نتایج جستجو برای: marine sediments

تعداد نتایج: 116648  

Journal: :Applied and environmental microbiology 1977
C P Gerba E M Smith J L Melnick

Several investigators have reported on the detection of enteric viruses in marine sediments, but none determined the efficiency of their methods and only limited volumes of sediment were sampled. The purpose of this investigation was to develop a quantitative method for detecting enteroviruses in marine sediments so that their relative proportion to viruses freely suspended in estuarine water c...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2006
T M Hill J P Kennett D L Valentine Z Yang C M Reddy R K Nelson R J Behl C Robert L Beaufort

Marine hydrocarbon seepage emits oil and gas, including methane ( approximately 30 Tg of CH(4) per year), to the ocean and atmosphere. Sediments from the California margin contain preserved tar, primarily formed through hydrocarbon weathering at the sea surface. We present a record of variation in the abundance of tar in sediments for the past 32,000 years, providing evidence for increases in h...

2014
Siwatt Pongpiachan

Identification of Tsunami deposits has long been a controversial issue among geologists. Although there are many identification criteria based on the sedimentary characteristics of unequivocal Tsunami deposits, the concept still remains ambiguous. Apart from relying on some conventional geological, sedimentological, and geoscientific records, geologists need some alternative "proxies" to identi...

2004
Andreas Teske

Site 1231 of the Ocean Drilling Project (ODP) was characterized by low concentrations of organic carbon, as well as low cell numbers and biological activity rates. A 16S rRNA survey was performed in order to analyse the microbial community composition of these central oceanic sediments. Archaeal 16S rRNA genes from subsurface sediments at Site 1231 (1.8, 9.0, and 43 mbsf) were affiliated with u...

Journal: :Environmental science & technology 2008
Jerome M Kemper Emaan Ammar William A Mitch

We report that hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) was rapidly destroyed by sulfides in the presence of black carbon, forming nitrite and formaldehyde, rather than toxic nitrosated reduction products. Although traditionally viewed as inactive sorbents, black carbons have been noted to participate in the destruction of certain contaminants, such as azo dyes, via quinonoid groups. Howev...

Journal: :Journal of applied microbiology 2005
D M Ferguson D F Moore M A Getrich M H Zhowandai

AIMS To determine the levels and species distribution of enterococci in intertidal and marine sediments and coastal waters at two beaches frequently in violation of bacterial water standards. METHODS AND RESULTS Faecal indicator bacteria were extracted from sediment and enumerated using membrane filtration. High levels of enterococci were detected in intertidal sediments in a seasonal river a...

2004
Jonathan Warrick

Introduction: The California Coastal Sediment Management Workgroup (CSMW) has requested proposals from the U.S. Geological Survey (USGS) Western Coastal and Marine Geology Team (WCMG) to evaluate the transport and fate of fine sediments discharged into California coastal waters. The rationale for this proposed work is a need to better understand the environmental consequences of beach nourishme...

2017
Andrea Nuzzo Andrea Negroni Giulio Zanaroli Fabio Fava

BACKGROUND Microbial reductive dechlorination of polychlorinated biphenyls (PCBs) plays a major role in detoxifying anoxic contaminated freshwater and marine sediments from PCBs. Known members of the phylum Chloroflexi are typically responsible for this activity in freshwater sediments, whereas less is known about the microorganisms responsible for this activity in marine sediments. PCB-respiri...

2015
Tao Zhang Neng Fei Wang Yu Qin Zhang Hong Yu Liu Li Yan Yu

This study assessed the diversity and distribution of fungal communities in eight marine sediments of Kongsfjorden (Svalbard, High Arctic) using 454 pyrosequencing with fungal-specific primers targeting the internal transcribed spacer (ITS) region of the ribosomal rRNA gene. Sedimentary fungal communities showed high diversity with 42,219 reads belonging to 113 operational taxonomic units (OTUs...

Journal: :Science 2014
Marshall W Bowles José M Mogollón Sabine Kasten Matthias Zabel Kai-Uwe Hinrichs

Sulfate reduction is a globally important redox process in marine sediments, yet global rates are poorly quantified. We developed an artificial neural network trained with 199 sulfate profiles, constrained with geomorphological and geochemical maps to estimate global sulfate-reduction rate distributions. Globally, 11.3 teramoles of sulfate are reduced yearly (~15% of previous estimates), accoun...

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