Underwater Grasses

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The Virginia Institute of Marine Science (VIMS) estimates 600,000 acres of underwater grasses were once present in the Chesapeake Bay. As of 2012, the Chesapeake Bay Program estimates a total of 48,191 acres are in the Bay. Since the mid-twentieth century, hundreds of thousands of acres of underwater grasses have been lost. So what does the loss of underwater grasses, or submerged aquatic vegetation (SAVs) mean for the Bay?

SAVs are an important part of the Bay’s ecosystem and provide a number of services.  Underwater grasses are a food source for waterfowl; they provide habitat and protection for juvenile blue crabs and several species of fish, such as striped bass and menhaden. Grasses take up nutrients that enter the Bay, improve water clarity and health. The plants provide oxygen to other organisms in the water. They are a buffer against shoreline erosion by reducing the impact of waves and currents on a beachfront.

Strong storms and pollution threaten SAVs. Excess nutrients entering the Bay result(ed) in acres of grasses lost, this century and last. Grasses absorb nutrients, but they can only absorb so much. With large amounts of nitrogen and phosphorous entering the Chesapeake watershed, underwater grasses have been inundated with nutrients, and have dramatically suffered. The decline of aquatic vegetation impacts ecosystem services, local economies and societies. The food industry, and the watermen that rely on the catches of the Bay, have been hit hard in recent years. A decrease in acreage of SAVs contributes to low crab populations, and was cited as a major source of a decline in crab numbers this past year. Fish are at more risk from predation from other species, leaving fewer fish to be harvested by Chesapeake watermen.

Restoration of underwater grasses is one solution to improving water quality and aquaculture, and reducing rates of erosion (or at least is a solution that I can directly play a part in). This weekend I am going to the Chesapeake Bay Foundation’s Grasses for the Masses program, dedicated to planting SAVs in designated areas in the Bay watershed. On Saturday I will attend a workshop where I will receive an aquaculture system with wild celery seeds. After growing the underwater grass in-home for 10-12 weeks, I will plant the wild celery this spring on the Potomac River in Mason Neck State Park, in a second workshop.

While doing this project, I am also looking into the permit process for growing grasses for personal research, off of property in the Northern Neck. I have been looking at VIMS 2012 SAV report and interactive map for more information on the historical presence of grass in this region (VIMS), as well as permit information from the Virginia Marine Resources Commission (VMRC). Updates to follow!

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