Biogeochemical processes governing boreal C cycling

Positive feedbacks will have a decisive impact on the climate by potentially amplifying the formation of greenhouse gases such as CO2 and CH4 (methane). BioGov focuses on the carbon cycle in northern boreal areas by examining the significance of forests, soil, and permafrost thawing for the transport of carbon (C) between these systems. It also looks at how the runoff of organic carbon from land to water affects lakes and coasts, as darker water reduces primary production and stimulates the production of greenhouse gases CO2 and CH4. These processes contribute to a self-reinforcing effect, intensifying warming (lakes are responsible for significant greenhouse gas emissions), and the warming itself will further increase the production of greenhouse gases. BioGov studies processes from the microbial level (bacteria and greenhouse gas production) to large-scale monitoring using satellite data and modeling. The project has two main objectives: 1) to understand and predict the production of greenhouse gases such as CO2 and CH4 in boreal areas under various climate scenarios, and 2) to produce data for better parameterization of soil models and Land System Models (LSMs) that are part of large-scale climate modeling. The significance of self-reinforcing feedbacks is crucial here. An aspect that has become more prominent is the importance of what are called non-linear responses, where systems can reach thresholds or tipping points, suddenly changing their character. Climate change is a central driver of such abrupt changes. Based on field studies from areas with thawing permafrost, lakes, lab experiments, and modeling, we aim to achieve a significantly better characterization of transport between various ecosystem components (atmosphere, land, water) at different scales. This will enable us to understand the complex boreal carbon cycle and thus better predict the drivers and effects of a changing climate.

Positive climate feedbacks can undermine policy efforts to minimise greenhouse gas (GHG) emissions. BioGov focuses on the high risk of mobilization of soil organic carbon (C) in the boreal biome as a consequence of warming and changes in precipitation, growing forest biomass (greening), and thawing of permafrost. The microbial transformation of C-stores is prone to boost GHG emissions, while thawing permafrost and increased precipitation will affect the flux of organic matter (OM) into lakes. Knowledge gaps on sensitivities of C cycling to climate change and shifts in ecosystem traits restrict our ability to make robust predictions of GHG trajectories using Land System Models (LSM). In particular, microbial and geochemical controls of OM processing under expected ecosystem transitions are poorly understood. BioGov aims to provide a process-based understanding of how organic C from soils and biomass is exported, processed and converted to GHG, including its transport along a land to water continuum at various spatial and temporal scales, as results of environmental changes. This project links terrestrial, aquatic and atmospheric processes, and unifies researchers from biology, geosciences and chemistry with modelers to address these complex issues of vital importance to climate and ecosystems. We will advance the 1-D representation in LSMs by adding linkages with lateral fluxes, across micro- to regional scale, between decomposition of OM, lateral transport of OM across the landscape, and vertical flux of GHG at three sites, in combination with laboratory experiments, using novel combination of state-of-the-art analysis methods, and national and regional water chemistry studies across a boreal ecosystem gradient. With high precision field and experimental data we will quantify key OM fluxes and processing rates enabling us to parameterize and validate models promoting more robust predictions of atmospheric GHGs under climate change.