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Enhancing Biodiversity and Environmental Quality

Preserving Our Resources for Future Generations

Safeguarding and enhancing the natural resource environment has become increasingly complex within environmental, social, resource and personal contexts. Through collaboration among researchers, industry, producers, environmental groups, and government, we are helping preserve a diverse and resilient environment for future generations.

Improving Water Quality by Examining the Occurrence of Common Pharmaceuticals in the Surface Water of Urbanizing and Rural Middle Tennessee Watersheds

Examination of Extracellular Nucleic Acid Binding Mechanisms on Soil Minerals

Improve Mechanistic Understanding of Microbial Processing of Soil Decay and its Long-term Responses to Climate Warming

Evaluate the Effects of Forest Restoration on Southeast Amphibian and Reptile Communities

Role of plant-soil feedback in the decline of oak seedling regeneration in upland Appalachian forests

Improving Water Quality by Examining the Occurrence of Common Pharmaceuticals in the Surface Water of Urbanizing and Rural Middle Tennessee Watersheds
Dr. Sam Dennis
Emerging contaminants such as human pharmaceuticals, are becoming pollutants of concern in freshwater systems.  The potential pathways include, but are not limited to their consumption, low human metabolic capability, and improper disposal of unused products.  With rural community development and potential urban sprawl, high consumption of pharmaceutical products in Middle Tennessee abounds.  Pharmaceuticals have been detected nationwide in different environmental matrices including wastewater effluents and surface water.  Moreover, in recent studies, pharmaceuticals have also been detected in rivers draining rural and urbanizing watersheds in Middle Tennessee.  On a national scale, pharmaceuticals that were detected included steroids, prescription drugs such as antibiotics, anti-depressants, anti-inflammatory drugs, hormones and over the counter drugs.  Their concentration ranges from parts per trillion to parts per billion in sewage treatment plants effluent and surface water environments, especially around outfall discharges.  It is noteworthy that many of these chemicals are suspected or are potential endocrine-disrupting chemicals, as well as having the potential for adverse environmental effects in freshwater systems.  The central hypothesis of this study is that the incidence of pharmaceuticals in surface water in urbanizing and rural watersheds exist, partly due to catchment land uses and outfall discharges.  Therefore, the overarching goal of the study is to provide a comprehensive assessment of two broad classes of pharmaceuticals based on their end-use for heart treatment ailments and as anti-inflammatory drugs.  These class of pharmaceuticals were selected based on their production volumes, availability based on over-the-counter sales, the number of prescriptions being filled, and their extended uses.  

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Examination of Extracellular Nucleic Acid Binding Mechanisms on Soil Minerals
Dr. Sudipta Rakshit
Nucleic acid binding on soil minerals can affect horizontal gene transfer processes (HGT).  Horizontal gene transfer by naked or free DNA may transfer genes to bacteria in the environment and thus can cause any potential adverse effects due to gene modification.  One of the important steps in HGT is the persistence of the free DNA in the soil environment and its availability to the bacteria.  Recent evidence indicates the chemical mechanisms by which free or naked DNA, often termed as extracellular DNA (eDNA), binds with soil minerals can regulate both the persistence and availability of the eDNA.  Currently, various sorption studies on nucleic acid binding on soil minerals failed to portray a systematic account of the major cause of persistence of the sorbed nucleic acids.  This research will serve as an important step toward a systematic understanding of nucleic acid binding on environmental surfaces and its effect on the persistence.  There is no clear consensus among the scientific communities or few investigations were conducted thoroughly to understand the detailed mechanisms underlying the eDNA persistence in the environment.  Very few studies highlighted the molecular level mechanisms of eDNA retention to soil minerals and organic matters.  While it is not possible to address all the questions required to understand the fate of DNA in the environment in one research work, this proposal promises to cover the key points necessary to build a consistent understanding of the fate of the DNA in the environment.  Specifically, we will address the particular mechanism by which DNA binds with permanent and variable charge minerals in the environment using advanced spectroscopic tools.  Permanent and variable charge minerals cover a major class of the minerals present in the soil environment.  Surface and interlayer charges are the major driving force of the sorption related processes by which DNA can be immobilized on the mineral surfaces.  Thus, in this program our main goal is to investigate detailed binding mechanism of extracellular DNA on soil minerals using macroscopic sorption studies and advanced molecular level spectroscopic tools.  The research will develop key information about the mechanisms of eDNA cycling in the environment leading to the improvement of management practices designed for controlling the spread of harmful unwanted genetic material such as antibiotic resistant genes (ARG).  This would help long term sustainability of society.

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Improve Mechanistic Understanding of Microbial Processing of Soil Decay and its Long-term Responses to Climate Warming
Dr. Jianwei Li
Humans are changing Earth's climate.  Two major consequences are the increasing global land surface mean temperature, and widespread active nitrogen deposition or nutrient enrichment.  These global changes not only affect plant growth (i.e., crop yield) but also the belowground microbial biomes upon which these aboveground plants depend.  My research work will help address how global warming and nitrogen fertilizers affect belowground microbial communities and the changes of microbes modify the greenhouse gas emission (i.e., CO2) to atmosphere and the pool size of soil organic matter, which is key for soil health, fertility and ecosystem sustainability.

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Evaluate the Effects of Forest Restoration on Southeast Amphibian and Reptile Communities
Dr. Bill Sutton
The historical range of the Longleaf Pine ecosystem once ranged throughout the southeast coastal plain of the Southeast United States in large contiguous forest tracts that totaled 24 million hectares.  However, a combination of fire suppression, anthropogenic development, and habitat conversion, has led to the overall decline of the Longleaf Pine ecosystem.  As these forest types have declined, so too have the unique plant and animal communities that have adapted to the growing conditions in these ecosystems.  One particular animal group (amphibians and reptiles) are especially tied to large, intact stands of Longleaf Pine and the biological conditions that are present within these ecosystems.  This proposed work will advance the scientific knowledge of vertebrate species conservation by evaluating the ecological benefits of Longleaf Pine forest restoration in a portion of the range of the Longleaf Pine ecosystem that has not been evaluated previously.  We will use a large-scale replicated field study to evaluate the impacts of Longleaf Pine restoration on amphibian and reptile communities.  This study will further our understanding of how restoration leads to changes in amphibian and reptile communities, which is essential given the global decline of this species group.  It is important to raise awareness of this declining ecosystem and the organisms that inhabit these landscapes.  Only by understanding the unique conditions that these habitats present, will we be able to understand the ecological importance - and thus the need to restore these ecosystems.   

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Role of Plant-soil Ffeedback in the Decline of Oak Seedling Regeneration in Upland Appalachian Forests 
Dr. Sarah McCarthy-Neumann
This research focuses on the mechanisms underlying the loss of oak dominant forests in the Eastern US. A sustained decline in oak recruitment will be both ecologically and economically devastating due to the outsized importance of this tree genus. The role of plant-soil feedbacks has been largely ignored as a likely mechanism for exacerbating the decline of oaks as mesophytic species such as red maple increase in abundance in these forests. The feedback between plants and their microbial community has come to the forefront of both plant and forest ecology in the last few decades with research showing large impacts on community dynamics in many ecosystems. In only the last 5 years, have we begun to discover that the type of mycorrhizal symbiont associated with a plant may drastically influence their interactions with the soil microbial community as well as other neighboring plants. We propose that as mesophytic tree species (largely associated with arbuscular mycorrhizal fungi) increase in abundance there is concomitant decline in soils associated with ectomycorrhizal fungi (critical to oak seedling establishment) exacerbating the decline of seedling establishment and recruitment. The complementary greenhouse- and field-based experimental work will complement the continuation of long-term (> 45 years) mapped forest stands that are experiencing a decline in oak and hickory adults as mesophytic trees have increased dramatically in abundance.