Ice-covered ponds in the Untersee Oasis (East Antarctica): Distribution, chemical composition, and trajectory under a warming climate

Climate change is impacting lakes and ponds in Antarctica. To that end, we investigated the distribution and chemical composition of ice-covered ponds in Untersee Oasis, East Antarctica. Thirty-nine ponds were inventoried, and the thirteen sampled ponds have low total dissolved solutes (TDS) with a...

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Bibliographic Details
Published in:Arctic, Antarctic, and Alpine Research
Main Authors: Benoit Faucher, Denis Lacelle, Nicole B. Marsh, David A. Fisher, Dale T. Andersen
Format: Article in Journal/Newspaper
Language:English
Published: Taylor & Francis Group 2021
Subjects:
ice-covered ponds
isotope geochemistry
modeling
freezing
evaporation
dronning maud land
Environmental sciences
GE1-350
Ecology
QH540-549.5
Dronning Maud Land
East Antarctica
Untersee
Antarc*
Antarctic and Alpine Research
Antarctica
Arctic
Online Access:https://doi.org/10.1080/15230430.2021.2000566
https://doaj.org/article/a64ca06215a4426eac0c49e4bdb7d8f2
Description
Summary:Climate change is impacting lakes and ponds in Antarctica. To that end, we investigated the distribution and chemical composition of ice-covered ponds in Untersee Oasis, East Antarctica. Thirty-nine ponds were inventoried, and the thirteen sampled ponds have low total dissolved solutes (TDS) with a Ca(Na)-SO4 or Na-Cl geochemical facies. Tritium and radiocarbon measurements of the total inorganic carbon (TIC) suggest that the ponds are recharged by modern snowmelt. Hierarchical cluster analysis grouped the ponds based on the amount of potential incoming solar radiation reaching their surface. Ponds receiving higher insolation develop moats or completely lose their ice cover during summer, have lower pH, and higher TDS, δ18O, total inorganic carbon, and δ13CTIC,which suggest CO2 availability is not limiting benthic photosynthetic activity. The ponds that receive lower insolation retain their full ice cover and remain well-sealed to direct exchanges with the atmosphere, have high pH, and lower TDS and TIC, and likely host a CO2-starved benthic microbial ecosystem. Therefore, the state of the ponds’ ice cover evolved their hydrochemistry along different trajectories. The findings can be used to predict the trajectory of the chemical composition of the ponds and effect on biological productivity as the phenology of their ice cover shifts under a warming climate.

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