Vulnerability of the peatland carbon sink to sea-level rise
Nature Publishing Group
This is the final version of the article. Available from Nature Publishing Group via the DOI in this record.
Freshwater peatlands are carbon accumulating ecosystems where primary production exceeds organic matter decomposition rates in the soil, and therefore perform an important sink function in global carbon cycling. Typical peatland plant and microbial communities are adapted to the waterlogged, often acidic and low nutrient conditions that characterise them. Peatlands in coastal locations receive inputs of oceanic base cations that shift conditions from the environmental optimum of these communities altering the carbon balance. Blanket bogs are one such type of peatlands occurring in hyperoceanic regions. Using a blanket bog to coastal marsh transect in Northwest Scotland we assess the impacts of salt intrusion on carbon accumulation rates. A threshold concentration of salt input, caused by inundation, exists corresponding to rapid acidophilic to halophilic plant community change and a carbon accumulation decline. For the first time, we map areas of blanket bog vulnerable to sealevel rise, estimating that this equates to ~7.4% of the total extent and a 0.22 Tg yr−1 carbon sink. Globally, tropical peatlands face the proportionally greatest risk with ~61,000 km2 (~16.6% of total) lying ≤5 m elevation. In total an estimated 20.2 ± 2.5 GtC is stored in peatlands ≤5 m above sea level, which are potentially vulnerable to inundation.
We wish to thank Dr. Zicheng Yu at Lehigh University for providing the map of global peatlands, and Dr. Damien Mansell (University of Exeter) who helped with data processing. Our thanks also go to Dr. Lisa Orme and Nicole Sanderson for laboratory support with 210Pb dating, and to Scottish Natural Heritage for arranging access to the site. We thank Howard Bowman for insightful comments on the initial manuscript draft. We are also grateful to the Natural Environment Research Council (NERC grant number NE/I012915/1) for the funding to support the work presented in this article.
Vol. 6, pp. 28758 - 28758