This past week, as well as next week, I have been in Oyster, VA (a new East Coast adventure!), in a two-week field study course about the Marine Biology of the Chesapeake Bay. Today, we volunteered with The Nature Conservancy to collect seagrass (eelgrass, to be precise, known scientifically as Zostera marina). Since 1999, when this part of the Chesapeake Bay was barren and completely void of seagrass, the population has been revitalized. Now, the majority of the seafloor is covered with the leafy grasses flowing in the waves, drifting with the ebb and flow of the tides.
Of the collected seagrass, about half of the leaves contain seeds. Upon returning to the mainland, the seagrass was put in a large tank with seawater, sourced directly from the bay, where it will be kept for about a week until the seeds fall. These seeds, once mature, will be sown in the northwest parts of the bay where recolonization has not been as successful.
There are natural causes of seagrass populations dying off, and humans are also playing an integral role, positive in some cases and negative in others, towards their recovery. The original decline in population was due to the combination of a quickly spreading disease (labyrinthula) and the intensity of hurricanes around the same time. It is now the interference of human action that hinders the recolonization of seagrass in the northwest parts of the bay.
Although this southern part of the Chesapeake, where we collected and where I am studying, is doing very well in terms of restoration and increasing biodiversity, the northwestern areas are not doing as well. One cause of this slow regrowth is due to nutrient runoff from nearby farms, which increases the amount of algae in the area, reducing the sunlight available to seagrasses. With less sunlight to use for photosynthesis, these aquatic plants aren’t thriving as they could be, or should be. This affects the variety of other sea animals that can live and thrive in the area, as well as oxygen production in the water, which can then migrate out into our atmosphere. It may seem like a simple seagrass problem, and there are also implications beyond the presence of seagrass. The existence and prospering of seagrasses is vital to the health of the Chesapeake Bay.
As a group, we spent two hours floating above seagrass beds, swimming along and collecting the leaves. I loved the experience, any occasion to throw on a wetsuit and float in the ocean for hours is a treat for me. However, it is the hope that eventually, the bay will be healthy enough for the seagrass to thrive and spread on its own.