MARIN COUNTY'S NEWS
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The Marine Mammal Center's Domoic Acid Trip
By Marie Siegenthaler
In response to the several outbreaks over the years, the lack of previous research, and sheer curiosity, the Marine Mammal Center is conducting research on the effects of domoic acid on marine life.
Domoic acid, C15H21NO6, is caused by a diatomic process of the algae Pseudonitzschia australis, a red algae often found in red tides. Like most algal blooms, the algae are triggered by an increase of nitrogen or phosphorous in the water. Unfortunately, why one type of algae blooms as opposed to another is unknown. The diatomic function in P. australis is thought to produce domoic acid as a waste product, as it seems to serve no purpose for the algae, but scientists are still not certain.
Though domoic acid is not persistent in the environment like petroleum, it is quickly usurped by filter feeders such as shellfish. These contaminated shellfish are then eaten by birds, sea lions, seals, and others large marine predators. It is through these shellfish that the predators become sick. A sea lion can clear raw domoic acid from its system within ten hours, but the fish aren't as forgiving.
However, it is not the synthesis of creating domoic acid that catches the interest of the Marine Mammal Center. The crux of their research is directed at the actual effects of domoic acid in marine life, chiefly mammals. The Center is looking at both the acute (immediate) and chronic (lasting) effects of domoic acid poisoning. They have already found that domoic acid is persistent in mammalian systems, but they have yet to see where it accumulates.
Surprisingly little research has been done since domoic acid was first isolated in 1958, but the known effects of domoic acid are remarkable. It is known to affect the neural system and hinder neural chemicals, causing literal insanity. It was domoic acid that made the seabirds attack people in Capitola, 1961, thus inspiring Alfred Hitchcock's "The Birds". Beached sealions and dolphins show signs of having seizured. Scientists also find that affected mammals have a greater flow of calcium into their cells.
But the threat of domoic acid is not limited to marine mammals and birds. Human beings are similarly affected by the poisoning in the event of eating contaminated shellfish, resulting in amnesia shellfish poisoning (ASP). ASP is characterized by confusion, the loss of short-term memory, and disorientation. Vomiting, abdominal cramps, severe headache, and diarrhea are a few of the lighter symptoms. In severe cases, victims will experience coma and death.
The Marine Mammal Center expects that this study will take three or four years to complete. They are being helped by University of California, Santa Cruz. UC Davis has also collaborated to work on the veterinary aspects. With this knowledge, they hope that they will be better prepared to identify, treat, and rehabilitate mammals afflicted with domoic acid poisoning.
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