Domoic acid, produced by marine algae, causes seizures and death in seabirds every year. In 2007, the “red tide” is unusually severe.
Small marine algae, also known as microalgae or phytoplankton, live in the top sunlit layer of seawater. Important in the ocean ecosystem, and a source of food for many marine animals, they are also known for causing toxic shellfish and seafood poisoning, otherwise known as red tide. These organisms produce some of the most dangerous toxins known. Pseudo-nitzschia spp., marine diatoms, produce the neurotoxin domoic acid.
Red tide is the result of algal bloom—the multiplication of phytoplankton to more than a million organisms per liter of seawater. When a phytoplankton such as Pseudo-nitzschia blooms, fish and shellfish that feed on the algae accumulate toxin in their tissues. These animals are unharmed, but mammals and birds that feed on them in turn are poisoned.
Domoic acid is a neurotoxin—it affects the brain, causing seizures, memory loss, and often death. Every year, algal blooms produce domoic acid off the California coast and kill birds. The 2007 season is turning out to be particularly deadly as birds, whales, sea lions, and dolphins wash up, dead or dying, on California beaches. Brown pelicans, listed as endangered, are of particular concern.
Articles about the 2007 red tide in California:
Hammill, Ryan and Cindy Carcamo. “Toxin Kills Birds, Sea Lions.” ocregister 2007: Apr 26.
International Bird Rescue Research Center. “Crisis Off Our Coast.”
Sources:
Northwest Fisheries Science Center: Harmful Algal Blooms Program.
Read about other threats to water birds:
