Research Interests

Aquatic ecology; community ecology; trait-based ecology; phytoplankton ecology, physiology and evolution; microbial ecology, global change and harmful algal blooms

Current Research

I am interested in how the interplay of biotic and abiotic factors structures phytoplankton communities in both freshwater and marine environments. Currently our lab focuses on the following questions:

Effects of Temporal and Spatial Heterogeneity on Phytoplankton Communities
We have been looking at how fluctuating resources such as light and nutrients affect competition and coexistence in phytoplankton. We are also interested in identifying and testing the mechanisms leading to heterogeneous vertical distributions of phytoplankton, such as subsurface chlorophyll maxima.

Ecological Traits, Trade-offs and Community Structure
We seek to understand how ecological traits and trade-offs determine plankton community structure under different environmental conditions. Using laboratory experiments and data analysis, we characterize growth and resource utilization traits, trade-offs and ecological strategies of major phytoplankton functional groups from both freshwater and marine environments. We then use mechanistic models, including adaptive dynamics techniques, to explain and predict the occurrence and dominance of these phytoplankton groups, the evolution of observed trait distributions and trade-offs between key functional traits. We also test model predictions in laboratory experiments with phytoplankton communities.

Broad Patterns in Plankton Diversity and Trait Distributions
We are interested in latitudinal and other large-scale patterns of phytoplankton diversity and distributions of key functional traits, such as cell size, resource utilization traits and thermal tolerances in marine and freshwater phytoplankton.

Global Change and Harmful Algal Blooms
I have a keen interest in how different aspects of the human-induced global change will impact aquatic ecosystems, phytoplankton communities in particular. Using experiments, field observations and models we investigate how diverse global change stressors, such as increasing temperature and nutrient loading, may alter phytoplankton community structure and dynamics, e.g., increasing the frequency and severity of Harmful Algal Blooms (HABs). We also collaborate with engineers in developing robotic fish capable of autonomous monitoring of HABs.

Invasive Microbes
We investigate the ecology of invasive, potentially toxic cyanobacteria, spreading into temperate latitudes from the tropics. We focus on determining the traits that make these cyanobacteria invasive and on community and ecosystem consequences of microbial invasions.

Nitrogen-fixers in phytoplankton communities
Because N-fixers are important players in both freshwater and marine ecosystems, we need to understand what governs their distributions and dynamics. We use experiments, continental-scale data analyses and models to understand how absolute and relative levels of nutrients, light, temperature and other variables determine the abundance of N-fixers in phytoplankton communities and their interactions with the rest of phytoplankton.

Lake Baikal
Lake Baikal in Siberia is the oldest and the most voluminous lake in the world, with an incredible diversity of endemic species. In collaboration with S. Hampton, M. Moore, L. Izmestyeva and E. Silow, we explore planktonic food web structure and dynamics, with an emphasis on interactions between endemic and cosmopolitan species and their responses to changing climate.