Seasonal and spatial heterotrophic bacterial dynamics and phosphorus uptake and regeneration in Lake Mendota, WI
Bacteria community dynamics and metabolism are relevant to understanding the mechanism of phosphorus cycling in eutrophic lake systems. In Lake Mendota, WI, heterotrophic bacterial abundance as measured by catalyzed reporter deposition fluorescence in situ hybridization (CARD FISH), 33PO4-3 uptake and regeneration, 14C- leucine incorporation, alkaline phosphatase activity, and a suite of chemical analysis were measured during 2009 ice-off period in order to identify seasonal and spatial trends.
We are investigating the feasibility of employing thermal manipulation, achieved via whole-lake destratification, to extirpate the cold water exotic rainbow smelt (Osmerus mordax) from Crystal Lake, WI. We focus here on the engineering implications of raising the hypolimnion water temperture to exceed the thermal range of the rainbow smelt. An energy balance approach was used to determine the timing and duration of mixing efforts to maximize heat gain and minimize loss to the atmosphere.
The MIRADA project was launched in the fall of 2007 to establish a Microbial Biodiversity Survey and Inventory across all 13 of the major aquatic (marine and freshwater) Long Term Ecological Research (LTER) sites in the NSF US LTER Program. The long-term objective of our study is to document and describe baseline diversity and relative abundance data for both common and rare members of microbial communities and to relate this diversity to the underlying physical and chemical environment.
Lake ice seasonality (freeze day, breakup day, and ice duration) is closely related to climate change and variability. Trends and changes in variability and extreme events are apparent. The shared variance between mean anomalies of ice duration and Northern Hemisphere land air temperature over the last 150 years is r2 = 0.47. Mean trends are in the direction of warming. Ice duration has the steepest decline with mean trends (days/decade) of 1.7 over the last 150 years, 1.1 over the last 100 years, and 6 over the last 30 years.
The EcoTrends Project began in 2004 as a joint collaboration among the LTER Program, USDA Agricultral Research Service, and the USDA Forest Service with two goals: (1) to create a book illustrating trends in long -term data and showing the value of long-term data across a network of sites in addressing continental-scale questions, and (2) to make long-term biotic and abiotic data easily accessible through a common web interface with a focus on derived or aggregated data to allow cross-site analyses to be made.
Valuing non-market ecosystem services in Wisconsin's northern lakes: invasive milfoil, green frogs, fishing quality, water clarity, and open space
Most ecosystem services that affect our quality of life are not bought and sold in the market, and thus we do not know what people would be willing to pay for them. What are the economic benefits of a decrease in air pollution? What are the economic costs of a Eurasian water-milfoil invasion? Environmental economists have honed several techniques to estimate such values, including Contingent Valuation (CV), hedonic price analysis, and the travel-cost method.
Shoreline development and growth of largemouth bass (Micropterus salmoides): a cross-lakes comparison
Lakeshore residential development is associated with decreases in riparian zone vegetation and littoral zone structure, and increased angling effort. Depending upon the species and their associated body size, fishes may respond differently to these changes. Responses may be particularly difficult to predict for species that undergo marked changes in habitat use and diet over ontogeny, such as the popular sportfish largemouth bass (Micropterus salmoides).
Predicting annual lake characteristics with comparative and temporal models: the importance of neighboring lakes and lake history in minimizing prediction errors
Two major foundations of ecosystem science are comparative analyses and long-term studies. Here, we explore the capacity of long-term and comparative data to predict lake characteristics (LCs). We ask if a variable is best explained by neighboring lakes (NL; comparative data), lake history (LH; temporal data), or by some combination of the two.
Global change may alter the frequency and seasonality of temperate lake mixing, with unknown ecosystem consequences. Mixing disrupts vertical chemical and physical gradients, such as dissolved oxygen (DO) and temperature, which then influence biological dynamics. We conducted a mixing manipulation to observe whole lake response to episodic mixing, with a focus on the physical and chemical drivers of bacterioplankton communities. We mixed a temperate, dimictic bog lake during summer stratification.
Whole-lake changes resulting from intensive trapping of the invasive rusty crayfish (Orconectes rusticus): Can we induce a regime shift?
Rusty crayfish (Orconectes rusticus) are invasive in the upper Midwest United States. They often reach high densities and negatively affect native crayfish species, aquatic macrophytes, benthic invertebrates, and some fish populations. However, in some lakes rusty crayfish do not achieve high densities and do not negatively affect native biota. We conducted a whole-lake experiment designed to remove rusty crayfish from Sparkling Lake, a part of the North Temperate Lakes LTER site in Vilas County, Wisconsin.