Quantifying sedimentary 'blue carbon' in relation to canopy cover in the seagrass meadows of Turneffe Atoll, Belize

Felgate, Stacey L. ORCID: https://orcid.org/0000-0002-9955-4948; Sanders, Richard ORCID: https://orcid.org/0000-0002-6884-7131; Andrade, Valdemar; Barry, Christopher D.G. ORCID: https://orcid.org/0000-0003-1844-848X; Brittain, Hannah; Carpenter, Stephen; Carrias, Abel; Cobb, Eliceo; Evans, Chris D. ORCID: https://orcid.org/0000-0002-7052-354X; Hunt, James; Lichtschlag, Anna ORCID: https://orcid.org/0000-0001-8281-2165; Mayor, Daniel J. ORCID: https://orcid.org/0000-0002-1295-0041; Peel, Kate; Price, David M.; Radford, Freya; Young, Arlene; Evans, Claire ORCID: https://orcid.org/0000-0003-0569-7057. 2024 Quantifying sedimentary 'blue carbon' in relation to canopy cover in the seagrass meadows of Turneffe Atoll, Belize. Frontiers in Marine Science, 11, 1371162. 14, pp. 10.3389/fmars.2024.1371162

Before downloading, please read NORA policies.

Preview

Text N538405JA.pdf - Published Version Available under License Creative Commons Attribution 4.0. Download (1MB) | Preview

Abstract/Summary

•Introduction: Seagrass sediments are important ‘blue carbon’ reservoirs which store climatically significant quantities of organic carbon (Corg) at the global scale. Seagrass meadows that overly these sediments also provide a range of critical ecosystem services including shoreline stabilization, storm surge protection, and fisheries nursery grounds. However, the controls over accumulation and the sources of organic C to these sediments beds are highly variable and poorly understood with the relative importance of hydrodynamic setting, species composition and canopy density being unclear. •Methods: Here we address these questions using the first observation-based estimates of Corg stocks and provenance on Turneffe Atoll, Belize, made via remotely-sensed habitat extent, local Corg data and isotopic data. Sedimentary Corg was highest in sediments underlying the most sheltered meadows and decreased with increasing exposure to wind and wave energy with the seagrass meadows in the central lagoon containing an extensive deposit of mangrove derived organic carbon, stabilized and protected by the overlying seagrass meadow. •Results: The influence of species composition appeared weak with the ubiquitous species T. testudinum occurring across a wide range of hydrodynamic regimes ranging from the most sheltered to the most energetic and being associated with a wide range of sedimentary organic C concentrations. Importantly from the perspective of remote sensing, org C concentrations were unrelated to canopy density. We hypothesize that this decoupling of organic C concentration from seagrass canopy cover reflects a much longer timescale for carbon storage in the sediments than the lifespan of the seagrass plants themselves and/or a substantial non seagrass derived organic C burden in seagrass sediments. Overall, we conservatively estimate that the top 30cm of sediments underlying the seagrass meadows overlying carbonate sediments on the atoll exterior store 0.58 x 106 Mg Corg, most of which is seagrass-derived, whilst the sediments underlying the meadows within the central lagoon store an additional 1.28 x 106 Mg Corg. When the maximum possible extent of seagrass is considered, this estimate increases to 3.54 x 106 Mg Corg. Substantial Corg stocks extending >1m depth were observed across all sites, and so these inventories are considered conservative. •Discussion: A preliminary ‘cost of loss’ for sedimentary Corg in the top 30 cm of Turneffe Atoll’s seagrass meadows, based on a carbon trading value of €60 tCO2 (eq), is estimated at €42 million for the outer atoll, increasing to €136 million when the mangrove-derived sediments of the central atoll are considered and €260 million when turbid areas are assumed to contain seagrass.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.3389/fmars.2024.1371162
Programmes:	NOC Programmes > Ocean BioGeosciences
UKCEH and CEH Sections/Science Areas:	Soils and Land Use (Science Area 2017-)
ISSN:	2296-7745
Additional Information. Not used in RCUK Gateway to Research.:	Open Access paper - full text available via Official URL link.
Additional Keywords:	blue carbon, seagrass, organic carbon, sediment carbon, stable isotopes, mangroves, atoll, Belize
NORA Subject Terms:	Ecology and Environment Marine Sciences
Related URLs:	Dataset
Date made live:	19 Nov 2024 15:08 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/538405

Actions (login required)

View Item

Document Downloads

More statistics for this item...