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1) Nutrient pollution in aquatic ecosystems.
Anthropogenic nutrient enrichment impairs integrity and alters the structure and function of aquatic ecosystems. While historic research has addressed how nutrients like nitrogen and phosphorus stimulate autotrophs (algae), nutrient pollution can also stimulate heterotrophic microbes (fungi and bacteria) to alter the flow of detritus-based energy and nutrients in ecosystems. However, we still lack understanding of how detritivore fitness and functional roles in ecosystems (nutrient recycling, decomposition) may change with nutrient enrichment. Understanding the effects of nutrients on detritus and detritivores is a focal theme of our research, toward advancing management and policy regarding nutrient pollution in freshwaters. |
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2) Mechanisms and ecology of aquatic priming effects
The “priming effect” involves additions of fast-decomposing labile organic matter to a system which in turn affects microbial acquisition and breakdown of slow-decomposing recalcitrant organic matter. Well-studied in terrestrial settings, priming remains poorly tested in aquatic settings but may strongly affect carbon and nutrient cycles, including breakdown of detritus. Evidence indicates algae provision labile carbon to decomposer fungi and bacteria on leaf litter, to possibly stimulate or inhibit litter decomposition. We are very interested in testing the mechanisms of priming and how priming effects respond to environmental change. |
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3) Bridging ecological stoichiometry and nutritional geometry
As distinct contemporary frameworks of organism nutrition, ecological stoichiometry (ES) and nutritional geometry (NG) offer unique approaches to understand nutritional constraints in ecological processes. In particular, NG uses state-space models, rooted in a currency of macronutrients including protein and carbohydrate, to focus on individual-level behavior, nutritional regulation, and fitness. In contrast, ES uses the currency of elements, often carbon, nitrogen, and phosphorus and their relative availability expressed as ratios, to link trophic levels and scales of biological organization. In our work, we seek complementary approaches from NG and ES to improve understanding of animal nutritional ecology. |
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4) Understanding animals' roles in ecosystem nutrient cycles
Egestion, or defecation, is a significant pathway of animal nutrient release. This particulate waste pathway is distinct from excretion of dissolved nutrient wastes. We are interested in the role of animal egestion in freshwater nutrient cycles, especially the diversity, significance, and ultimate fates (such as microbial breakdown) of particulate egesta, and how these attributes compare to those of dissolved excreta. This work will advance science linking animal traits and diversity with ecosystem functions. |
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