About the Trace Gas Biogeochemistry Group

A young man and woman draw water from a bog while squatting on a boardwalk.

About Us

We study the response of carbon, nitrogen and other element cycles to climate and land use change. Our research is located in subarctic, temperate, and tropical biomes that include tundra, forested, urban, and agricultural areas. We focus on trace gas biogeochemistry within these ecosystems, developing and utilizing a variety of techniques such as in-situ sensors, remote sensing, and process-based modeling from local to global scales. We work at the intersection between science and society, collaborating with students, educators, stakeholders, and citizens.

We seek to advance scientific discovery through collaboration, mentorship and outreach by building a strong, diverse and inclusive research community. We pursue questions of both fundamental scientific interest and broad societal relevance, while at the same time encouraging our group members’ unique motivations and interests and the benefits they bring. We communicate research in creative ways to increase the broader impact of our work by engaging stakeholders, the public and K-12 teachers and students.

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Principal Investigators
Ruth Varner
Alexandra Contosta

Research Staff
Apryl Perry
Florencia Fahnestock NA

Graduate Students
Apryl Perry: Drivers of CH4 ebullition in a temperate fen

Cheristy Jones: Terrestrial-Aquatic interaction in Arctic catchments

Shannon Van Hise: Assessing how forestry armoring mitigates soil disturbances during winter logging operations

Chelsea Oti: Microbial influence in methane oxidation in arctic lake sediments

Claudia Guillot-Wallace: Water-rock interactions in a peatland ecosystem undergoing permafrost thaw

Sadid Hossain: Impact of Seaweed-Supplemented Dairy Cow Excreta on Soil Greenhouse Gas Emissions

Brendan Murphy: Effects of livestock grazing on soil C & N

Peter Tansey: Effects of foundational species loss on soil carbon storage

Jannatul Ferdous: Focus is on Climate-Smart Agriculture, finding ways to reduce greenhouse gas emissions while improving soil health

<< Content coming soon  >>

  • From Archaea to the Atmosphere (NASA IDS: R. Varner PI) This project aims to scale emissions of methane across the arctic using a combination of microbial and isotopic measurements, UAS surveys to map vegetations, biogeochemical modeling and remote sensing. This project is part of NASA's Arctic Boreal Vulnerability Experiment (ABoVE).
  • Exploring the interactions between carbon cycling, land use and climate change (NASA CCS; J. Xiao is PI). This project examines land use-climate interactions in the human-dominated region of southern New Hampshire that includes urban, suburban, agricultural, and forested land uses.
  • Soil carbon storage and greenhouse gas losses in intensively grazed pastures (USDA ORG; PI A. Contosta). This study explores linkages among grazing management, soil carbon storage, and greenhouse gas losses through a combination of field measurements, lab analyses, and process-based modeling. We are translating our research into a decision support system that will enable organic dairy farmers to make science-based pasture management decisions that promote soil C sequestration and reduce soil greenhouse gas emissions.
  • Promoting ecosystem services during the conversion of forests to fields in New England (USDA AFRI, R Smith PI). This project seeks to determine how forest-to-agriculture conversions, particularly pasture and silvopasture, affect ecosystem services such as nutrient retention, water availability, climate regulation, and forage supply.
  • Winter Climate Change in the Northern Forest (NSRC; A. Contosta). The goal of this work is to determine how climate change impacts winter ecological and biogeochemical processes, and how this changing winter landscape affects Northern Forest communities.
  • Winter Weather Whiplash (SESYNC; A. Contosta). This project is developing a suite of winter weather whiplash indices and associated physical, ecological, biogeochemical, and socioeconomic response metrics to determine the extent to which winter weather whiplash events have cascading impacts on ecosystems and their services.
  • DOE funded Isogenie project (R. Varner).
  • Global Sustainable Bioenergy Initiative (Nell Campbell).
  • Bringing DNDC into the Predictive Ecosystem Analyzer (PEcAn) project (ESRC)(Varner, Contosta, Campbell). This project is expanding our capacity for ecosystem model analyses at scales relevant for policy and land management by integrating the ecosystem model DeNitrification-DeComposition (DNDC) into the PEcAn system.

Trace gas analysis using CH4 using a gas chromatograph equipped with a flame ionization detector (GC-FID; Shimadzu 8A); and CH4, CO2, and H2O vapor  (Cavity Enhanced Absorption Spectroscopy (OF-CEAS); LI-COR 7810).  We also have a laser to measure del13-CH4 (Aerodyne, Inc.).

  • Conference, December 5-19, 2025
    Cheristy Jones is presenting at AGU looking at landscape drivers of stream CO2 and CH4 emissions.
  • Workshop, November 10-14, 2025
    Cheristy Jones attended Greenland Science Week and presented on our work at Kobbefjord, Greenland which examines terrestrial-aquatic conductivity and catchment carbon flux.
  • News Article, October 2, 2024
    UNH: Climate change impact on forests may be less than expected
  • Clarice Perryman, along with two other graduates students from UNH, was awarded an Outstanding Student Presentation Award at the Fall Meeting of the American Geophysical Union.
  • Contosta was featured in a short film highlighting open source and transparent data collection, modeling, and decision support tools for sustainable agriculture.
  • Contosta and colleagues publish a paper examining changes in the timing and duration of the vernal window in Global Change Biology (doi: 10.1111/gcb.13517).

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