Research Interests

Photo credit: Shimi RiiPopulation Dynamics of Photosynthetic Picoeukaryotes in the Oligotrophic Oceans

My Ph.D. research in the Church Lab at the University of Hawai’i at Manoa focuses on the population dynamics of eukaryotic phytoplankton and their roles in the carbon cycle in the Pacific Ocean. I conduct time-series and mesocosm experiments to find out their nutrient and habitat preferences (such as light and temperature). For Chapter 1 of my research, I found that photosynthetic picoeukaryotes may be integral components of the oceanic carbon cycle because of their really high per-cell rates of primary production! This work was recently published in Limnology and Oceanography. As part of this project, I have participated on research cruises for the Center for Microbial Oceanography: Research and Education (C-MORE) and the Hawaii Ocean Time-series (HOT) Program.

Specialties: Photosynthetic pigments, primary production, molecular analyses of the 16S and 18S rRNA genes, Illumina next-generation sequencing, phytoplankton isolation and culturing, flow cytometry, fluorometry, microscopy

This research has been funded by the National Science Foundation.


0319_4Exploring the Ecology of reoccurring associations between Trichodesmium spiralis and pennate diatoms

Together with my undergraduate scholar Lisa Hall, we are working to characterize this potentially symbiotic relationship between a commonly found nitrogen fixing cyanobacteria and eukaryotic phytoplankton. We plan to examine this relationship through several microscopy methods and molecular tools.

Specialties: Epifluorescence, confocal, and scanning electron microscopy, molecular analyses with rbcLhetR, and 18S rRNA genes, molecular cloning

This research has been funded by the National Science Foundation and Undergraduate Research Opportunities Program (LH).


IMG_0150Microalgal Lipids as Feedstock for Biofuel

I worked as a Biochemical Research Specialist for Cellana, a JV with Royal Dutch Shell from 2007-09, where I performed large-scale growth experiments of microalgae in photobioreactors and open ponds to discover the ideal algal candidate for biofuel.

Specialties: Fluorometry, neutral lipid quantification and characterization, total lipid extraction, starch analysis


eddy2Nutrient-Phytoplankton-Export Dynamics in Hawaiian lee Cyclones

For my M.S. thesis research, I studied mesoscale eddies that occur seasonally in the lee of Hawai‘i due to topography and strong tradewinds. We observed elevated levels of macronutrient concentrations and phytoplankton composition, but minimal particle carbon export, as highlighted in Benitez-Nelson et al. (2007) Science. My work on the evolution of the bloom within one of these eddies was published in Rii et al. (2008) DSR II.

Specialties: Photosynthetic pigments, macronutrient analyses, particle interceptor traps, particulate C, N, P, and Si

This research was funded by the National Science Foundation.


Cancer magisterOptimal foraging behavior in juvenile Cancer magister

Before I became an oceanographer, I was trained as a marine biologist at UCLA. One of my first research projects was to investigate the foraging behavior of juvenile dungeness crabs on Nutricola clam distributions in mudflats. I’ve also studied monkeyface prickleback homing behavior using PIT tags, maintained Capitellid tube worm cultures, examined chemical communication cues using a video motion analyzer, and tracked parrotfish feeding on coral re-growth.

For a full list of my research activities and publications, check out my CV.