A. Urbanization and vectors of human disease.
Mentor: Dr. Shannon LaDeau. One student.
The human incidence of vector-borne disease has risen among urban populations in the past decade, including annual recurrence of West Nile virus in the United States and dengue virus globally. Managing human disease risk requires an understanding of how mosquito populations grow and behave in human-dominated landscapes. There are over sixty different species of mosquito in the mid-Atlantic region, but only a small number are important vectors of human disease. REU students will use experimental and statistical methods to investigate how environmental variables that reflect human presence (e.g., storm water management practices, diurnal temperature ranges, road salt, nitrogen) influence mosquito community ecology.
B. Microbial processes in urban ecosystems.
Mentor: Dr. Peter M. Groffman. One student.
The maintenance of “natural” microbial nutrient cycling processes in urban ecosystems is important to the functioning of these systems. Students can participate in several different projects that are part of the Baltimore Ecosystem Study (BES), a long-term study of Baltimore, Maryland, including: the effects of exotic species on soil nutrient cycling processes, microbial processes in urban riparian forests and nutrient cycling in forest, agricultural and residential areas within the city.
C. What, if anything, controls tick populations and tick-borne disease?
Mentors: Drs. Richard S. Ostfeld and Felicia Keesing. One student.
Blacklegged ticks (Ixodes scapularis) are the vectors of several human diseases, including Lyme disease. Local abundance of ticks infected with pathogens is a key risk factor for these diseases. Students will be guided in devising projects to ask what biotic and abiotic factors might regulate ticks. For example, ticks can be attacked by forest-floor fungi, and the abundance of fungi might be influenced by exotic plants. Ticks appear to benefit from the protection provided by thick leaf litter, but exotic earthworms might reduce leaf litter thickness. Small mammal hosts that support tick populations might be affected by vegetative cover and food availability on the forest floor. Some of the factors that potentially regulate tick populations could be amenable to manipulation for the benefit of human health. Students will be encouraged to explore both the basic science and its translation for public use.
D. Investigating people's ideas about ecosystems.
Mentors: Dr. Alan R. Berkowitz, and Cary Education Staff. One or two students.
Understanding ecosystems is increasingly vital for decision making and citizenship, yet ecosystem literacy eludes educators and the public. REU students will have the opportunity to explore basic questions about thinking and learning, and how people use scientific understanding in citizenship contexts. Their findings will contribute to Institute and other education and outreach programs. Students may choose to design and carry out their own investigations, with audiences such as youngsters in the Institute’s Ecology Summer Day Camp, or teachers in Institute workshops. Alternatively, they might delve into rich collections of student, teacher and adult responses to surveys and interviews done by past students and education researchers. Data is available from the Earthworms and Ecosystems, Teaching the Nature of Ecological Science, Data Exploration in Ecology, and the Pathways to Environmental Science Literacy projects. Students will meet the Cary Institute’s Institutional Review Board’s requirements for human subjects research, and will gain experience in social science research linked to ecological inquiry.
E. The impact of synthetic compounds on stream ecosystem function.
Mentors: Drs. Emma Rosi-Marshall and Heather Bechtold. One or two students.
Safeguarding the supply of high quality clean drinking water is one of the largest challenges facing humankind. Although advances in technology have allowed humans to keep pace with agricultural and health needs, they have also introduced contaminants such as fertilizer and pharmaceutical compounds into aquatic ecosystems. Increased nutrients can alter ecosystem processes such as growth and production, while the effects of pharmaceuticals are not currently understood. We will examine the effects of pharmaceuticals and/or nutrients on stream ecosystem function by designing studies for either the laboratory or field. The student will focus on an ecosystem process such as retention and uptake of compounds or growth and production of biota. In addition to the experimental study, the student will also examine the prevalence of the compound being studied and examine its use and production. This aspect of the research will allow the student to put her or his research in the larger context of nutrient and novel containments, how widely used these compounds are, and what measures are available for their disposal and removal. Currently, there are no regulations controlling the maximum level of exposure from pharmaceuticals or nutrients (except nitrogen) in aquatic ecosystems. We will explore the relative benefits and costs of these compounds and whether the compound studied merit regulation based on our results. The student will write a scientific paper on the research findings and may writean article for the public exploring issues of environmental exposure and regulation of these compounds.
F. Songbird Behavioral Ecology: How do veeries use their songs to communicate?
Mentor: Dr. Kara L. Belinsky. One or two students.
Veeries are one of many species of songbirds that migrate from the neotropics to sing and breed in the forests of North America every summer. Each species of songbird uses a species-specific repertoire of songs and other vocalizations (calls) to communicate. During the breeding season, most songbirds use their vocalizations to choose their mates and defend the territories in which they breed. Veeries have eerily beautiful and unusually complex songs in addition to a large repertoire of calls. As an REU student, you will design and carry out a project exploring one or more aspect of veery communication; for example you might focus on describing the function of the complex repertoire of songs and calls that these birds use, or you might investigate how males and females tending nests use songs and calls to coordinate their efforts. For your project you can expect to observe veery singing and nesting behavior in the field, and catalogue and analyze song recordings in the lab. In addition, you will also have the opportunity to work with graduate students and field assistants to capture and color-band veeries and find/monitor veery nests.
G. Temperature effect on size-structure of zebra mussels (Dreissena polymorpha).
Mentors: Dr. Dave Strayer and Jessica Gephart. One Student.
Invasive zebra mussels (Dreissena polymorpha) first became abundant in the Hudson River in 1992. For the first 13 years of the invasion, the population showed strong cohort dynamics, alternating between being dominated by large and small mussels. In 2005 however, the population became consistently dominated by small mussels. The size structure shift likely resulted from increased mortality (Strayer et al. 2011), partially due to blue crab predation (Carlsson et al. 2011), but other factors, including disease and poor physiological condition may also be important. The Hudson River provides a unique opportunity to study the effects of rising water temperatures on the invasive zebra mussel and how changes in the size structure alter the ecosystem impacts because researchers at the Cary Institute have monitored the zebra mussel over the past 20 years, and there is evidence that the Hudson river is warming (Seekell and Pace 2011). Temperature could lead to small-bodied mussels through three main mechanisms: 1) mortality may increase more in large-bodied mussels than in smaller-bodied mussels, eliminating large mussels; 2) mortality may increase in all size classes at high temperatures such that few mussels survive to a large size class; 3) high temperatures may reduce growth rates. The REU student will investigate these three possibilities with growth experiments conducted at temperatures between 18 and 34°C for small, medium and large zebra mussels.
H. Body size and the effects of ecosystem engineering by organisms.
Mentor: Dr. Clive G. Jones. One or two students.
This project involves applying principles of body size scaling rules (i.e., how some features of organisms, such as metabolic rate, scale as a function of body size) to the diverse effects of ecosystem engineers -- the extended influences they have on their physical surroundings (i.e., rock, soils, sediments). Such engineering activities include bio-erosion, bioturbation, and the formation of burrows, depressions, mounds and impoundments. Scaling rules ascertain the degree to which per capita biomass of species can account for variation in the magnitudes of these extended effects. The approach provides a quantitative way to compare different ecosystem engineering species (e.g., sponges versus parrot fish that both erode corals), while also potentially affording an explanation for effect magnitudes (e.g., chemical versus mechanical erosion, respectively). The REU student projects will involve compiling data sets from published literature on many different species and then analyzing them (i.e., a lab-based project). Possible projects include: rock erosion by microbes, lichens, plants and mollusks (and comparison with coral erosion data from a 2012 REU project); pits, depressions, mounds, and impoundments (and comparison with a recently created burrow size data base); and animal bioturbation. Students should be interested in the search for general ecological principles; be interested in exploring the application potential of findings; have an aptitude for literature data mining; be able to construct and manage databases; and conduct statistical analyses (e.g., regression).
I. Hudson River wetlands and climate change.
Mentor: Dr. Stuart E.G. Findlay. One student.
The freshwater reach of the tidal Hudson River includes about 200 tidal wetlands that provide numerous valuable ecological services. These wetlands are at risk due to both rising sea levels and increased salinity intrusion. Understanding both the mechanisms of sediment accumulation and sensitivity of processes to higher salt levels will be crucial to predicting the future state of these ecosystems. An REU student can investigate one of several aspects of these problems, such as a consideration of how sediments are retained in different sites or how quickly salt water influences the ecology of the wetlands.