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...
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...
Bench scale column studies were used to examine the partitioning of microorganisms between groundwater
and a geologic medium and to examine the effect of hydrogeology (i.e., porous- versus fracture-flow) on
organism partitioning. Replicated columns were constructed with intact basalt core segments that contained
natural fractures and with the same basalt...
Ocean Drilling Program (ODP) Leg 204 to Hydrate Ridge, located on the continental slope offshore Oregon (USA), was the first drilling expedition dedicated to understanding gas hydrate processes in accretionary complexes and provided a testbed for a number of different techniques for estimating the gas hydrate content of sediments. It...
Genomic libraries derived from environmental DNA (metagenomic libraries) are useful for characterizing
uncultured microorganisms. However, conventional library-screening techniques permit characterization of
relatively few environmental clones. Here we describe a novel approach for characterization of a metagenomic
library by hybridizing the library with DNA from a set of groundwater isolates, reference...
Methane hydrate found in marine sediments is thought to contain gigaton quantities of methane and is
considered an important potential fuel source and climate-forcing agent. Much of the methane in hydrates is
biogenic, so models that predict the presence and distribution of hydrates require accurate rates of in situ
methanogenesis....
The degradation of organic carbon in subseafloor sediments on continental margins contributes to the largest reservoir of methane on Earth. Sediments in the Andaman Sea are composed of ~ 1% marine-derived organic carbon and biogenic methane is present. Our objective was to determine microbial abundance and diversity in sediments that...
Microbial communities in cores obtained from methane hydrate-bearing deep marine sediments (down to more than 300 m below the seafloor) in the forearc basin of the Nankai Trough near Japan were characterized with cultivation-dependent and -independent techniques. Acridine orange direct count data indicated that cell numbers generally decreased with sediment...
Sporosarcina pasteurii is known to produce calcite or biocement in the presence of urea and Ca²⁺. Herein, we report the use of novel ultramicrosensors such as pH, Ca²⁺, and redox sensors, along with a scanning electrochemical microscope (SECM), to monitor a real-time, bacteria-mediated urea hydrolysis process and subsequent changes in...