By Hand and By Robot, An Eelgrass Meadow Recovers

Day three at the Joemma Beach eelgrass meadow dawns cool and cloudy, but notably calmer after yesterday’s whitecaps.

We are not in the water long before others approach to see why we have donned wetsuits and hoods and snorkels offshore from Whiteman Cove — first a seal, then a pair of paddle boarders. We hold up clumps of eelgrass. Water streams off their tangled blades.

Jeff Gaeckle, the scientist with the Department of Natural Resources who is responsible for this — the most successful eelgrass restoration project in Puget Sound to date — kept the day’s briefing simple. He will finish up our multiday survey of the eelgrass meadow. The rest of us are to plant as much eelgrass as possible.

We stand in waist-deep water around floating bins filled with seawater and bundles of eelgrass. Gaeckle harvested these offshoots from a large meadow near DuPont Wharf. We tease them apart, find their brownish rhizomes, and tie them in pairs with twine along an L-shaped length of rebar. Twenty shoots per rebar.

When we have a handful of rebar Ls fully loaded with eelgrass, we swim to a stretch of bare sand where Gaeckle has stapled a 50-foot tape to the seafloor. We dive down and, at 6-inch increments, wiggle the rebar just under the sand’s surface. The twine will disintegrate as the plant roots establish, and the rebar can later be retrieved. Slowly, a line of waving eelgrass stretches into the murk and out of sight. 

Nearby, an undersea robot is doing much the same job. I float over to see it in action. Its nickname is Grasshopper 4. All week, a team from the startup company Reefgen has been putting it through its paces, seeing how it performs in a real-world environment, tweaking its systems.

Reefgen was the first company to build a coral-planting robot. Its new ambition is to adapt the system to plant seagrasses. Grasshopper 4 has an array of propellers housed like fans to hop it from planting site to planting site. A flexible tube connects it to a boat, where engineers control its movement and monitor its progress on an array of screens. When the robot is ready to plant, they pop a small bamboo stake strapped with eelgrass into the mouth of the tube. The stake is carried by suction down to the robot. The robot vibrates as it pushes the stake and its payload of eelgrass into the sediment.

Yesterday, Grasshopper 4 had trouble getting over piles of sand. It now sports pink children’s skis acquired from Sports Basement.

Today, the team’s primary challenge is how to avoid jams in the tube.

“First we figure out what works,” says CEO Chris Oakes, who spends the entire day in the water with a grin on his face, “then we figure out how to do it fast.”

With a robot, there will be no need to hand-plant eelgrass, which can only be done at the lowest tides of the year. By the end of the day, Grasshopper 4 has planted over 100 shoots.

Also here is Lara Breitkreutz, a graduate student at the University of Washington. Breitkreutz studies the genetics of Puget Sound’s eelgrass meadows. She is particularly interested in tracking the genetics of eelgrass restoration sites. In a place like this, where transplants from a number of nearby meadows have been interplanted, which genetic stocks adapt most quickly? How do they interact? Will they interbreed over time?

In contrast to Chesapeake Bay or the Outer Banks, where some of the most successful eelgrass restoration efforts have occurred, Puget Sound eelgrass flowers infrequently and spreads largely by rhizomes, asexually, meaning that our meadows have far less gene mixing than the East Coast meadows. In our week at Joemma, we find just a few “repros,” as Breitkreutz calls the reproductive flowering stalks.

Gaeckle points out to us the eelgrass transplanted from Rocky Bay to the north. It looks wispy and short compared to its cousins. The Rocky Bay meadow has only about three genetically distinct individual plants. They thrive there. Will they do well here, over time? How will they interact with their larger cousins from DuPont and elsewhere?

Breitkreutz sees the Joemma meadow as the perfect place to ask these questions, particularly given its proximity to the recently restored Whiteman Cove tidal channel.

“It’s an interesting place because you have one restoration site impacting another restoration site,” says Breitkreutz. The stress placed on the meadow by fine sediments released from the cove may help show which genetic stocks are best able to cope with disturbance.

Joemma Beach always strikes me as a special little pocket of biodiversity. Go on the pier and you’ll be surrounded by purple martins, kingfishers, pigeon guillemots, cormorants, seals, anemones, starfish. North and south, forest leans over the beach.

Now, having seen the eelgrass meadow here, I know the diversity extends offshore. I take time to snorkel over the meadow’s thickest stretches. It’s one thing to read about the importance of such meadows as nurseries for young fish and quite another to see in person how psychedelic they are. Take a geoduck siphon I find. I grew up stubbing my toes on the lumpy heads of geoducks at low tide. I now realize I have never seen one in its full glory. It is completely open, both holes perfectly round and fringed with strikingly colorful anemone-like hairs.

I pass a small blue starfish and drifting pile perch. Crabs bowl into each other to get a taste of a broken cockle. Gaeckle says one of the biggest open questions surrounding Puget Sound eelgrass meadows is an in-depth quantification of their biodiversity. It would be an expensive project. He would need to hire scuba divers or purse seiners or deploy camera traps. He says, for example, there are more nudibranchs in meadows farther north. But a complete picture of a meadow’s usage by all the critters that enter it during different seasons? Such understanding remains an aspiration.

On an edge of the meadow, I find a black-eyed hermit crab. This is a large species with colorful, orange-banded legs. Its tall eye stalks are alert.

Nearby, I notice a shrimp moving its way. I backstroke to hover behind them.

It seems certain they will touch. The crab holds still. Will it grab the shrimp? Will they square off? I don’t know what it says about me that I expect a flash of conflict, but when the shrimp reaches the crab, it merely uses its legs to push off the crab’s shell. Neither reacts. They kind of bounce off each other and go their separate ways as if such shoulder-rubbing happens all the time in the eelgrass.