projects

Snow Hydrology in Peatland Dominated Catchments

NSF Hydrological Sciences Grant #2153802 Forest, Frost, and Flow: Snow Hydrology of Spatially Heterogeneous and Hydrologically Connected Peatland Catchments

Peatlands, a subset of wetlands that store organic carbon in the form of peat, cover only 3% of the globe but are responsible for storing more than 30% of all soil carbon. They are one of the most efficient carbon stores on the planet and are a critical buffer against global warming. Many of these peatlands are found along two latitudes: right above the equator in areas like Florida, Malaysia, and Southeast Asia; and right below the Arctic Circle in Canada, Scandinavia, and Russia. My research focuses on the latter for another critical climate change reason: winter. A peatland’s ability to maintain vast carbon stores is driven by its hydrology, specifically the water table. As winter temperatures and snowfall regimes change due to global warming, peatland hydrology shifts too, in ways that may decrease the carbon-trapping potential of these essential ecosystems. To figure out if and how peatlands are responding to these changes, we study the shifts in hydrologic connectivity under different snow regimes in peatland-dominated watersheds.

For more information see:

• M. W. Jones, S. F. Dymond, S. D. Sebestyen, X. Feng, Forest structural diversity increases snow accumulation in low-relief watersheds, in prep for Hydrological Processes
• M. W. Jones, S. D. Sebestyen, S. F. Dymond, G-H. C. Ng, X. Feng, Frost Decouples Spring Streamflow from Snowmelt in Headwater Catchments, Journal of Hydrology, 2023. https://doi.org/10.1016/j.jhydrol.2022.128801
• M. W. Jones, S. Dymond, S. D. Sebestyen, X. Feng, Forest Architecture Controls on Snow in Mississippi Headwater Catchments, WaterSciCon, Saint Paul, MN, June 2024
• M. W. Jones, X. Feng, K. Hoffman, S. D. Sebestyen, S. Dymond, Snow, soil frost, and hydrologic connectivity in peatland watersheds, Western Snow Conference, Flagstaff, AZ, April 2023

Integrating Peatlands into Land Surface Models

Peatland hydrological processes are largely ill-represented in global land surface models. Many models, including the Community Land Model (CLM), overestimate the water table depth in peatland-dominated regions which could be affecting long term carbon dynamic predictions. One reason for this deficiency is that peatlands are spatially heterogeneous, and their distinct landscape units occur on a scale smaller than most model grids. Other peatland features such as surface microtopography and lateral flow across low gradient hillslopes are difficult to mimic in models but play large roles in dictating hydrologic flows. In this research we test the applicability of the new subgrid hillslope feature of CLM 5.0 to model the spatial heterogeneity of peatland watersheds and compare the results to existing representations of peatland hydrology in non-subgridded CLM using both statistical and hydrological performance metrics.

For more information see:

• M. W. Jones, S. Swenson, S. D. Sebestyen, S. F. Dymond, X. Feng, Hillslope Representations of Peatland Catchments in the Community Land Model, in prep for Journal of Advances in Modelling Earth Systems (JAMES)
• M. W. Jones, S. Swenson, S. D. Sebestyen, S. F. Dymond, X. Feng, Representing Peatland Heterogeneity in CLM5.0 Using Subgrid Hillslope Methods, American Geophysical Union Fall Meeting, San Francisco, CA, December 2023

Modelling Methane Emissions from Wetlands with Dichotomous Noise

The net production of carbon products (e.g., DOC, CO2, CH4) within peatlands is strongly controlled by hydrological dynamics and microbial composition. Because oxygen diffusion is greatly inhibited in water, water table depths define the vertical oxic-anoxic boundary within the peatland soil column that mediates different metabolic pathways. As a result of these hydro-biogeochemical interactions, carbon emissions from peatlands are affected by water table dynamics—the emission rates from fluctuating water table regimes will deviate from those resulting from stable hydrological conditions. To help elucidate the role of water table fluctuations in these biogeochemical reactions, we use a stochastic approach to model the random switching between inundated and aerated soil conditions. Although this model will not be able to capture spatially explicit advection or diffusion processes, the analytical treatment of our parsimonious model allows us to relate the total emissions in a given period to (1) the mean frequency of switching between aerated and inundated periods, (2) the kinetic order of decomposition reactions, and (3) the relative rates of production versus consumption. This stochastic approach will lay the groundwork for predicting the temporal variations in metabolic pathways—including their pulsing, lagged, or hysteretic dynamics—to hydrological dynamics in the future.

For more information see:

• M. W. Jones, X. Feng, Water Table Fluctuations Drive Wetland Methane Emissions, in prep for Geophysical Research Letters