Environmental Microbiology and Microbial Ecology Commons^™

Impacts Of Salinity On Microbial Enzyme Activity In Coastal Waters, Natali Ariyoshi

Honors Theses

Microbial extracellular enzymes are critical for the breakdown of organic matter and nutrient cycling in aquatic ecosystems. Extracellular enzyme activity serves as an indicator of nutrient turnover rates, metabolic states, and nutrient limitations within an ecosystem. Coastal ecosystems are especially dynamic as the influx of freshwater from inland runoff or seawater intrusion from storm surges can lead to fluctuations in salinity which can restructure microbial communities and alter enzymatic activity. Despite the ecological significance of these changes, few studies have explored the effects of short-term salinity shifts on microbial extracellular enzyme activity in coastal waters. This study investigated the effects …

Impacts Of Land Development On Soil Microdiversity And Antibiotic Production, Dennis Guillen Castro, Robert Garcia, Jonathan Castro, Davida Smyth

Masters Theses (Archived)

The impact of land development on soil microbial diversity and antibiotic production is critical due to industrial expansion and the scarcity of effective antibiotics. Low Impact Development (LID) aims to preserve ecosystems, but its effectiveness in maintaining microbial diversity is uncertain. This study compares soil samples from nine sites: undisturbed (UD), residential (RD), and Madla Greenway (GW) within the VIDA development area and Texas A&M University-San Antonio campus. Isolated microbes were screened for antibiotic production and genetically characterized. Preliminary findings indicate that UD sites harbor greater microbial abundance, and a higher proportion of antibiotic-producing microbes compared to GW and RD …

A Review On Validation Of Enzyme Linked Immunosorbent Assay (Elisa) Techniques For Detection And Quantification Of Different Contaminant In Aquatic Environment, Sanwal Aslam, Zhen Zhang, Ali Muhammad

Journal of Bioresource Management

In world, contaminants and microbes are considered as serious problem in house water supplies as well as in aquatic environment for life. As a result, different countries are working to set level of these contaminants and microbes in domestic supply of water and in aquatic environment. In addition to these scientists are also working on reliable sampling and then their suitable analysis method for accuracy. It is also very important to improve and give justification for analytical techniques used in laboratories, which enable us to monitor level of various contaminants in aquatic environment. In this review, we have focused on …

A Mathematical Model For Transport And Growth Of Microbes In Unsaturated Porous Soil, Harihar Khanal, Andrei Ludu, Ramesh Chandra Timsina, Kedar Nath Uprety

Publications

In this work, we develop a mathematical model for transport and growth of microbes by natural (rain) water infiltration and flow through unsaturated porous soil along the vertical direction under gravity and capillarity by coupling a system of advection diffusion equations (for concentration of microbes and their growth-limiting substrate) with the Richards equation. (e model takes into consideration several major physical, chemical, and biological mechanisms. (e resulting coupled system of PDEs together with their boundary conditions is highly nonlinear and complicated to solve analytically. We present both a partial analytic approach towards solving the nonlinear system and finding the main …

Utilizing Plastic-Degrading Microbes For Plastic Degradation, Brandon Garcia

Global Sustainable Development Projects

Our oceans are full of pollution and a large portion of those are plastics. They resist degradation from the elements and have long half-lives. About 300 million metric tons of plastic are dumped into our oceans every year. Many of these include polyethylene (PE), polypropylene (PP), polystyrene (PS), etc. Much of this is not recycled and so there is a massive accumulation of it present in our oceans. Microbes tend to form biofilms on these plastics and break them down. However, the relationship between plastics and the diversity of biofilm communities are being understood as well as how we can …

Effects Of Warming On Decomposition Of Submerged Plant Litter And Associated Microorganisms In Streamside Channels, Kaity Ackerman

Electronic Theses and Dissertations

Surface air temperatures are predicted to increase in the near future, which will likely affect microbial activity and carbon flow in stream ecosystems. I performed an experiment in streamside channels at Coweeta Hydrological Laboratory, NC to assess responses of litter-associated microorganisms to moderate increases in water temperature (5 levels, ambient to +4°C). The objectives of the experiment were to determine: (1) if there are differences in the magnitude of responses to temperature among various microbial parameters and (2) whether microbial responses to temperature vary among plant litter of different carbon quality. Thus, I measured litter decomposition rate, fungal biomass (ergosterol), …

Isolation Of Caldatribacterium (Op9) And Investigation Of Its Potential Interactions With A Novel, Co-Cultivated Thermodesulfobacterium Species, Toshio Alvarado

Electronic Theses, Projects, and Dissertations

Atribacteria (OP9), candidate phylum with no representatives in pure culture, is found in various anaerobic environments worldwide. “Caldatribacterium”, a lineage within Atribacteria that is predicted to be a strictly anaerobic sugar fermenter based on cultivation-independent genomic analyses, is currently being maintained in lab enrichment cultures with fucose as its sole growth substrate. Metagenomics and 16S rRNA gene tag sequencing indicated that the fucose culture was a co-culture of “Caldatribacterium” and an uncultivated member of the genus Thermodesulfobacterium. Due to failed attempts to isolate “Caldatribacterium” by dilution-to-extinction and plating, it was hypothesized that “Caldatribacterium” is dependent in some way on the …

Marine Sequestration Of Carbon In Bacterial Metabolites, Oliver J. Lechtenfeld, Norbert Hertkorn, Yuan Shen, Matthias Witt, Ronald Benner

Faculty Publications

Linking microbial metabolomics and carbon sequestration in the ocean via refractory organic molecules has been hampered by the chemical complexity of dissolved organic matter (DOM). Here, using bioassay experiments and ultra-high resolution metabolic profiling, we demonstrate that marine bacteria rapidly utilize simple organic molecules and produce exometabolites of remarkable molecular and structural diversity. Bacterial DOM is similar in chemical composition and structural complexity to naturally occurring DOM in sea water. An appreciable fraction of bacterial DOM has molecular and structural properties that are consistent with those of refractory molecules in the ocean, indicating a dominant role for bacteria in shaping …

Respiration And Carbon Dioxide Accumulation In Soil Microcosms, Jasity Murphy

Pursuit - The Journal of Undergraduate Research at The University of Tennessee

The thawing of permafrost leads to liberation of soil organic matter and microbial component resulting in significant effect on the carbon cycle. Changes in permafrost soils upon the global climate warming would significantly impact microbial soil activity. Currently, not a great deal is known about what happens to the microbial community after the permafrost thaws. The activity of microbial community was determined in microcosms experiment using respirometry. To assess the CO₂ fluctuations during permafrost thawing a titration experiment was performed. Based on calculations using the respirometric equation it was found that CO₂ production increases with temperature, core depth, …

Denitrification In Great Basin Hot Springs, Austin Mcdonald, Brian P. Hedlund

Undergraduate Research Opportunities Program (UROP)

Hydrogen has been proposed to fuel primary production in the Aquificae dominated hot springs of Yellowstone National Park (Spear, et al. 2005), a finding the authors generalized to all hot springs. However, clone libraries derived from Great Basin springs contain few 16S ribosomal RNA (rRNA) gene sequences from Aquificae and many from unknown microorganisms. In the same springs, alternative electron donors rival the reducing power of hydrogen. This project will try to cultivate the uncharacterized microbes of two Great Basin springs and determine which electron donors they can use.

Nitrogen is key to life. In its reduced form, ammonia, it …

Spatial And Temporal Patterns In The Microbial Diversity Of A Meromictic Soda Lake In Washington State, Pedro A. Dimitriu, Holly C. Pinkart, Brent M. Peyton, Melanie R. Mormile

All Faculty Scholarship for the College of the Sciences

The microbial community diversity and composition of meromictic Soap Lake were studied using culture-dependent and culture-independent approaches. The water column and sediments were sampled monthly for a year. Denaturing gradient gel electrophoresis of bacterial and archaeal 16S rRNA genes showed an increase in diversity with depth for both groups. Late-summer samples harbored the highest prokaryotic diversity, and the bacteria exhibited less seasonal variability than the archaea. Most-probable-number assays targeting anaerobic microbial guilds were performed to compare summer and fall samples. In both seasons, the anoxic samples appeared to be dominated by lactate-oxidizing sulfate-reducing prokaryotes. High numbers of lactate- and acetate-oxidizing …