As the Port of Kingston undertakes its long-planned dredging of the boat launch and dock access areas, you may have heard that they are undertaking some mitigation activities to offset the affect removing bottom sediments has on the biology below. One part of that mitigation program is an eelgrass transplanting and growing project. This is a very cool thing.

What is eelgrass (Zostera marina) and why would the regulatory authorities want the port try to removing plants carefully and trying to grow them during the dredging period? Eelgrass is a native aquatic perennial herb, one species of seagrass, which lives the shallow submerged estuary areas in the water of Puget Sound and is doing well in a large area of Appletree Cove. It is also found throughout the Northern Hemisphere, as far north as the arctic and Iceland.   It spreads mostly from the growth of rhizomes (stems that grow under the sediment, perpendicular to gravity/laterally, not down like roots). From the rhizome plants send out roots to hold the plant in soft, muddy substrates, and leaves for photosynthesis.  It also produces flowers and seeds at the right time of year.

The leaf blades grow to various lengths, held upright by buoyancy, and depending on the water depth, can grow to various lengths depending on the amount of light that penetrates down to the plants. For example, in Appletree cove leaf blades can be range from 6 inches to 2 feet long and are ¼ to ½ inches wide. In deeper areas of Puget Sound where the water clarity is good and light can penetrate down on a consistent basis blades can grow much longer. These blades are creating oxygen by active photosynthesis, but there are also little incubators for so much more. Their blade surfaces become a resting place for egg masses of snails and other creatures, attachment points for seaweeds, platforms for bacteria and other single-celled organisms that are grazed off by small zooplankton. They are pretty active places.

The blades form a virtual mini forest. They sway with the water flow and tides causing the water to slow around them dissipating the energy in the water somewhat. As the water slows the silt or other organic materials once suspended, begins to fall down and deposit on the bottom around the plants. So the sediment bed around eelgrass “grows” with nutrient and organic-rich materials. These materials nourish the plants and the other sea creatures in the eelgrass bed. In this fertile environment the bed also expands horizontally by vegetative spreading of the eelgrass from their rhizomes and to a less extent, by seeds dispersion. It forms patches on the bay bottom.

These eelgrass patches become home to many organisms. They are vital nurseries for young fish, crabs, snails, worms. Some unique fish called the bay pipefish (Syngnathus leptorhynchus), a relative of the seahorse that is native to our area. It lives in among the eelgrass blades floating vertically since they look like eelgrass blades; a perfect camouflage.

Eelgrass also provide a food source for black brant geese, the smaller black geese that visit out area in the fall/winter either to stay or more likely on their way to migrate south to Mexico.

Eelgrass beds have suffered unexplained die-offs in the past. One major die-off event on the east coast in the 1930s essentially killed all the eelgrass for many years. Some areas on the pacific coast have exhibited some similar symptoms in the recent past. Hopefully this is not an omen of events to come. There is one other type of eelgrass locally (Zostera japonica) an intruder. It too may affect our native eelgrass as it spreads through are area.

We need every blade of native eelgrass we can get.

We applaud the Port of Kingston for undertaking an eelgrass nursery project and hope it is very successful. Next time you visit the beach or are on the water in Appletree Cove, look for eelgrass. We have many healthy beds of it on the south side of the bay and along North Beach. If you take time to look closely, you will see much life there. Low tides are especially good time to investigate an eelgrass bed.

— Betsy Cooper is a board member and stream monitor at Stillwaters Environmental Education Center.