Water levels in several NTL-LTER study lakes reached historical lows during the summer of 2009, owing to general decreases in precipitation and increases in total evaporation during the ice-free seasons of 1998-2009. Balancing a water budget for temperate lakes is difficult, requiring detailed measurements of precipitation, groundwater fluxes and surface flows to estimate the amount of water lost through evaporation. The NTL-LTER Trout Bog site has long-term records of meteorological conditions, including terrestrial and solar radiation from ...

Emerging research shows that hot spots for biological processing of elements such as nitrogen and phosphorus can be important in water bodies. We are exploring the importance of potential hot spots as well as cold spots for biological processing of these nutrients. The north temperate lakes (NTL) LTER has immediate access to diverse water bodies, including not only lakes but also abundant streams, rivers, and wetlands of various sizes and shapes. We are studying these habitats to answer questions related to ecosystem structure, functioning, hydrology, and biogeochemistry, with an emphasis on habitats ...

My research is generally concerned with understanding the impacts of changing environmental conditions on natural and managed vegetation ecosystems. To perform my research I use a dynamic global vegetation model which simulates ecosystem processes such as carbon, water and energy cycling at both large and small spatial scales. Future work as a PhD student will investigate the impact of land management as well as changing climate on landscapes within the Yahara Watershed. Other general interests include the relationship between climate and vegetation and the role of computer modeling within environmental science.

Part of this research is about long-term heterotrophic bacterial community patterns in Lake Mendota, Wisconsin. Heterotrophic bacteria are responsible for nutrient cycling in aquatic systems. These preliminary abundance data indicate seasonal patterns in bacterial taxa (OTU’s). We will perform time-series analysis with these data together with environmental variables (water chemistry and meteorological factors) in order to investigate drivers of the bacterial community ...

Eutrophication of surface waters is of increasing concern worldwide, and is the most significant water quality issue in Lake Mendota, WI. Water quality in Lake Mendota, WI has implications for human health, aquatic organisms, and recreation.

How do lake levels affect invaded ecosystems in northern Wisconsin? Lake levels in northern Wisconsin are currently at historic lows, and climate models predict this trend to continue.  Lowered lake levels affect littoral habitats and associated communities; however specific effects on native and invasive species are poorly understood ...

Can an ecosystem dominated by an invasive species be forced into an alternate stable state of low invader abundance? Invasive rusty crayfish (Orconectes rusticus) adversely affect native biota when present at high densities; however, at low densities their effects are minimal.  Lakes with high and low densities of rusty crayfish may represent alternate stable states, meaning that crayfish at low densities could be maintained ...

Rainbow smelt are an invasive fish species that was first detected in the Laurentian Great Lakes in the 1920’s and have since spread to numerous inland lakes. As of 2005, rainbow smelt have invaded 24 inland Wisconsin lakes and have the potential to spread to many more. In Wisconsin’s Northern Highland Lake District, rainbow smelt have been associated with several negative impacts on lake food webs.  For instance, rainbow smelt have been associated with shifts in zooplankton community structure, reductions in yellow perch densities, extirpation of ciscoes, and walleye recruitment failure.

Lake Mendota is an eutrophic lake that harbors an abundant and diverse array of bloom-forming cyanobacteria (also called blue-green algae). The cyanobacterial community is highly variable, contains numerous nitrogen (N2) fixing and non-N2 fixing genera, and has multiple genotypes capable of forming ephemeral, and possibly toxic, blooms. Nutrients play an integral role in structuring the cyanobacterial community, but it is unclear how phosphorus (P), nitrogen (N), and trace metal limitation might influence seasonal to decadal community dynamics ...