2012 Project Descriptions
Project 1 - Kathy Shea - Ecology of the St. Olaf Natural and Agricultural Lands 2012
Students working with me will focus on applied research on the St. Olaf Natural Lands studying biodiversity, growth patterns, and soil characteristics in forest and prairie ecosystems restored after agricultural use. We will also work on maintenance of restored forest and prairie areas, and examine the effects of different agricultural practices on soil quality and agricultural yields.
We documented an increase in prairie biomass production after the large prairie burn in fall 2010. We will examine biomass production in 2012 and determine if it is linked to burn pattern, plant species diversity, soil nutrient levels or soil respiration. We will also measure carbon and nitrogen content in plants and soils to track changes in carbon stocks and nutrient use. Pollinators are critical to the success of many species in the prairie and we plan to collect baseline data on pollinator diversity.
As part of the long-term maintenance of the Natural Lands we will work on several projects. Invasive species are a constant problem in managing natural areas and we will focus on removal of buckthorn, reed canary grass and garlic mustard. As the size of the natural lands has increased more wildlife is using the area. We will monitor deer exclosures with the long-term goal of determining the effects of deer herbivory on tree seedling growth. Students will learn to identify the possible bird species using a series of nest boxes set up as a bluebird trail and will monitor nesting success of bluebirds and other species using the nest boxes. We will also set up a series of 20 x 20 m plots for long-term study of tree growth. Once the plots are set up tree diameter will be measured and future measurements will document tree growth and carbon storage.
The agricultural studies involve working with local farmers to document soil characteristics, nutrient run-off from fields and optimum levels of fertilizer needed to both make a profit and reduce nutrient run-off from fields. Research on soil properties, plant nutrients, farming methods, and economic returns provide “on-farm” research to help farmers make appropriate decisions about nitrogen management. Results will be compared among farms with different farming methods from conventional tillage, to no-till and sustainable farming such as the rotational production system developed by the Rural Enterprise Center.
Students will have the opportunity to explore their own research questions related to the projects described and will work with other St. Olaf or REU students. In addition to an interest in fieldwork and a biology background, experience with GIS and/or statistics would be helpful. Students working during the summer will be encouraged to use some of this research as the basis for an independent research project during the academic year.
Project 2 - Jean Porterfield and John Schade - Linking Genetics and Environmental Science
Wetland ecosystems are an important landscape feature, performing myriad ecosystem services, including purifying water and supporting biodiversity. Wetlands are also a source of trace gases such as methane (CH4) and nitrous oxide (N2O), both of which are powerful greenhouse gases. On the St. Olaf College campus, 15 wetlands have been restored since 1992 to preserve biodiversity and to mitigate runoff of nutrients and other pollutants to downstream ecosystems. These wetlands range in size from small, ephemeral prairie potholes to large permanent ponds, and fluctuate substantially in depth of surface water throughout the year. Although the benefits of wetland construction are generally thought to outweigh the costs of greenhouse gas emissions, this is still controversial, particularly given the possibility that global warming may stimulate higher rates of trace gas production as wetlands get warmer.
A complex set of microbial processes contributes to net production of CH4 and N2O in wetland soils. Our objective in this work is to investigate CH4 and N2O dynamics in wetland soils on the St. Olaf College campus using laboratory and field experiments to estimate rates, and molecular analyses to identify the organisms involved and to link process rates to microbial diversity and the presence of specific functional genes. We also plan to explore the possible use of 13C and 15N natural abundance and isotopic tracer experiments to measure process rates, and to identify when and where these processes are significantly influencing trace gas emissions.
These experiments will be conducted on a variety of wetlands that differ in size, source of organic matter inputs, dissolved oxygen concentrations and nutrient loading. We also plan to assess temporal variation, in particular the influence of seasonal changes in the depth of water, as water content of soils has been identified as an important driving variable for both methanogenesis and methanotrophy. Stable isotope experiments take advantage of the fact that the two pathways of methanogenesis (acetoclastic and hydrogenotrophic) produce CH4 with different levels of 13C under certain conditions. This allows for the potential use of natural abundance data and mixing models to estimate relative contributions.
Students working on this project will learn and develop diverse research skills, from field sampling to biogeochemistry to molecular genetics. They will use the information gathered to develop hypotheses to improve our understanding of the factors that influence greenhouse gas emissions of wetlands and the implication of these processes for wetland reconstruction.
Project 3 - Paul Jackson - Ecosystem assessment of an impaired coldwater brook trout stream
Brook trout are native to Minnesota, but have been lost or displaced from many of their native habitats due to pollution, habitat destruction and competition with non-native species. Several streams in southeastern Minnesota, however, are currently under threat of pollution, nutrients, sedimentation, and E. coli, mostly from surrounding agriculture. A local brook trout stream is no exception; Rice Creek (also known as SpringBrook), is currently listed as impaired for nitrate, turbidity, and E. coli, largely due to its agricultural watershed. The student involved in this project will complete a monitoring program for temperature, a longitudinal temperature profile, turbidity (i.e. sedimentation), and nutrients in the brook trout stream to help us better understand current conditions and identify potential “problem areas” in the stream. Building on the results from the previous year we will also investigate some aspects of trout ecology - including determining essential habitat/spawning areas and food sources. The information gained from this study will provide valuable insight and background that will help guide future restoration and conservation efforts in this stream. The student will be advised by Dr. Jackson, working closely with local government units, non-profit watershed partnerships, Trout Unlimited and the Minnesota Department of Natural Resources.
Project 4 - Steven Freedberg - Ecological barriers to interspecific gene flow in freshwater turtles
In the absence of barriers to gene flow, interspecific hybridization is predicted to result in the loss of genetic distinctness between the hybridizing species and the ultimate extinction of one parent species. Recently, my lab has identified a complex of freshwater turtle species (Graptemys sp.) that are capable of hybridization and gene introgression in parts of their range. This gene exchange is noteworthy in light of the fact that the species diverged several million years ago and show extensive morphological and behavioral divergence. These turtles are characterized by distinct ecological niche differentiation, with dietary specialization ranging from molluscivory to herbivory to insectivory.
We are interested in examining the consequences of recent secondary contact and hybridization in these turtles in a large area of sympatry in Weaver Dunes, Minnesota, where phenotypic observations indicate that hybridization is ongoing. Specifically, if hybrids are trapped in an “adaptive valley” between dietary specializations, they may not be optimally suited to exploit either resource, presenting an obstacle to gene flow between species. The proposed project will utilize genetic markers for the mitochondrial control region and a nuclear intron to quantify the extent of hybridization in this region. Tissue samples will be taken and d13C and d15N analyzed with the Isotope Ratio Mass Spectrometer in order to establish dietary differences among species and in hybrids. Students will collect samples in the field and run laboratory analyses as well. Students will analyze the results and will discuss with Dr. Freedberg ways to modify and add to the experimental design, particularly with respect to quantifying fitness correlates in hybrid animals and novel application of stable isotopes. The results can shed light on the factors affecting reproductive isolation and speciation in nature.
Project 5 - Jay Demas - Ecological Light Pollution and Circadian Photoreception
Most organisms organize their behavior on a daily schedule. For example, nocturnal species, such as mice, are relatively active at night (foraging for food, mating, etc.) and are relatively quiescent during the day. An internal clock in the brain, the suprachiasmatic nucleus (SCN) regulates the timing of these daily behaviors. The roughly 24 hour periodicity of the clock is intrinsic. However, to be useful this clock must be synchronized with the outside world. A small group of neurons in the retina, called mRGCs, are wired directly to the SCN and report light levels indicating whether it is currently daytime or nighttime, a process termed photoentrainment. These neurons express melanopsin, a light sensing protein that makes them intrinsically photosensitive.
This evolutionarily ancient system for sensing daily rhythms in environmental lighting evolved in a world free from the pollution of artificial lighting. Light pollution is growing faster than the human population and recent changes in lighting technology (e.g. LEDs) have lead to changes in both the amount and spectral content (i.e. color) of this pollution. The ecological impact of disrupting circadian rhythms is poorly understood, but is likely to chronically stress some species, modify the relative timing of daily behavior between species, and alter the onset of seasonal behaviors such as migration.
Given mRGCs’ ability to see without additional input from other retinal neurons, it is surprising that mRGCs are, in fact, extensively connected to the rest of the retina. They receive a constant barrage of information from other retinal cell types about the light striking the retina. An important open question is determining whether and how this input from other neurons in the retina improves the estimate of light levels made by mRGCs. We will tackle this question using mice as a model system to take advantage of available genetic mutants. We will use multielectrode arrays and pupil constriction to record light responses from mouse mRGCs with and without input from other retinal neurons.
Project 6 - Mike Swift - Zooplankton Ecology in Northern Lakes
Zooplankton are the herbivore trophic level in lakes and form the important link between algae and fishes. Zoplankton have incredibly interesting behavior. Several vertically migrate in the water column -- they swim from deep in the lake where it is dark to the surface each evening to feed and swim back down to avoid visually-feeding fishes at dawn. Some, like Chaoborus and Leptodora are predators that feed on other zooplankton species. Some, like Polyphemus, swim around and around together in large "swarms" near the shore. My students will have the opportunity to study these or other aspects of zooplankton ecology in Low Lake and nearby beaver ponds in northern Minnesota. Research projects will be conducted in a semi-wilderness setting at the Coe College Wilderness Field Station (WFS) near Ely, MN. My students must be willing to study aquatic biology by canoe, live and work in an atmosphere of intensive teaching and research, and work independently and cooperatively. My students will begin their research on campus (1+ weeks), complete their field sampling at the WFS where I'll be teaching aquatic ecology (5+ weeks) and complete their project on campus (2+ weeks). Potential research projects include the following: the effects of prey size and swimming ability on Chaoborus predation; patterns of diel vertical migration by Chaoborus larvae or Daphnia; characteristics of swarming behavior of Polyphemus; zooplankton biodiversity -- distribution of zooplankton taxa in the Low Lake area.
Project 7 - Diane Angell - Small Mammals and Prairies
Next summer we will continue projects trapping small mammals in remnant and restored prairies in and around Northfield. Prairies are one of our most endangered biomes and small mammals play crucial roles as predators, prey, seed dispersers and grazers.
We will have several goals this summer. We will trap at multiple locations to look at the species composition of remnant and restored prairies. We will explore the food resources that different species of small prairie mammals rely on by using stable isotope analysis of fur clippings. Finally we will continue to focus on the prairie vole (Microtus ochrogaster), a species categorized by the state of Minnesota as a species of special concern. The prairie vole has disappeared from much of southern Minnesota as prairie has been converted to cultivated land. Remaining populations are essentially isolated on small patches of prairie remnants. Research students need to be independent and motivated! Evenings setting traps and early morning trap checks are required.
Project 8 - Diane Angell - Biodiversity and Sustainable Agriculture
This project will be the start of a large collaborative group working on longer term research related to sustainable agriculture in and around Northfield. Understanding and quantifying the effects of different agricultural practices on biodiversity continues to be important as farmers and government entities consider the costs and benefits of these practices. We will collaborate with other St. Olaf faculty to compare the pollinator, bird and small mammal diversity on different farms. Pollinator surveys will focus on bumblebees (Bombus spp.) and will follow up on surveys conducted during the summer and fall of 2011. Birds will be surveyed visually and small mammals will be live trapped. A knowledge of area birds and a willingness to learn the different Minnesota bumblebees will be important. Research students also need to be flexible and comfortable working with a variety of people with different backgrounds as they interact with local farmers.
