Microbial ecology of the stratified water column of the Black Sea as revealed by a comprehensive biomarker study   总被引：2，自引：0，他引：2  

Stuart G. Wakeham  Rudi Amann  Katherine H. Freeman  Ellen C. Hopmans  Bo Barker Jrgensen  Isabell F. Putnam  Stefan Schouten  Jaap S. Sinninghe Damst  Helen M. Talbot  Dagmar Woebken 《Organic Geochemistry》2007,38(12):2070-2097

The stratified water column of the Black Sea is partitioned into oxic, suboxic, and euxinic zones, each characterized by different biogeochemical processes and by distinct microbial communities. In 2003, we collected particulate matter by large volume in situ filtration at the highest resolution to date for lipid biomarker analysis and bacterioplankton for enumeration of major prokaryotic groups. Abundances of several prokaryotic groups were estimated using CARD-FISH probes specific for Bacteria, Archaea (Crenarchaeota and Euryarchaeota), epsilonproteobacteria (mainly sulfide oxidizers) and sulfate reducing bacteria. We also measured a wide range of bacterial and archaeal lipid biomarkers. Depth distributions of diagnostic biomarkers are matched with zonation of microbial processes, including aerobic bacterial oxidation of methane, oxidation of ammonium by bacteria and archaea, metal reduction, and sulfide oxidation at the chemocline, and bacterial sulfate reduction and anaerobic oxidation of methane by archaea in the anoxic zone. Cell densities for archaea and sulfate reducing bacteria are estimated based on water column biomarker concentrations and compared with CARD-FISH results.  相似文献   

Using Strong Solar Coronal Emission Lines as Coronal Flux Proxies     

Falconer  David A.  Jordan  Stuart D.  Brosius  Jeffrey W.  Davila  Joseph M.  Thomas  Roger J.  Andreatta  Vicenzo  Hara  Hirohisa 《Solar physics》1998,180(1-2):179-191

We investigate the possibility that strong EUV lines observed with the Goddard Solar EUV Rocket Telescope and Spectrograph (SERTS) provide good proxies for estimating the total coronal flux over shorter wavelength ranges. We use coordinated SERTS and Yohkoh observations to obtain both polynomial and power-law fits relating the broad-band soft X-ray fluxes to the intensities of Fexvi 335 Ú and 361 Ú, Fexv 284 Ú and 417 Ú, and Mgix 368 Ú measured with SERTS. We found that the power-law fits best cover the full range of solar conditions from quiet Sun through active region, though not surprisingly the cooler Mgix 368 Ú line proves to be a poor proxy. The quadratic polynomial fits yield fair agreement over a large range for all but the Mgix line. However, the linear fits fail conspicuously when extrapolated into the quiet-Sun regime. The implications of this work for the Heii 304 Ú line formation problem are also briefly considered.  相似文献   

Agricultural Chemical News     

Stuart Cohen 《Ground Water Monitoring & Remediation》1998,18(1):60-62

  相似文献   

Spectral Analysis in Geophysics: M. Båth. Developments in Solid Earth Geophysics no. 7. Elsevier,Amsterdam, 1974, 570 pp., 101 fig., Dfl. 120.00     

Stuart Crampin 《Tectonophysics》1975,27(1):83-84

  相似文献   

Polycyclic aromatic hydrocarbons in Recent lake sediments—I. Compounds having anthropogenic origins     

Stuart G. Wakeham  Christian Schaffner  Walter Giger 《Geochimica et cosmochimica acta》1980,44(3):403-413

Polycyclic aromatic hydrocarbons (PAH) in sediment cores from Lake Lucerne, Lake Zürich, and Greifensee, Switzerland, and Lake Washington, northwest U.S.A., have been isolated, identified and quantified by glass capillary gas chromatography and gas chromatography/mass spectrometry. Surface sediment layers are greatly enriched in PAH—up to 40 times—compared to deeper layers. In addition, concentration increases in upper sediments generally correspond to increasing industrialization and urbanization in the catchment basins of the lakes. Few PAH could be detected in pre-industrial revolution sediments, indicating that background levels for most PAH in aquatic sediments are extremely low.These results are consistent with an anthropogenic source for most of the aromatic hydrocarbons present in the modern sediments. A comparison of PAH distributions in the sediments and in possible source materials shows that urban runoff of street dust may be the most important PAH input to these lacustrine sediments. There is evidence that a significant contribution to the PAH content of street dust comes from material associated with asphalt.  相似文献   

Poly cyclic aromatic hydrocarbons in Recent lake sediments—II. Compounds derived from biogenic precursors during early diagenesis     

Stuart G. Wakeham  Christian Schaffner  Walter Giger 《Geochimica et cosmochimica acta》1980,44(3):415-429

  相似文献   

PCBs in the Hudson River     

Stuart G Wakeham 《Marine pollution bulletin》1976,7(11):206-211

Hydrocarbon distribution in sediments from three lakes are related to the level of human activity in the respective drainage basins. Petroleum hydrocarbon contamination is found in surface sediments of a lake surrounded by a major city, compared to no detectable contamination in a lake located in a National Park.  相似文献   

Active mud volcanoes on the upper slope of the western Nile deep-sea fan—first results from the P362/2 cruise of R/V Poseidon   总被引：1，自引：0，他引：1  

Tomas Feseker  Kevin R. Brown  Cecile Blanchet  Florian Scholz  Marianne Nuzzo  Anja Reitz  Mark Schmidt  Christian Hensen 《Geo-Marine Letters》2010,30(3-4):169-186

In February 2008, cruise P362/2 was undertaken aboard R/V Poseidon to the Giza and North Alex mud volcanoes (MVs) on the upper slope of the western Nile deep-sea fan. Emitted fluids were strongly depleted in chloride and rich in hydrocarbons, predominantly of thermogenic origin. In-situ sediment temperature measurements indicate extremely high and moderate levels of activity for the North Alex MV and Giza MV, respectively, and suggest rapid changes from dormant to active stages. Both the physical properties of core sediments (e.g., color and magnetic susceptibility), and their assemblages of micro- and nannofossils point to different sources for the two mud volcanoes. Biostratigraphic dating suggests source depths of 2,100–2,450 mbsf for the Giza MV and 1,150–1,550 mbsf for the North Alex MV. Very high temperatures of up to 70°C in shallow sediments at the North Alex MV can be explained only if the fluid source were warmer and deeper than the sediment source.  相似文献   

Completing the loop: from data to decisions and back to data     

Stuart Hamilton 《水文研究》2007,21(22):3105-3106

  相似文献   

The correlation between the distribution of galaxies and 21-cm emission at high redshifts     

J. Stuart B. Wyithe  Abraham Loeb 《Monthly notices of the Royal Astronomical Society》2007,375(3):1034-1042

  相似文献