Lance Lab

Research

Ecotoxicology

Our lab is examining various aspects of ecotoxicology. We are particular interested in sublethal effects, epigenetic effects, intra- and inter-population variation in tolerance, and adaptation to contaminants (and stressors in general).

Cu, Zn, and Constructed Wetlands:

Top: Controlled lab study. Middle: Experimental mesocosms. Bottom: Constructed wetlands (field site).

To date most of our studies have focused on Cu and Zn. An artificial wetland (H-02) was constructed on the Savannah River Site in 2007 to treat process and storm water discharge from an industrial facility. The primary issues with the outfall water are elevated Cu, Zn, and pH. Constructed wetlands can provide new habitat for local wildlife, but if poor water quality limits recruitment, these wetlands could become “population sinks.” David Scott and I have financial support from the National Nuclear Security Administration to assess the potential impacts of their H-02 constructed wetlands on local pond-breeding amphibians. We are experimentally examining the effects of trace metal exposure on the southern toad (Bufo terrestris), the eastern narrow mouth toad (Gastrophryne carolinensis), and the southern leopard frog (Lithobates sphenocephalus). By monitoring a partial drift fence near the wetland we are also keeping track of which amphibian species are colonizing and successfully reproducing in the wetlands.
 
We have found a lot of variation in tolerance to Cu among species, populations, and clutches. Some of our current work is focusing on parental effects on fitness and whether there is a genetic basis to tolerance. We are conduct controlled crosses of southern toads to create full and half sib families, experimentally examining offspring for phenotypic responses to Cu exposure, and then using RADtag SNP and gene expression studies. We also have built transcriptomes for southern toads, southern leopard frogs, green frogs, and bull frogs and have numerous gene expression studies in the works.

Coal Combustion Wastes:

Southern toad, Anaxyrus terrestris, metamorph from a Cu study

On the Savannah River Site we have access to several areas with coal fly ash contamination. We also are looking at the effects of coal combustion wastes on amphibians and alligators and on trophic transfer. One current study is looking at whether the skin secretions (and potentially the immune response) of southern toads or spadefoot toads (Scaphiopus holbrookii) are altered due to exposure to contaminated soils. This work is in collaboration with Cathy Bevier at Colby College. The alligator work involves raising gators on contaminated and uncontaminated diets and looking at impacts on physiology and gene expression and is in collaboration with Tracey Tuberville, David Scott, and Brian Metts.

Contaminants and Disease: Our lab is particularly interested in how natural and anthropogenic stressors may impact disease dynamics. We have several studies underway investigating how exposure to contaminants may alter susceptibility to disease. Currently these studies include amphibian (chytrid and ranavirus) and avian (malaria) diseases and will likely soon include wild hogs.

Radioecology

Left to right: Low dose irradiation facility (LoDIF) mesocosm showing Cs-137 irradiator. Turtle (Trachemys scripta) fibroblast containing a chromosomal translocation detected by multiplex fluorescence in situ hybridization (mFISH)—photo by Brant Ulsh. Comet assay showing DNA damage in spadefoot toad. Hopefully we will soon be studying wolves in Belarus!

SREL has a long history of studying radioecology. We have a one of a kind facility (Low Dose Irradiation Facility) for looking at the impacts of chronic low dose irradiation. The facility is primarily set up for aquatic species and is ideal for fish (right now we are writing up studies of gene expression changes in medaka fish chronically exposed to Cs-137). However some amphibian studies have been conducted there and we are planning for some invertebrate and additional amphibian studies in 2013.
 
Very soon we will be setting up a study on fathead minnows. In collaboration with Carmel Mothersill (McMaster University) we’ll be comparing the sublethal effects of an alpha emitter (Ra) and gamma emitter (Cs) on physiology, reproduction, and genetics in fatheads.
 
This fall Jim Beasley and I will be heading to Belarus for a workshop discussing a really exciting research effort we are a part of looking at dose rates and effects of chronic radiation exposure in free ranging animals (including wolves, bison, and deer) in Chernobyl. Brant Ulsh will also be a part of the Belarus project and he and I will also be doing work on the SRS looking at the impacts of contaminants on gene expression and DNA damage.

Population and Conservation Genetics

Left to right: Aerial view of one of the 400+ Carolina Bays on the SRS. Stacey Lance with David Civitello and an anesthetized gray fox. SRS Wetlands of differing hydroperiods, with hypothetical dispersal paths for amphibians between source and sink populations. Gopher frog, Lithobates capito, an at-risk species of interest. The SRS is one of the few areas left in South Carolina with breeding populations.

The Savannah River Site has more than 400 Carolina bay isolated wetlands which are home to more than 40 species of amphibians. Our lab has begun collecting tissue samples from numerous species from across the site for landscape genetics studies. One of our major areas of interest is dispersal patterns and connectivity among the wetlands. Species of focus so far include gopher frogs, southern toads, southern leopard frogs, tiger Salamanders, marbled salamanders, mole salamanders. We are also interested in how the landscape of various hydroperiod wetlands is going to change with the changing climate. Many pond breeding amphibians can only successfully reproduce in wetlands with particular hydroperiods. With a changing climate we may see a shift in hydroperiods one way or the other. We are investigating avenues for adaptive management of amphibians by constructing wetlands of particular hydroperiods. To make that work it is critical to understand the dispersal capabilities and gene flow barriers for different species to ensure plans include a landscape of wetlands that will preserve the long term health of populations dependent upon isolated wetlands.
 
In addition to site-wide and regional studies we are conducting some focused studies on bays with long term demographic data. For example, one site, Rainbow Bay, has been studied extensively since 1978. The entire bay is encircled with a drift fence with pitfall traps on both sides of the fence. The fence has been “run” every day for over 30 years!!! All of my research at Rainbow Bay is in collaboration with David Scott. David has been the primary person running the bay and maintaining the data for over 20 years. When the Rainbow Bay project started mole salamanders (Ambystoma talpoideum) were the dominant species and marbled salamanders (A. opacum) were very rare. Now, over 30 years later, the roles have reversed. We have accurate estimates of the census size for every year since 1978 and we have tissue samples from cohorts over the last 30 years. By combining the long-term data with genetic analyses we’ll be able to examine the relationship between census size and effective population size in a declining population and expanding population.

Behavior Studies

We are part of a collaborative study on mating behavior of blue-footed boobies.

My background is in animal behavior and it remains a strong interest. Some of the studies in my lab include mating behavior in marbled salamanders, mole salamanders, blue-footed boobies, and alligators. We are also incorporating more behavioral endpoints in our ecotoxicology studies.