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REU Mentors and Projects

2016: Biosphere-Atmosphere-Hydrosphere Interactions in a Changing Global Environment

Below are the research projects and faculty who worked with REU students in the summer of 2016. Click on a topic to learn more about a faculty member's research.

Mobilization of Carbon and Mercury from Forests to Lakes

Paul Drevnick, University of Michigan 

Luke Nave, University of Michigan 

Mobilization of Carbon and Mercury from Forests to Lakes

Mercury is a notoriously hazardous pollutant that accumulates in fish, posing health risks to humans who eat fish. From a peak in the 1980s, concentrations of mercury in fish in the Great Lakes region have declined – due to pollution controls – but are again on the rise. The rise, we hypothesize, is a result of changes in the coupled biogeochemical cycling of carbon and mercury. REU students have the opportunity to contribute to this project via collecting data in real-time and/or by a paleolimnology approach to determine the role of greater export of DOC from watersheds in mobilizing mercury to lakes. Additional project possibilities include studying relationships between geomorphology, soil development and biogeochemistry, effects of soil-dwelling organisms on carbon cycling, and wetland ecosystem structure and function.

Effects of introduced zebra mussels on dragonfly populations

Ola Fincke, University of Oklahoma

Invasive species and hydrosphere-biosphere interactions:  Effects of introduced zebra mussels on dragonfly populations

Freshwater ecosystems, a crucial part of Earth’s hydrosphere, are challenged by a diverse array of invasive species.  One of the most problematic in North America is zebra mussels, which adhere to virtually any hard surface, including the exoskeleton of dragonflies. Because dragonflies are important predators, both as larvae and adults, negative effects of colonization by introduced zebra mussels could have direct impacts on aquatic and terrestrial food webs. 

An REU student could quantify the consequences of zebra mussel colonization on dragonfly larvae, as well as the relative abundance of the adult dragonflies as part of a long-term monitoring program at UMBS. REU students could work on various effects of invasive zebra mussels on the behavior and fitness of native dragonflies (Hagenius brevistylus, Macromia illinoisensis), and their responses to this novel selective pressure.

UMBS Forest Ecosystem Study

Chris Gough, Virginia Commonwealth University

Luke Nave, University of Michigan

Chris Vogel, University of Michigan

UMBS Forest Ecosystem Study

Forests of northern Michigan provide ecosystem services including the capture and sequestration of carbon, retention of nutrients, maintenance of organismal and ecosystem diversity, and protection of surface and ground water quality. Our collaborative team conducts research on the scientific underpinnings of these ecosystem services, with particular emphasis on landscape and community ecology, forest succession, carbon and nitrogen biogeochemistry, botany and mycology. 

We conduct this research in a variety of settings, including a large-scale experimental treatment forest (stem girdling of >6700 trees in 2008) and a pair of long-term chronosequences (stands aging from 20 to >200 years old), utilizing proven methods to understand forest functioning at all stages of succession.

Student collaborators on the UMBS Forest Ecosystem Study team have numerous research options. Some examples include: 1) how shifts in forest composition and structure alter forest carbon cycling; 2) mechanisms behind sustained high rates of carbon storage in a maturing forest; 3) fungal processes controlling decomposition and tree nutrient supply.

Organic Atmospheric Aerosols Derived from Michigan Forests

Robert Griffin, Rice University

James Flynn, University of Houston

Organic Atmospheric Aerosols Derived from Michigan Forests

Atmospheric particulate matter, including aerosols, can contribute to the heat budget and impact air quality in forested areas, but how they do so depends on their composition. Both animals and plants are affected by the impacts of these particles, yet there is much we have to learn about how particles form before we can predict composition, properties, and impacts. Aerosols arising from biogenic (e.g. from trees) and anthropogenic volatile organic compounds, such as those found in Michigan forests, present interesting challenges, some of which result from a lack of measurements of the precursors and products of the chemistry from which they arise. This project will study some aspects of the chemistry through measurement of precursors and products using a mobile sampling facility as part of a north-south transect of the United States.

Student collaborators will participate in a summer field campaign at the PROPHET site at UMBS and will assist researchers with the collection and analysis of data using state-of-the-art instrumentation and numerical techniques to investigate the role of nitrate radical chemistry in particle formation by determining organic nitrogen content in aerosols.

Rising Carbon Dioxide and Plant Defense Against Herbivores

Dave Karowe, Western Michigan University

Rising Carbon Dioxide and Plant Defense Against Herbivores

Rising atmospheric carbon dioxide, caused by the burning of fossil fuels, is causing plants to have higher levels of carbon but lower levels of nitrogen in their leaves. Today, most plants can respond to attack by herbivores by rapidly increasing their levels of chemical defenses, but this is a nitrogen-intensive response because it requires rapid synthesis of RNA and enzymes. A student working with me could investigate whether, when grown under the CO2 levels our atmosphere will have at the end of the century, plants 1) have higher pre-attack levels of carbon-based chemical defenses, due to higher carbon content of leaves, but 2) are less able to respond to attack by increasing levels of these same chemical defenses, due to lower nitrogen content of leaves.

 

Global Atmospheric Change and Carnivorous Plants

Dave Karowe, Western Michigan University

Carnivorous plants, such as pitcher plants and sundews, use their leaves to capture both carbon and nitrogen. However, they experience a trade-off between these two goals, since green tissue is best for photosynthesis but red tissue is best for prey attraction. An REU student could determine whether, in response to altered availability of atmospheric carbon and/or nitrogen, carnivorous plants are able to adjust their investment in carbon capture traits vs. nitrogen capture traits. For instance, an REU student could design a study to ask whether pitcher plants alter the red:green ratio of their tissues when exposed to future higher CO2 levels and/or future higher amounts of atmospheric nitrogen deposition.

How does wetland restoration alter greenhouse gas flux?

Beth Lawrence, DePaul University

Shane Lishawa, Loyola University Chicago

How does wetland restoration alter greenhouse gas flux?

Hybrid cattail (Typha X glauca) is an opportunistic wetland invader that reduces native biodiversity and alters ecosystem functioning.  During the 2015 growing season, we will be implementing large scale (60x60m plots) restoration treatments (biomass harvest, mow, control) in Typha-dominated Cheboygan Marsh, MI to promote native marsh biodiversity recovery and create a source of renewable energy.  However, little is known about how restoration will influence greenhouse gas fluxes (CO2, CH4, N2O).   Removal of Typha biomass may reduce the availability of labile organic matter and thus reduce greenhouse gas emissions, whereas mowing may increase carbon availability and result in greater flux rates.  

An REU student working on this project will design an experiment to test how Typha restoration treatments alter field-based greenhouse gas fluxes and will gain extensive field and laboratory experience.

New Resources, New Choices for Grazers in Altered Aquatic Foodwebs

Rex Lowe, Faculty Emeritus, Bowling Green State University

New Resources, New Choices for Grazers in Altered Aquatic Foodwebs

The increased growth of aquatic vascular plants in aquatic ecosystems following exotic mussel-facilitated water clearing provides habitat for epiphytic periphyton. This research will explore links in the enhanced littoral food web. Specifically we will explore resource partitioning among invertebrate grazers on epiphytic periphyton in the littoral zone.

Interaction of Stream Flow and Benthic Organisms

Paul Moore, Bowling Green State University

David Edwards, Bowling Green State University

Interaction of Stream Flow and Benthic Organisms

Stream flow is the primary abiotic factor influencing stream ecosystem function. Physical forces associated with the flow can affect in-stream organisms. However, natural systems have increasingly been under siege through flow alterations in the form of dams, land use, and storm events through global climate change. An understanding of the direct and indirect pervasive effects associated with the natural flow regime is crucial to identifying and predicting responses of organisms (and by extension ecosystem processes) to flow alterations. How organisms respond to flow can also enhance our interpretation of any evolutionary adaptations to flow. All of this is vastly important when we consider human influence to natural systems in the context of global climate change.

A student with this theme could in-depth examine benthic organisms above and below dam sites, or the response(s) of organisms to changes in a flow regime (velocity, magnitude or rate of change, drought, etc.). Students could also examine how flow physically allocates resources in different habitats, or some aspect of lake versus river invertebrate ecology.

Forest Floor Food Web Ecology

Shannon Pelini, Bowling Green State University

Forest Floor Food Web Ecology

We look forward to collaborating with a student interested in working at the intersection of global change and community and ecosystem ecology using forest floor food webs. We examine the responses of forest floor invertebrates (worms, millipedes, insects) to environmental changes. In particular, we aim to determine how climate-induced forest disturbance and corresponding changes in temperature mean and variance impact 1) invertebrate interactions with other organisms and 2) nutrient cycling processes they control such as decomposition and nutrient leaching. A student working with us will have the opportunity to participate in field surveys and field and lab experiments.

Climate Change and Wetland Ecology

Robert Pillsbury, University of Wisconsin – Oshkosh

Climate change and wetland ecology

Virtually all wetlands are already affected by climate change, and will be more strongly affected in the future. Water temperatures will rise, water levels may fall (or rise), lake summer stratification periods will increase, and the chemical composition of freshwater may change. All of these changes may impact organisms that live in lakes, ponds, rivers, and streams, including algae, zooplankton, and mollusks. Effects will certainly differ among taxa, and may also differ among feeding guilds, and between native and invasive species.

An REU student working with me could choose among a variety of questions.  For instance, a student might ask whether warming of lake water will favor certain species of algae, aquatic plants, and/or zooplankton over others.  A student could also ask whether warming of lake water will have different effects on native mollusks, such as clams, than on invasive mollusks, such as zebra mussels.

Climate Change, Biosphere-hydrosphere Interactions, and the Ecology of Damselflies

Steve Pruett-Jones, University of Chicago

Climate change, biosphere-hydrosphere interactions, and the ecology of damselflies

Because they develop as larvae in aquatic environments and live as adults at the land-water interface, damselflies are strongly influenced by both the hydrosphere and the biosphere. Climate change is likely to affect many components of both the hydrosphere (e.g. water temperature and flow rate) and the biosphere (e.g. vegetation composition), which may in turn affect damselfly growth, behavior, and resistance to gregarine parasites. Damselflies may therefore serve as a “sentinel species” for ecological consequences of climate change.

Building on previous work, an REU student could investigate the effects of variation in stream temperature and flow on the frequency and severity of gregarine parasite infection, and consequences of parasitization on the biology, behavior, and morphology of Calopteryx maculata, the dark-winged damselfly. The work will involve fieldwork, behavioral observations, damselfly collection, and analysis of parasite loads.

Climate Change Effects on the Threatened Pitcher’s Thistle on Lake Michigan Dunes

Brian Scholtens, College of Charleston and Claudia Jolls, East Carolina University

Climate change effects on the threatened Pitcher’s thistle on Lake Michigan dunes

The Laurentian Great Lakes basin houses the world’s largest concentration of freshwater dunes, which in turn support more endemic species than any other part of the basin. Yet, this rich biodiversity is exposed to an unsettling and increasing variety of threats, including climate change and invasive plant and herbivore species. Since 1993, we have studied Cirsium pitcheri, Pitcher’s thistle, a federally threatened plant endemic to the dunes and shorelines of the upper Great Lakes. Because Pitcher's thistle has no means of vegetative reproduction, successful seed set is critical for population persistence and survival of this iconic species. Unfortunately, seed predation by two invasive beetles, Larinus planus and Rhinocyllus conicus, can reduce Pitcher’s thistle seed output by 50-95%.

Pitcher’s thistle is one of several federally listed plant species predicted to be most impacted by climate change. Populations at the southern edge of the species range declined by 50% from 2005-2010. Modeling of the suitable climate envelope predicts contraction of range and a shift east, possibly away from the shores of Lake Michigan to Lake Ontario, where limited dune systems occur. The interactions among climate change, non-target biocontrol impacts, and invasive species are important new threats for Pitcher’s thistle and the dune ecosystem.

Climate change will increase temperature under, at, and above the dune surface. An REU student working with us could ask, for instance, how seed germination will be affected by temperatures under and at the dune surface, or how seed predation by invasive beetles will be affected by temperatures at and above the dune surface. Other project addressing weevil distribution, phenology, and host specificity may also be possible.