SHRINK – Is Global Warming Shrinking Soil Microorganisms?

Global oppvarming påvirker alt liv på jorden, inkludert de aller minste - mikroorganismer. I prosjektet vårt (SHRINK) studerer vi hvordan temperaturendringer påvirker mikrober og deres evne til å utføre forskjellige funksjoner. Jordmikroorganismer er for eksempel ansvarlige for utslipp av milliarder av tonn karbon fra jord til atmosfæren i form av CO2, en potent drivhusgass. Imidlertid kan de også bidra til å beholde karbon i jorden og fremme veksten av planter, som i sin tur kan fjerne CO2 fra atmosfæren. SHRINK-prosjektet har som mål å forstå konsekvensene av oppvarmingsinduserte endringer for mikrobielle celler, mikrobielle samfunn og viktige mikrobielle funksjoner som har global relevans. Ved å gjøre dette håper vi å få en bedre forståelse av hvordan aktiviteten i jord vil endre seg i en varmere fremtid - vår fremtid. Denne kunnskapen vil hjelpe oss med å forutsi og håndtere effektene av global oppvarming.

Soil microorganisms are responsible for the degradation of soil organic carbon (C) and the subsequent release of billions of tons of CO2 to the atmosphere. It is of great concern that global warming is increasing microbial activities and microbial-derived CO2 emissions from soils, especially in northern regions. To meet national and global climate action plans, such as Norway’s Climate Action Plan for 2021–2030 and the UN 2030 Agenda for Sustainable Development, we urgently need to understand soil-climate feedback loops triggered by warming, including underlying microbial activities. SHRINK is based on our recent discovery that soil microorganisms exposed to warming reduce their cellular numbers of ribosomes, their “protein production factories”. Since ribosomes are universal, highly abundant, and constitute a large fraction of the cell mass, a reduction will have extensive implications. For example, microbial cells require less energy and matter to synthesize ribosomes, and consequently, less cellular space is needed to harbour them. These spared resources (energy, matter, space) can be simply saved or re-allocated, possibly leading to smaller cells, accelerating microbial activities, and increasing microbial-derived CO2 emissions. SHRINK will advance our understanding of microbial responses to soil warming and reveal the molecular basis of ribosome reduction, uncover the effect of this key physiological mechanism on microbial cells and their physiological states, and assess implications for soil ecosystems and microbial-derived CO2 emissions from soils. Furthermore, the temperature-dependent regulation of cellular ribosome contents and the subsequent cellular resource re-allocations might represent the key module to advance and refine metabolic models, ecosystem simulations, and Earth system models. Thus, SHRINK will eventually help to better understand, predict, and manage soil-climate feedbacks in a warmer future – our future.