On June 12, while surveying a private lagoon in San Diego County, biologists ran across a strange, 14-inch-high mat of algae. Not only did it look unlike anything they had seen before, but it had infiltrated, squashed, and killed a 30-by-60-foot patch of 4-foot-high eelgrass.
Rachel Woodfield, part of the research team that made the discovery, sent a specimen to seaweed taxonomist Paul C. Silva of the Jepson Herbarium at the University of California, Berkeley. "I took one look," he recalls, "and it just screamed, 'I'm a weed! Get out of my way!'"