Hur påverkar klimatförändringar sjöar och hav? / The potential effects of global climate change on oceans and lakes
Global increases in atmospheric CO2 and temperature are associated with an increase in the temperature of freshwater lakes and marine ecosystems. The ice breakup in lakes occur earlier which gives an opportunity for phytoplankton to grow early in the season. Another effect is a prolonged period of stratification in the lakes. Warming also may cause a shift of species in phytoplankton community. Climate models indicate that bluegreen algae will increase in relative abundance under the predicted future climate. The effects of climate change on marine ecosystems are related to shifts in water temperature, circulation, stratification, nutrient input and pH. An increase in temperature will create a rising sea level, decreasing sea-ice extent in Antarctica and Arctic and a altered patterns of ocean circulation and freshwater input. A greater light penetration into the water column caused by a reduction in sea ice may increase open-water phytoplankton primary production, although nutrient limitation could reduce the level of increase in primary production. In tropical waters are coral reefs very vulnerable to minor increases in temperature. A rising atmospheric CO2 and a resulting increased oceanic CO2 uptake will also reduce the sea-surface pH. A drop in pH makes it more difficult for corals to secrete and maintain their skeletons.