Eelgrass

Growing on some of our protected island beaches where the bottom is made up of relatively clean sand to mud, often a mix, eelgrass, Zostera marina, is down there in the lower intertidal zone and 18 feet or so into subtidal waters. Estuaries, where fresh and salt water meet, create a somewhat lower salinity situation that eelgrass is particularly partial to.

Length of the blades varies from two to four feet - each blade or leaf generally about as wide as a pencil and fairly deep grass green in color. The plants are perennials - grow quickly - fall back somewhat during our chillier months. Not really a grass, and unlike seaweeds we're familiar with, eelgrass is a true marine vascular plant - a flowering seed-producing one - one of but a few adapted to sea life.

To begin down there in the soft botton mud and sand, eelgrass has a "great set of roots" tangled creeping rhizomes which enable them to spread and form wonderful "root balls". These help immensely in the stabilization of sandy muddy beaches - help prevent wind and waves from eroding away the substrate.

And moving upward to include the stems and blades, we're fortunate that offshore in some areas along our islands are large colonizations referred to as "meadows". Fortunate because eelgrass meadows are prodcuctive places. They provide homes to many animals: shrimps, snails, nudibranches, fishes, anemones, crabs, and jellys, to mention a few.

Important too to marine life is the fact that extensive eelgrass beds or meadows with leaves floating upward slow the flow of water, thus once again helping erosion control.

Brittle stars and other animal life can be found in the root-rhizome mass. Bacteria and diatoms colonize the leaves. (In the late summer a thick brownish layer of single celled diatoms coat them.) These microscopic forms provide a rich food source for many creatures.

Pacific herring spawn on the leaves - the herring themselves a food souce for larger fish. Salmon dine among the blades as they make their way out to sea. Dungeness crabs spend the better part of their adult life in the meadows. And Brant geese and some other avian species also find eelgrass-foraging fine.

Then at the end of an already significant life span eelgrass breaks down into fine organic matter of detritus which also provides nutrient materials for life forms such as bacteria and other microbial organisms, and detritus feeders such as worms and sea cucumbers.

Important to our beaches and marine life? Incredibly so.

Plan a visit to an eelgrass bed on a low tide day. Consider searching over, under, and through the blades for the many species of life making their homes there.