The level of carbon dioxide has increased tremendously over the past few years by nearly 40%, that is from approximately 280ppm in preindustrial times to 384ppm in 2007(Solomon et.al 2007). Nearly one third of anthropogenic carbon dioxide is being absorbed by the oceans today(Science Daily, May 24, 2008) . Uptake of carbon dioxide by the oceans is not a harmful phenomenon , but excess of it leads to a reduction in pH thereby altering the fundamental seawater chemistry, commonly known as ocean acidification . This rising levels of atmospheric carbon dioxide is mainly due to anthropogenic activities such as burniig of fossil fuels , chopping and burning down tropical forests for new agricultural lands and tourism purposes,etc. are taking place at large scales , thereby releasing enormous amounts of carbon dioxide gas in the atmosphere.The total human carbon dioxide emissions amounts to approximately 560 billion tons.(ref paper 1). Currently , the rise in atmospheric carbon dioxide is 30 times faster than in the past, at present the levels are higher in comparision to several million years.(REF PAPR 1 nthr ref is mentd too). Studies show that increase in the carbon levels is also due to volcanic vents present in the ocean but these amount to less than 0.5% of anthropogenic emissions ( lters ref). Ultimately this increased acidity can hamper marine organisms and the calcification process which some of the organisms use to form calcium carbonate and skeletal structures. Organisms ranging from corals to the most important bacteria responsible for earth’s climate are known to be under threat due to acidification.( Science Daily, march 31, 2010). Oceans function as a sink that take up half of carbon dioxide emitted by human. Without this sink, the concentration of greenhouse gases would have been higher; hence, the planet would have been much warmer. Increase in atmospheric carbon dioxide levels leads to an increased uptake of the gas during the air – gas transfer process by ocean surface waters resulting in a shift in seawater chemistry- lowering ocean pH and ultimately decreasing the concentration of carbonate ions and increasing the concentration of bicarbonate ion and hydrogen ion.( paper 1 ). Absorption of anthropogenic carbon dioxide by oceans reduces the saturation state of seawater with respect to aragonite and calcite, two important and common calcium carbonate secreted by marine organisms. Experiments with calcareous organisms point out that calcification is reliant on the carbonate saturation state of seawater.( ref AR1 ).
Increase in hydrogen ion concentration means the pH is low and hence there is an increase in acidity. With every one unit decrease in pH there is a 10 fold increase in hydrogen ion concentration (EPOCA).
Oceans absorb carbon dioxide from the atmosphere
Oceans functions as a sink that takes up half of the anthropogenic carbon dioxide. Without it there would have been an increase in the...