Research

Our research examines how aquatic organisms and ecosystems are impacted by nutrient and anthropogenic stressors. We use a variety of experimental approaches to answer questions ranging from highly controlled laboratory experiments to observational studies in lakes. Questions, hypotheses, and methods are framed within the ecological/biological stoichiometry framework, which facilitates the atom to ecosystem approach by tracking elements through abiotic and biotic pathways of lake ecosystems. Some common methodologies we use include measuring nutrient concentrations, elemental composition of aquatic organisms, phytoplankton pigment concentrations, cyanotoxin concentrations, microscopy, and different omics techniques.

Below are examples of projects that have been published or are current active research.

Ecophysiology of cyanobacteria

Past research has focused on how nutrient such as nitrogen (N) and phosphorus (P) affect the growth and cyanotoxin production in both N-fixing and non-N-fixing genera

Current research

  1. How current and past nutritional environments affect the growth, pigment physiology, N-fixation rates, and ionome (the whole elemental composition) in N-fixing cyanobacteria populations

  2. Examine how different light, temperature, and nutrient concentration, ratios, and form affect the growth-tradeoff of N-fixing cyanobacteria

  3. Determine if common xenobiotics at environmental relevant concentrations affect the growth, elemental composition, and cyanotoxin production of common harmful cyanobacteria genera.

  4. Understand the prioritization of nutrient allocation to growth, maintenance, and toxin production in both N-fixing and non-N-fixing cyanobacteria

Controls and limits of primary and secondary production in lakes and reservoirs

Past Research

  1. Determining the limiting nutrient through phytoplankton growth bioassays and sampling the microbial community to see how the community responds to different nutrient limitations.

  2. Determine how the lake nutrient environment affects the growth, nutrient use efficiency, and elemental composition of field caught Daphnia

Current Research

  1. Use high frequency continuous monitoring to examine how the vertical mixing dynamics affects nutrients and phytoplankton biomass and elemental composition

  2. Explore how hypolimnetic nutrient additions affect the growth and cyanotoxin concentrations phytoplankton communities

How food quality and anthropogenic stress affect the metabolism and ecophysiology of Daphnia

Past research has focused on two areas

  1. Probing metabolic pathways to identify potential nutritional biomarkers in Daphnia.

  2. Examining how common aquatic contaminants affect the metabolism of Daphnia using metabolomic techniques

Current research

  1. Use the Stoichiometric Ecotoxicology framework to examine ecophysiological responses of zooplankton to both nutritional and contaminant stress