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L.L. Knobel

Publications and source records attributed to L.L. Knobel.

At least 19 recordsLinked to original sources
USGS2002

A hydrogen-based subsurface microbial community dominated by methanogens

The search for extraterrestrial life may be facilitated if ecosystems can be found on Earth that exist under conditions analogous to those present on other planets or moons. It has been proposed, on the basis of geochemical and thermodynamic considerations, that geologically derived hydrogen might support subsurface microbial communities on Mars and Europa in which methanogens form the base of the ecosystem1-5. Here we describe a unique subsurface microbial community in which hydrogen-consuming, methane-producing Archaea far outnumber the Bacteria. More than 90% of the 16s ribosomal DNA sequences recovered from hydrothermal waters circulating through deeply buried igneous rocks in Idaho are related to hydrogen-using methanogenic microorganisms. Geochemical characterization indicates that geothermal hydrogen, not organic carbon, is the primary energy source for this methanogen-dominated microbial community. These results demonstrate that hydrogen-based methanogenic communities do occur in Earth's subsurface, providing an analogue for possible subsurface microbial ecosystems on other planets.

Nature↗
USGS2001

Radiochemical and chemical constituents in water from selected wells south of the Idaho National Engineering and Environmental Laboratory, Idaho

The U.S. Geological Survey and the Bureau of Land Management, in cooperation with the U.S. Department of Energy, sampled water from five stock wells to monitor water quality of the Snake River Plain aquifer south of the Idaho National Engineering and Environmental Laboratory. The samples were analyzed for selected radiochemical and chemical constituents. The concentrations of strontium-90, transuranic elements, and cesium-137 in all samples were less than the reporting level. Concentrations of tritium in four samples and concentrations of gross alpha-and beta-particle radioactivity in all samples were greater than the reporting level. Most of the inorganic-constituent concentrations were greater than the minimum reporting levels. Concentrations of all 63 purgeable organic compounds analyzed for were less than the respective minimum reporting levels.

Open-File Report↗
USGS1998

Geochemistry of the northern Atlantic Coastal Plain aquifer system

Sediments of the northern Atlantic Coastal Plain comprise a complex multiaquifer flow system. On a large scale (greater than 500 square miles) ground water in this system evolves from predominantly calcium magnesium bicarbonate water with a low dissolved-solids content and low pH, near outcrop-recharge areas, to predominantly sodium bicarbonate water with a high-dissolved solids content and high pH, downgradient. This sodium bicarbonate water then grades into a sodium chloride water. This large-scale predictable progression of hydrochemical facies results from the summation of many smaller scale geochemical processes that chiefly depend on the sedimentary depositional environments of the aquifers.

Northern Atlantic coastal plain↗
USGS1994

Documentation of hydrochemical-facies data and ranges of dissolved-solids concentrations for the northern Atlantic Coastal Plain aquifer system, New Jersey, Delaware, Maryland, Virginia and North Carolina supplement to Professional paper 1404-L

Hydrochemical-facies data and ranges of dissolved- solids concentrations used to construct hydrochemical-facies maps and sections for U.S. Geological Survey Professional Paper 1404-L have not been previously published. In this report, the data are contained on a 3-1/2 high-density diskette in a file presented in American International Standard Code for Information Exchange (ASCII) format. The file requires about 0.2 megabyte of disk space on an IBM-compatible microcomputer using the MS-DOS operating system.

Delaware, Maryland, New Jersey, North Carolina, Vi↗
USGS1994

Stable isotopes of hydrogen and oxygen in surface water and ground water at selected sites on or near the Idaho National Engineering Laboratory, Idaho

Relative stable isotopic ratios for hydrogen and oxygen compared to standard mean ocean water are presented for water from 4 surface-water sites and 38 ground-water sites on or near the Idaho National Engineering Laboratory (INEL). The surface-water samples were collected monthly from March 1991 through April 1992 and after a storm event on June 18, 1992. The ground-water samples either were collected during 1991 or 1992. These data were collected as part of the U.S. Geological Survey's continuing hydrogeological investigations at the INEL. The relative isotopic ratios of hydrogen and oxygen are reported as delta H-2 and as delta 0-18, respectively. The values in water from the four surface-water sites ranged from -143.0 to -122 and from -18.75 to -15.55, respec- tively. The values in water from the 38 ground- water sites ranged from -141.0 to -120.0 and from -18.55 to -14.95, respectively.

Open-File Report↗
USGS1992

Comparison of the effects of filtration and preservation methods on analyses for strontium-90 in ground water

From 1952 to 1988, about 140 curies of strontium-90 were discharged in liquid waste to disposal ponds and wells at the INEL (Idaho National Engineering Laboratory). Water from four wells was sampled as part of the U.S. Geological Survey's quality-assurance program to evaluate the effects of filtration and preservation methods on strontium-90 concentrations in ground water at the INEL. Water from each well was filtered through either a 0.45- or a 0.1-micrometer membrane filter; unfiltered samples also were collected. Two sets of filtered and two sets of unfiltered water samples were collected at each well. One of the two sets of water samples was field acidified. Strontium-90 concentrations ranged from below the reporting level to 52±4 picocuries per liter. Descriptive statistics were used to determine reproducibility of the analytical results for strontium-90 concentrations in water from each well. Comparisons were made with unfiltered, acidified samples at each well. Analytical results for strontium-90 concentrations in water from well 88 were not in statistical agreement between the unfiltered, acidified sample and the filtered (0.45 micrometer), acidified sample. The strontium-90 concentration for water from well 88 was less than the reporting level. For water from wells with strontium-90 concentrations at or above the reporting level, 94 percent or more of the strontium-90 is in true solution or in colloidal particles smaller than 0.1 micrometer. These results suggest that changes in filtration and preservation methods used for sample collection do not significantly affect reproducibility of strontium-90 analyses in ground water at the INEL.

Environmental Monitoring and Assessment↗