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Quantifying archaeal community autotrophy in the mesopelagic ocean using natural radiocarbon.
An ammonia-oxidizing, carbon-fixing archaeon, Candidatus "Nitrosopumilus maritimus," recently was isolated from a salt-water aquarium, definitively confirming that chemoautotrophy exists among theExpand
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Ultra small-mass AMS 14C sample preparation and analyses at KCCAMS/UCI Facility
We have developed techniques for accurately and precisely measuring samples containing less than a few hundred micrograms of carbon, using a compact AMS system (NEC 0.5 MV 1.5SDH-1). DetailedExpand
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THE PHYTOLITH 14C PUZZLE: A TALE OF BACKGROUND DETERMINATIONS AND ACCURACY TESTS
Over the past decades, analysis of occluded carbon in phytoliths (opaline silica mineral bodies that form in and between plant cells) has become a workhorse of paleoclimate and archaeologicalExpand
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Analysis of plutonium isotopes in marine samples by radiometric, ICP-MS and AMS techniques
IAEA reference materials (radionuclides in the marine environment) collected in areas affected by nuclear reprocessing plants and nuclear weapons tests have been analysed by semiconductorExpand
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The Keck Carbon Cycle AMS Laboratory, University of California, Irvine; initial operation and a background surprise.
A new radiocarbon accelerator mass spectrometry (AMS) laboratory for carbon cycle studies has been established at the University of California, Irvine. The 0.5MV AMS system was installed in mid-2002Expand
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Recent (< 4 year old) leaf litter is not a major source of microbial carbon in a temperate forest mineral soil
Microbial communities in soil A horizons derive their carbon from several potential sources: organic carbon (C) transported down from overlying litter and organic horizons, root-derived C, or soilExpand
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Radiocarbon Dating from 40 to 60 ka BP at Border Cave, South Africa
Abstract We present 21 radiocarbon dates on 19 charcoal samples from the sedimentary sequence preserved in Border Cave, South Africa. The background radiocarbon activity for charcoal from the caveExpand
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Blank assessment for ultra-small radiocarbon samples: chemical extraction and separation versus AMS
The Keck Carbon Cycle AMS facility at the University of California, Irvine (KCCAMS/UCI) has developed protocols for analyzing radiocarbon in samples as small as ~0.001 mg of carbon (C). Mass-balanceExpand
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Re-anchoring the late Pleistocene tephrochronology of New Zealand based on concordant radiocarbon ages and combined 238U/230Th disequilibrium and (U–Th)/He zircon ages
Abstract The caldera-forming Rotoiti eruption from Okataina volcano was one of the largest rhyolite events of the last 100 ka in the Taupo Volcanic Zone, New Zealand. Its associated widespread tephraExpand
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Possible source of ancient carbon in phytolith concentrates from harvested grasses
Plants absorb and transport silicon (Si) from soil, and precipitation of Si within the living plants results in micrometric amorphous biosilica particles known as phytoliths. During phytolithExpand
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