic variability, exhibiting strong changes in sea ice extent, retreat of the majority 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 new 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 strong 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 marked 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 (<10m) surface layers close to Marr Ice Piedmont, associated with enhanced ocean stratification. Isotopic tracers help to deconvolve the complex spatio-temporal scales inherent in the coastal freshwater budget, and hence improve knowledge of the separate and cumulative physical and ecological impacts. |
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