Speaker
Description
Long-term ecosystem experiments are essential for capturing immediate responses to environmental change, assessing ecosystem resistance and resilience, and identifying persistent legacy effects. At the AnaEE experimental facility Brandbjerg (CLIMAITE) in Denmark, we investigated how elevated atmospheric CO₂ and prolonged drought altered ecosystem carbon and nitrogen dynamics.
In the first study, we revisited a temperate grassland/heathland ecosystem seven years after the termination of a multi-factorial Free-Air CO₂ Enrichment (FACE) experiment. While elevated CO2 initially drove a significant increase in soil carbon and nitrogen stocks, these pools normalized rapidly following the cessation of the treatments. However, the current soil carbon pool retained detectable legacy signals of the former CO₂ enrichment, indicating that a substantial fraction of the new carbon accumulated during the FACE experiment was stabilized while older carbon pools were partially decomposed due to priming. These findings indicate a highly dynamic carbon turnover in the system providing new insights into the stability and resilience of soil carbon under climate change.
In the second study, we examined ecosystem carbon flux responses to long-term drought and incorporated drought effects into a stepwise ecosystem carbon balance modelling framework. Gross primary productivity (GPP) and ecosystem respiration (Reco) exhibited asymmetric responses, indicating different sensitivities of carbon uptake and carbon release processes to prolonged drought stress. Furthermore, our modelling results demonstrated the importance of allowing key ecosystem parameters to vary under environmental stress, thereby improving projections of ecosystem carbon dynamics under future climate scenarios.
Together, our findings highlight that ecosystem legacy effects and metabolic asymmetries are key determinants of carbon cycling in a changing climate. By integrating long-term observations, this work underscores the essential role of AnaEE research infrastructures in capturing the complex, time-lagged, and non-linear ecosystem responses to undergoing global change.
Keywords:
Climate change, carbon dynamics and balance, modeling
| Are you participating to the "AnaEE Environmental Rising Star Award "? | Yes |
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