Eelgrass Details
There are seven recognized species of seagrasses that grow along the North American coastline. Zostera marina more popularly known as Eelgrass is the most prevalent seagrass growing along the Massachusetts coastline. Eelgrass as well as other sea grasses are often denoted as “submerged Aquatic Vegetation” or SAV. The biologists created this label to help distinguish them from algae which are not considered plants but rather are classified as protistas. Eelgrasses are true flowering plants.
Although, Eelgrass does grow totally submerged in salt water it does produce roots, stems, leaves, and flowers. Their roots are strong and extensive enough that they actually help to stabilize the bottom sediments. to achieve pollination the pollen kernels drift in the water until they collide with a different flower and attach themselves to its stigma. Because Eelgrass requires maximum light penetration to mature, it usually prefers to grow just below the low tide line.
Eelgrass beds are the wetlands of the shallow coastal ecosystems.
They are critical because they supply food and camouflage for a wide number of commercially and recreationally significant animals and their prey. In addition their naturally occurring leaf canopy soothes the water and acts as a filter for latent matter.
Unfortunately the Eelgrass beds were hit hard between 1930-1931 by an epidemic that destroyed nearly ninety percent of the active patches along the Atlantic coast. However, as a result of careful conservation measures the beds are beginning to make a come back. The Northeastern University Marine Science Center is doing its part by hosting Eelgrass experts such as Dr. John Vavrinec and Kate Hall from the Pacific Northwest National Laboratory(PNL), in Washington State to study the Eelgrass beds in Nahant Bay. During a talk they gave for SWIM they informed us that our Eelgrass beds are doing so well they were able to very carefully transplant some of the grass into selected sites in Boston Harbor to help replenish its depleted Eelgrass population. They also explained that they were mindful not to take too much grass from any one spot so that our Nahant beds will remain lush and healthy.
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1. Eelgrass
2. Common mummichog
3. Moon jelly (polypoid stage)
4. Common periwinkle
5. Striped killifish
6. Coiled tube worm
7. Soft-shell clam
8. Parchment tube worm
9. Hermit Crab
10. Nudibranch
11. Sheepshead minnow
12. Encrusting bryozoan
13. Burrowing anemone
14. Sand Shrimp
15. Short-spined brittle star
16. Bay scallop
Pilayella littoralis
So what is that stinky, slimy, brown stuff that washes up on the beaches dotting the Nahant, Lynn, and Swampscott shoreline? Anyone who has driven along Lynn Shore Drive on a hot August day with the windows down knows exactly what we are talking about. The culprit is a fast growing, free-floating species of brown algae called Pilayella littoralis. As many long time Nahant residents can attest to, this is not a new problem. This particular form of algae has been observed in Nahant Bay as early as 1902. Yes, it too enjoys the four star accommodations offered by Nahant. So much so that it has returned year after year in greater quantities.
Despite intensive research conducted by organizations such as Northeastern University Marine Science Center, the National Park Service, Massachusetts Institute of Technology, and the University of Rhode Island, the exact origin of Pilayella littoralis remains a mystery. After careful analysis of their own collected data, current patterns, and anecdotal evidence, the scientist working for the National Park Service suggested that this form of algae may arise on the rocky bottom of the northern New England shoreline and is then transported south by the Gulf of Maine currents. As a result of prevailing winds,tides,waves and optimal geographic features it is trapped and eventually deposited on the beaches surrounding the Nahant Bay, Broad Sound, the Cape, and Rhode Island. This region of coastline apparently contains the ideal growing conditions like temperature, light, depth, and level of nutrients that promotes the vigorous growth of this algae. In fact it has been observed that in areas containing the perfect growing elements it can double its weight in six to ten days.
I’m sure by now you are thinking that’s all well and fine, but what about its nasty stench. While the smell is reminiscent of sewage, it is not dangerous to humans or animals. It is also not indicative of polluted water. Although it is disgusting to swim in, the waters off Nahant beach have consistently passed routine water tests. The awful smell is actually the by- product of a natural process. Like all living organisms, when the algae dies and washes up on shore it begins to decompose. As it continues to decay it releases a sulfide imbued gas with a pungent odor that almost always brings an instant frown to the faces of potential beach goers and local residents.
I realize that you are probably not ready to become chummy with Pilayella littoralis but algal ecologist Carol Thornber has said that we should try to embrace the positive attributes of the algae. Drift algae such as Pilayella littoralis perform important ecosystem functions like providing a habitat for small marine invertebrates that are a food source for larger organisms such as fish and birds. It is also a main staple for grazing marine herbivores. For this reason the use of herbicides to kill it would be disastrous for the entire marine ecosystem. The Department of Conservation and Recreation in conjunction with the Metropolitan District Commission and other academic institutions created the Algae Task Force to better manage the Pilayella littoralis problem.
Although many innovative removal techniques like the large vacuum dredge system created by MIT scientists to suck up the Algae have been tested, the best solution presently seems to be frequent tractor powered rakings to scrape the algae off the beaches. The regular clean-ups have been successful in reducing the odor and decreasing the overall algal growth in the surf zone. However with the ongoing support of state, municipal, and federal agencies the Algae Task Force continues to investigate possible re-uses or more environmentally sound disposal methods for Pilayella littoralis. Unfortunately, until then you will have to keep holding your nose when driving along Lynn Shore Drive.
Note: Thanks for visiting us!!!!
