Luise Gleason


Years participated in RESESS: 2023


An Overview

Program: RESESS Boulder

Major: Earth Science

Academic Affiliation: University of California, Santa Barbara

Mentors: Dr. Nikki Lovenduski


Luise Gleason is a rising senior at UCSB in California. Majoring in Earth Science with an emphasis in climate and environment, she plans to continue her education in her native Europe with a master’s degree. Luise has always been drawn to the natural world, but it was her photography that ignited her passion for environmental protection and finally motivated her to change her career from design and marketing to science. Ultimately, she would like to incorporate her communication skills from her previous profession to convey scientific knowledge to the public. As a RESESS intern, she is looking forward to gaining her first research experience with a deep dive into paleoclimates.


Asteroid impacts, nuclear wars, or solar radiation management geoengineering can cause stratospheric ozone depletion, which is expected to enhance ultraviolet (UV) radiation at Earth’s surface. Exposure to higher levels of UV radiation reduces phytoplankton productivity. This negative impact could disrupt the marine food web and diminish carbon sequestration. Previous laboratory research studies have experimentally determined phytoplankton UV damage functions, also called biological weighting functions (BWF). These can be used to quantify the species-specific UV damage to photosynthesis, a process called photoinhibition, when phytoplankton are subjected to different wavelengths of light. We incorporated BWFs into the Marine Biogeochemistry Library (MARBL), the ocean biogeochemical component of the Community Earth System Model version 2 (CESM2). This modification enabled MARBL to simulate photoinhibition in four different phytoplankton functional types (PFT) before and after the injection of 1000 Tg of ozone-depleting halogens. Modeled responses of phytoplankton photosynthesis allowed us to quantify net phytoplankton production (NPP) perturbations driven by UV inhibition. Results reveal that changes in photosynthesis are not solely dependent on the anatomical structure of phytoplankton (e.g., shelled vs. unshelled), but that they are also connected to other environmental conditions as specified in CESM2, including variations in the duration and magnitude of UV exposure, light penetration depth, species depth distribution, nutrient availability, and seawater temperature. In order to better predict effects of ozone depletion on planktonic organisms, future modeling studies should include species-dependent physical and chemical properties that lead to photoprotective mechanisms, which have the potential to counteract UV photoinhibition.