Decomposition of plant material is a major global flux of carbon (C) that is thought to be controlled by climate, litter quality, and microbial community. Process-based models can represent these controls but may not correctly represent the importance of each of these drivers. We are parameterizing the microbially-explicit MIcrobial-MIneral Carbon Stabilization (MIMICS) model to correctly represent the relative importance of these drivers and will investigate this parameterization under global change.

Soil organic matter (SOM) is central to ecosystem functions, including carbon storage, nutrient provisioning, and as a habitat for soil fauna. In past couple decades several influential conceptual frameworks have emerged that shape our understanding of SOM dynamics. In this review, we evaluate the empirical evidence and model representation of the ideas in these conceptual frameworks, as well as identify inconsistencies and future directions. This work is accepted for publication in the Journal of Geophysical Research-Biogeosciences.

There is evidence to suggest that mineral-associated organic carbon (MAOC) may increase, while particulate organic carbon (POC) may decrease, under increased precipitation, leading to no change in total soil carbon but with important restructuring of this globally important carbon pool. To investigate this, we have sampled soils at a long-term irrigation experiment at an annually burned prairie in northeastern Kansas (Konza LTER) and measured soil organic matter dynamics and controls. This work was published in Soil Biology & Biochemistry.

National parks are both places of exploration and places of conservation. Thus, it is important to understand how visitation affects park ecosystems. We are researching whether local N pollution from cars driving through the RMNP is affecting roadside ecosystems. We performed a proof-of-concept test in summer 2020 and are executed a complete project in summer 2021. This work was published in Water, Air, & Soil Pollution.

Increased nutrient availability with global change will modify future biogeochemistry. To better understand this variation, we investigated the responses of soil C and N coupling and stability in soil organic matter fractions to nutrient fertilization across a global set of grasslands, in collaboration with the Nutrient Network. This work is published in Biogeochemistry.

Biochar, a sustainable soil amendement that enhances carbon sequestration, is likely to affect other aspects of soil.  We assessed whether biochar diffeerntly affected soil and fertilizer N in a greenhouse study. We find that biochar had a stronger influence on fertilizer N but fairly limited effects overall. Details of this work are avaiable here.

Project partners: Francesca Cotrufo and Steven Fonte

Methane emissions and isotopic composition over a thaw gradient in a subarctic peatland. Mentor: Ruth Varner, UNH

Characterizing ice nucleating particles at the Western US Coast. Mentor: Sonia Kreidenweis, CSU

Plant and soil biogeochemistry over a bedrock gradient. Mentor: Julie Bryce, UNH