who puts the asset in grass?

by Kate Freeman

​Eelgrass: a coastal treasure. 

​As residents of California, we have an extra special relationship to grass. We watch it paint the hillsides gold in summertime. We learn to live without it on our lawns. We have even legalized the use of psychoactive grass for adults. While the quality of one’s lawn or cannabis laws are both rich and riveting topics, I am not here to discuss grass in either regard. Today, I would like to bring to your attention the under-glorified yet inimitable grasses of the sea — and by that, I mean seagrass!

Seagrass beds, or meadows, provide essential habitat for marine life.

Did you know that one of our preserves, the Estero Americano, is adjacent to a tidal estuary hosting one of the most important seagrass habitats in the county? I didn’t either until very recently. Last week at the Estero, I had the opportunity to meet Andrew Weltz, a marine scientist at California Department of Fish and Wildlife (CDFW), as he and other researchers set out on their annual seagrass survey. The ribbon-like native eelgrass, Zostera marina, is specifically what they were after. 

Perhaps you’ve spied those long and narrow green leaves below the water’s surface and assumed they were seaweed. If so, brace yourself for some life-altering information: Eelgrass is not seaweed or algae but an angiosperm (a plant that has flowers and produces seeds) that spends its entire life underwater. Does this sound remarkable? Well, it is! Since they are plants, seagrasses must grow in shallow water that is also clear, allowing enough sunlight for photosynthesis.
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Eelgrass really does put the ass(et) in grass. Eelgrass beds provide habitat for 200 times more animals than adjacent sandy or muddy habitats. Seagrass communities host dynamic and intricate food web relationships, giving the Jersey Shore (or whatever reality TV trash you prefer) a run for its money. Birds, crabs, fish, shrimp, marine polychaetes, clams and isopods all rely on seagrass beds for food and shelter. The densely growing leaf clusters essentially serve as underwater Eco Resorts, providing food, shelter and even yoga classes for privileged visitors.  

Black Brant feeding on eelgrass.

These havens play an important role in the lifecycles of Coho salmon and steelhead trout by offering a cool place for fish to hang out, as well as food, protection from predators and spawning grounds. Eelgrass beds also serve as a nursery area for herring. Herring are a preferred salmon snack, and herring eggs also happen to be a food source for diving ducks, like surf scoters and greater scaup. In winter months, shorebirds, wading birds and waterfowl rely on eelgrass beds as a vital food source. Black brant, which migrate 3,000 miles from their arctic breeding grounds, feed almost exclusively on eelgrass during stopover points. I can only imagine the horror if something got between me and my food source (kale, chocolate, wine) after a 5-mile run … let alone a 3,000-mile transcontinental journey!

While grass has a reputation for giving people the munchies, eelgrass is not just about the food. This plant is a true environmentalist — it survives purely on prana/sunlight, thank you very much. Eelgrass is an unsung superhero of our coasts, preventing erosion, improving water quality by trapping nutrients and sediments, and producing oxygen, which is critical for marine animals. The absorption of nutrients helps prevent harmful algal blooms, which are detrimental to other marine life — when there are excess nutrients in the water, phytoplankton multiply, decreasing dissolved oxygen content and blocking sunlight for other organisms.

At this point you’re probably thinking all right, we get it, eelgrass is a tree-hugging, dirt-worshipping, Prius-driving little angel. But this species goes above and beyond all that — it actually sequesters carbon! According to researchers at the UC Davis Bodega Marine Lab, one acre of seagrass sequesters 7,401 pounds of carbon per year, equivalent to CO2 emissions from an automobile traveling 3,860 miles. That’s almost a year’s worth of me driving to work (ashamed-face emoji here).

If you haven’t gotten the message, I’ll say it right now loud and clear: SEAGRASSES PROVIDE INDISPENSABLE ECOSYSTEM SERVICES FOR OUR BAYS AND ESTUARIES! Unfortunately, like much of the life along and within our coastal waters, they are threatened. Seagrasses are in global decline due in large part to human disturbances from dredging and boating, excessive input of nutrients and sediment, and changes to the coastal food web due to overfishing. Ongoing monitoring, like that being done by CDFW, NOAA the Bodega Marine Lab, and others, is crucial.
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​Eelgrass beds are protected as “special aquatic sites” under Section 404(b)1 guidelines of the Clean Water Act, designated as Essential Fish Habitat under the Magnuson-Stevens Fishery Conservation Management Acts, and protected under CDFW regulations; however, they are still extremely vulnerable to impacts from humans. No action is insignificant — when recreating in Bodega or Tomales Bay, you can help by checking for seagrass and being sure not to disturb these sensitive communities. Part of our mission here at the Land Trust is to protect and restore the region’s precious and complex coastal ecosystems. Our work in places like the Estero Americano and the Sonoma Baylands is possible only with the support of our incredible partners, volunteers and members. So, thank you, and let eelgrass be your gateway drug to bayland habitat appreciation. ​

The Estero Americano Preserve estuary: home to valuable eelgrass communities.

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Kate Freeman is stewardship assistant project manager for Sonoma Land Trust. 

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