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Ocean Accidification is a phenomenon where the acidity of seawater turns below normal. This relates to the physical and chemical properties of the ocean itself, which of course is directly related to atmospheric conditions. The main cause is the result of global warming phenomenon. Ocean acidification is a major issue of climate change that will change the life of the world due to the increased concentration of atmospheric carbon dioxide dissolved in large quantities of seawater and a very rapid dissolution process due to the effects of rising temperatures. As widely known, anthropogenic carbon pollutants are predominantly from burning fossil fuels (coal, petroleum and natural gas). Cement production and tropical forest burning contribute to the amount of emissions accumulated in the atmosphere. Along with the increasing population growth along with the necessary facilities and infrastructure including various types of buildings, highways, lighting and transportation, land conversion can not be avoided anymore. Thus, we have never realized that economic development has reduced the ecological balance a little bit, and it goes on and on without anyone being able to set limits.
The current climate change is the accumulation of the impact of disruption of ecological balance. Gruber et al. (1996) calculates that marine waters are capable of absorbing half of the emissions released by the burning of fossil fuels in the atmosphere since the beginning of the industrial revolution. Revelle & Suess (1957), the first initiator of carbon dioxide (CO2) measurements in the Pacific region, also argues that CO2 that is not absorbed by plants will end up in the oceans. This situation will of course change the chemical equilibrium of seawater because the increase of CO2 gas solubility is predicted to be able to decrease the pH up to 7.7. The average sea acidity level is 8 8.5 (Kleypas et al., 2006). Based on studies from various sources namely Kleypas et al. (2006); The Royal Society (2005) and IPCC (2001), schematically find a causal path of climate change phenomena triggered by increased human activity, one of which is land use change. Increased concentrations of greenhouse gases, one of which is atmospheric CO2, leads to the capture of ultra violet rays and heat energy in the troposphere layer. In addition to forming a hot trap blanket, CO2 gas also causes acidity symptoms in the waters as a result of increased adsorption of CO2 gas from the atmosphere to the surface waters
Ocean acidification is the term given to the process of descending sea water pH levels that are now occurring due to the absorption of carbon dioxide in the atmosphere resulting from human activities (such as the use of fossil fuels). According to Jacobson (2005), the pH at sea level is expected to fall from 8.25 to 8.14 from 1751 to 2004. In a natural carbon cycle, atmospheric CO2 concentration represents a flux balance between the oceans, the land and the atmosphere. Land use change, fossil fuel use, and cement production result in additional CO2 sources into the Earth's atmosphere. Some CO2 is absorbed by plants on land and some are absorbed by the oceans. When the CO2 dissolves, it reacts with water to form an ionic and non-ionic equilibrium that is: free dissolved carbon dioxide (CO2 (aq)), carbonic acid (H2CO3), bicarbonate (HCO3-), and carbonate (CO3-) . The ratio (ratio) of these species depends on sea water temperature and alkalinity (the acid neutralizing capacity of a solution). Dissolved CO2 will also cause a rise in the concentration of hydrogen ions (H +) in the ocean, thus reducing the pH of the ocean (remember the lower the pH value, the more acidic a solution).
According to Orr et al. (2005), since the start of the industrial revolution, the pH of the ocean has decreased by approximately 0.1 units, and is expected to continue to fall to 0.3 0.4 units by 2100 due to the increasing amount of CO2 gas due to human activities being absorbed. Although CO2 absorption by the oceans will help improve the climate effects of CO2 emissions, it is believed also that there will be negative consequences for shellfish organisms that utilize calcite and aragonite from calcium carbonate to form shells. These organisms play a role in the marine food chain.
Under normal conditions, calcite and aragonite are stable on the surface of the water because the carbonate ions are in very saturated conditions. With the decline of sea water pH, the concentration of carbonate ions will also decrease, and when the carbonate is in unsaturated condition, the structure formed from calcium carbonate becomes brittle and will be easily dissolute / dissolute. The results showed that the corals (Gattusoet al., 1998), algacoccolithophorThis will divert energy from other energy needs. So that the biological and chemical processes that the coral do will begin to be disturbed, for example like the activity of metabolism and reproduction. Of course, it would be very detrimental to the survival of the reef itself. In addition, other studies have suggested that CO2 doubling in the atmosphere will cause coral calcification ability to decrease from 10%. Obviously this will affect the morphology and physiology of the growing corals. Until now no studies have shown that corals have resistance to changes in acidity levels. This certainly warns us all to prevent the occurrence of ocean accidification that can affect not only the corals, but also on all organisms that perform calcification activities.
Salam Reef. Save Our Coral.
Material of Coralogy Lecture by Dr. Ir. Diah Permata Wijayanti, M.Sc
Coral Reef And Ocean Accodification by Joan a. Kleypas and Kimberly K. Yates