Questions about applications or the program should be directed to the CZNet-REU Program Coordinator, Veronica Sosa Gonzalez.
CZ Cluster(s): Urban
Location: University of Maryland, College Park, MD
Short project description: Stream water quality and sediment fluxes are strongly influenced by watershed topography, bedrock type, soil thickness, and floodplain morphology. In the Urban Fall Zone watersheds, soils are deeper under hillslopes than near the streams, which greatly influences storage and delivery of water, solutes, nutrients, and sediment to streams. The REU student will visit potential field sites, develop ideas, and work both individually and with our research group to characterize stream/floodplain morphology, subsurface soil-bedrock characteristics, and monitor sediment or solute transport in urbanized Fall Zone watersheds. The student will have the opportunity to develop an independent project that combines field data on soil thickness (from seismic data) and field data on channel morphology with GIS topographic data to evaluate changes in critical zone structure as a function of position relative to the stream profile and urban structures. The student may focus on stream channels, floodplains, wetlands, hillslope sites, or some combination of these. Characterization of floodplain and channel morphology will be conducted using field and remotely sensed methods. Sediment transport projects could use both sensor and field data to monitor transport of coarse and fine sediment fractions. The student will be able to collaborate with scientists and students at UMD who are working with the Coastal CZ project and potentially develop collaborative projects with both research groups.
Short project description: Human activities in urban systems have left a legacy of chemical contamination. This novel “cocktail” of chemicals can disrupt a wide range of CZ processes. These disruptions not only can identify crucial risks to humans in regions with dense populations, they also allow fundamental insight into how all critical zones work. The REU associated with the Urban CZC at the University of Pittsburgh will examine patterns of metals in urban soils and evaluate implications for the CZ. The focus will be on the fundamental question: “How do patterns of human activity create consistent, predictable patterns of chemical anomalies in soils?” which can be examined in both directions. The student may identify patterns in time or space from rich data archives and spend their time examining potential human forcings that dictate the pattern. Or, they may be fascinated by the biogeochemical implications of specific human or urban processes and design a field sampling and lab analysis campaign to characterize how these patterns develop. The investigations could take place both within a Cluster site or across Cluster sites along the Fall Zone from Philadelphia to Raleigh.. Previous undergraduate work has used a field X-Ray Fluorescence spectrometer to map soil metal concentrations at fine scales in green infrastructure installations, reanalyzed a water sample archive collected from urban streams, and evaluated the interactions between groundwater chemistry and storm water fluxes.
Location: Colorado School of Mines, Golden, CO
Mentor(s): Dr. Kamini Singha
Short project description: Water drives watershed-scale processes that ecosystems are dependent on. Despite this importance, hydrologists are still working to understand how water is stored and transmitted in the shallow subsurface—in a region known as the Critical Zone—and how changing precipitation inputs impact water availability and the transport of contaminants. The objective of this work is to identify how: 1) groundwater storage varies throughout watersheds, 2) variation in storage impacts water quality and/or tree productivity, and 3) climate change will alter storage dynamics. The REU student will gain experience using hydrological and geophysical tools, and will gather data such as flow rates, solute concentrations, and electrical resistivity to work on for their final project. The student will work closely with their Mines mentors to analyze the data. This project will include field work in Colorado as well as time in the computer lab at Colorado School of Mines.
CZ Cluster(s): Dust^2
Location: Brigham Young University, Provo, UT
Short project description: The aim of this research is to determine the effects of aeolian dust transport on the biogeochemistry of lake systems, focusing on the impacts on the lake microbiome. Previous work has shown a significant change in the lake microbiome following dust addition, but little research has assessed the long-term viability of the microbial communities that arise. The REU student will design an investigation characterizing the lake microbiome before and after dust addition. By examining both DNA and RNA, the student will be able to observe not only which species are present, but also which species remain viable over time. Dust samples can be collected from the region immediately surrounding the Great Salt Lake and applied to water samples from the Great Salt Lake, Utah Lake, and Deer Creek Reservoir. Dust addition experiments and lab work will be carried out over the summer.
CZ Cluster(s): Drylands
Location: University of Texas at El Paso, El Paso, TX
Mentor(s): Dr. Jennie McLaren
Short project description: Pedogenic carbonates form in soils in natural drylands worldwide, and have been studied intensively, including morphology, deposition mechanisms and accumulation rates. Pedogenic carbonate develops because dissolved bicarbonate (HCO2-) and calcium (Ca2+) react to form calcite (CaCO3), carbon dioxide (CO2) and water (H2O):
2HCO3- + Ca2+ → CaCO3(s) + CO2(g) + H2O Rxn (1)
These pedogenic carbonates can range from 1 to 93% CaCO3 in carbon accumulation zones in drylands. Pedogenic carbonates have been shown to complex with phosphorus (P) present in dryland soils, rendering most P unavailable for plant and microbial access and use. Consequently, plants and microbes have adapted P-acquisition strategies including root exudates and extracellular enzymes to access this mineral-bound P. However, it is unclear whether pedogenic carbonates play a significant role in immobilizing P and how pedogenic carbonate quantities impact this P immobilization. The REU student will design an investigation to look at pools of soil P availability along a gradient of pedogenic carbonate to determine whether there exists a correlation between carbonates and P availability. Measurements of organic and inorganic pools could identify the most important sources of P for plant and microbial communities along the carbonate gradient.
Short project description: The Coastal Critical Zone Network is a collaborative, multi-disciplinary research project that investigates the effects of salinization and flooding on marsh migration into forested and agricultural lands on the Delmarva Peninsula. Coastal forests and agricultural fields are converting to salt marshes as a result of two driving mechanisms: slow processes (e.g., sea-level rise) and fast processes (e.g., storm surges and tides). The flooding and salinization associated with these processes drive landscape changes that are affected by feedback among coupled hydrological, ecological, geomorphological, and biogeochemical processes. The occurrence of these mechanisms and the nature of their feedbacks, which differ between forested and agricultural land, determine the rate and extent of landscape transformation and the associated changes in elemental stores and fluxes in the coastal CZ. The REU student will participate in research that helps to address a question in one of our four major topical areas: hydrology, ecology, geomorphology or biogeochemistry. The student will identify their specific research question based on their interest and design a project that fits their level of research experience.
CZ Cluster(s): CINet
Location: University of Illinois at Urbana-Champaign, Champaign, IL
Mentor(s): Dr. Bruce Rhoads
Short project description: Intensive management of agricultural landscapes in the upper midwestern United States has resulted in increased rates of water runoff and soil erosion. Although these effects are well-documented, the influence of increased amounts of runoff and soil erosion on the sediment dynamics of river systems are rather poorly understood, especially spatial or temporal variation in these dynamics. The REU student will examine temporal and spatial variations in sediment dynamics in the upper Sangamon River basin of Illinois, an intensively managed agricultural watershed where event-scale data on river sediment fluxes are being collected at multiple locations throughout the watershed. The student will work with these data to characterize how sediment concentrations and loads vary over time at particular sampling locations and over space between different sampling locations. The student also can explore how temporal and spatial variations of sediment flux may be related to controlling factors, such as storm characteristics, seasonality of land cover, and geomorphic or vegetation attributes of riparian corridors. Through field and lab training, the student will learn how river sediment data are collected and analyzed.
Short project description: In the Anthropocene, the Earth system is experiencing transitions that are unprecedented in human history. Potential and ongoing ecosystem state changes threaten billions of individuals, highlighting the need to better understand the factors that determine ecosystem recovery or transition in the face of overlapping disturbances. This project seeks to characterize the recovery of watersheds affected by mega fire (extensive and severe wildfires >400km2) and various land-uses in a semiarid region. The research will take advantage of four years of data from an extensive and high frequency hydrochemical sensor network in central Utah. Because of the high level of spatiotemporal resolution, the REU student will be able to use complex systems tools (e.g., self-organizing maps, agent-based models, and neural networks) to address questions such as: 1) How does mega fire affect river flow and chemistry for different ecosystem types during postfire recovery? 2) How do various human disturbances (e.g., impermeable surfaces, grazing, irrigated crops, and water extraction) influence river flow and chemistry? 3) How does weather variability (e.g., extreme precipitation events and multi-year droughts) modulate links between wildfire, human disturbance, and hydrochemistry? And 4) How coupled are terrestrial and aquatic successional trajectories? The student will join Professor Abbott and graduate students in a campaign to collect and analyze data at hundreds of field sites near Provo, UT. The student’s project will include fieldwork, lab processing, and advanced data analysis.