A toxin produced by algae has contaminated the marine ecosystem off the coast of California, poisoning marine mammals and leading authorities to advise people against eating crabs from the area extending from Oregon to Santa Barbara. Domoic acid, a toxic chemical produced by algae, has contaminated the marine food web to a greater extent this year than previous years, according to research biologists. It has killed sea mammals in the area and poisoned other species. (The New York Times)