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Biogeosciences Discuss., 9, 10785-10845, 2012
www.biogeosciences-discuss.net/9/10785/2012/ doi:10.5194/bgd-9-10785-2012 © Author(s) 2012. This work is distributed under the Creative Commons Attribution 3.0 License. |
Oxygen and indicators of stress for marine life in multi-model global warming projections
1Climate and Environmental Physics, Physics Institute, University of Bern, Sidlerstrasse 5, 3012 Bern, Switzerland
2Oeschger Centre for Climate Change Research, University of Bern, Zähringerstrasse 25, 3012 Bern, Switzerland
3Atmospheric and Oceanic Sciences Program, Princeton University, Sayre Hall, Forrestal Campus, Princeton, NJ 08544, USA
4Laboratoire des Sciences du Climat et de l'Environnement (LSCE), L'Orme des Merisiers Bât. 712, 91191 Gif sur Yvette, France
5Geophysical Fluid Dynamics Laboratory, NOAA, Princeton, New Jersey, USA
6Geophysical Institute, University of Bergen, Allégaten 70, 5007 Bergen, Norway
7Bjerknes Centre for Climate Research, Bergen, Norway, Allégaten 55, 5007 Bergen, Norway
8Uni Bjerknes Centre, Uni Research, Allégaten 55, 5007 Bergen, Norway
9Helmholtz Centre for Ocean Research Kiel (GEOMAR), Düsternbrooker Weg 20, 24105 Kiel, Germany
10Institute of Geosciences, University of Kiel, Ludewig-Meyn-Str. 10, 24098 Kiel, Germany
11Max-Planck-Institut für Meteorologie, Bundesstrasse 53, 20146 Hamburg, Germany
Abstract. Decadal-to-century scale trends for a range of marine environmental variables are investigated using results from seven Earth System Models forced by a high greenhouse gas emission scenario. The models as a class represent the observation-based distribution of the fugacity of oxygen (fO2) and carbon dioxide (fCO2), and the logarithm of their ratio, i.e. the Respiration Index (RI), albeit major mismatches between observation-based and simulated values remain for individual models. All models project an increase in SST between 2 °C and 3 °C by year 2100, a decrease in upper ocean pH and in the saturation state of water with respect to calcium carbonate minerals, and a decrease in the total ocean inventory of dissolved oxygen by 2% to 4%. Projected fO2 changes in the thermocline show a complex pattern with both increasing and decreasing trends reflecting the subtle balance of different competing factors such as circulation, production, remineralisation, and temperature changes. Projected changes in the total volume of hypoxic and suboxic waters remain relatively small in all models. A widespread increase of fCO2 in the thermocline is projected. The median of the thermocline fCO2 distribution shifts from 350 μatm in year 1990 to 700–800 μatm in year 2100, primarily as a result of the invasion of anthropogenic carbon from the atmosphere and is responsible for the widespread decrease in the RI outside low oxygen regions. The co-occurrence of changes in a range of environmental variables indicates the need to further investigate their synergistic impacts on marine ecosystems and Earth System feedbacks.
Citation: Cocco, V., Joos, F., Steinacher, M., Frölicher, T. L., Bopp, L., Dunne, J., Gehlen, M., Heinze, C., Orr, J., Oschlies, A., Schneider, B., Segschneider, J., and Tjiputra, J.: Oxygen and indicators of stress for marine life in multi-model global warming projections, Biogeosciences Discuss., 9, 10785-10845, doi:10.5194/bgd-9-10785-2012, 2012.