34 research outputs found
Processes of Change in Information Systems Development: A Multiple Case Study Analysis
Michael M. Masoner is an Associate Professor of Accountancy in the School of Accountancy at Southern Illinois University at Carbondale. Andreas I. Nicolaou is an Assistant Professor of Accounting in the Department of Accounting and Finance at Morgan State University
Municipal Solid Waste Landfills Harbor Distinct Microbiomes
Landfills are the final repository for most of the discarded material from human society and its built environments. Microorganisms subsequently degrade this discarded material in the landfill, releasing gases (largely CH4 and CO2) and a complex mixture of soluble chemical compounds in leachate. Characterization of landfill microbiomes and their comparison across several landfills should allow the identification of environmental or operational properties that influence the composition of these microbiomes and potentially their biodegradation capabilities. To this end, the composition of landfill microbiomes was characterized as part of an ongoing USGS national survey studying the chemical composition of leachates from 19 non-hazardous landfills across 16 states in the continental U.S. The landfills varied in parameters such as size, waste composition, management strategy, geography, and climate zone. The diversity and composition of bacterial and archaeal populations in leachate samples were characterized by 16S rRNA gene sequence analysis, and compared against a variety of physical and chemical parameters in an attempt to identify their impact on selection. Members of the Epsilonproteobacteria, Gammaproteobacteria, Clostridia, and candidate division OP3 were the most abundant. The distribution of the observed phylogenetic diversity could best be explained by a combination of variables and was correlated most strongly with the concentrations of chloride and barium, rate of evapotranspiration, age of waste, and the number of detected household chemicals. This study illustrates how leachate microbiomes are distinct from those of other natural or built environments, and sheds light on the major selective forces responsible for this microbial diversity
Correction to GeoChip-Based Analysis of Microbial Functional Gene Diversity in a Landfill Leachate-Contaminated Aquifer
Correction to GeoChip-Based
Analysis of Microbial
Functional Gene Diversity in a Landfill Leachate-Contaminated Aquife
GeoChip-Based Analysis of Microbial Functional Gene Diversity in a Landfill Leachate-Contaminated Aquifer
The functional gene diversity and structure of microbial
communities
in a shallow landfill leachate-contaminated aquifer were assessed
using a comprehensive functional gene array (GeoChip 3.0). Water samples
were obtained from eight wells at the same aquifer depth immediately
below a municipal landfill or along the predominant downgradient groundwater
flowpath. Functional gene richness and diversity immediately below
the landfill and the closest well were considerably lower than those
in downgradient wells. Mantel tests and canonical correspondence analysis
(CCA) suggested that various geochemical parameters had a significant
impact on the subsurface microbial community structure. That is, leachate
from the unlined landfill impacted the diversity, composition, structure,
and functional potential of groundwater microbial communities as a
function of groundwater pH, and concentrations of sulfate, ammonia,
and dissolved organic carbon (DOC). Historical geochemical records
indicate that all sampled wells chronically received leachate, and
the increase in microbial diversity as a function of distance from
the landfill is consistent with mitigation of the impact of leachate
on the groundwater system by natural attenuation mechanisms