Dumas Bay: Wake up and smell the sea lettuce

Like many Federal Wayers, I’ve been reading about the stinking sea lettuce problem at Dumas Bay for a while now.

I grew up with the occasional wind shift bringing the Tacoma Aroma to town during the 1970s.

Now, however, Federal Way is developing its own body odor problems. The body being Dumas Bay, and the odor coming from an overgrowth of sea lettuce.

The excess seaweed is definitely a local nuisance. It is also a symptom of a larger problem: The declining health of Puget Sound. On a recent sunny August day, I visited Dumas Bay myself to see how bad the problem is.

Sea lettuce is a common aquatic plant in the Sound and is an important element of the Puget Sound marine food web. I’m well familiar with it from my days as a little F-Dubber, prowling the shorelines of Poverty Bay and Dumas Bay for geoducks, crab, skipping stones, driftwood and anything else that might catch a boy’s attention. Sea lettuce was a common sight in the intertidal zone, usually found in small patches.

What I saw at Dumas Bay, however, was anything but small and patchy. I arrived at low tide and found the entire sandy beachfront glopped with the translucent, spinach-green plant. In some places, it was more than 4 inches thick, making for a very slimy, slippery walk to the water. I’d last been to Dumas Bay four years ago. At that time, there was nothing like this widespread infestation. Something had changed in the environment, and recently.

I ran into a local beachwalker, a longtime resident, who confirmed that the sea lettuce proliferation was indeed a recent development. Like most terrestrial plants, the seaweed is seasonal, making use of the growing season to reproduce and spread before pulling back in the fall. This year’s growth had been smaller than recent years, owing to our sporadic summer weather. Nor had it begun to stink much, yet. But if and when it does, a city-sponsored sea lettuce removal program will swing into action.

So, what has changed at Dumas Bay to bring about the overgrowth of the little green stinker? It’s hard to say precisely. It’s likely not any one thing, but instead the result of the Dumas Bay ecosystem reaching a tipping point that favors sea lettuce growth.

Dumas Bay is at the receiving end of creeks that drain stormwater from the Twin Lakes and North Shore areas, including the two golf courses. It may be that fertilizers and other compounds flowing from these sources have reached a level that feeds the lettuce. Or, these freshwater contaminants, in conjunction with an increasingly warmer and more polluted Sound, have created those conditions.

Something has changed in the bay and Sound that is fomenting the vegetation that is creating such a stink. A number of bays around the Sound experience similar problems.

I’ve spent the past 10 years studying the habitat of the Hylebos Creek Watershed and I’ve seen this pattern repeated endlessly. When the equilibrium of a natural plant community gets upset, aggressive plant species — whether they’re native or nonnative — proliferate. In the forest, we see Himalayan blackberry; in the water we see (and smell) the sea lettuce.

One of the biggest threats to Puget Sound is the very invisibility of its environmental ailments. In Federal Way, with its miles of shoreline and million-dollar views, the Sound looks more than all right to the average F-Dubber. When I looked past the sea lettuce and across to Maury Island, the Sound looked fantastic; as beautiful and breathtaking as it has always looked to me over the past four decades.

But if you look at the sea lettuce, and certainly, if you smell it, that should signal problems beneath the waves. Sea lettuce removal may help make the summers bearable in Dumas Bay, but the Sound’s future is gloomy unless Puget Sound residents and decision makers get serious about solving our environmental challenges.

The alternative may be perpetual sea lettuce removal.

Chris Carrel is a lifelong Federal Way resident and executive director of the Friends of the Hylebos, a nonprofit conservation organization working to preserve and restore Hylebos Creek and the West Hylebos Wetlands. Contact: chinook@hylebos.org or (253) 874-2005.

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