In late 2007, seabirds off the coast of California began to die in record numbers. The waterproof nature of their feathers and been wrecked, and they were soaked to the skin. Without an insulating layer of air trapped within their plumage, the damp birds were suffering from extreme cold. These are exactly the type of problems that seabirds face when they blunder into oil spills, but in this case, not a drop of petroleum had entered the water. The problem was a biological one.
At the same time, Monterey Bay in California was plagued by a massive “red tide” – a bloom of microscopic algae called dinoflagellates. These blooms can include millions of cells in just a millilitre of water and some species churn out toxins that kill local wildlife. Sea lions, dolphins, sea otters, manatees, whales and even humans have all succumbed to these poisons, either directly or by eating contaminated food.
David Jessup from the Marine Wildlife Veterinary Care and Research Center found that these algae were the source of the birds’ misfortune, but not because they were secreting toxins. Instead, they produced a foam that was loaded with surfactants – wetting agents. These are the chemicals used in detergents; they lower the surface tension of a liquid and allow it to spread more easily over a surface. This foam was the agent behind the seabirds’ water-logged feathers.