According to a new Report from the United Nation, about 24 million tonnes of CO2 from industrial society is absorbed into the sea every day, turning whole oceans more acidic.
Researchers from the Alfred Wegener Institute in Bremerhaven are examining how ocean life responds to the acidification. Some corals, for example, are unable to rebuild their exoskeletons. Fish may be less able to swim against currents. The researchers’ findings are incorporated into the part of the UN’s Fifth Climate Assessment Report published at the end of March. For the first time, the report features a chapter documenting the effects of rising CO2 emissions on ocean ecosystems.
The oceans absorb more than 25 per cent of the carbon dioxide we release into the air. Since the start of the industrial revolution, the oceans have absorbed around one half of this greenhouse gas which we humans have blown into the atmosphere through exhaust pipes and chimney stacks. Without this natural store, the carbon dioxide concentration in the air would today be far higher and it would be a great deal warmer on the Earth. However, the more carbon dioxide penetrates into the oceans, the more carbonic acid is created. This process impacts the chemistry of the seawater and reduces its pH value and makes the oceans more acidic..
The pH value specifies whether a liquid is acidic, basic or alkaline. With an average pH value of 8.2, seawater is typically slightly basic. However, this value has declined to 8.1 over the past two hundred years. “This may not sound like a lot, but the pH values are logarithmic, i.e. mathematically compressed. This means that if the pH value drops by 0.1 units, the seawater becomes 30 per cent more acidic”, explains Prof. Jelle Bijma, bio geochemist at the Alfred Wegener Institute. By 2100, the pH value of the oceans is expected to drop by a further 0.3 to 0.4 units so that the seawater would become 100 to 150 per cent more acidic. This does not mean that the oceans would actually turn into acid. With values around 7.7, they would still remain basic but from a relative point of view they are more acidic than they were before.
The researchers assume that above all organisms with lime shells and skeletons such as corals and mussels will suffer from increasing ocean acidification. In particular, the calcification process of such organisms becomes increasingly more difficult and the lime shells even start to dissolve.
How ocean acidification impacts individual organisms has far reaching consequences for the entire ecosystem: starting from the food chain through to the carbon content in the atmosphere. “Calcifying algae, for example, build biomass by photosynthesis. But they also store carbon in the lime scales of their housing. When they die, they drop to the bottom of the ocean.
Meanwhile, on 3 April 2014 United Nations Secretary-General Ban Ki-moon from Brussels called for transformative collective action to tackle Climate change.
LTEconomy, 09 April 2014
BBC news - http://www.bbc.com/news/magazine-26755189
Alfred Wegener Institute on Ocean Acidification – http://www.awi.de/en/news/focus/2013/ocean_acidification/
Facts and figures on ocean acidification - http://www.unesco.org/new/en/natural-sciences/ioc-oceans/priority-areas/rio-20-ocean/blueprint-for-the-future-we-want/ocean-acidification/facts-and-figures-on-ocean-acidification/
United Nations Secretary-General Ban Ki-moon calls for transformative collective action to tackle Climate change - http://www.un.org/apps/news/story.asp?NewsID=47496