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A re-evaluation of wetland carbon sink mitigation concepts and measurements: a diagenetic solution


Gallagher, JB and Zhang, K and Chuan, CH, A re-evaluation of wetland carbon sink mitigation concepts and measurements: a diagenetic solution, Wetlands, 42, (3) Article 23. ISSN 0277-5212 (2022) [Refereed Article]


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Copyright 2022 The Author(s) Licensed under Creative Commons Attribution 4.0 International (CC BY 4.0)

DOI: doi:10.1007/s13157-022-01539-5


The capacity of wetlands to mitigate greenhouse gas (GHG) emissions is the sum of two services: the protection of vulnerable organic stocks from remineralisation, and the capacity to sequester GHGs relative to their anthropogenic replacements. Organic carbon accumulation (CA) down through the sediment column is often taken as the measure of sequestration because of its capacity to record long-term variability and trends. However, we demonstrate that: i) CA is not equivalent to sequestration as net ecosystem production (NEP) for open systems; it requires the subtraction of the initial deposition rate of labile allochthonous carbon sources; ii) CA also requires subtraction of intrinsically allochthonous recalcitrants down through the sediment column, and together with subtraction of autochthonous recalcitrants from organic stock services; iii) CA as a climatic mitigation service also requires a diagenetic correction, as the annual deposition of labile organic carbon continues to remineralise over the long-term; and iv) preserving of a wetland has a significantly greater mitigation potential than restoring one. To address the above concerns, a global diagenetic solution is proposed, applied and tested for a tropical seagrass and mangrove. As expected, traditional CA estimates were disproportionately larger than their respective diagenetically modelled NEPs, and together with stocks fell within the ranges reported in the literature, with a final carbon accreditation highly dependent on the choice of their anthropogenic replacements. The review demonstrates that mitigation concepts and measurements for natural carbon sequestration solutions require re-evaluation to avoid GHG emissions above their capacity or reduce the ability to fulfil emission targets.

Item Details

Item Type:Refereed Article
Keywords:wetlands, blue carbon, teal carbon, black carbon, carbon accumulation, carbon sequestration, carbon stocks, net ecosystem production, allochthonous recalcitrants, autochthonous recalcitrants, protection, restoration
Research Division:Environmental Sciences
Research Group:Climate change impacts and adaptation
Research Field:Carbon sequestration science
Objective Division:Environmental Policy, Climate Change and Natural Hazards
Objective Group:Mitigation of climate change
Objective Field:Climate change mitigation strategies
UTAS Author:Gallagher, JB (Dr John Barry Gallagher)
ID Code:149151
Year Published:2022
Web of Science® Times Cited:1
Deposited By:Oceans and Cryosphere
Deposited On:2022-03-15
Last Modified:2022-10-24
Downloads:6 View Download Statistics

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