判断题 Scientists have identified the likely culprit in a disease that has devastated sea stars along the west coast of North America. Genomic detective work and lab experiments show that the wasting disorder is associated with a previously unknown virus. With the discovery comes a deeper mystery, however, the sea star—killing virus is far from new. The authors of the study found it in museum samples up to 72 years old, so scientists are puzzled about why the current outbreak has been so severe.
"This is probably the most extensive and devastating disease of marine invertebrates that has happened," says ecologist Bruce Mange of Oregon State University, Corvallis, who was not involved in the new research. "It"s a major concern."
The enigmatic disease came to broad attention in June 2013, when recreational divers near Vancouver, British Columbia, and Seattle, Washington, began noticing legions 0f dying sea stars. The sea stars first developed lesions, then began to lose their arms, and finally decayed into piles of skeletal ossicles (bits of calcium carbonate such as a star"s plates and spines). As the year progressed, the disease was seen in more and more locations in the waters off California.
Although there have been minor outbreaks in previous decades, this one is much more widespread, and more than 20 species of sea stars have been afflicted; other kinds of echinoderms, the animal group to which sea stars and sea urchins belong, have not. Researchers have raced to collect samples and conduct laboratory experiments to investigate any pathogens that might be involved. A feature in Science earlier this year, now available for free, examined the mystery.