James Doten, Carbon Sequestration Program Manager, Minneapolis Health Department
Nicholas Vetsch, Environmental Engineer at Stantec Consulting Services Inc.
The state of Minnesota set itself ambitious climate and socio-environmental goals with its new Climate Action Framework and Climate Equity Plan. The comprehensive climate action plans include reaching carbon neutrality between 2030 and 2050, and achieving net-negative emissions thereafter, which will require removal of carbon dioxide from the atmosphere. A major carbon dioxide removal (CDR) technology readily implementable in Minnesota is biochar production and use. Biochar, the carbon-rich residue derived from biomass pyrolysis , is regarded as having a higher readiness than other CDR technologies because it is already available at various production scales.
The increasing interest in biochar production in urban areas is motivated, beyond CDR, by the multiple applications that biochar can have for municipalities and the abundant availability of green-waste biomass for biochar production in large cities like Minneapolis. While traditionally viewed as a soil amendment for agriculture, the number of uses for biochar has been expanding over the past several years. Many of these uses are directly applicable to urban environments. Urban uses for biochar include tree planting, turf and soils quality management, compost additive, bioremediation, stormwater management, urban agriculture, green roofs, and construction materials. More research is required to understand which biochar characteristics are most important for different end uses and what the ranges are for those characteristics. This project is designed to match Minneapolis feedstock availability with the range of production parameters of the city’s new pyrolysis plant so that the city can produce high quality and safe biochars with the optimal material properties for its various urban application.
This project is needed as it integrates critical research needs with direct field implementation, and soil, water, and climate protection efforts for the benefit of all Minnesotans. This project will generate critical knowledge for the successful implementation of a resilient and equitable bioengery-biochar solution for carbon management in the City of Minneapolis. Project outcomes will assist the City of Minneapolis in accomplishing the goals set by its Bioenergy-Biochar Action Strategy and Climate Action Plan that outline a roadmap to reducing citywide greenhouse gas emissions. Specifically, the project will help reducing green-waste by turning it into a value-added product and carbon-sink. This will reduce state carbon emission by effectively sequestering carbon as biochar.
Ray Riley, Loam Bio
Understanding of how carbon (C) enters and leaves soil, the largest active terrestrial C pool, represents a key research priority due to rising global temperatures associated with increasing atmospheric carbon dioxide concentrations. Microorganisms play a direct role in C retention in a wide range of terrestrial ecosystems through their inputs of dead cells (a.k.a necromass), which form a significant fraction of the soil organic C pool. Despite growing interest in characterizing the dynamics of fungal necromass decomposition as a critical factor impacting soil C persistence, only one study to date has tested how necromass decomposition rates may be altered by changing environmental conditions. Although that study suggests fungal necromass decomposition rates may in fact be sensitive to increased temperatures, possibly due to interactions with moisture availability, the unique environmental conditions of peatlands makes it unclear how representative these results are in normally drained upland systems.
To address current uncertainty in the sensitivity of fungal necromass decomposition to altered environmental conditions, we propose to conduct a field-based decomposition experiment at the University of Minnesota Cloquet Forestry Center in Cloquet, MN. Specifically, during summer 2023, we will incubate fungal necromass in the B4Warmed experiment, which includes a factorial combination of warming and reduced rainfall treatments. In addition to measuring how rates of mass loss from fungal necromass differ among ambient, warmed, droughted, and warmed + droughted treatments, we will also characterize how these treatments alter the structure of the microbial decomposer communities using molecular identification. Finally, we will analyze the chemistry of the remaining necromass to determine which components of decomposing fungal necromass are most sensitive to warmer and drier conditions. “
Collectively, this study will provide critical insight into determining how altered environmental conditions impact fungal necromass decomposition, which will ultimately inform how soil C sequestration is being affected by ongoing climate change. Additionally, the work will create a new partnership between public university and private company scientists under the shared goal of mechanistically understanding how soil C can be effectively managed. The technical training of a graduate student will also help in building a more inclusive and diverse STEM workforce. Finally, through presentations at scientific meetings and involvement in community events, the PI and graduate student will share knowledge with diverse audiences about the links between soils, decomposition, and climate change.
Kristen Bland, The Nature Conservancy
Randall Kolka, U.S. Forest Service
It has been estimated that drained peatlands, without restoration, may account for 41% of the global carbon budget for maintaining a threshold temperature increase of 1.5-2 degree C . Peatland restorations are increasingly being done to address climate change by re-wetting them by blocking the ditch, for both carbon and hydrologic benefits. Rewetting drained peatlands will reduce CO2 emissions caused by decomposing organic matter but it may increase methane release, a stronger greenhouse gas (Hemes et al. 2018). Therefore water level in restored peatlands need to be optimized to minimize GHG emissions
In Minnesota, there is about 1 million acres of drainage-impacted peatlands and peatland restoration is being actively pursued by state agencies, non-profits like The Nature Conservancy (TNC) and private mitigation bank companies. Our study will help determine the optimal water level of restored peatlands to maximize their carbon sequestration benefit. We will work with TNC and state partners such as the Minnesota Board of Soil & Water Resources (BWSR) to incorporate our study findings into design standards for restored peatlands.
The data will be analyzed to determine the potential for water level management and wetland design to reduce GHG emissions. The findings will directly inform peatland restoration strategies through the “Peatland Playbook” of the TNC, Mn-ND-SD Chapter. We also anticipate producing at least one scientific publication from the mesocosm study. We will do a presentation to the TNC international Peatland Network in 2024 and likely present at one other conference, such as AGU.