Seagrass Management Plan for Big Lagoon and Santa Rosa Sound

Schwenning, Lisa

Seagrass beds have long been recognized as a critical coastal habitat for estuarine fisheries and wildlife. They also function as a direct food source for fish, waterfowl, and sea turtles, major contributors of organic matter to marine food webs, participants in nutrient cycling processes, and stabilizing agents in coastal sedimentation and erosion processes (Texas Parks and Wildlife, 1999). Seagrass health and acreage is directly proportional to the health and status of many commercially and recreationally important seafood species such as shrimp, crabs, scallops, redfish, speckled trout, and mullet. Pensacola Bay has been impacted by numerous sources of pollution, resulting in a system that does not have the natural biodiversity and productivity expected of a system of this complexity. As human population concentrates along our coastlines, anthropogenic impacts to seagrass habitats increase through nutrient loading from runoff, light reduction from increased turbidity and phytoplankton blooms , increased boat traffic, and more direct vessel impacts such as propeller scarring (Fonseca, Kenworthy, and Thayer, 1998). Point sources in the Pensacola Bay area are regulated through FDEP permits, and many point source discharges to the Bay System have been eliminated over the last several years. However, stormwater runoff (urban and landscaping) is the largest source of polluting nutrients, which can lead to eutrophication in Santa Rosa Sound and Big Lagoon. Stormwater is also a major contributor of suspended sediments to these bodies of water. Untreated stormwater contributes nine times more oxygen demanding substances to waterbodies than most point sources (FDEP, n.d.). Tourism and recreational boating have been on the rise over the last decade. The main effects of these industries are related to boat operations, marina construction, and small localized oil spills in marinas. Recreational boating can also have a direct impact on shallow grass beds through propeller scarring. Scarring of seagrasses can be avoided if caution is used where seagrasses are present. Dredge and fill activities have been widely recognized as a major anthropogenic disturbance contributing to the destruction of seagrass meadows. The direct and immediate effect of dredging on seagrass communities is mortality due to removal and /or burial. Proper and controlled dredging can alleviate much of the turbidity caused by boat traffic bottoming out within marked channels. Floating turbidity curtains allow for proper maintenance without causing a detrimental amount of turbidity. The FDEP Ecosystem Restoration Section is currently involved in the second year of a seagrass monitoring study within Santa Rosa Sound and Big Lagoon. The study involves four major areas of research; seagrass monitoring, water quality monitoring, photosynthetically active radiation (PAR) monitoring, and porewater sulfide sampling. Results of this study suggest that immediately after a rainfall, stormwater input inhibits the amount of sunlight available to the seagrass. The effects are measured not only immediately after a storm, but because the turbidity takes time to settle, inhibited sunlight is evident for days after the rainfall. To ensure that the water and sediment quality remain beneficial to the seagrass community, a series of objectives will need to be accomplished: 1) community acceptance of seagrass as an important habitat; 2) development of specific water quality guidelines and criteria to protect seagrass beds; and 3) developing and implementing Best Management Practices (BMPs) which protect seagrasses. Education can be the best and most lasting way in which to protect seagrass. If done successfully, education will lead to behavioral changes that will reduce impacts on this important ecosystem (Texas Parks and Wildlife, 1999).

Seagrass Management Plan for Big Lagoon and Santa Rosa Sound

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