Anthropogenic activities and nearshore communities
As part of The Jefferson Project at Lake George, I survey nearshore communities to understand the long-term consequences of urban developments on littoral environments. Each month, I survey the chemistry, algae, zooplankton, and macroinvertebrates at dozens of locations across the lake. These data are also coupled with high-frequency sensor data and food-web models to predict the effects of anthropogenic activities on ecosystem functions such as lake metabolism, and ecosystem services such as water quality and clarity.
The effects of invasive species
Invasive species that are established within an area are thought to negatively affect ecosystem function and disturb habitats, paving the way for new invasive species. To understand if invasive species compete or facilitate one another, I use functionally diverse invasive mollusks in experimental freshwater communities. In collaboration with Dr. Bill Hintz, we are also investigating how invasive species’ interactions are altered by anthropogenic factors such as road salt runoff and nutrient inputs. The goal of this research is to understand if we can make predictions about the effects that numerous invasive species will have in various environmental conditions. Future research efforts will investigate ways that we can improve niche modeling for invasive species in freshwater systems, and how new opportunities for invasions are being facilitated by human activities.
Road salt and freshwater salinization
The application of deicers like NaCl in the United States has increased from 1-2 million tons in 1950 to nearly 20 million tons in 2010. The increased costs of NaCl, potentially negative effects on human health, and the degradation of roadside habitats has driven agencies to seek alternative deicers and organic additives that make NaCl more effective. Numerous alternatives and additives are being applied across North America, without any knowledge of their effects in aquatic ecosystems. Some commonly used additives include organic distillation byproducts and beet juice byproducts. I am investigating the effects of road salt alternatives and additives on aquatic communities. These studies are extremely important for understanding how food webs, biodiversity, and species’ traits are altered by road salts and additives. I have found that alternative deicers and deicer additives alter food webs, change phosphorus cycles, increase microbial activity, and affect traits such as the timing of reproduction and emergence frequency. Future research will focus on the effects of these organic additives on microbial composition, and algal competition dynamics in freshwater systems. Additionally, the Relyea lab is collaborating with dozens of researchers around the world through the GLEON Network to experimentally test the effects of road salts on freshwater communities.
Species coexistence and patterns of diversity
Area, energy, and heterogeneity are often invoked as the primary drivers of species richness patterns. Yet, there are few tests of how these factors interact to affect patterns of species richness. I use experimental freshwater communities and a model zooplankton system to better understand the mechanisms by which environmental factors interact to affect species richness patterns.