نتایج جستجو برای: sediment core

تعداد نتایج: 250295  

2006
Steven L. Forman Martin Melles

This study focused on the luminescence dating of sediments from Lake El’gygytgyn, a meteorite impact crater 100 km north of the Arctic Circle in northeast Siberia, formed 3.58 Ma ago. The sediment is principally eolian deposited in to a lake with nearly permanently ice. The fine-grained polymineral and quartz extracts taken from nine distinct levels from the upper 12.3 m of sediment core PG1351...

2013
D. Magens Alfred Wegener F. Niessen

Determination of and preliminary results from the high-resolution physical properties record of the AND-1B sediment core from beneath Ross Ice Shelf, Antarctica" (2007). Summary A more than 1200 m long sediment core was drilled beneath McMurdo Ice Shelf near Ross Island (Antarctica) in austral summer 2006/07 (ANDRILL-MIS Project). High-resolution whole-core physical properties were determined a...

Journal: :Environmental science and pollution research international 2016
Parthasarathi Chakraborty Krushna Vudamala Kartheek Chennuri Kazip Armoury P Linsy Darwin Ramteke Tyson Sebastian Saranya Jayachandran Chandan Naik Richita Naik B Nagender Nath

Total Hg distributions and its speciation were determined in two sediment cores collected from the western continental marginal high of India. Total Hg content in the sediment was found to gradually increase (by approximately two times) towards the surface in both the cores. It was found that Hg was preferentially bound to sulfide under anoxic condition. However, redox-mediated reactions in the...

2012
D. P. Pompeani B. A. Steinman M. B. Abbott

A multi-proxy analysis of two sediment cores from Rantin Lake are used to reconstruct past lake-level changes and to make inferences about millennial-scale variations in precipitation/evaporation (P/E) balance in the southern Yukon, Canada between 10,900 and 3,100 cal yr BP. Analyses of calcium carbonate and organic matter concentration, magnetic susceptibility, titanium content, dry bulk densi...

Journal: :Archives of environmental contamination and toxicology 2005
S Hashimoto A Horiuchi T Yoshimoto M Nakao H Omura Y Kato H Tanaka K Kannan J P Giesy

Endocrine-disrupting chemicals with estrogenic activity (e.g., alkylphenols) have been detected in coastal Japan. We aimed to determine estrogenic activity in extracts of river water, seawater, sediments, and sediment cores from Tokyo Bay by in vitro gene expression assay. Fifty-one of 57 extracts had some estrogenic activity. E2 equivalents (ng E2 equivalents per gram dry weight or per liter a...

2017
Marion H. Stagars Sonakshi Mishra Tina Treude Rudolf Amann Katrin Knittel

Anaerobic microbial hydrocarbon degradation is a major biogeochemical process at marine seeps. Here we studied the response of the microbial community to petroleum seepage simulated for 190 days in a sediment core from the Caspian Sea using a sediment-oil-flow-through (SOFT) system. Untreated (without simulated petroleum seepage) and SOFT sediment microbial communities shared 43% bacterial genu...

Journal: :Science 1984
D J Stanley T A Nelsen R Stuckenrath

Radiocarbon dating and sedimentological studies of closely spaced cores indicate movement during the Holocene of sediments on the New Jersey continental slope and upper rise between Wilmington and Lindenkohl canyons. The uneven time-stratigraphic thickness of the late Quaternary sediment sections between cores and the nonuniform deposition rate at any given core site and among core sites show t...

2016
Ai-jun Wang Ahmed Kawser Yong-hang Xu Xiang Ye Seema Rani Ke-liang Chen

Heavy metal contamination of aquatic environment has attracted global attention owing to its abundance, persistence, and environmental toxicity, especially in developing countries like Bangladesh. Five heavy metals, namely chromium (Cr), copper (Cu), nickel (Ni), lead (Pb) and zinc (Zn) were investigated in surface and core sediments of the Karnaphuli River (KR) estuary in Chittagong, Banglades...

Journal: :Applied and environmental microbiology 2003
John P Bowman Robert D McCuaig

16S ribosomal DNA (rDNA) clone library analysis was conducted to assess prokaryotic diversity and community structural changes within a surficial sediment core obtained from an Antarctic continental shelf area (depth, 761 m) within the Mertz Glacier Polynya (MGP) region. Libraries were created from three separate horizons of the core (0- to 0.4-cm, 1.5- to 2.5-cm, and 20- to 21-cm depth positio...

2012
Byron A. Steinman Mark B. Abbott Daniel B. Nelson Nathan D. Stansell Bruce P. Finney Daniel J. Bain Michael F. Rosenmeier

Simulations conducted using a coupled lake-catchment isotope mass balance model forced with continuous precipitation, temperature, and relative humidity data successfully reproduce (within uncertainty limits) long-term (i.e., multidecadal) trends in reconstructed lake surface elevations and sediment core oxygen isotope (dO) values at Castor Lake and Scanlon Lake, north-central Washington. Error...

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