Carbon Fixation and Storage in Mangrove Forests University of Virginia Jay Zieman, Jose Fuentes, Paolo D’Odorico, Deborah Lawrence, Mark White University of Virginia

Coastal Interface Ecosystems These consist of Seagrasses, Mangroves, and Salt Marshes They are among the most productive ecosystems on earth. Salt marshes are temperate. Mangroves are tropical and subtropical. Seagrasses run from the tropics to the boreal regions.

Mangrove Functions Naturally High Primary Productivity – One of the most productive tropical ecosystems Very High Habitat Values Sites of Nitrogen Fixation Rich Fisheries Stabilization of Coastal Interface

Mangrove Losses Non-sustainable harvest for charcoal Deforestation for - Development – Housing and Industrial - Shrimp Ponds - Cattle Ranching - Tourism

Forest Response: Why Mangroves ? Terrestrial forests sequester carbon from colonization to maturity. When most terrestrial forests mature, they become carbon neutral -- Cin = Cout. Exceptions: Mangroves; Boreal Conifer Forests With sea level rise mangrove forests can sequester carbon, in the form of peat, indefinitely The mature Florida mangroves have stored up to 6m of peat -- storing C for thousands of years

Distribution Pattern Notice the distibution pattern. You can see that quite clearly Red Mangrove are going to be most important to fish. Black Mangrove do have a limited prop root system but not as extensive

Tall Mangroves in the Western Florida Everglades

Measuring Mangrove Productivity and Carbon Assimilation Until 2004 75 year old manual methods used which widely underestimate assimilation – leaf litter fall and trunk diameter. No belowground estimates Since 2004, state-of-the-art: Eddy Covariance Flux Towers.

Mangrove distribution in Florida Everglades Miami Shark River Slough Taylor Slough Flux tower

Seasonal differences in carbon assimilation Late winter/Spring Summer Reduced nighttime respiration and maximum midday photosynthesis Greater nighttime respiration and midday photosynthesis deactivation

Carbon Assimilation Compared to FluxNet Sites Amazonian forest (Malhi et al.) Everglades mangrove forest for 2004 From: Baldocchi et al. 2001

New Findings Everglades’ mangroves assimilated atmospheric carbon dioxide at the rates of 7-9 t C ha-1 during 2004-2005 seasons. Diffuse sunlight in humid mangrove canopies results in elevated light use efficiencies, meaning greater amounts of carbon assimilation for a given light level.

Trajectory and wind speed at landfall for hurricane Wilma in October 2005 Trajectory of hurricane Wilma during October 2005 Wind speed associated with October 2005

Hurricane Wilma destroyed nearly 30 percent of trees

Mangrove defoliation resulting from hurricane Wilma in October 2005 Courtesy of Thomas J Smith, USGS

Flux tower in the western Florida Everglades Tower destroyed by hurricane Wilma Tower installed after hurricane Wilma

Ecosystem Response to Hurricane Wilma November March Averaged diurnal fluxes of carbon assimilation for November reveal equivalent levels of nighttime respiration, but reduced carbon fluxes during the day. The reduced carbon fluxes following Wilma are attributed to reduced canopy foliage, as an estimated 30% of the trees in this area were destroyed in the hurricane. We expected increase respiration as time progressed due to the great number of fallen trees in this area as a result of Wilma.

Panama vs Florida Studies In Florida the carbon assimilation was measured in before (pristine wilderness) and after (heavily damaged) studies In Panama, we would propose two towers, one in a pristine area as a control and one in an area undergoing restoration Mangroves in Panama are ideally suited for carbon sequestration as they undergo fewer natural stresses that the subtropical mangroves

Motivation for future research in Panama The ability of mangrove forests to provide the services of carbon sequestration remains largely unknown. Traditional approaches only provide carbon stocks and cannot provide net ecosystem carbon exchange. Tower-based observing systems allow us to investigate carbon exchange processes at different time scales. These field observations permit us to investigate the ecosystem response to on-going climate change, sea level rise, and disturbances. With continuous and long-term data sets, we can quantitatively assess the contribution of mangrove ecosystem restoration to carbon assimilation.