Disciplines

Environmental Indicators and Impact Assessment | Environmental Monitoring | Marine Biology | Natural Resources and Conservation | Oceanography

Abstract (300 words maximum)

Seagrasses are keystone species that support coastal biodiversity, but not all species of seagrasses provide the same ecosystem services. Although seagrasses occupy a small area of marine habitat, they provide many ecosystem services. They stabilize sediments, remove nutrients, provide habitat and food for diverse marine life, and promote carbon storage in sediments. Jobos Bay is the second largest estuary in Puerto Rico and contains salt marshes, mangroves, and seagrass beds. The native seagrass, Thalassia testudinum, is the most abundant seagrass in the bay; however, a seagrass species from the Indian Ocean, Halophila stipulacea, began invading in recent years. The impacts of H. stipulacea have not been well-studied, and it is not yet known if the invasive species is displacing the native species or growing only in areas that were previously non-vegetated. This study investigates the effect of the invasive species on carbon storage in Jobos Bay. If the native species contributes more detritus to the sediments but is being outcompeted by the invasive species, it will mean less organic matter is stored in the sediments as the invasion progresses. Between March 7-20, nine cores were extracted from four different habitat types: 1) a T. testudinum bed, 2) a H. stipulacea bed, 3) an unvegetated area, and 4) an area where an algal accumulation extirpated an H. stipulacea population. The cores were sliced in 1 cm increments. Slices were dried and combusted at 500 C to determine bulk density and organic carbon content. Patterns in the amount of carbon storage across the depths and habitat types will be compared. Estimates of carbon storage will help natural resource managers understand potential impacts of the invasive species on ecosystem services.

Academic department under which the project should be listed

CSM - Ecology, Evolution, and Organismal Biology

Primary Investigator (PI) Name

Troy Mutchler

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Estimating Blue Carbon Stocks in Native and Non-Native Seagrass Beds of Jobos Bay, PR

Seagrasses are keystone species that support coastal biodiversity, but not all species of seagrasses provide the same ecosystem services. Although seagrasses occupy a small area of marine habitat, they provide many ecosystem services. They stabilize sediments, remove nutrients, provide habitat and food for diverse marine life, and promote carbon storage in sediments. Jobos Bay is the second largest estuary in Puerto Rico and contains salt marshes, mangroves, and seagrass beds. The native seagrass, Thalassia testudinum, is the most abundant seagrass in the bay; however, a seagrass species from the Indian Ocean, Halophila stipulacea, began invading in recent years. The impacts of H. stipulacea have not been well-studied, and it is not yet known if the invasive species is displacing the native species or growing only in areas that were previously non-vegetated. This study investigates the effect of the invasive species on carbon storage in Jobos Bay. If the native species contributes more detritus to the sediments but is being outcompeted by the invasive species, it will mean less organic matter is stored in the sediments as the invasion progresses. Between March 7-20, nine cores were extracted from four different habitat types: 1) a T. testudinum bed, 2) a H. stipulacea bed, 3) an unvegetated area, and 4) an area where an algal accumulation extirpated an H. stipulacea population. The cores were sliced in 1 cm increments. Slices were dried and combusted at 500 C to determine bulk density and organic carbon content. Patterns in the amount of carbon storage across the depths and habitat types will be compared. Estimates of carbon storage will help natural resource managers understand potential impacts of the invasive species on ecosystem services.