A historical reconstruction of the Baltic Sea pH environment experienced by marine organisms
Due to the increasing amount of dissolved anthropologic CO2 in the world’s oceans, the carbonate system and its equilibria are changing. One of the main consequences is a higher concentration of hydrogen ions measured by a decrease of pH, known as ocean acidification. Many aspects of the physiology...
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| Format: | Thesis |
| Language: | English |
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2012
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| Online Access: | https://oceanrep.geomar.de/id/eprint/19992/ https://oceanrep.geomar.de/id/eprint/19992/1/Burkhard%20von%20Dewitz%20Diploma%20Thesis.pdf |
| Summary: | Due to the increasing amount of dissolved anthropologic CO2 in the world’s oceans, the carbonate system and its equilibria are changing. One of the main consequences is a higher concentration of hydrogen ions measured by a decrease of pH, known as ocean acidification. Many aspects of the physiology and ecology of marine organisms, expected to be influenced by ocean acidification, are currently under intense investigation by marine biologists. Besides the more obvious impacts like the deficiency of calcification of marine invertebrates, fish species and their ability to cope with the shifting carbonate system are also becoming objects of interest. In recent studies evidence was given that opposed to adult fish, early life stages tend to be especially affected by elevated CO2 levels on growth, survival and behavior. Experimental CO2 treatment levels have been oriented mostly on predictions for ocean surface water and seldom exceeded 1000 ppm with a corresponding pH of approx. 7.7. The Baltic Sea however, is frequently characterized by extreme conditions of low pH and low oxygen due to its specific hydrography and was shown in previous studies to have a low buffering capacity of CO2 as a result of its low salinity. Besides some regional pH-environment studies and modeling of pCO2 conditions in terms of release and uptake of CO2 at the surface, the pH-environment of the Baltic Sea has not been investigated over long timescales. In this study an overview of the spatio-temporal properties during the last 50 years of the pH-environment of the Baltic Sea derived from hydrographic data obtained from the ICES oceanographic database is provided. In particular, horizontal, vertical and seasonal variations were identified and quantified. Additionally, measurement and model results of the spatio-temporal distribution of eggs and adults of Baltic cod (Gadus morhua) and of one copepod species (Pseudocalanus acuspes) were used to investigate the pH-environment experienced by pelagic Baltic Sea inhabitants. Thereby, the ambient ... |
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