Photo courtesy of Maine Department of Environmental Protection

Crocuses are popping up amidst the last of winter’s icy crust and buds are growing fatter by the day. We eagerly watch and wait for the first flowers of spring. I watch for the blossoms of a plant that flowers under the water. Its flowers are understated – like stacks of tiny yellowish-green vases waving at the tip of each stalk. Its name comes from the way its skinny leaves sways in the water like tiny eels. This flowering underwater plant is eelgrass, Zostera marina. It grows close to shore just below the water line and in the shallow waters of calm inlets. You may have seen its swept mats on the mudflats when the tide is out, have been brushed by it while swimming in a protected cove, or gotten a boat prop or anchor tangled up in it. This simple marine grass is quite critical to our coastal ecosystem and its spring blossoms ensure that there is plenty of it in the coming season.

Every spring, drifting pollen fertilizes eelgrass flowers – the same plant can even pollinate itself since it has both male and female flowers. Little reproductive shoots form and then break off the parent plant, floating to the surface where they release hundreds of seeds. The seeds float in the current until they are ready to plant themselves in the mud and grow new eelgrass plants. But that’s just one way eelgrass reproduces. It can also reproduce right from the root structures, entire beds forming from a single plant that produces new shoots. The roots of eelgrass grow horizontally through the mud. That allows it to spread across an area and also provides another important function – it holds the mud in place. This helps to stabilize shorelines and protect them from erosion and also keeps the water clear. It is a pretty smart plant in that it facilitates its own good growing conditions. Eelgrass needs clean clear water to grow so that it can capture sunlight. Combine clear water, sunlight and healthy plants and you get a whole bunch of Oxygen, yet another one of eelgrass’s important ecological contributions.

While those long wavy green stalks are producing Oxygen, they are also providing a virtual underwater forest. The protection eelgrass provides makes it ideal as a nursery for juvenile fish and shellfish. As North America’s most wide-ranging marine flowering plant, its importance in ocean ecosystems has not gone unnoticed. The National Oceanic and Atmospheric Administration (NOAA) describes eelgrass as “one of nature’s most valuable and productive habitats in our marine environment.”

Look around now and you’ll likely see a fair amount of healthy eelgrass, but back in 2012-2013 that was not the case. Invasive European green crabs snipped off its delicate blades and burrowed into its root structures. Surveys of eelgrass conducted by the Maine Department of Environmental Protection (DEP) and the Casco Bay Estuary Partnership (CBEP) in 2013 measured a loss of more than 55 percent of eelgrass bed coverage as compared to 2001-2. This led to restoration efforts by a group convened by CBEP called the Casco Bay Eelgrass Consortium. They launched a pilot study in two locations in upper Casco Bay to identify sites for restoration projects where they could test and measure the success of transplant techniques. The areas were surveyed again in 2018 and showed positive results. Full reports are available through Maine’s Geolibrary.

The results in Casco Bay are good news. But, the question is what is happening in the rest of the state. The last time statewide mapping was done was in the early 2000s. A bill recently introduced in the legislature aims to remedy this. LD 559, sponsored by Representative Jay McCreight, D-Harpswell, has received unanimous bipartisan support from the Legislature’s Environment and Natural Resources Committee and now awaits full approval and funding. McCreight, who is also the House chair of the Legislature’s Marine Resources Committee, notes that, “This is a great example of working together for the good of a critical marine resource. The importance of restoring mapping is a key piece because we need to know where it thrives and where it struggles and use that information for decisions about restoration and protection.” Mapping could better inform things like Natural Resources Protection Act permitting, oil spill response actions and the review of aquaculture lease applications.

Eelgrass is clearly not your average plant. It is worth investing in its health as a measure of the overall health of our oceans. As Angela Brewer of Maine DEP’s Marine Unit says, “Eelgrass is such an interesting and dynamic species because its mere presence or absence, and condition, can indicate so much about the surrounding environment.” Take a look at these underwater plants this spring and be glad for those thick grassy mats that support ocean life along our coasts.

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