Ocean Acidification
Ocean Acidification
Oceans absorb a large portion of carbon dioxide from the atmosphere. When carbon dioxide is absorbed by the water surface, it undergoes chemical reactions to transform into carbonic acid, causing a decrease in the pH of seawater. This phenomenon is called "ocean acidification" or "OA" for short. Increased CO2, both anthropogenic and natural, is altering the global carbon cycle in the oceans.
Since the Industrial Revolution, ocean surface pH values ??have decreased from 8.2 to 8.1, approximately 0.1 units. The average pH of ocean surface water is projected to decrease by 0.3-0.5 pH units by 2100. On a logarithmically increasing pH scale, a 0.1 change corresponds to a tenfold increase in acidification.
Surface water pH changes (from 1986-2005 to 2081-2100) (IPCC 2003)
The most commonly observed effects of calcium carbonate depletion as seawater pH decreases have been damage to the shells and skeletons of marine plankton, benthic mollusks, echinoderms, and reefs. Acidification prevents many organisms that use calcium for growth or shell formation, such as mussels, corals, and scallops, from doing so due to increased acidity. This is because every chemical reaction occurs within a specific pH range. Reactions necessary for shell formation cannot occur in an increasingly acidic environment. As oceans become more acidic, the formation of calcium carbonate shells and skeletons will become increasingly difficult. By the middle to late 20th century, some oceans will be so corrosive that even existing forms of calcium carbonate will dissolve.
Life on the evolutionary timeline has adapted to low carbon dioxide levels in its environment. Therefore, current life depends on these low values, and it is unclear to what extent species will adapt to continuously rising carbon dioxide levels. High carbon dioxide levels and exposure to highly acidic waters can lead to mass mortality (Adams and Caldeira 2008). In some organisms, efforts to balance pH changes reduce their reproductive and growth capabilities. Because the change is so rapid, many species are not genetically adapted to ocean acidification.
The massive increase in carbon dioxide emissions is the biggest factor in increasing ocean acidification. The current concentration of carbon dioxide in the atmosphere is at its highest level during the history of human civilization. Unless anthropogenic CO2 emissions are significantly limited or controlled by other factors, ocean pH levels will continue to fall. Ocean acidification has a devastating effect on marine microorganisms, especially some phytoplanktonic microorganisms. While the ultimate consequences of acidification are still unclear, it is known to directly affect coral reefs, commercial fisheries, fishing-free protected areas, zooplankton, and phytoplankton, the primary producers. Although there is no national policy on this issue, similar to climate change, regional administrations in various countries have included ocean acidification in their Fisheries and Aquaculture Resources management and control and have begun to take appropriate measures (OCBP 2009).
The impact of acidification on all seas is inevitable. Current studies on oceanic acidification show that the warm and mid-latitude Mediterranean and Black Seas will not be the first regions to be affected. Furthermore, the Mediterranean is highly saturated with calcite and aragonite at all depths, has high alkalinity, and is homogeneous. Due to these characteristics, the Mediterranean can act as a buffer against acidification caused by increasing CO2 (Schneider et al. 2007). Similarly, the Black Sea also has a very high calcite saturation in its surface waters (Tyrrell et al. 2008). These alkalinity characteristics alone tend to slow the onset of the increase in oceanic acidification on a global scale. However, factors such as the expanding and increasing population surrounding these sea regions, rapid urbanization and industrialization, and the absorption of acidic compounds from rivers and the atmosphere by coastal areas, have the potential to increase terrestrial sources of acidification, affecting polar regions and areas not yet reached. Therefore, ongoing projects concerning the effects of ocean acidification, particularly on the Mediterranean and Black Seas, need to be supported.
Sources:
http://www.pmel.noaa.gov/co2/story/What+is+Ocean+Acidification%3F
The effect of ocean acidification on phytoplankton/Murat Yeşiltaş:
http://webcache.googleusercontent.com/search?q=cache:9x_1FzILMpkJ:www.researchgate.net/profile/Murat_Yesiltas3/publication/276978992_Okyanuslarn_Asidifikasyonunun_Fitoplanktona_Etkisi/links/555cb21508ae6f4dcc8bcc2e+&cd=7&hl=tr&ct=clnk&gl=tr
http://www.dogagozculeri.org/okyanusyasaminatehdit.pdf
http://usa.oceana.org/what-ocean-acidification
http://www.ciesm.org/online/monographs/Menton08.pdf
Permission to quote must be obtained from TUDAV via email.
Oceans absorb a large portion of carbon dioxide from the atmosphere. When carbon dioxide is absorbed by the water surface, it undergoes chemical reactions to transform into carbonic acid, causing a decrease in the pH of seawater. This phenomenon is called "ocean acidification" or "OA" for short. Increased CO2, both anthropogenic and natural, is altering the global carbon cycle in the oceans.
Since the Industrial Revolution, ocean surface pH values ??have decreased from 8.2 to 8.1, approximately 0.1 units. The average pH of ocean surface water is projected to decrease by 0.3-0.5 pH units by 2100. On a logarithmically increasing pH scale, a 0.1 change corresponds to a tenfold increase in acidification.
Surface water pH changes (from 1986-2005 to 2081-2100) (IPCC 2003)The most commonly observed effects of calcium carbonate depletion as seawater pH decreases have been damage to the shells and skeletons of marine plankton, benthic mollusks, echinoderms, and reefs. Acidification prevents many organisms that use calcium for growth or shell formation, such as mussels, corals, and scallops, from doing so due to increased acidity. This is because every chemical reaction occurs within a specific pH range. Reactions necessary for shell formation cannot occur in an increasingly acidic environment. As oceans become more acidic, the formation of calcium carbonate shells and skeletons will become increasingly difficult. By the middle to late 20th century, some oceans will be so corrosive that even existing forms of calcium carbonate will dissolve.
Life on the evolutionary timeline has adapted to low carbon dioxide levels in its environment. Therefore, current life depends on these low values, and it is unclear to what extent species will adapt to continuously rising carbon dioxide levels. High carbon dioxide levels and exposure to highly acidic waters can lead to mass mortality (Adams and Caldeira 2008). In some organisms, efforts to balance pH changes reduce their reproductive and growth capabilities. Because the change is so rapid, many species are not genetically adapted to ocean acidification.
The massive increase in carbon dioxide emissions is the biggest factor in increasing ocean acidification. The current concentration of carbon dioxide in the atmosphere is at its highest level during the history of human civilization. Unless anthropogenic CO2 emissions are significantly limited or controlled by other factors, ocean pH levels will continue to fall. Ocean acidification has a devastating effect on marine microorganisms, especially some phytoplanktonic microorganisms. While the ultimate consequences of acidification are still unclear, it is known to directly affect coral reefs, commercial fisheries, fishing-free protected areas, zooplankton, and phytoplankton, the primary producers. Although there is no national policy on this issue, similar to climate change, regional administrations in various countries have included ocean acidification in their Fisheries and Aquaculture Resources management and control and have begun to take appropriate measures (OCBP 2009).
The impact of acidification on all seas is inevitable. Current studies on oceanic acidification show that the warm and mid-latitude Mediterranean and Black Seas will not be the first regions to be affected. Furthermore, the Mediterranean is highly saturated with calcite and aragonite at all depths, has high alkalinity, and is homogeneous. Due to these characteristics, the Mediterranean can act as a buffer against acidification caused by increasing CO2 (Schneider et al. 2007). Similarly, the Black Sea also has a very high calcite saturation in its surface waters (Tyrrell et al. 2008). These alkalinity characteristics alone tend to slow the onset of the increase in oceanic acidification on a global scale. However, factors such as the expanding and increasing population surrounding these sea regions, rapid urbanization and industrialization, and the absorption of acidic compounds from rivers and the atmosphere by coastal areas, have the potential to increase terrestrial sources of acidification, affecting polar regions and areas not yet reached. Therefore, ongoing projects concerning the effects of ocean acidification, particularly on the Mediterranean and Black Seas, need to be supported.
Sources:
http://www.pmel.noaa.gov/co2/story/What+is+Ocean+Acidification%3F
The effect of ocean acidification on phytoplankton/Murat Yeşiltaş:
http://webcache.googleusercontent.com/search?q=cache:9x_1FzILMpkJ:www.researchgate.net/profile/Murat_Yesiltas3/publication/276978992_Okyanuslarn_Asidifikasyonunun_Fitoplanktona_Etkisi/links/555cb21508ae6f4dcc8bcc2e+&cd=7&hl=tr&ct=clnk&gl=tr
http://www.dogagozculeri.org/okyanusyasaminatehdit.pdf
http://usa.oceana.org/what-ocean-acidification
http://www.ciesm.org/online/monographs/Menton08.pdf
Permission to quote must be obtained from TUDAV via email.
