Variability in the Carbon Storage of Seagrass Habitats and Its Implications for Global Estimates of Blue Carbon Ecosystem Service
Top Cited Papers
Open Access
- 5 September 2013
- journal article
- research article
- Published by Public Library of Science (PLoS) in PLOS ONE
- Vol. 8 (9), e73748
- https://doi.org/10.1371/journal.pone.0073748
Abstract
The recent focus on carbon trading has intensified interest in ‘Blue Carbon’–carbon sequestered by coastal vegetated ecosystems, particularly seagrasses. Most information on seagrass carbon storage is derived from studies of a single species, Posidonia oceanica, from the Mediterranean Sea. We surveyed 17 Australian seagrass habitats to assess the variability in their sedimentary organic carbon (Corg) stocks. The habitats encompassed 10 species, in mono-specific or mixed meadows, depositional to exposed habitats and temperate to tropical habitats. There was an 18-fold difference in the Corg stock (1.09–20.14 mg Corg cm−3 for a temperate Posidonia sinuosa and a temperate, estuarine P. australis meadow, respectively). Integrated over the top 25 cm of sediment, this equated to an areal stock of 262–4833 g Corg m−2. For some species, there was an effect of water depth on the Corg stocks, with greater stocks in deeper sites; no differences were found among sub-tidal and inter-tidal habitats. The estimated carbon storage in Australian seagrass ecosystems, taking into account inter-habitat variability, was 155 Mt. At a 2014–15 fixed carbon price of A$25.40 t−1 and an estimated market price of $35 t−1 in 2020, the Corg stock in the top 25 cm of seagrass habitats has a potential value of $AUD 3.9–5.4 bill. The estimates of annual Corg accumulation by Australian seagrasses ranged from 0.093 to 6.15 Mt, with a most probable estimate of 0.93 Mt y−1 (10.1 t. km−2 y−1). These estimates, while large, were one-third of those that would be calculated if inter-habitat variability in carbon stocks were not taken into account. We conclude that there is an urgent need for more information on the variability in seagrass carbon stock and accumulation rates, and the factors driving this variability, in order to improve global estimates of seagrass Blue Carbon storage.Keywords
This publication has 46 references indexed in Scilit:
- Historical trends in trace metal and sediment accumulation in intertidal sediments of Moreton Bay, southeast Queensland, AustraliaChemical Geology, 2012
- Paleoreconstruction of estuarine sediments reveal human‐induced weakening of coastal carbon sinksGlobal Change Biology, 2011
- Seagrass community metabolism: Assessing the carbon sink capacity of seagrass meadowsGlobal Biogeochemical Cycles, 2010
- Seagrass sediments as a global carbon sink: Isotopic constraintsGlobal Biogeochemical Cycles, 2010
- Feedback effects in a coastal canopy‐forming submersed plant bedLimnology and Oceanography, 2010
- Very high‐resolution seismo‐acoustic imaging of seagrass meadows (Mediterranean Sea): Implications for carbon sink estimatesGeophysical Research Letters, 2008
- Holocene and modern sediment storage in the subtropical macrotidal Fitzroy River estuary, Southeast Queensland, AustraliaSedimentary Geology, 2007
- Structural Constituents of the Seagrass Posidonia australisJournal of Agricultural and Food Chemistry, 2007
- Carbon Burial Rates in Sediments and a Carbon Mass Balance for the Herbert River Region of the Great Barrier Reef Continental Shelf, North Queensland, AustraliaEstuarine, Coastal and Shelf Science, 2002
- Controls upon inner‐shelf sedimentation, Cape York Peninsula, in the region of 12°SAustralian Journal of Earth Sciences, 1998