The Risk of Ocean Acidification to Ocean Ecosystems

• Main Author: Turley, CM
• Format: Report
• Language: English
• Published: United Nations Environment Programme 2016
• Subjects: Chemistry; Earth Sciences; Ecology and Environment; Marine Sciences; Ocean acidification
• Online Access: http://plymsea.ac.uk/id/eprint/7779/; http://plymsea.ac.uk/id/eprint/7779/1/Turley%202016%20TWAP%20Chapter5%20UNEP-IOC.pdf; http://www.geftwap.org/publications/open-ocean-spm

Ocean acidification is a process that refers to major changes to the ocean’s carbonate chemistry, mainly caused by ocean uptake of anthropogenic emissions of carbon dioxide. This process involves a decrease in ocean pH (important for regulation of the internal acid balance and physiological health of many organisms) carbonate ions and calcium carbonate minerals such as aragonite and calcite (important for shell and skeleton builders) and an increase in bicarbonate ions (important for algal photosynthesis). To understand what marine ecosystems may look like in the future if carbon emissions continue unabated, it is necessary to know the severity of the perturbation that different ecosystems will be exposed to and their ability to adapt within the time-scales of change. The severity and speed of ocean acidification, the exposure and vulnerability of the component organisms of an ecosystem to ocean acidification and their role in an ecosystem contribute to the risk of impacts to ecosystem structure and function. Although there are great uncertainties moving from impacts on individual organisms to impacts on complex marine ecosystems, these basic changes to marine chemistry pose a substantial risk to marine ecosystem structure and function through the impacts on the growth, physiology, behaviour, predator-prey interactions, competitiveness and population dynamics of individual species and how these may cascade through the rest of the ecosystem. Some organisms are able to adapt to ocean acidification, especially if food resources are high, by trading-off energy from one physiological function to another, although this may impact their long-term survival and ecosystem function. Foodwebs where vulnerable organisms provide key trophic links, especially those exposed to undersaturated waters in polar, sub-polar and upwelling regions where severity will be greatest, will be at high risk of impact from ocean acidification. However, ecosystems formed by the aragonitic skeletons of deep-sea or tropical corals are also at ...