Estuarine Clean

Rikke Jeppesen (left) says although a saturation of algae is harmful to Elkhorn Slough, algae in moderation is healthy. “If you could harvest the algae and sell it, that would be great,” she says, but adds that a use for harvested algae is still being figured out.

In galoshes that rise to just below her knees, ecologist Rikke Jeppesen stands at the bank of one of the many wetland areas across the Elkhorn Slough National Estuarine Reserve in Moss Landing. With her facemask under her chin and sunglasses on top of her head, she rattles off a set of numbers from the digital monitor in her hands as volunteer Celeste Stanik stands close by, taking down the information onto her clipboard.

“849, 22.4, 2.3, 4.7,” Jeppesen mumbles as her other volunteer partner, Margie Kay, collects litter.

A thick black wire snakes down from Jeppesen’s monitor and disappears into the algae-covered pool. At the other end of this leash is a piece of equipment Jeppesen calls Snoopy, a cylindrical device which looks like a futuristic version of a SuperSoaker but is, in fact, much more advanced. Snoopy is a YSI EXO2 water quality sonde and, by measuring levels of pH, chlorophyll, dissolved oxygen, conductivity and turbidity, it paints a detailed picture of Elkhorn Slough’s health otherwise invisible to the naked eye.

Funded by the federal government, Jeppesen, Snoopy and a mix of volunteers are out here once a month, collecting water quality data and sending it to the National Estuarine Research Reserve System. A slough is where saltwater and freshwater meet, creating a not entirely common natural habitat whose sensitivity requires close watch and stewardship. Just like at sloughs across the country, Jeppesen and her team at Elkhorn track baseline water quality levels. The effort here has been ongoing since 1996, making it the longest continuous collection of water quality data on the Central Coast.

“If we don’t know what the baselines are, we don’t know how things are shifting,” Jeppesen says. “You can say, ‘Oh, what climate change?’ This effort is so we can look at the data and know the rate of change. We only know what the changes are if we know what it was before.”

By the day’s end, the three women will have spent four hours under the sun and collected samples from more than 20 sites across the slough, from under bridges, next to boat docks and at roadside pools. Jeppesen points to one such pool that is draped under fluorescent green algae.

“This is a good example of bad,” she says. Jeppesen explains that human development – roads, bridges, railroads – has clogged up several areas of the slough, offering the tides only narrow culverts and tidal gates through which to move. About 50 percent of the slough’s water, she says, is restricted from its natural circulation.

The Elkhorn Slough watershed winds around agricultural fields, which makes it vulnerable to runoff packed with fertilizers. The fertilizer saturates the water with nutrients resulting in algae blooms that are exacerbated by the limited circulation afforded to the water. Floating algae, which is so thick in some areas that it looks like grassy sludge and is capable of trapping fish, represent the most impacted bodies of water.

“Algae produce oxygen during the day, but at night, it breathes and draws the oxygen levels in the water down to zero,” Jeppesen says. “If you’re a fish, at least you can move to a different area. An oyster, on the other hand, has to essentially hold its breath.”

Low oxygen doesn’t kill an oyster, but studies show it does stunt their growth.

“If the water quality was better in these areas, you might see more fish, which might mean you see more birds feeding on the fish,” Jeppesen adds.

“It’s no secret, the main problem for Elkhorn Slough is nutrient loading and it’s coming from agricultural runoff. I think everyone who lives in this area, they care – about the slough and about the land. It’s not useful to point fingers. The key is to work together and find projects that everyone can do because we are all here.”

Jeppesen says farmers have been open to solutions that go as far as taking land near the watershed out of crop production. It’s an ongoing conversation. Restoration efforts in the upper estuaries of the slough created natural buffers between agricultural fields and the watershed and have successfully revived water quality in some areas.

Christopher Neely covers a mixed beat that includes the environment, water politics, and Monterey County's Board of Supervisors. He began at the Weekly in 2021 after five years on the City Hall beat in Austin, TX.

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