Celia Faiola
Ecology & Evolutionary Biology
Research in the Faiola laboratory broadly explores topics related to the sources, transformations, and fate of chemical signals in the soil-plant-atmosphere continuum. A major focus of our research is studying plant volatile emissions in a changing climate, and how changes to plant emissions alter atmospheric chemistry processes. In particular, we investigate the influence of plant volatile emissions on the production of secondary organic aerosol (SOA) and its climate-relevant properties, which can generate feedbacks influencing ecosystem health and land-atmosphere volatile fluxes. In addition to plant-atmosphere interactions, our lab also studies plant-microbe interactions belowground. We are interested in the interplay between plant local adaptation, soil legacy, and plasticity in imparting climate stress resilience. The Faiola lab’s research focuses on the following three broad themes.
1) Plant Stress Emissions and Atmospheric Aerosol Formation.
One of the largest uncertainties in climate change projections are associated with the radiative forcing from atmospheric aerosol. This uncertainty is due, in part, to the complex processes associated with the biota’s role in the formation of secondary organic aerosol (SOA)—including climate change feedbacks related to plant stress. Our lab conducts SOA studies in the laboratory using real plant emissions as an SOA precursor and compares SOA production between healthy and stressed plant emissions. Our work has shown that sesquiterpenes play a particularly important role in controlling SOA production from a complex mixture of real plant volatiles. In particular, our work was the first to demonstrate that acyclic sesquiterpene emissions induced after aphid stress promote fragmentation reactions (as opposed to functionalization reactions), which ultimately decrease SOA production during ozonolysis chemistry. We also explore resulting climate-relevant properties of SOA produced under these different conditions, including particle composition and viscosity.
PICTURE: Schematic showing plant-aerosol interactions
2) Identifying and Characterizing Missing Sources of Plant Volatile Emissions.
Traditional studies of atmospheric aerosol formation from plant volatile emissions have focused on simplified chemical systems using an individual standard compound to represent plant emissions or have targeted field observations over a limited number of ecosystem types. This means we could be missing important sources of plant volatiles in our models. We investigate SOA formation chemistry using real plant volatile emissions as an SOA precursor to identify important compounds contributing to particle production that may have been overlooked. We conduct these experiments using a range of different plant functional types.
PICTURE: Baccharis salicifolia growing in the UCI greenhouse for laboratory experiments.
3) Urban Ecology, Urban Greening, and Atmospheric Aerosols.
Urban greening programs are becoming increasingly popular, but it isn’t clear which trees should be targeted for these planting programs. Different plants emit very different types of volatile compounds which could all influence SOA production, composition, and toxicity. To address this topic, we investigate SOA formation and particle toxicity from a range of plant volatile emissions representing different plant functional types.
PICTURE: Schematic showing that some tree types could exacerbate air quality issues if they are planted in urban areas. From Gu et al., 2021, Environmental Science & Technology