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Tag: Calcium

Distribution of coldwater and tropical coral reefs
Coral reefs are marine ridges or mounds, which have formed over millennia as a result of the deposition of calcium carbonate by living organisms, predominantly corals, but also a rich diversity of other organisms such as...
01 Feb 2008 - by Hugo Ahlenius, UNEP/GRID-Arendal
Regional trends in biochemical oxygen demand (BOD)
Biochemical oxygen demand is an indicator of the organic pollution of freshwater. Alkalinity (concentration of calcium carbonate or CaCO3) is another indicator of freshwater quality. These graphics compare the concentrat...
17 May 2005 - by Philippe Rekacewicz, UNEP/GRID-Arendal
Calcium levels in major rivers
This graphic shows the average calcium levels, in milligrams per litre, at major river mouths for the time periods 1976 to 1990 and 1991 to 2000. The graphic also shows the changes in average calcium levels between these...
17 May 2005 - by Philippe Rekacewicz, UNEP/GRID-Arendal
Coldwater coral reefs, distribution
Scientists are just beginning to learn about the many species in the remote, deep waters of the polar oceans. Corals, for example, are not limited to the warm, shallow waters of the tropics. They also exist in many cold,...
31 Jul 2008 - by Hugo Ahlenius, UNEP/GRID-Arendal
Coldwater coral reefs, distribution
Scientists are just beginning to learn about the many species in the remote, deep waters of the polar oceans. Corals, for example, are not limited to the warm, shallow waters of the tropics. They also exist in many cold,...
21 May 2010 - by Hugo Ahlenius, UNEP/GRID-Arendal
Freshwater alkalinity: 1976-2008
Alkalinity is commonly used to indicate a water body’s capacity to buffer against acidity; that is, the ability to resist, or dampen, changes in pH. Thus, alkaline compounds in water, such as bicarbonates, carbonates, an...
26 Jan 2009 - by Philippe Rekacewicz (Le Monde diplomatique), February 2006