Grasslands — Research — Kathiravan Meeran

ClimGrass Experiment

ClimGrass manipulates temperature (+3 °C via IR heaters), atmospheric CO2 (~+300 ppm), and rainfall to study grassland responses. Plots also undergo drought and combined treatments. (link).

We find that warmer climate under eCO2 can alter drought and post-drought responses of ecosystem CO2 fluxes and of C allocation from photosynthesis to belowground respiration (link).

Warming and elevated CO2 plots at ClimGrass — Combined warming and elevated CO2 treatment plots at ClimGrass used to test future climate scenarios.

Drought treatment infrastructure — Rain‑out shelters and control systems imposing growing‑season drought on alpine grassland.

ClimGrass site panorama — Site overview: replicated plots with IR heaters and CO2 distribution lines.

Post-harvest sampling at plots — Post‑harvest sampling to quantify biomass and nutrient stocks after treatments.

Iceland Natural Warming

At a geothermal site in Iceland, natural soil warming revealed rapid carbon losses from subarctic grasslands—up to ~40% of soil C lost within the first years. Microbial communities adapted to higher temperatures, but the carbon cycle accelerated: more plant carbon transferred to microbes and released as CO2 (link).

N became limiting, and increased plant productivity could not compensate for the C loss. Stable 13C tracers mapped carbon pathways and showed reduced ecosystem carbon storage under warming.(link).

Geothermal warming gradients in Iceland — Natural geothermal gradients provide a space‑for‑time analogue for long‑term soil warming.

Geothermal vent at the subarctic site — Active vent heating soil profiles—ideal for testing temperature effects on carbon stocks.

13CO2 pulse labelling of grassland — 13CO2 pulse labelling to trace fresh plant carbon into microbial biomass and CO2 efflux.

Laboratory incubation of soils — Laboratory incubations isolating temperature sensitivity of microbial respiration and priming.

Field sampling in subarctic grassland — Field sampling campaign across the gradient to quantify stocks and process rates.

Field sampling with collaborators — Collaboration in the field—joint sampling with Prof. Ivan Janssens’ team.

Another geothermal vent location — Additional vent site illustrating heterogeneity in soil heating.