Using X-ray computed tomography (CT) scanning to characterize the physical characteristics of soil and sediment cores allows scientists to observe and analyze stratigraphy without destroying the integrity of different layers. Microbiologists often work with geologists to characterize the microbial communities in such cores; however, X-rays are known to be destructive...
Marine sediments are one of the largest habitats for microbial life on earth. These microorganisms play critical roles in biogeochemical cycling both within the subsurface and between the sediment and water columns. However, microbial communities in sediments are highly heterogeneous and the factors defining microbial community structure and metabolic function...
In recent decades the habitat of North American beaver (Castor canadensis) has expanded from boreal forests into pan-Arctic tundra ecosystems. It is unknown how the advance of beavers into Arctic watersheds will impact microbial communities responsible for the mineralization of organic matter (OM), which has implications for carbon cycling. To...
Greenhouse gases effects are a leading contributor to climate change; reducing harmful effects of these gases is important for future generations. Worldwide, household consumption makes up seventy-two percent of greenhouse gas emissions, followed by government consumption at ten percent, and investments at eighteen percent (Hertwich, 2009). In order to understand...
The use of ureolytic bacteria for the remediation of contaminated groundwater aquifers by inducing calcium carbonate precipitation is being studied in order to establish a better understanding of the modeling and prediction of how the bacteria will act in situ. This research has pursued the use of various ureolytic bacteria...
Marine sediments contain an abundance of methane that is biologically produced
and plays a significant role in the global carbon cycle. Microbes responsible for the
carbon cycle in marine sediments, and the processes that they carry out, need to be
characterized in order to fully understand the role of this...
Aquifers are an important storage location and source of fresh groundwater. They may become polluted by a number of contaminants including mobile divalent radionuclides such as strontium-90 which is a byproduct of uranium fission. A method for remediating such divalent radionuclides is sequestration through co-precipitation into calcium carbonate. Calcium carbonate...
Microbial-induced calcite (CaCO₃) precipitation (MICP) is a well-known natural phenomenon where microbes precipitate calcite in their environment as a result of metabolic activity. It has recently been of interest as a bioengineered technique to stabilize soils for construction applications. A known metabolic pathway to induce MICP is ureolysis, where introduced...
With rising concentrations of CO₂ in the Earth's atmosphere causing
concern about climate change, many solutions are being presented to
decrease emissions. One of the proposed solutions is to sequester excess
CO₂ in geological formations such as basalt. The deep subsurface is known
to harbor much of the microbial biomass...
Marine sediments are vast sources and reservoirs of methane, a potent greenhouse gas. Most of this methane is anaerobically oxidized by archaea before it can reach the overlying ocean, though the efficiency of this process often depends on methane fluxes and mechanisms of fluid transport. Anaerobic methanotrophic archaea, or ANME,...
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Frederick S. Colwell
Abstract
Marine sediments are vast sources and reservoirs of methane
Freshwater systems cycle carbon along a spatial and temporal biogeochemical continuum, across which ecosystem processes contribute to transformations of organic matter (OM). Various ecological constraints impact rates OM transformation and production and consumption of the energetic end of respiration, methane. Microbiological processing and complete reduction of carbon substrates to methane...
Extraction of natural gas from shale formations using the process of hydraulic fracturing (fracking) requires the use of thousands of cubic meters of fluid. Hydraulic fracturing fluids are pumped under pressure into shale formations, fracturing the shale and releasing pockets of trapped gases. When the pressure in a natural gas...
Thirty-two chemoheterotrophic bacteria were isolated from unsaturated subsurface soil samples obtained from ca. 70 m below land surface in a high desert in southeastern Idaho. Most isolates were gram positive (84%) and strict aerobes (79%). Acridine orange direct counts of microbes in one subsurface sample showed lower numbers than similar...
Oregon State laboratories are responsible for a significant portion of the university’s overall resource and energy consumption, and therefore minimizing waste in a sustainable way should be a top priority for the university while aiming for carbon neutrality by 2025. This study addresses major factors that should be considered when...
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Rick Colwell, Committee Member, representing the College of Earth, Ocean, and
Atmospheric
Igneous oceanic crust encompasses ~60% of Earth’s surface and is composed of basalt glass and mafic, ultramafic, and felsic minerals. A vast marine aquifer lies within the crust, exchanging geochemically altered fluids with seawater from the overlying ocean at ridge crests, flanks, seamounts, and outcrops where permeable crust is exposed....
In the last three decades we have learned a great deal about microbes in subsurface environments. Once, these habitats were rarely examined, perhaps because so much of the life that we are concerned with exists at the surface and seems to pace its metabolic and evolutionary rhythms with the overt...
Bacteria and algae isolated from a wastewater oxidation pond were inoculated onto opposing surfaces of double-layer agar plates (Lutri plates) to determine the usefulness of such plates for studying microbial interactions. The altered growth characteristics of various algae depending on the species of bacteria on the adjacent medium surface indicated...
Freshwater cyanobacterial blooms are a nuisance and health threat in the Pacific Northwest. The accepted methods of characterizing these blooms by microscopic cell counts cannot differentiate between toxic and non-toxic strains of the cyanobacterium Microcystis. Also, there is limited understanding of freshwater cyanophage that may control bloom dynamics. In order...
The coast of Oregon is highly dynamic, with beach and dune morphodynamics constantly evolving in response to physical and ecological forcing at scales ranging from seconds to decades and meters to tens of kilometers. Evaluating spatial and temporal trends in shoreline evolution is paramount in understanding and eventually developing a...
The subsurface microbial biosphere in the igneous oceanic crust has implications for global geochemical cycling, early life on Earth, and the search for life on Mars. Microscopic evidence of a subsurface microbial ecosystem includes biotic alteration textures associated with basaltic glass. The exact conditions in the basaltic layer that make...