Biologist
Geology, Minerals, Energy, and Geophysics Science Center
Email:
jmcfarland@usgs.gov
Office Phone:
650-329-5241
Fax:
650-329-5203
ORCID:
0000-0001-9672-8597
Supervisor:
Mark P Waldrop
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These datasets are from an incubation experiment with a combination of two minerals (feldspar or amorphous aluminum hydroxide), one living species of bacteria (Escherichia coli), and one added form of C (Arthrobacter crystallopoietes necromass). We characterized the sorptive properties of the minerals with batch sorption experiments using four low molecular weight C substrates (glucose, oxalic acid, glutamic acid, p-hydroxybenzoic acid): this data is provided in the SterileSorptionData file. We then conducted a 3-wk long incubation in serum vials or imaging chambers. In both incubations, feldspar (200 mg) or amorphous aluminum hydroxide (100 mg) was given 1 of 4 different treatments: (1) a water control with autoclaved...
Categories: Data;
Tags: Mineralogy,
Raman spectroscopy,
Soil Sciences,
USGS Science Data Catalog (SDC),
biota, All tags...
carbon cycling,
carbon isotope analysis,
environment,
mineralogy,
sorption, Fewer tags
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Geophysical measurements and related field data were collected by the U.S. Geological Survey (USGS) at the Alaska Peatland Experiment (APEX) site in Interior Alaska from 2018 to 2020 to characterize subsurface thermal and hydrologic conditions along a permafrost thaw gradient. The APEX site is managed by the Bonanza Creek LTER (Long Term Ecological Research). In July 2018, soil temperature and moisture sensors were installed at six out of the nine instrument locations (APEX1, APEX2, APEX3, APEX4, APEX7, APEX9). Thermistors (PS103J2, US Sensor, Orange, CA, USA) were placed at depths of 5, 30, 60, 120, and 180 centimeters (cm) with three replicates. Three sites (APEX1, APEX4, APEX9) contained an additional single...
Categories: Data;
Types: Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
Shapefile;
Tags: Alaska,
Bonanza Creek,
Disturbance,
Fairbanks North Star,
GGGSC, All tags...
Geology, Geophysics, and Geochemistry Science Center,
Hydrologic processes,
Land Change Science Program,
Permafrost,
U.S. Geological Survey,
USGS,
environment,
field monitoring stations,
geoscientificInformation,
hydrologic processes,
permafrost,
soil moisture,
soil temperature, Fewer tags
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Though the primary sources of organic matter to soil are plant inputs, the role of microorganisms as mediators of soil organic carbon preservation is increasingly recognized in the context of biological contributions to long-lived soil organic matter. However, current knowledge of sub-soil processes is insufficient to model microbial-derived carbon flow particularly at depth. Using a previously studied paleo-marine terrace (90 ka) located just north of Santa Cruz, CA, we characterized for three depths in the soil profile (-25, -75, and -125 cm) the short-term (days to weeks) and intermediate-term (months to years) fate of some of the most dynamic components of soil organic matter pools, low molecular weight organic...
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Abiotic sorption experiments were conducted with four carbon substrates (glucose, glutamic acid, oxalic acid, para-hydroxybenzoic acid) on four clay minerals (kaolinite, feldspar, ferrihydrite, amorphous aluminum hydroxide) after sterilization by gamma irradiation. The adsorption isotherms were carried across a range of substrate carbon concentrations (0, 20, 100, and 500 mg carbon per L) and pH conditions (approximately 5 – 9) in a background of 10 mM NaCl for 48 hours. The data release contains measured pH values and carbon concentrations before and after the sorption experiments. The release provides derived values of carbon sorption (e.g., carbon sorbed per mineral surface area) as well as characterization of...
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Abstract (from http://www.nature.com/nature/journal/v521/n7551/full/nature14238.html): Over 20% of Earth’s terrestrial surface is underlain by permafrost with vast stores of carbon that, once thawed, may represent the largest future transfer of carbon from the biosphere to the atmosphere1. This process is largely dependent on microbial responses, but we know little about microbial activity in intact, let alone in thawing, permafrost. Molecular approaches have recently revealed the identities and functional gene composition of microorganisms in some permafrost soils2, 3, 4 and a rapid shift in functional gene composition during short-term thaw experiments3. However, the fate of permafrost carbon depends on climatic,...
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