The toxic algae bloom — or “red tide” — that has killed dozens of sea birds and mammals in local waters recently is mystifying marine experts and fanning local concerns about global warming.
Some people are convinced that human-made pollutants are at the root of the algae, a naturally occurring plant form that is a food source for fish at lower levels of the marine food chain, such as krill and crustaceans.
Researchers are reporting the highest levels ever seen of this algae and the neurotoxin domoic acid that is carried in it, which is alarming news.
When pelicans and sea lions or dolphins eat fish or shellfish carrying the toxin, it is passed up the food chain to them. Apparently, the fish aren’t affected by the toxin.
The algae bloom has been reported all along the Pacific shore, from Washington state to Southern California. The algae doesn’t bloom regularly, but when it does it releases the toxin, which causes disorientation and short-term memory loss in the affected animals. It can also affect humans, but shellfish beds are closed to commercial harvesting when the toxin is present.
In the wild, the sick animals can no longer fend for themselves and often die. It is a very sad sight to see.
Some are demanding that polluted Aliso Creek be immediately cleaned up — as if that were even possible — to stop the algae bloom from proliferating in local waters.
Aliso Creek, with its greenish, contaminated waters that flush millions of gallons a day in runoff from the higher elevations of South Orange County to the ocean, is at the top of everyone’s environmental “to do” list.
But it’s simply unrealistic to believe that Aliso waters alone are responsible for an algae bloom that is reported worldwide, from Japan to Prince Edward Island.
Researchers are working to determine the cause of the toxic algae and to see if something can be done about it.
While global warming may be the culprit, it is also possible that the algae would occur in any case.
According to the Marine Mammal Center in Marin County and researchers at UC Santa Cruz, the fact that there are abundant sea lions accounts for the high numbers that we see sick and dying onshore.
While the loss of several hundred of these animals is a terrible thing, it actually is a small dent in the population of sea lions, which number around 160,000 to 180,000, the researchers point out.
While the specter of global warming — and humankind’s responsibility for it — is troubling, it is more likely that the algae bloom is, as the UC Santa Cruz researchers believe, simply a “natural phenomenon.”