I work at Stanford Earth with Prof. Robert Jackson, the Global Carbon Project, and the international community of eddy-covariance scientists (FLUXNET), on a global synthesis of wetland methane emissions. My background is in terrestrial and wetland biogeochemistry, with a focus on trace gas flux measurement and isotope analyses. More recently, I've become interested in the use of machine learning applied to predictive modeling of the global carbon cycle.
Bachelor of Science, University Of Stirling (2010)
Doctor of Philosophy, University of California Berkeley (2016)
Where old meets new: An ecosystem study of methanogenesis in a reflooded agricultural peatland
GLOBAL CHANGE BIOLOGY
2020; 26 (2): 772–85
Reflooding formerly drained peatlands has been proposed as a means to reduce losses of organic matter and sequester soil carbon for climate change mitigation, but a renewal of high methane emissions has been reported for these ecosystems, offsetting mitigation potential. Our ability to interpret observed methane fluxes in reflooded peatlands and make predictions about future flux trends is limited due to a lack of detailed studies of methanogenic processes. In this study we investigate methanogenesis in a reflooded agricultural peatland in the Sacramento Delta, California. We use the stable-and radio-carbon isotopic signatures of wetland sediment methane, ecosystem-scale eddy covariance flux observations, and laboratory incubation experiments, to identify which carbon sources and methanogenic production pathways fuel methanogenesis and how these processes are affected by vegetation and seasonality. We found that the old peat contribution to annual methane emissions was large (~30%) compared to intact wetlands, indicating a biogeochemical legacy of drainage. However, fresh carbon and the acetoclastic pathway still accounted for the majority of methanogenesis throughout the year. Although temperature sensitivities for bulk peat methanogenesis were similar between open-water (Q10 = 2.1) and vegetated (Q10 = 2.3) soils, methane production from both fresh and old carbon sources showed pronounced seasonality in vegetated zones. We conclude that high methane emissions in restored wetlands constitute a biogeochemical trade-off with contemporary carbon uptake, given that methane efflux is fueled primarily by fresh carbon inputs.
View details for DOI 10.1111/gcb.14916
View details for Web of Science ID 000511917700045
View details for PubMedID 31710754
- An open-source database for the synthesis of soil radiocarbon data: International Soil Radiocarbon Database (ISRaD) version 1.0 EARTH SYSTEM SCIENCE DATA 2020; 12 (1): 61–76
FLUXNET-CH4 synthesis activity: objectives, observations, and future directions
Bulletin of the American Meteorological Society
2019; in press
View details for DOI 10.1175/BAMS-D-18-0268.1