Oklahoma State University

Curent Research Interests



Zooplankton Ecology

Zooplankton play an important role in aquatic ecosystems because they represent the major link in energy transfer from lower to higher trophic levels. We are currently working on several projects related to zooplankton community structure. First, we are working with colleagues from the US, Poland, Belarus, and Russia to better understand how local (e.g., abiotic and biotic processes within an individual site) and regional (e.g., movement and dispersal of individuals across the landscape) factors influence zooplankton community structure. This research is being conducted in Poland and is funded by the Polish Ministry of Science. Second, we are working with the US Army Corps of Engineers and Dr. Jim Long (Department of Natural Resource Ecology and Management, OSU) to determine if created shallow water habitats (chutes and backwaters) in the lower Missouri River support higher levels of zooplankton production than mainstem habitats. Most native fish use zooplankton during at least some part of their life cycle; therefore, it is important to determine if these created habitats are providing valuable prey resources.


Invasive Species

Over the past several years our lab has conducted research on the ecology and management of aquatic invasive species. Recently this research has focused on the invasive zebra mussel (Dreissena polymorpha). While the impacts of zebra mussels on natural lakes in the northeastern part of the US have been well document, relatively little was known about how they impact human-made reservoirs that dominate Oklahoma and other southern states. We have been studying population dynamics of zebra mussels in several Kansas reservoirs for the past 15 years and have conducted several laboratory and field studies to determine how zebra mussels affect nutrients and phytoplankton in eutrophic reservoirs. These results have important implications because they suggest that very productive systems with high levels of nutrient enrichment may limit the success of this invader.  We are also currently developing models that can be used to assess vulnerability of individual reservoirs to invasion by zebra mussels.


Wetland Ecology and Management

Wetlands are one of the most productive, but disturbed habitats in the US.   Relative to other aquatic habitats, wetlands have been less studied and additional information is needed about wetland condition and function in order to develop effective management strategies and restoration plans. With Drs. Craig Davis (Natural Resource Ecology and Management, OSU) and Mona Papeş (Zoology, OSU) we have received funding from the US Environmental Protection Agency to better understand the ecology and function of wetlands. We are currently working on projects to define reference wetland conditions and developing GIS models that can be used to predict wetland conditions from landscape characteristics in the absence of field collected data. Combined, the results from our research should not only help us to better understand ecosystem function in wetlands, but also better manage, restore, and protect these important ecosystems.

Eutrophication in Lakes and Reservoirs

Eutrophication, the enrichment of aquatic ecosystems with plant nutrients including phosphorus, is one of the leading causes of pollution in aquatic ecosystems. One of the most significant consequences of nutrient enrichment is the development of cyanobacterial blooms that can produce algal toxins and/or taste and odor compounds that cause drinking water to taste and smell bad. Over the past several years, our lab has completed several projects related to the ecology and management of cyanobacteria. We are also interested in understanding how phosphorus cycles in reservoirs and have studied internal phosphorus loading from anoxic sediments. We have shown that the amount of phosphorus that is released from anoxic sediments can be predicted from the land use characteristics of a reservoir – more phosphorus is released from sediments in reservoirs that have a greater percentage of cropland in their watershed (Carter and Dzialowski, 2012).