Creature Feature: Eelgrass!
Eelgrass, Zostera marina, lays low at low tide. Even when laying down, eelgrass provides habitat for other important intertidal life, like this sea star.
Zostera marina bends and sways gracefully when tidal currents start to flow. Photo by Padilla Bay NERR.
Pastures in the sea?
Grass can live in the sea? Yes! The only flowering plants that live in the sea are sea grasses and they have found ways to survive in every area of the world ocean. There are dozens of kinds of seagrasses, like turtle grass and manatee grass (hmmm, who do you suppose grazes in pastures of those grasses?). But, just three types of seagrass live in the Salish Sea: surf grass, Phyllospadix scouleri, and two types of Eelgrass.
Grass for eels or eel-like grass?
Wait, if turtles depend on turtle grass and manatees depend on manatee grass, do eels depend on eelgrass? Well, not in the Salish Sea. There are no actual eels in this part of the world (hint: check eel-like fish for fins on the sides. Eels have no pectoral or pelvic fins). Eelgrass was actually named for its long, eel-like leaves. The two types of eelgrass here are dwarf or Japanese eelgrass, Zostera japonica, and Pacific eelgrass, Zostera marina.
Can you tell the difference between Pacific and Japanese eelgrass? Photo by Washington Department of Natural Resources (WDNR).
Pacific eelgrass is native to our waters and the dwarf or Japanese eelgrass came all the way from, you guessed it, Japan.
Nature detectives! Can you imagine ways Japanese eelgrass crossed the whole Pacific Ocean to grow in the Salish Sea?
Japanese eelgrass is usually narrower and shorter and lives in shallower water than the broader- and longer-leafed native species.
Eelgrass babies
Eelgrass reproduces with flowers, just like many land plants. Instead of dusty pollen spread by bees, birds, and bats, though, it has super sticky pollen that floats on the currents to other plants (no underwater hummingbirds). This is how they trade genetic material and make seeds (see figure to the side). But they also have another trick up their sheaths. They can reproduce by sending out additional rhizomes, which grow new shoots from their growing tips (see figure below).
Eelgrass grows shoots from rhizomes, sideways-growing roots. Their vertical roots are just barely below the surface, but rhizomes can be a meter long. Diagram courtesy of James Cook University, Australia.
Eelgrass gives protective habitat to hundreds of important (and weird) wildlife species, like this Pacific spiny lumpsucker (see previous Creature Feature). Photo by Joe Gaydos.
Can you find a Taylor’s sea hare (nudibranch) hiding in the eelgrass? This is a common eelgrass meadow friend. Photo by WA Dept of Natural Resources.
Besides water, living things are mostly made from carbon or just “C” for short. Did you find all the C’s in the diagram? Blue C refers to the stuff made from carbon (plant matter and dead critters) that gets trapped for a long time in the soil beneath seagrass meadows, salt marshes, and mangroves. This C used to be greenhouse gases before plants slurped it up during photosynthesis. The more C that gets trapped by plants, the less is in the air and this helps slow down global warming, a win for life on Earth! Diagram by Restore America’s Estuaries.
Eelgrass seeds. Shaped like tiny, striped barrels or maybe puny pickles, are only a few millimeters long. Photo by Friday Harbor Labs, UW
If grass could be a Salish Sea Hero
We weren’t sure if eelgrass should be our Creature Feature or Salish Sea Hero this month. Why? Just like you Salish Sea Heroes out there, eelgrass is always working to improve habitats in the Salish Sea! Both eelgrass species provide a long list of helpful jobs, called ecosystem services, that have earned them a revered place amongst Salish Sea Heroes. Here are just a few of their heroic feats:
Substrate stabilization Eelgrass spreads roots and sideways roots, called rhizomes, in sand and mud, stabilizing loose sediment so it can’t be washed away or erode. This helps keep the water clear, too.
Shore protection Eelgrass grows in thick meadows that slow down and lower the height of waves that could otherwise wash away our beaches and bluffs. This saves us a lot of money.
Water purification Eelgrass takes up pollutants from the water. Acting like natural water purifiers, each plant improves water quality for other wildlife.
Oxygen production Eelgrass produces so much oxygen, you can see and hear oxygen gas bubbles forming and popping on a sunny day, like a fizzing symphony of photosynthesis!
Habitat for hundreds Eelgrass provides homes to hundreds of species of animals and even other photosynthesizers, who hitch themselves to the leaves, like ferns on rainforest trees.
Baby animal hideaway Critters that are important to fishers, like Dungeness crab, herring, and Pacific salmon, depend on eelgrass as nursery areas for their young. People depend on these animals for food and income to support their families.
Big $$$ All of these ecosystem services equal millions of dollars every year for coastal communities.
Eelgrass meadows provide homes for some of our favorite foods! These Dungeness crab were caught in eelgrass meadows in Skagit Bay, WA. Photo by Matt Castle.
When is carbon blue?
Climate coolers Seagrasses, including eelgrass, cool the climate by:
first, turning lots of greenhouse gases (the invisible gases in our atmosphere, like carbon dioxide (CO2) and methane) into leaves and roots through photosynthesis, and
second, trapping plant matter and sediments that sink and get buried within the meadows. The buried plant matter is made of carbon that used to be a gas in the air. Now it is locked away under mud, under water, without oxygen. Without oxygen it can’t decompose and turn into a gas again until it gets dug up. In some seagrass meadows with deep roots, this can be over 1,000 years. In eelgrass meadows, it is a shorter time, possibly due to their short roots and getting dislodged easily.
This ocean-based carbon trapping coolness is called “BLUE CARBON.” Blue because it’s in the ocean and there is a land/tree-based carbon storage program called REDD (Reducing Emissions from Deforestation and Destruction).
third, people can speed up this cooling coolness. People and businesses can actually offset, or make up for the CO2 they release when they fly, drive, turn on lights, heat or cool their homes, burp, toot, or otherwise burn stuff, by paying to plant seagrass that will trap that CO2 long term. Now that’s cool.
This is a graph of how fast carbon gets trapped in different types of ecosystems. How do seagrasses rate compared to forests? They are among the top 3 blue carbon superstars! Graph by McLeod et al. 2011.
Meriel Kaminsky, Environmental Science student, collects a sediment core, a tube full of sand and mud from an eelgrass meadow where carbon is stored. She later measured the amount of carbon in this core in a laboratory at Western Washington University. Photo by Mira Lutz Castle.
With all these ecosystem services, it is wise to take good care of our eelgrass in the Salish Sea! Before non-indigenous people knew about all the gifts eelgrass meadows bring, they were dredged out, built over, filled in with dirt, diked off, and accidentally poisoned in the name of progress. With the arrival of colonists/settlers came farming, often filling in estuary areas and blocking them off from the tides to plant crops.
Shipping goods required piers and docks, which blocked out sunlight that eelgrass need. Seaside industry required roads and sea walls to keep the sea out of the towns and the shores from caving in. Concrete, creosote, and asphalt helped shore up the land, but also caused waves that washed away eelgrass soils, leaving gravel and cobble behind. Industrial and yard chemicals in stormwater changed the water quality for sensitive eelgrass. All this, plus warming and rising waters make life rough for eelgrass today.
Luckily, newcomers are learning what tribes and First Nations always knew; eelgrass protects our shores, water, and valuable resources. We need it here in the Salish Sea.
Restoration brings hope!
While asking the native peoples how the eelgrass meadows help would have been a good idea a couple hundred years back, wise people are doing what it takes to replant eelgrass where they can. City, county, and state governments, tribes, First Nations, counties, nonprofit organizations, and natural resources departments throughout the sea are working together to restore these helpful ecosystems. School groups even partner with eelgrass experts to help plant sometimes! Can you imagine an eelgrass nursery in your school?
Find out more about restoring eelgrass in Washington Department of Natural Resources’ cool story map here: https://www.dnr.wa.gov/SeagrassRestoration
Bundling eelgrass and attaching them to sod staples with twist-ties. Photo by Michael Kyte. Method by Fred Short.
Eelgrass bundled and twist-tied onto a staple. Photo by Marine Sciences Laboratory, Pacific Northwest National Laboratory (PNNL). Method by Fred Short.
A little underwater gardening! A diver digs a hole and pushes the staple into the sediment with eelgrass tied on. Good luck little eelgrass bundle! Photo by Marine Sciences Laboratory, Pacific Northwest National Laboratory (PNNL) Method by Fred Short.
What can you do?
As always, avoid toxic cleaners and lawn products at your home to help keep the water clean. Ride your bike or walk when you can to help keep the climate cool. Look for eelgrass restoration opportunities near you and ask your teacher if your school can partner with one of the projects nearby. Eelgrass can use some fellow Salish Sea Heroes!
Clues to how Japanese eelgrass crossed the Pacific Ocean to take up residence in the Salish Sea:
*Clue 1: Eelgrass makes great packing material when dried.
*Clue 2: Pacific oysters are a favorite of oyster farmers in Washington and Oregon.
*Clue 3: Pacific oysters originated in Japan.