Ozone affects plant, insect, and soil microbial communities and threatens terrestrial ecosystems and biodiversity

Ground-level ozone is a greenhouse gas formed from precursors emitted by anthropogenic activities. Ozone concentrations have been considerably elevated since the pre-industrial period, and are predicted to stay elevated for many decades to come. Because ozone is a strong oxidant, ozone pollution presents potential risks to the health of organisms.

Can ozone pollution affect terrestrial biodiversity? In a new study published in the journal Science Advances, authors provide the first comprehensive assessment of how ozone pollution can alter the structure and function of terrestrial ecosystems, and, thus, threaten biodiversity.

Authors demonstrate that the composition of plant communities can change as a result of different sensitivity to ozone among plants. They also demonstrate that ozone affects the foliar chemical composition and the composition of emitted biogenic volatile organic compounds (BVOCs). Such changes in plant chemical composition can alter herbivory, i.e. the consumption of plant material by animals, as the selection of host plants by insect herbivores and grazing depend on the nutritional quality of plant tissues. Likewise, BVOCs act as communication signals not only among plants but also between plants and insects. Insects use the information from the BVOCs to orient themselves in the environment and trace host plants. Hence, authors show that changes in the foliar chemical composition and the composition of the emitted BVOCs can alter plant-insect interactions. 

Authors also illustrate that ozone can affect the decomposition process, alter the expression of microbial genes involved in carbon cycling, and decrease carbon cycling. In addition, they concentrate evidence showing that ozone pollution can impair nitrogen cycling and decrease soil microbial biomass. These suggest disturbed plant-soil feedbacks, with potentially affected soil microbial communities.  

Finally, authors suggested that Atlantic islands in the Northern Hemisphere, the Mediterranean Basin, equatorial Africa, Ethiopia, the Indian coastline, the Himalayan region, southern Asia, and Japan host a high endemic richness that is at high ozone risk by 2100.

The results of this study suggest that ozone should be included in global assessments of threats to terrestrial biodiversity. “The study sets the path forward for a new generation of studies that will address ozone impacts on the biodiversity, and is expected to generate much interest for advanced interdisciplinary researches addressing this environmental issue” says the lead author, Prof. Evgenios Agathokleous of the Nanjing University of Information Science & Technology, China.

Reference: Agathokleous, E., Feng, Z., Oksanen, E., Sicard, P., Wang, Q., Saitanis, C.J., Araminiene, V., Blande, J.D., Hayes, F., Calatayud, V., Domingos, M., Veresoglou, S.D., Peñuelas, J., Wardle, D.A., De Marco, A., Li, Z., Harmens, H., Yuan, X., Vitale, M., Paoletti, E. (2020). Ozone affects plant, insect, and soil microbial communities: A threat to terrestrial ecosystems and biodiversity. Science Advances 6: eabc1176. DOI: 10.1126/sciadv.abc1176

Photo caption and credit: Effects of elevated ozone on aboveground ecosystem processes. Source: Agathokleous et al. (2020).

Link to paper: https://advances.sciencemag.org/content/6/33/eabc1176