Monoterpene emissions from vegetation, a ‘thermometer” of plant health

Global vegetation is considerably affected by rising temperatures, for example the emissions of bVOCs, such as monoterpenes will increase with rising temperatures. Mnoterpenes role in the earth’s system extend from communication signals to influencing atmospheric processes. Image: Nature website.

Terrestrial vegetation emits biogenic volatile organic compounds (bVOCs), particularly vast amounts of monoterpenes (MT; C10H16), into the atmosphere in response to abiotic drivers such as temperature. MT, in turn, influence ecological interactions and atmospheric chemistry. As global temperatures continue to rise and extreme heat events become more frequent, the temperature sensitivity of forests is emerging as a critical issue for understanding the impacts of climate change on forest ecosystems and atmospheric chemistry. One important aspect of this sensitivity is this emission of bVOCs, such as MT, which will increase with rising temperatures.

In a new paper published in One Earth journal, authors study these greater MT emissions resulting from rising temperatures that can have far-reaching and uncertain consequences for the biosphere, potentially disrupting its delicate balance and feedback mechanisms among ecology, atmospheric chemistry and climate.

Global emissions are usually estimated as a function of temperature with a fixed exponential relationship (β coefficient) across forest ecosystems and environmental conditions. The authors of this new study applied meta-analysis algorithms on 40 years of published monoterpene emission data and showed that the relationship between emissions and temperature is more sensitive and intricate than previously thought. “Considering the entire dataset, our analyses indicate that co-occurring environmental factors modify the temperature sensitivity of the emissions that are primarily related to the specific plant functional type (PFT). Implementing a PFT-dependent β in a biogenic emission model, demonstrated that atmospheric processes are exceptionally dependent on monoterpene emissions which are subject to amplified variations under rising temperatures“, explains Prof. Efstradios Bourtsoukidis, from The Cyprus Institute.

The results obtained in this study, however, suggest that the temperature responses of MT emissions may exhibit dynamic variations throughout the tree’s age. According to the authors should be noted that while a clear relationship between PFT and the β coefficient became evident, the role of the other parameters might have been underappreciated due to the frequently unreported values.

“With newly discovered biogenic MT sources and the challenge of modeling co-occurring environmental drivers on the biosphere, our study highlights the need for more process oriented research of biosphere-atmosphere interactions, particularly in tropical, pan-Arctic, grassland, and agricultural ecosystems. As the effects of climate change intensify, biogenic VOC emissions from global vegetation will play a crucial role in evaluating the health of ecosystems and influencing the atmospheric oxidation capacity, with implications for the chemical composition, aerosols, and climate”, concludes Prof. Josep Peñuelas from CREAF-CSIC.

Bourtsoukidis, E., Pozzer, A., Williams, J., Makowski, D., Penuelas, J., Matthaios, V., Lazoglou, G., Yañez-Serrano, A., Ciais, P., Lelieveld, J., Vrekoussis, M., Daskalakis, M., Sciare, J. 2024. High temperature sensitivity of monoterpene emissions from global vegetation. Communications Earth & Environment 5, 23 (2024). doi: 10.21203/