There were reports about the effects of global warming on algal bloom . As a geographer both interests me , besides i have a life-science background so i have natural interest in these. I have found an interesting and somewhat convincing post on Watts Up With That?. Here it is:
It seems that global warming is as easy to blame as “the devil made me do it” these days. Almost anything can be blamed on global warming it seems. It has become the new universal evil, replacing the threat of communism as the new global menace. But it doesn’t always deserve the blame for things that happen in our world, and with a little digging, you can often find that blaming global warming for a variety of ills and changes is about as credible as blaming the boogeyman. Consider algae blooms for example.
Earlier this year we saw this story
ScienceDaily (Apr. 7, 2008 ) — You know that green scum creeping across the surface of your local public water reservoir? Or maybe it’s choking out a favorite fishing spot or livestock watering hole. It’s probably cyanobacteria — blue-green algae — and, according to a paper in the April 4 issue of the journal Science, it relishes the weather extremes that accompany global warming. more…
Now we have this new factual story:
Scientists solve riddle of toxic algae blooms
Ed Struzik, Canwest News Service, Published: Tuesday, July 22, 2008
EXCERPT: After a remarkable 37-year experiment, University of Alberta scientist David Schindler and his colleagues have finally nailed down the chemical triggers for a problem that plagues thousands of freshwater and coastal ecosystems around the world.
Fifty years ago, no one knew what exactly caused algae blooms to appear on lakes and rivers. There was some evidence to suggest that carbon, nitrogen and phosphorous, which are associated with agricultural runoff and waste water, were responsible. But small-scale experiments weren’t able to show which were more important.
Schindler seemed to solve the problem when he and his colleagues conducted a number of groundbreaking experiments in northern Ontario in the 1960s and early 1970s. In a famous 1974 aerial photograph published by the journal Science, two portions of their experimental Lake 226 were highlighted. One side was treated with carbon, nitrogen and phosphorous. The other was treated with just carbon and nitrogen.
The side receiving phosphorous rapidly developed a huge bloom of blue-green algae. The side not receiving phosphorous remained in near-pristine condition.
Schindler’s latest series of long-term experiments shows that nitrogen removal completely fails to control blue-green algae blooms. He proved this by manipulating nitrogen and phosphorus levels on Lake 227 for 37 years. Nitrogen control, he found, only encouraged algae blooms.
Conclusion? Phosphates and Nitrogen. Not global warming.