Jas Ogiste
Oberlin College and Conservatory
Research Mentor: Abigail Swann
Project: Plant Physiological Responses to Increasing Atmospheric CO2
My name is Jas Ogiste and I am a rising senior double-degree student at Oberlin College and Conservatory, pursuing degrees in Environmental Studies and Piano Performance. This summer, I had the privilege of working under the mentorship of Dr. Abigail Swann and closely with UW Department of Atmospheric Sciences graduate student Claire Zarakas.
While most of the attention directed towards the increase in concentrations of atmospheric CO2 has been focused on its radiative consequences as a greenhouse gas, rising CO2 levels may also affect key components of plant physiological responses. Transpiration refers to the movement of water through a plant and its evaporation through pores in its leaves, called stomata. Evaporation refers to the evaporation of surface water from the soil and from leaf surfaces, and evapotranspiration is the sum of transpiration and evaporation. Future rates of evaporation are likely to increase due to increasing temperatures; on the other hand, transpiration rates are expected to decrease due to stomatal closure. These contradictory responses are both due to rising concentrations of CO2 and will play a role in water availability in a future climate.
For my project, I was interested in observing how a 1% annual increase in CO2 concentrations would affect rates of evapotranspiration and plant transpiration. In the simulation, CO2 concentrations increase by 1% each year from pre-industrial levels of 280 ppm to 1140 ppm. I compared two experiments, one where the full effects of this increase are seen in both the atmosphere and on land, looking at the effects of CO2 as a greenhouse gas, and one where there is only a plant physiological response to this change, looking at the effects of CO2 exclusively as a component of photosynthesis. I used output from the Community Earth Systems Model in order to generate figures.
I found that levels of plant transpiration decreased dramatically over the course of the simulation, while evapotranspiration levels increased. On a global scale, leaf surface evaporation and soil evaporation increase enough over time to offset this decrease in transpiration, causing a net increase in evapotranspiration over time, despite transpiration accounting for nearly 50% of total evapotranspiration. The effects of CO2 as a greenhouse gas can counteract its role as a component of plant photosynthesis and its effect on stomatal conductance.
I had such an incredible research experience and I gained a number of valuable skills, especially learning Python and how to analyze output from climate models. It was a pleasure to meet all of the other interns, both virtually and in-person during our poster session at the University of Washington. I am so grateful to all of the members of the Ecoclimate Lab and to CICOES for providing an amazing internship this summer.
Project Introduction:
Poster:
