Impacts of Active Versus Passive Re‐Wetting on the Carbon Balance of a Previously Drained Bog

Nyberg, Marion; Black, T. Andrew; Ketler, Rick; Lee, Sung‐Ching; Johnson, Mark S.; Merkens, Markus; Nugent, Kelly A.; Knox, Sara

doi:10.1029/2022jg006881

Cited by 6 publications

(1 citation statement)

References 81 publications

(164 reference statements)

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“…Seventeen years after rewetting, our site is still in a transitional phase in which a CO2 sourceto-sink shift took place. While the CO2 sink strength is increasing and annual CH4 emission is declining, this confirms that the time needed for a restored ecosystem to return to its long-term CO2 sink function may vary from years to several decades 41,42 . Though the ecosystem at our site has shifted to only a weak annual CO2 sink during the last two years of measurements (2020: -1.25 ± 0.09 and 2021: -0.46 ± 0.07 t CO2-C ha -1 yr -1 ), the avoided CO2 emission (over time) is already substantial when comparing to the net CO2 emissions from drained temperate nutrient-rich sites (3.6 t CO2-C ha -1 yr -1 : 1.8 -5.4, 95% confidence interval, n = 13) 4 .…”

Section: Discussionmentioning

confidence: 57%

Long-term flux measurements suggest dynamic emission factors are needed for rewetted peatlands

Kalhori,

Wille,

Gottschalk

et al. 2023

Preprint

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Rewetting drained peatlands is recognized as a leading and effective natural solution to curb greenhouse gas (GHG) emissions. However, rewetting creates novel ecosystems whose emission behavior is not well captured by the currently used emission factors (EFs). These EFs are static and do not capture the temporal dynamics of GHG emissions. Hence, they often do not reflect the true emission reduction potential after rewetting. Here, we provide long-term data showing a mismatch between actual emissions and default EFs and revealing the temporal patterns of annual CO2 and CH4 fluxes in a rewetted peatland site in northeastern Germany. We show that site-level annual emissions of CO2 and CH4 approach the IPCC default EFs and those suggested for the German national inventory report only between 13 to 16 years after rewetting. Over the entire study period, we observed a source-to-sink transition of annual CO2 fluxes with a decreasing trend of -0.36 t CO2-C ha-1 yr-1, and a decrease in annual CH4 emissions of -23.6 kg CH4 ha-1 yr-1. Our results indicate that EFs should represent the temporally dynamic nature of peatlands post rewetting and consider the effects of site characteristics to better estimate associated GHG budgets.

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Section: Discussionmentioning

confidence: 57%

Long-term flux measurements suggest dynamic emission factors are needed for rewetted peatlands

Kalhori,

Wille,

Gottschalk

et al. 2023

Preprint

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Response of testate amoeba assemblages to peatland drain blocking

Evans,

Mullan,

Roe

et al. 2023

Wetlands Ecol Manage

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Peatlands represent globally important habitats and carbon stores. However, human impacts and climate change leave peatlands with a substantial management challenge. Degradation of peatland habitats and their hydrological integrity is increasingly counteracted through the rehabilitation of peatlands including re-wetting and drain blocking. Research into how such management interventions affect peatland microbial assemblages is limited. Here, we investigate the response of testate amoebae (established unicellular amoeboid protist indicators of hydrological conditions in peatlands) to drain blocking on three small lowland raised bogs in Northern Ireland, UK. We sampled Sphagnum adjacent to areas of focused flow near sites of damming in addition to control sites away from dam blocking. These restoration measures show complex but meaningful results after restoration. We observe several key developments following dam blocking: (i) species diversity increases; (ii) unambiguous wet indicator taxa appear in increasing abundance at dammed sites; (iii) and transfer-function reconstructed water-table depths show wetter conditions in the dammed sites. These findings imply wetter conditions after restoration, where routine monitoring presented no clear trend in water-table depths. We found no statistically significant assemblage-level response to experimental or environmental variables, which may be related to antecedent conditions and significant periods of drought during the study period. Thus, caution is advised when utilising testate amoebae for bioindication until their assemblage-level response to restoration is better understood. Nevertheless, this study emphasises the potential of an indicator-taxa based approach to applying testate amoebae as contemporary bioindicators of peatland restoration—particularly on short-term timescales immediately following restoration.

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Practical Guide to Measuring Wetland Carbon Pools and Fluxes

Bansal,

Creed,

Tangen

et al. 2023

Wetlands

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Wetlands cover a small portion of the world, but have disproportionate influence on global carbon (C) sequestration, carbon dioxide and methane emissions, and aquatic C fluxes. However, the underlying biogeochemical processes that affect wetland C pools and fluxes are complex and dynamic, making measurements of wetland C challenging. Over decades of research, many observational, experimental, and analytical approaches have been developed to understand and quantify pools and fluxes of wetland C. Sampling approaches range in their representation of wetland C from short to long timeframes and local to landscape spatial scales. This review summarizes common and cutting-edge methodological approaches for quantifying wetland C pools and fluxes. We first define each of the major C pools and fluxes and provide rationale for their importance to wetland C dynamics. For each approach, we clarify what component of wetland C is measured and its spatial and temporal representativeness and constraints. We describe practical considerations for each approach, such as where and when an approach is typically used, who can conduct the measurements (expertise, training requirements), and how approaches are conducted, including considerations on equipment complexity and costs. Finally, we review key covariates and ancillary measurements that enhance the interpretation of findings and facilitate model development. The protocols that we describe to measure soil, water, vegetation, and gases are also relevant for related disciplines such as ecology. Improved quality and consistency of data collection and reporting across studies will help reduce global uncertainties and develop management strategies to use wetlands as nature-based climate solutions.

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Impacts of Active Versus Passive Re‐Wetting on the Carbon Balance of a Previously Drained Bog

Cited by 6 publications

References 81 publications

Long-term flux measurements suggest dynamic emission factors are needed for rewetted peatlands

Long-term flux measurements suggest dynamic emission factors are needed for rewetted peatlands

Response of testate amoeba assemblages to peatland drain blocking

Practical Guide to Measuring Wetland Carbon Pools and Fluxes

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