title: Organic carbon inventories in natural and restored Ecuadorian mangrove forests.
abstract: Mangroves can capture and store organic carbon and their protection and therefore their restoration is a component of climate change mitigation. However, there are few empirical measurements of long-term carbon storage in mangroves or of how storage varies across environmental gradients. The context dependency of this process combined with geographically limited field sampling has made it difficult to generalize regional and global rates of mangrove carbon sequestration. This has in turn hampered the inclusion of sequestration by mangroves in carbon cycle models and in carbon offset markets. The purpose of this study was to estimate the relative carbon capture and storage potential in natural and restored mangrove forests. We measured depth profiles of soil organic carbon content in 72 cores collected from six sites (three natural, two restored, and one afforested) surrounding Muisne, Ecuador. Samples up to 1 m deep were analyzed for organic matter content using loss-on-ignition and values were converted to organic carbon content using an accepted ratio of 1.72 (g/g). Results suggest that average soil carbon storage is 0.055 ± 0.002 g cm(-3) (11.3 ± 0.8% carbon content by dry mass, mean ± 1 SE) up to 1 m deep in natural sites, and 0.058 ± 0.002 g cm(-3) (8.0 ± 0.3%) in restored sites. These estimates are concordant with published global averages. Evidence of equivalent carbon stocks in restored and afforested mangrove patches emphasizes the carbon sink potential for reestablished mangrove systems. We found no relationship between sediment carbon storage and aboveground biomass, forest structure, or within-patch location. Our results demonstrate the long-term carbon storage potential of natural mangroves, high effectiveness of mangrove restoration and afforestation, a lack of predictability in carbon storage strictly based on aboveground parameters, and the need to establish standardized protocol for quantifying mangrove sediment carbon stocks.
authors.affiliation: Institute for the Environment, The University of North Carolina at Chapel Hill , Chapel Hill, North Carolina , USA.
authors.forename: Amanda G
authors.initials: AG
authors.lastname: DelVecchia
authors.affiliation: Department of Biology, The University of North Carolina at Chapel Hill , Chapel Hill, North Carolina , USA.
authors.forename: John F
authors.initials: JF
authors.lastname: Bruno
authors.affiliation: Department of Geology, The University of North Carolina at Chapel Hill , Chapel Hill, North Carolina , USA.
authors.forename: Larry
authors.initials: L
authors.lastname: Benninger
authors.affiliation: Department of Marine Science, The University of North Carolina at Chapel Hill , Chapel Hill, North Carolina , USA.
authors.forename: Marc
authors.initials: M
authors.lastname: Alperin
authors.affiliation: Institute for the Environment, The University of North Carolina at Chapel Hill , Chapel Hill, North Carolina , USA.
authors.forename: Ovik
authors.initials: O
authors.lastname: Banerjee
authors.affiliation: Colegio de Ciencias biologicas y ambientales, Universidad San Francisco de Quito , Cumbayá, Diego de Robles y Vía Interoceánica, Quito , Ecuador.
authors.forename: Juan
authors.initials: J
authors.lastname: de Dios Morales
keywords: Aquaculture; Blue carbon; Carbon sequestration; Carbon storage; Loss-on-ignition; Mangroves