University of Vermont

Rubenstein Ecosystem Science Laboratory

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Potential REU Projects:

Interdisciplinary Research on Human Impacts in the Lake Champlain Ecosystem

Our REU program focuses on the intersections of human activity and societal structure with the Lake Champlain ecosystem, how these intersections have impacted Lake Champlain, and how these impacts feed back to influence human behavior and society. The strength of this framework is the opportunities for students to work in teams to link interdisciplinary approaches within the natural sciences or between the natural and social sciences. By assisting each other, students will be exposed to and better understand the connection of their primary research area to a secondary discipline and its associated methods.

The combinations of human-induced alterations to Lake Champlain (e.g., invasive species, eutrophication, and habitat fragmentation) and Lake Champlain's highly heterogeneous habitats (e.g., warm, shallow and isolated bays to deep open waters of the main lake) provide a rich template on which students can pose research questions and test hypotheses across both natural and social sciences. Below is a list of possible summer projects in which students can participate, although we also encourage students to think about other or related research projects to explore.

Project Descriptions

Project 01: Economic and ecological impacts of native species designation for sea lamprey

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Invasive sea lamprey have a devastating ecological and economic impact in the Great Lakes. Sea lamprey control programs and lake trout hatchery programs to mitigate losses to sea lamprey are appropriated with public funds. Despite these high-cost control and hatchery programs for many decades, lake trout restoration in the Great Lakes has met with limited success. Lake Champlain is in a similar situation, with an expensive sea lamprey control program and an expensive, hatchery-dependent lake trout population. Furthermore, there is current controversy over the invasive status of sea lamprey in Lake Champlain (Bryan et al. 2005, Waldman et al. 2006). These observations suggest some basic questions about the current and historical sea lamprey management paradigm - is the public receiving a sufficient return on investment with the sea lamprey control program? If sea lamprey control and hatchery stocking were discontinued, would the systems eventually stabilize? Students will work with economic and ecological models to address these questions. These questions are uncomfortable for management agencies and consumptive resource users (e.g., angling community), providing an opportunity for students to place their research in the context of scientific norms and revolutions (Kuhn 1962).

Project 02: Have invasive alewife altered growth dynamics of salmonids?

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Alewife were first discovered in Lake Champlain in 2003 and have since become a major component of the pelagic fish community. A concomitant decrease in native rainbow smelt populations suggest predator salmonid populations have had a major shift in their diets over the last decade. Using the State of Vermont’s extensive historical and contemporary monitoring data, students will test the hypothesis that salmonid (e.g., lake trout, Atlantic salmon) growth has changed as a result of a shift in the forage base.

Project 03: Use of environmental transcriptomics to understand the bacterial catabolic pathways induced in relation to algal bloom formation and bloom die-off

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Bacteria are the primary means of remineralization and nutrient recycling in aquatic systems. However, we have little understanding of the scope of catabolic pathways that are used by bacteria for this recycling, their phylogenetic distribution, and the preference by which different species utilize nutrients from these complex environments. Students will test the basic hypothesis that bacterial communities and catabolic pathways change during algal bloom formation. They will use RNA-seq on samples collected before, during, and after cyanobacteria blooms from different regions of Lake Champlain with varying levels of blooms to: (1) identify new pathways likely involved in catabolism of algal products; (2) use bioinformatics to assign these genes to likely source taxa; and (3) use rank correlations to infer preferred nutrient sources in the abundant bacterial taxa.

Project 04: Impact of cyanobacteria blooms on property values in the Lake Champlain basin

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The frequency and intensity of cyanobacteria blooms have been increasing in Lake Champlain over the last decade (Watzin et al. 2011, Smeltzer et al. 2012). Although there is much concern over the economic impacts of the blooms, actual research on these impacts has been minimal. Students will use the Lake Champlain Basin Property Sales Dataset 2000-2012 to estimate the economic impacts of cyanobacteria blooms on lake property values across different regions of the lake with varying bloom intensities. Multivariate analyses will be used to control for confounding factors (e.g., distance to Burlington) to isolate the effects of the blooms. Students will test the hypothesis that cyanobacteria blooms have a negative impact on property values. Additional projects could address cyanobacteria impacts on tourism.

Project 05: Relative Importance of Exogeneous and Endogenous Sources of Phosphate for Algal Blooms

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The contribution of phosphorus sources fueling algal blooms remains a central question in limnology and water quality management. External sources of phosphorus to lakes include point (e.g., wastewater effluent, urban stormwater) and non-point contributions (e.g., agriculture, unpaved road networks), whereas internal sources of phosphorus include lake sediments or recycled biological materials. To track internal and external phosphorus sources to Lake Champlain, students will use a combination of analytical and process-based studies to test hypotheses regarding the internal (e.g., diffusive flux of phosphorus from sediments) and external (e.g., riverine/terrestrial phosphorus inputs) origins of phosphorus to the system. Students will learn traditional methods of environmental phosphorus analysis (Worsfold et al. 2005), enzymatic techniques for assessing phosphorus bioavailability in soils and sediments (Bunemann 2008), and isotopic methods (Young et al. 2009) for identifying internal and external sources of phosphate to Lake Champlain. Students will test the hypothesis that external climatic drivers (e.g., temperature, precipitation, wind) determine the origin of phosphorus loads to the lake, whether from internal aquatic sources (e.g., sediments, seston, macrophytes) during warm, dry periods or from external terrestrial sources during periods of high riverine discharge. The bioavailability and origin of phosphorus loads will be related to information on algal abundance collected at long-term monitoring stations within Lake Champlain (Smeltzer et al. 2012) and a continuous biogeochemical monitoring platform in Missisquoi Bay.

Project 06: Effects of algal blooms and eutrophication on virulence of the bacterial pathogen Pseudomonas aeruginosa

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Pseudomonas aeruginosa is a common bacterium in freshwater ecosystems and is enriched on submerged surfaces, particularly near aquatic vegetation and nitrogen fixing cyanobacteria. While the primary source of P. aeruginosa infections is household and hospital plumbing (Hardalo and Edberg 1997, Trautmann et al. 2005), there are significant numbers of P. aeruginosa eye and skin infections contracted from freshwater environments (Speert 2002). We already know that P. aeruginosa is enriched in human-impacted lakes and rivers (Selezska et al. 2012), efficiently utilizes nutrient pulses (Ferenci 1996), chemotaxes towards nitrogen-fixing cyanobacteria (Gallucci and Paerl 1983), and survives and grows in the presence of Mycrocystis aeruginosa and Anabaena species (Yuan et al. 2009, Bomo et al. 2011, Kang et al. 2012). This knowledge opens up the fundamental question of whether the environment of the algal bloom, or eutrophic conditions in general, enhance or repress the virulence systems of P. aeruginosa. Students will address these questions using a combination of sampling, laboratory microcosms, and ex situ laboratory experiments. Students will: (1) quantify the abundance of P. aeruginosa in samples from different regions of Lake Champlain and assess in relation to water chemistry and intensity of algal blooms; (2) measure the effect of filtered lake water from various sampling times on P. aeruginosa virulence; and (3) co-culture P. aeruginosa with the dominant cyanobacteria from Lake Champlain to determine the impact on bacterial virulence.

Project 07: Relative importance of green and brown food webs as a function of cyanobacteria blooms

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Cyanobacteria are thought to disrupt energy flow in green food webs (i.e., phytoplankton-zooplankton-fish) through a number of mechanisms including mechanically disrupting feeding of zooplankton (Demott and Moxter 1991), toxin production (Hansson et al. 2007), and poor food quality (Ahlgren et al. 1992). Although evidence of this bottleneck has been demonstrated at the cyanobacteria-zooplankton interface, little work has been done to test if this bottleneck carries over to higher trophic levels, and if so, what the long-term consequences may be. The hypothesis is that cyanobacteria blooms are energetic dead ends; the standing stock of primary producer biomass is inaccessible to the green food web pathway. However, this biomass may become available to higher trophic levels through the brown food web (detritus-based), if upon senescence cyanobacteria are transformed to accessible energy via bacteria decomposition (Edwards et al. 1990) and available to detrivores such as benthic macroinvertebrates, protozoa, and rotifers (e.g., Goedkooop et al. 1998, Work 2003). Energetic pathways may thus shift from predominantly pelagic to benthic. Students will conduct research on trophic pathways, including diet, growth, and tracer (stable isotopes and fatty acids) studies to test this hypothesis about the strength and directionality of energy flow before, during and after algal blooms. As an example, bacteria produce unique fatty acid signatures that if conserved across trophic levels could provide a means to estimate relative importance/shifts in dominant energetic pathways (Haack et al. 1994).

Project 08: Evolutionary impacts of habitat fragmentation on aquatic organisms

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Aquatic organisms typically undergo ontogenetic, seasonal, or daily migrations in search of food, shelter, or spawning sites. Thus, their population health depends on the availability and quality of two or more disparate habitats and their connectivity (e.g., Jones et al. 2003). Human activities that alter habitat quality or connectivity may have significant negative effects on organism abundance, distribution, ecology, and evolution, but these impacts may vary depending on species’ life histories. Students will collect species of varying mobility (e.g., mussels, snails, logperch, yellow perch, alewife, and rainbow smelt) across and within regions separated by causeways to test for genetic differentiation. Microsatellite markers will be used to examine isolation by distance and historic bottleneck events indicating change in population connectivity (e.g., Templeton et al. 1990, Turner et al. 2000). The hypothesis is that species with more limited mobility will show greater differentiation across regions separated by barriers than within regions, and greater differentiation than species with higher mobility.

Project 09: Do causeways restrict fish movement?

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Habitat fragmentation and its effects on fish movements is well studied in rivers, but is much less understood within lakes where opportunities to study such processes is extremely limited. The numerous causeways built 100-160 years ago in Lake Champlain provide opportunities to assess the impacts of causeways on fish movement in lakes. Genetic and tagging studies indicate that lake whitefish in Lake Michigan have genetically differentiated sub-populations, but move widely throughout the lake after spawning (Ebener and Copes 1985, VanDeHey 2009), characteristics which make this species particularly vulnerable to isolation by barriers. Causeways in Lake Champlain may restrict movement of lake whitefish between spawning and feeding areas, resulting in local population declines. Students will use data from acoustically-tagged fish and acoustic telemetry arrays (Clements et al. 2005) positioned at causeway openings and adjacent open areas of the lake to assess if, when, and under what conditions movement through causeways occurs. In the first year, students will test hypotheses such as (1) lake whitefish have extensive home ranges, (2) causeways obstruct seasonal movements of lake whitefish between spawning, overwintering, and summer feeding areas, and (3) movement of lake whitefish between regions is limited to seasons when there is no thermal stratification.

Project 10: Numerical Hydrodynamic Model of Lake Champlain

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The physical environment of lakes is shaped by the hydrodynamic processes that impact the distribution of water temperature, nutrients, dissolved oxygen and sediments. In turn, the physical environment shapes the growth and survival of the lake biota, including algae. In this project we will focus on understanding the hydrodynamics and circulation in Missisquoi Bay, a shallow bay on Lake Champlain that is particularly susceptible to harmful algal blooms (HABs). We will develop a simple one-dimensional numerical model in either Matlab or Python to predict what meteorological forcing conditions lead to strong stratification and high residence times in the bay, both of which are important conditions in understanding algal bloom dynamics. In particular we can investigate the sensitivity of the model results to the vertical distribution of radiant heating, which is a very difficult parameter to accurately assess. We will compare model results to data collected in the bay in the previous two summers when the bay exhibited contrasting conditions in HABs.

Project 11: How will the invasion of quagga mussels affect zebra mussels in Lake Champlain?

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Currently, 49 exotic species are established in Lake Champlain and several others are predicted to invade in the next few years. Quagga mussels have been found within a few miles of the lake; elsewhere, quagga mussels have invaded after zebra mussels were established and have steadily replaced zebra mussels (e.g., Ricciardi and Whoriskey 2004). We plan to quantify the distribution, density, population structure, and substrate preferences of adult zebra mussels in Lake Champlain in anticipation of the arrival of quagga mussels to provide a baseline for evaluating effects of a new invader. Students will collect mussels and demographic data using a remotely operated robot, ponar grabs, and snorkeling.

Project 12: Pharmaceuticals contaminants in Lake Champlain

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Pharmaceutical contaminants pose a range of risks to ecosystems and public health (Jones et al., 2004). Recent work by USGS has found chemical pollutants, including pharmaceuticals, in 80% of surface waters tested across the country, but only limited studies have investigated concentrations of pharmaceuticals in Lake Champlain. Students will conduct research to determine concentrations of pharmaceutical contaminants in Lake Champlain and test hypotheses about their primary sources.

Project 13: Assessing the Economic Value of Clean Water in the Lake Champlain Basin

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Water quality in Lake Champlain plays a central role in enhancing the quality of life of basin residents, driving tourism to the lake counties of Vermont and New York, and sustaining the regional economy through the delivery of ecosystem goods and services. Lake Champlain provides potable water for households, clean water for recreation, and both water supply sources and wastewater sinks for industries throughout the basin. Understanding the lake’s contribution to the economy and continued development of the region requires a broad investigation of the variety of factors that contribute to and rely on the water quality of the lake. The interconnected relationship between humans and nature will inform the economic valuation component of this project. The analysis will be conducted over multiple spatial scales ranging from changes in property values at the parcel scale (hedonic model) to regional economic output across the entire Lake Champlain basin (input-output model). Results will provide a multi-layered assessment of the economic impacts of water quality changes on tourism, housing values and regional economic output. This research effort, funded in part by the Lake Champlain Basin Program, will support regional planning efforts to protect and restore water quality in the Lake Champlain basin.

REU student(s) will support data collection and processing tasks leading to the development of econometric models quantifying the economic value of lake water quality. They will test for statistical relationships among natural characteristics, human impacts and cultural preferences in the region and use their findings to build economic valuation models. Depending on student interests, opportunities to learn (or enhance) GIS, database management, Python programming and statistical analysis will be offered. Finally, there is also the opportunity to develop educational materials targeting non-technical audiences to communicate the research findings (e.g., fact sheets, web site development).


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Last modified February 10 2014 12:11 PM