Journal cover Journal topic
Biogeosciences An interactive open-access journal of the European Geosciences Union
Biogeosciences, 12, 2347-2363, 2015
http://www.biogeosciences.net/12/2347/2015/
doi:10.5194/bg-12-2347-2015
© Author(s) 2015. This work is distributed
under the Creative Commons Attribution 3.0 License.
Research article
21 Apr 2015
Glacial meltwater and primary production are drivers of strong CO2 uptake in fjord and coastal waters adjacent to the Greenland Ice Sheet
L. Meire1,2,3, D. H. Søgaard1, J. Mortensen1, F. J. R. Meysman2,4, K. Soetaert2, K. E. Arendt1, T. Juul-Pedersen1, M. E. Blicher1, and S. Rysgaard1,5,6,7 1Greenland Institute of Natural Resources, Greenland Climate Research Centre, P. O. Box 570, Kivioq 5, 3900 Nuuk, Greenland
2Royal Netherlands Institute of Sea Research (NIOZ), Department of Ecosystem Studies, Korringaweg 7, 4401 Yerseke, the Netherlands
3University of Ghent (UGent), Marine Biology Laboratory, Krijgslaan 281 (S8), 9000 Ghent, Belgium
4Department of Analytical, Environmental and Geochemistry, Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050 Brussels, Belgium
5Centre for Earth Observation Science, Department of Environment and Geography, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
6Department of Geological Sciences, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
7Arctic Research Centre, Aarhus University, 8000 Aarhus, Denmark
Abstract. The Greenland Ice Sheet releases large amounts of freshwater, which strongly influences the physical and chemical properties of the adjacent fjord systems and continental shelves. Glacial meltwater input is predicted to strongly increase in the future, but the impact of meltwater on the carbonate dynamics of these productive coastal systems remains largely unquantified. Here we present seasonal observations of the carbonate system over the year 2013 in the surface waters of a west Greenland fjord (Godthåbsfjord) influenced by tidewater outlet glaciers. Our data reveal that the surface layer of the entire fjord and adjacent continental shelf are undersaturated in CO2 throughout the year. The average annual CO2 uptake within the fjord is estimated to be 65 g C m−2 yr−1, indicating that the fjord system is a strong sink for CO2. The largest CO2 uptake occurs in the inner fjord near to the Greenland Ice Sheet and high glacial meltwater input during the summer months correlates strongly with low pCO2 values. This strong CO2 uptake can be explained by the thermodynamic effect on the surface water pCO2 resulting from the mixing of fresh glacial meltwater and ambient saline fjord water, which results in a CO2 uptake of 1.8 mg C kg−1 of glacial ice melted. We estimated that 28% of the CO2 uptake can be attributed to the input of glacial meltwater, while the remaining part is due to high primary production. Our findings imply that glacial melt\-water is an important driver for undersaturation in CO2 in fjord and coastal waters adjacent to large ice sheets.

Citation: Meire, L., Søgaard, D. H., Mortensen, J., Meysman, F. J. R., Soetaert, K., Arendt, K. E., Juul-Pedersen, T., Blicher, M. E., and Rysgaard, S.: Glacial meltwater and primary production are drivers of strong CO2 uptake in fjord and coastal waters adjacent to the Greenland Ice Sheet, Biogeosciences, 12, 2347-2363, doi:10.5194/bg-12-2347-2015, 2015.
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Short summary
The Greenland Ice Sheet releases large amounts of freshwater, which strongly influences the biogeochemistry of the adjacent fjord systems and continental shelves. Here we present seasonal observations of the carbonate system in the surface waters of a west Greenland tidewater outlet glacier fjord. Our data reveal a permanent undersaturation of CO2 in the surface layer of the entire fjord and adjacent shelf, creating a high annual uptake of 65gCm-2yr-1.
The Greenland Ice Sheet releases large amounts of freshwater, which strongly influences the...
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