Sequential destabilization of C and N in biogeochemical cycles to increasing temperatures in the subartic region

SOCRATES

National Projects

Project duration:

Jan 2022 to Aug 2025

The vulnerability of high-latitude soils to temperature increases may differ between mineral and organic soils, and this may be due to the large N losses that mineral soils may suffer during the first years after the onset of warming. This mechanism is not considered by models, but may be the key to the large divergences between observed and predicted soil C losses. SOCRATES will use the expertise of a multidisciplinary group of world-leading researchers in ecosystem stoichiometry, state-of-the-art isotope methods, an exceptional international training network and unique experimental stations in Icelandic geothermal systems and Swedish peatlands. This will reveal the sequence of destabilisation mechanisms that lead to C losses in high-latitude soils in response to warming.

Introduction

Global warming can trigger enormous releases of carbon (C) from high-latitude soils, causing positive feedbacks to the climate system. Climate change projections are however still largely uncertain, partly due to the lack of accurate representation of vegetation and soil microbial feedbacks and the interactions of nitrogen (N) and C cycles. Warming enhances soil organic matter mineralization (SOM) (i.e. soil C outputs) to a higher degree than vegetation productivity (i.e. soil C inputs), resulting in large C losses from northern soils.

Pioneer results from our research team suggest that the vulnerability of high latitude soils to warming differs between mineral and organic soils, and this may be due to large soil N losses from mineral soils during the first years of warming. This mechanism is not considered by ecosystem models, what may be the key for the large divergences between observed and predicted soil C losses. The initial cascade of destabilization mechanisms triggered by increasing temperatures is pivotal to understand the biogeochemical processes that lead C losses from high latitude soils, but it remains unexplored due to the lack of long-term field warming experiments.

Actions

SOCRATES will make use of the expertise of a multidisciplinary group of world-leading researchers on ecosystem stoichiometry, cutting-edge isotopic methods, an exceptional international training network and of the existence of unique research sites in Icelandic geothermal systems and Swedish peatlands. All this will allow to uncover the sequence of destabilization mechanisms that lead to C losses in high latitudes soils in response to warming. The comparison of key biogeochemical processes on permafrost thawing gradients in peatlands and on long-term (>50-year-old) and recently warmed (transplanted) mineral soils will allow, for first time, to shed light on two fundamental knowledge gaps:

The occurrence of progressive shifts in activities and stoichiometric needs of soil microbes
The arise of asynchronies between the rates of microbial N mineralization and plant N uptake.

SOCRATES will therefore deliver entirely novel insights into potential future alterations due to climate warming, consolidate long-term international synergies within and beyond the academic sector and position our group in the forefront of climate change biogeochemistry research in the European Research Area (ERA).

Proyecto PID2021-129081OA-I00 financiado por MCIN/AEI /10.13039/501100011033 y por FEDER Una manera de hacer Europa