Magnesium Perchlorate as an Alternative Water Trap in AMS Graphite Sample Preparation: A Report On Sample Preparation at Kccams at the University of California, Irvine

Santos, Guaciara M.; Southon, John; Druffel-Rodriguez, Kevin C; Griffin, Sheila; Mazon, Maya

doi:10.1017/s0033822200039485

Cited by 144 publications

(144 citation statements)

References 2 publications

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“…⌬ 14 C values for all GDGTs were measured at the Keck Carbon Cycle AMS facility at the University of California, Irvine by using the ultra-micro AMS methods of Santos et al (42). Further methods for the quantification of sample processing blanks and error corrections made to measurements are reported in Supporting Text, which is published as supporting information on the PNAS web site.…”

Section: Methodsmentioning

confidence: 99%

Quantifying archaeal community autotrophy in the mesopelagic ocean using natural radiocarbon

Ingalls

Shah

Hansman

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

419

382

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An ammonia-oxidizing, carbon-fixing archaeon, Candidatus ''Nitrosopumilus maritimus,'' recently was isolated from a salt-water aquarium, definitively confirming that chemoautotrophy exists among the marine archaea. However, in other incubation studies, pelagic archaea also were capable of using organic carbon. It has remained unknown what fraction of the total marine archaeal community is autotrophic in situ. If archaea live primarily as autotrophs in the natural environment, a large ammonia-oxidizing population would play a significant role in marine nitrification. Here we use the natural distribution of radiocarbon in archaeal membrane lipids to quantify the bulk carbon metabolism of archaea at two depths in the subtropical North Pacific gyre. Our compound-specific radiocarbon data show that the archaea in surface waters incorporate modern carbon into their membrane lipids, and archaea at 670 m incorporate carbon that is slightly more isotopically enriched than inorganic carbon at the same depth. An isotopic mass balance model shows that the dominant metabolism at depth indeed is autotrophy (83%), whereas heterotrophic consumption of modern organic carbon accounts for the remainder of archaeal biomass. These results reflect the in situ production of the total community that produces tetraether lipids and are not subject to biases associated with incubation and͞or culture experiments. The data suggest either that the marine archaeal community includes both autotrophs and heterotrophs or is a single population with a uniformly mixotrophic metabolism. The metabolic and phylogenetic diversity of the marine archaea warrants further exploration; these organisms may play a major role in the marine cycles of nitrogen and carbon.biomarkers ͉ carbon isotopes ͉ microbial ecology ͉ nitrogen cycle ͉ oceanography N onthermophilic archaea represent up to 40% of the free-living prokaryotic community in the water column of the world's oceans (1-6), but until recently there has been limited information about the sources of carbon and energy that fuel these organisms (7-11). The characteristic membrane lipids of planktonic archaea include glycerol dialkyl glycerol tetraethers (GDGTs) (12). These compounds are ubiquitous in marine sediments and ocean water (12-15). The relative abundance of individual GDGTs recovered from sediments is used to reconstruct sea-surface temperatures (16)(17)(18). This distribution, known as TEX 86 , has been shown through experimental manipulation of surface-water mesocosm experiments to respond to changes in incubation temperature (18). In addition, the ␦ 13 C values of GDGTs display a remarkably constant offset from ␦ 13 C values of dissolved inorganic carbon (DIC) over a range of settings and geologic time (13,(19)(20)(21). The collective metabolic activities of the numerous archaea in the ocean are likely to play a significant role in the cycling of organic carbon (OC) and nutrients, and their membrane lipids show significant utility for paleoceanography. However, neither the metabolic requiremen...

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Section: Methodsmentioning

confidence: 99%

Quantifying archaeal community autotrophy in the mesopelagic ocean using natural radiocarbon

Ingalls

Shah

Hansman

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

419

382

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“…The graphite was formed at 540°C. Magnesium perchlorate is used to trap water (44), and it was replaced for every new sample.…”

Section: Methodsmentioning

confidence: 99%

Radiocarbon dating of charcoal and bone collagen associated with early pottery at Yuchanyan Cave, Hunan Province, China

Yuan

Bar‐Yosef

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

157

101

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Yuchanyan Cave in Daoxian County, Hunan Province (People's Republic of China), yielded fragmentary remains of 2 or more ceramic vessels, in addition to large amounts of ash, a rich animal bone assemblage, cobble and flake artifacts, bone tools, and shell tools. The artifacts indicate that the cave was a Late Paleolithic foragers' camp. Here we report on the radiocarbon ages of the sediments based on analyses of charcoal and bone collagen. The best-preserved charcoal and bone samples were identified by prescreening in the field and laboratory. The dates range from around 21,000 to 13,800 cal BP. We show that the age of the ancient pottery ranges between 18,300 and 15,430 cal BP. Charcoal and bone collagen samples located above and below one of the fragments produced dates of around 18,000. These ceramic potsherds therefore provide some of the earliest evidence for pottery making in China.ancient ceramics ͉ archaeology ͉ 14 C ͉ Yangzi River

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“…The samples were washed with an acid-base-acid pretreatment described by Santos [28] to remove any surface contaminants. After washing to neutral pH with de-ionized water, the samples were put into a vacuum oven with a drying temperature of 50°C for 24 h. The samples were prepared at the College of Urban and Environmental Science & Laboratory for Earth Surface Process, Peking University.…”

Section: Sample Preparationmentioning

confidence: 99%

Regional Δ14C patterns and fossil fuel derived CO2 distribution in the Beijing area using annual plants

Ding

et al. 2011

Chin. Sci. Bull.

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Magnesium Perchlorate as an Alternative Water Trap in AMS Graphite Sample Preparation: A Report On Sample Preparation at Kccams at the University of California, Irvine

Cited by 144 publications

References 2 publications

Quantifying archaeal community autotrophy in the mesopelagic ocean using natural radiocarbon

Quantifying archaeal community autotrophy in the mesopelagic ocean using natural radiocarbon

Radiocarbon dating of charcoal and bone collagen associated with early pottery at Yuchanyan Cave, Hunan Province, China

Regional Δ14C patterns and fossil fuel derived CO2 distribution in the Beijing area using annual plants

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