Phase I: Broad Bay Lease # 21054
Background Information: During Phase I of the SAV work, a pilot study was completed by the Virginia Institute of Marine Science (VIMS). VIMS collected seeds from donor beds, processed the seeds for germination, stored and maintained them, transported viable seeds to the construction site, planted the seeds at desired densities, and monitored the seeded area post construction during the first year to determine the success of the effort from both an initial germination and subsequent growth and survival of two seagrass species selected for restoration at a specific site in the Lynnhaven River, eelgrass (Zostera marina) and widgeongrass (Ruppia maritima). Due to the success of Phase I, the VIMS contract has been extended to continue work on restoring SAV in Broad Bay during Phase III of the project.
Size: 2 acres
Status: Monitoring (See monitoring report in the Report link)
Phase II: No SAV restoration took place during this phase.
Background Information: N/A
Phase III: Broad Bay Lease # 21049, 21048 and 21050
Background: Due to the success of the Phase I pilot study to re-establish SAV within Broad Bay, the Virginia Institute of Marine Science is continuing their work within the City leases. VIMS is in the process of gathering data to find the best suitable areas within these leases for SAV meadows to survive.
Size: 25 acres
Status: Planning and gathering data
Submerged aquatic vegetation (SAV) has suffered extensive losses in many regions of the world, including Chesapeake Bay. Worldwide, the loss has been at a rate of 110 km2 per year since 1980 with a total of 29% of the SAV present in 1879 lost (Waycott et al 2009). Similar losses to SAV, particularly to the main climax species, eelgrass (Zostera marina), have occurred in Chesapeake Bay, mainly due to declines in water quality and increasing water temperatures (Orth et al. 2010). However, in recent years eelgrass has been demonstrating a shift in its historical growth patterns, with its biomass peaking earlier in the growing season and summer declines beginning earlier in the Chesapeake Bay due to warming waters caused by human-accelerated climate change.
Adaptation and resilience to climate change impacts has been evident by an increase in reproductive output and regrowth from Z. marina seedlings following declines, as well as expansions of a more temperature tolerant species, widgeongrass (Ruppia maritima), into areas previously dominated by eelgrass. This expansion reverses as the eelgrass recovers, allowing SAV coverage to be maintained over time if both species are present. This is very important, as the presence of SAV increases water clarity by stabilizing bottom sediments, establishing a positive feedback loop whereby the presence of SAV allows for improved water quality, which allows the SAV to survive, persist and potentially expand (Van der Heide et al. 2011). This same feedback loop can make restoration of SAV very challenging once it is entirely extirpated, as poor water clarity and quality over unvegetated bottom then inhibits successful SAV re-establishment (Maxwell et al. 2017). This suggests that larger, direct seeding efforts that are capable of quickly establishing at least several acres of SAV at once has a higher success rate than smaller scale (square meter to several square meter transplants) and recent data has supported this.