Underwater Bay Grasses

Importance of Underwater Grasses

• Underwater grasses filter polluted runoff, provide food for waterfowl, and provide essential habitat for blue crabs, juvenile rockfish (striped bass), and other aquatic species. 
• There are more than a dozen varieties of underwater grasses that grow in shallow water regions of the Bay and its rivers. 
• Underwater grasses are one of the best barometers of the Bay's water quality because they are associated with clear water, and their presence helps improve water quality. Their leaves and stems baffle wave energy and help settle out sediments. Their roots and rhizomes bind the substrate. 
• Underwater grasses also take up nitrogen and phosphorus that, in overabundance, lead to algae blooms that can degrade water quality. Decomposing underwater grasses provide food for benthic (bottom-dwelling) aquatic life. 
• Migrating waterfowl, such as ducks and geese, eat underwater grasses. 
• CBF is working to help meet the Bay Program's 2010 goal of 185,000 acres of underwater grasses covering the bottom of the Bay and its tidal tributaries.

Chief Threat to Grasses: Poor Water Quality

•  At its most pristine, the Bay may have supported several hundred thousand acres of underwater grasses. 
• Since the 1950s, there has been a tremendous decline of grass beds due to degraded water quality. In 1972, huge amounts of rainfall and runoff caused by Tropical Storm Agnes dealt a devasting blow to many grass beds.
• Underwater grasses continued to decline to a documented low of 38,000 acres in 1984. From 1984 to 1993, underwater grasses increased to 73,000 acres.

Current Status: Mixed

• Underwater grasses were on the rise in the early 2000s due to prolonged drought, which kept pollutants from the land locked in the soil. In 2001-2002, grasses increased to 90,000 acres in the Chesapeake Bay and its tributaries.
• The most recent Bay data collected in 2008 show Bay grasses covering 73,063 acres, or 39.5 percent of the 185,000-acre Bay restoration goal. The 2008 data show an 18 percent increase in underwater grasses from 2007.

Restoration Solutions

Improving water quality is key to restoring underwater grasses. All of CBF's activities—from land-use planning to wetland protection and riparian buffer planting—are designed to help restore and protect underwater grasses, as well.

• CBF is working to help meet the Bay Program's 2010 goal of 185,000 acres of underwater grasses covering the bottom of the Bay and its tidal tributaries.  
• CBF engages volunteers to grow underwater grasses in homes, schools, and businesses to transplant at appropriate restoration sites.
• CBF works with the underwater grass species wild celery in the Grasses for the Masses restoration program in Virginia. 
• CBF uses knowledge gained from volunteer restoration efforts to help increase underwater grasses in the Bay and its tributaries. 
• Where water quality is good enough to support underwater grass survival, hands-on restoration efforts can help establish, expand, or diversify grass communities.

CBF hopes its simultaneous efforts to improve water quality and restore and protect underwater grasses will start an "ecological chain reaction" in which improved water quality promotes grass growth. Scientists hope this process will further improve water quality for expansion of more underwater grasses.