(This is a world wide problem. - promoted by Asinus Asinum Fricat)
Algae blooms have been in the news lately primarily as an adjunct to sporting news, what with the vast bloom that was choking the sailing event venues of the Olympic games in China. Much more serious is the impact on health and on the food supply.
There are several types of algae blooms, each having a different bad effect. The ones that make the news most often are those commonly referred to as 'red tides,' but are more properly called Harmful Algal Blooms (HABs.) These are blooms of poison-producing algae, which can spread neurotoxins through the food web, sickening or killing everything from plankton to humans.
Join me below the fold for a brief bit of phycology (the study of algae) below the fold... |
The Woods Hole Oceanographic Institution provides a quickie fact sheet on HABs:
Unfortunately, a small number of species produce potent neurotoxins that can be transferred through the food web where they affect and even kill the higher forms of life such as zooplankton, shellfish, fish, birds, marine mammals, and even humans that feed either directly or indirectly on them.
It goes on to describe various forms of fish and shellfish poisoning in humans caused by algae that should not be read by hypochondriacs.
A second form of algae bloom is the so-called "green bloom," which, while not toxic, still can cause widespread die-offs of aquatic life by depleting the water of oxygen.
Algae blooms have been increasing in recent years, both in frequency and in their geographic scope, creating ever-greater stress on the food system and on aquatic ecosystems.
Why have they been expanding? Although some of the expansion has been attributed to non-native species being introduced by global shipping into ecosystems where there is no existing predator, the primary causes are not a surprise. As an article in today's Financial Times succinctly puts it:
"There is clear evidence from around the world that algal blooms are increasing in geographical spread, density and duration," says Geoffrey Codd, of Dundee University, president of the British Phycological Society.
"This is due to a range of factors but a major one is the increasing discharge of nutrients from human activities into our water bodies," he adds. Industrial and agricultural activities are responsible, with run-off of nitrogen and phosphorous fertilisers especially important.
Rising water temperatures, due to climate change, are a second factor that combine with increasing nutrient levels - eutrophication - to stimulate algal growth.
Just one more way in which our so-called miraculous industrial agriculture is in fact bringing long-term deterioration to our food supply and posing a threat to human health. |
