Some science…
Modeling Marine Primary Productivity and Carbon Sequestration during the Mid Miocene Warming (~15 million years ago)
The ocean absorbs almost a third of anthropogenic carbon dioxide emissions annually, and phytoplankton drive much of this uptake through photosynthesis. Aside from being a crucial component of the carbon cycle, phytoplankton produce about half of our oxygen and act as the base of the marine food web. Despite their importance, their predicted response to modern warming and ocean acidification remains unclear. I am using Community Earth System Model (CESM) simulations of the Middle Miocene period and enabling an ocean biogeochemistry model to analyze shifts in phytoplankton functional groups seasonally and between different atmospheric carbon dioxide levels. By quantitatively comparing phytoplankton growth, zooplankton grazing, and net primary productivity levels, I can estimate the changes in the efficiency of the biological carbon pump under warming. I use a past warm climate in Earth’s history so that I can validate the simulation output against real-world fossil evidence. This project combines climatology and carbon-cycling with physical, chemical, and biological oceanography. The paper is in preparation.
The moving figures to the left show seasonal shifts in photosynthetically available radiation and marine carbon fixation at the lower carbon dioxide level. The plot shows latitudinal differences in particulate organic carbon flux at 100 meter depth after the atmospheric carbon dioxide level has been doubled.
Equilibrium Climate Sensitivity Variations to Changing Climate, Geography, and Ocean Heat Transport
As anthropogenic emissions rise and the world warms faster than ever before, scientists hope to refine estimates of our modern equilibrium climate sensitivity (ECS) — the amount of warming in response to doubled atmospheric carbon dioxide. Modeling past fluctuations in ECS through Earth’s history can better our understanding of warming trends driven by climate-controlling mechanisms, like the water vapor, cloud, and surface albedo feedbacks. I built and ran slab-ocean CESM simulations of four distinct periods in Earth’s history (Cretaceous, Eocene, Oligocene, and pre-industrial) to compare ECS. This project totaled 18 simulations at varying carbon dioxide levels, geographic configurations, and ocean heat transport strengths. The paper has been submitted to the journal Geophysical Research Letters.
The figures to the right show the ECS for different climates, the main feedbacks driving warming and their percent change with doubled carbon dioxide, and spatial patterns of warming under doubled carbon dioxide levels.
CO2- and Orbitally- Driven Oxygen Isotope Variability in the Early Eocene
Severe warming and changes in the water cycle are projected to continue under increased greenhouse gas emissions. Following a higher emissions pathway, the Earth’s carbon dioxide level could eventually reach heights not seen since the Early Eocene (~55 million years ago). In this study, I used sensitivity experiments to investigate the climatic and hydrological response to changes in Earth’s carbon dioxide and orbit under Early Eocene conditions in order to understand the impact these forces had on global temperature and precipitation trends. I compare the output to soil carbonate and leaf fossil evidence to verify the model output. This project also served to strengthen comprehension of environmental signals in terrestrial isotopic records and the impact of orbit under a warming climate. The paper was published in Climate of the Past in 2024.
The figure to the top-left shows seasonal changes in atmospheric water isotopes, which are partly controlled by temperature and precipitation patterns, between two extreme orbits under a higher carbon dioxide level. The figure below that shows a model-data comparison between seasonal soil water model output and soil carbonate evidence.
Coccolithophore Growth under Warming and Acidification; Element Incorporation in Calcium Carbonate Biominerals of Marine Calcifiers
As an undergraduate, I spent three years studying the growth rates of Emiliani huxleyi (coccolithophore phytoplankton) under varying temperature and pH conditions. The project served as a contribution to a larger effort to use lab studies to predict coccolithophore survival in the near-future under modern warming. Aside from the lab studies, I contributed to a project on elemental ratios in biogenic marine calcium carbonates, which are widely used in geobiology and paleoenvironmental reconstructions. I conducted data analysis, namely PCA (principle component analysis) and NMDS (non-metric multidimensional scaling) plotting in R in collaboration with other team members. I co-authored a Frontiers paper published in 2021.
The top-left figure shows a heatmap displaying the log10-transformed differences between apparent partition coefficients and published partition coefficients from inorganic mineral precipitation experiments. The top-right figure shows an NMDS ordination of the elemental ratio data. The bottom figure shows an NMDS ordination of elemental ratios for calcitic and aragonitic organisms only, separated by species.
Earlier Research Ventures
I also had the chance to contribute to research projects in the Sustainable LA - Grand Challenges (SLA) program, as well as the Sustainable Action Research (SAR) program at UCLA. As part of SLA, my team and I investigated and wrote a cost-benefit analysis on a potential water treatment facility for UCLA administration and stakeholders. As part of SAR, my team and I presented community gardens and food security solutions to UCLA administration. We also created a food-sustainability curriculum for the Geffen Academy at UCLA.
