Rotting sea lettuce a foul sign of Sound pollution
Blooms fed by excess nitrogen stink up the air in summer
Sitting outside to enjoy a summer day while she did some embroidery, Judy Pickens noticed her eyes were beginning to bother her. Was it her contacts? Pollen? But she also had a sore throat. Was she coming down with a cold?
Pickens went inside, and she got better. But the irritation returned when she ventured outside again the next day, and then again soon after.
"I kept thinking: What is wrong with me?" Pickens said. Pretty soon, she realized it probably had something to do with that awful smell that sometimes wafts through her West Seattle neighborhood, the scent that "reminds me of high school chemistry, when we mixed stuff together."
Eventually the stench was traced to seaweed rotting on the beach. When the weather turns hot, the rotting produces hydrogen sulfide -- which, yeah, smells like some experiments in high school chemistry.
The nasty odor outside Pickens' home above Fauntleroy Cove in the early 1980s marked the first public notice of what has become an increasingly common phenomenon: Apparently gorged on sewage and polluted runoff, a seaweed known as sea lettuce is growing in great green gobs at coves and bays around Puget Sound. It indicates a probable imbalance in the ecosystem, state officials and alarmed residents say.
"Green tides," they call the windrows and heaps that invade the beaches some summers.
It's another red flag that signals urgency about the need to restore Puget Sound, state officials fear.
The phenomenon isn't new, but what worries observers is that the sea lettuce appears to be growing rapidly, probably fueled by population growth and development in the region. It's poorly understood -- largely because no one has spent much time studying it.
The Legislature is trying to find a way to deal with it, but without a lot of success.
A 2000 report by the state government's Puget Sound Action Team examined the problem at more than 20 spots around the Sound. Since then, it's also cropped up at Dumas Bay in Federal Way, off southern Bainbridge Island and near Seattle's Shilshole Bay.
No one yet understands all the factors that influence the phenomenon.
"There seems to be an increase in the amount of sea lettuce in Puget Sound," Greg Bargmann of the state Department of Fish and Wildlife told Federal Way residents recently. "It just seems that we're getting more and more reports from residents of seaweed piled 6 or 12 inches high."
One resident troubled by the seaweed is Gale Cool, who lives by the beach on Bainbridge Island.
"I really began to notice it in the last few years, especially," Cool said. "Why is there getting to be more and more?"
Scientists have been warning for some time that increasing urbanization and the resulting dirty water that runs off after it rains are polluting the Sound. That rainwater carries with it nitrogen, which encourages the growth of plants and has been linked by scientists to seaweed blooms worldwide.
Nitrogen also is dumped as part of treated sewage. And it comes out of septic tanks.
Ron Thom, a marine biologist who has studied Puget Sound seaweeds since the early 1980s, says sea lettuce blooms here appear to be related to such factors as increased fertilization of lawns and runoff from streets.
"It's linked to development and population," Thom said.
Continue reading this article from the Seattle P-I:
Rotting sea lettuce a foul sign of Sound pollution
