Use of dust storm observations on satellite images to identify areas vulnerable to severe wind erosion     

Carol S. Breed  John F. McCauley 《Climatic change》1986,9(1-2):243-258

Blowing dust is symptomatic of severe wind erosion and deterioration of soils in areas undergoing dessication and/or devegetation. Dust plumes on satellite images can commonly be traced to sources in marginally arable semiarid areas where protective lag gravels or vegetation have been removed and soils are dry, as demonstrated for the Portales Valley, New Mexico. Images from Landsat and manned orbiters such as Skylab and the Space Shuttle are useful for illustrating the regional relations of airborne dust plumes to source areas. Geostationary satellites such as GOES are useful in tracking the time-histories of episodic dust storms. These events sometimes go unrecognized by weather observers and are the precursors of long-term land degradation trends. In areas where soil maps and meteorological data are inadequate, satellite images provide a means for identifying problem areas where measures are needed to control or mitigate wind erosion.  相似文献   

Isotopic composition of silicon in meteorites     

Carol Molinivelsko  Toshiko K. Mayeda  Robert N. Clayton   《Geochimica et cosmochimica acta》1986,50(12):2719-2726

Samples of bulk meteorites show only mass-dependent fractionation of silicon isotopes. No isotopic anomalies were found. The variation of the ratios ²⁹Si/²⁸Si and ³⁰Si/²⁸Si over the meteorite classes is small; 1%. per mass unit difference. The average Si isotopic composition for each class of meteorites is identical, within analytical uncertainties. This is quite unlike O, whose anomalous isotopic abundances in bulk samples differentiate among the classes of meteorites. The overlapping abundance ranges of Si isotopes among many classes of meteorites suggest closed-system behavior for this element prior to meteorite accretion and allow calculation of an average solar system Si isotope composition.  相似文献   

Pyrolysis-GC characterization of whole rock and kerogen-concentrate samples of immature Jurassic source rocks from NW-Germany     

Carol Arnosti  Peter J. Müller   《Organic Geochemistry》1987,11(6)

Nine rock samples from three Jurassic stratigraphic units of a shallow core from NW Germany were analyzed by pyrolysis-gas chromatography. The units contain a mixed Type-II/III kerogen (Dogger-α), a hydrogen-rich Type-II kerogen (Lias-), and a hydrogen-poor Type-III kerogen (Lias-δ). All of the kerogen was immature (R_o = 0.5%). Two sets of kerogen concentrates (“AD”: HCl/HF followed by a density separation, and “A”: only acid treatment) prepared from the rock samples were also analyzed to make a detailed comparison of the pyrolysates of rock and corresponding kerogen-concentrates.Hydrogen-index (HI) values of the kerogen concentrates prepared from organic-carbon poor rock were nearly 200% higher than HI values of the rock samples. Changes in HI were minimal for the samples containing Type-II kerogen. The A and AD samples from the C_org-poor rock yielded pyrolysates with n-alkane series of very different molecular lengths. Pyrograms of the rock samples had n-alkane series extending to n-C₁₄; the chromatograms of the A samples reached the n-C₁₄-nC₂₀ range. The AD samples from C_org-poor rock and all three sample types from the C_org-rich rock had n-alkane series up to n-C₂₉. The benzene/hexane and toluene/heptane ratios for the C_org-poor rock and A samples were far higher than for the AD samples, which had ratios similar to those of all three sample types from the C_org-rich rocks. These results indicate that choice of kerogen preparation method is critical when C_org-poor samples are analyzed.  相似文献   

Book reviews     

Carol Stoker  S. K. Sinha  David Pimentel 《Climatic change》1984,6(1):99-102

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The Geochemical Evolution of Riparian Ground Water in a Forested Piedmont Catchment   总被引：2，自引：0，他引：2  

Douglas A. Burns  L. Niel Plummer  Jeffrey J. McDonnell    Eurybiades Busenberg  Gerolamo C. Casile  Carol Kendall  Richard P. Hooper  James E. Freer  Norman E. Peters  Keith Beven  Peter Schlosser 《Ground water》2003,41(7):913-925

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Bathymetric patterns of deep-sea gastropod species diversity in 10 basins of the Atlantic Ocean and Norwegian Sea     

Carol T. Stuart  & Michael A. Rex 《Marine Ecology》2009,30(2):164-180

Bathymetric patterns of macrofaunal species diversity are best documented in the western North Atlantic where diversity is a unimodal function of depth, peaking in the mid-bathyal zone and being depressed in the upper slope and abyss. There are few inter-basin studies of diversity-depth trends that are controlled for taxonomy, sampling gear, and diversity measures. In this paper, we compare gastropod diversity gradients in the North American Basin of the Atlantic to estimates of diversity in 9 other regions: the Norwegian Sea, West European Basin, Guiana Basin, Gambia Basin, Equatorial Mid-Atlantic, Brazil Basin, Angola Basin, Cape Basin and Argentine Basin. All samples were collected with epibenthic sleds, and diversity calculated by the Sanders-Hurlbert normalized expected number of species. While sampling in other regions is generally less complete than in the western North Atlantic, results indicate that a unimodal pattern is not universal. Diversity can increase, decrease or show no relationship with depth. The level of diversity also varies among basins relative to the western North Atlantic, being depressed in the Norwegian Sea, at bathyal depths in the eastern North Atlantic, and below an oxygen minimum zone in the Cape Basin, and generally elevated at tropical latitudes and in abyssal regions where food supply is high. Associations between gastropod diversity and the ecology and geology of basins suggest that productivity, oxygen concentration, hydrographic disturbance and evolutionary-historical processes may be implicated in shaping bathymetric diversity gradients, but specific causes are difficult to discern. Much more intensive sampling, analyses of other major taxa, and more detailed ecological data are necessary to understand deep-sea biogeography at within- and between-basin spatial scales.  相似文献   

ENVIRONMENTAL DEGRADATION IN BRAZILIAN AMAZONIA: PERSPECTIVES IN US NEWS MEDIA*     

Jacob Bendix  Carol M. Liebler 《The Professional geographer》1991,43(4):474-485

While news media play a major role in shaping public opinion and government policy, existing literature suggests that coverage of both the third world and environmental issues is superficial and crisis-oriented. This study uses the example of Amazonian deforestation to explore the quantity and content of coverage in influential American newspapers. We found that coverage included a wide range of (sometimes) contradictory theories regarding the causes of deforestation, and that the amount, but not the nature, of the coverage changed in response to a “crisis.”  相似文献   

An ensemble climate projection for Africa     

Carlo Buontempo  Camilla Mathison  Richard Jones  Karina Williams  Changgui Wang  Carol McSweeney 《Climate Dynamics》2015,44(7-8):2097-2118

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Comparison of Enterococcus density estimates in marine beach and bay samples by real-time polymerase chain reaction, membrane filtration and defined substrate testing     

Ferretti JA  Tran HV  Cosgrove E  Protonentis J  Loftin V  Conklin CS  Grant RN 《Marine pollution bulletin》2011,62(5):1066-1072

Currently, densities of Enterococcus in marine bathing beach samples are performed using conventional methods which require 24 h to obtain results. Real-time PCR methods are available which can measure results in as little as 3 h. The purpose of this study was to evaluate a more rapid test method for the determination of bacterial contamination in marine bathing beaches to better protect human health. The geometric mean of Enterococcus densities using Enterolert® defined substrate testing and membrane filtration ranged from 5.2 to 150 MPN or CFU/100 mL and corresponding qPCR results ranged from 6.6 to 1785 CCE/100 mL. The regression analysis of these results showed a positive correlation between qPCR and conventional tests with an overall correlation (r) of 0.71. qPCR was found to provide accurate and sensitive estimate of Enterococcus densities and has the potential to be used as a rapid test method for the quantification of Enterococcus in marine waters.  相似文献   

Organic carbon amendments for passive in situ treatment of mine drainage: Field experiments     

Matthew B.J. Lindsay  David W. BlowesPeter D. Condon  Carol J. Ptacek 《Applied Geochemistry》2011,26(7):1169-1183

A field-scale experiment was conducted to evaluate various organic C sources as amendments for passive treatment of tailings pore water. Varied mixtures of peat, spent-brewing grain (SBG) and municipal biosolids (MB) were assessed for the potential to promote dissimilatory sulfate reduction (DSR) and metal-sulfide precipitation. Five amended cells and one control were constructed in the vadose zone of a sulfide- and carbonate-rich tailings deposit, and the geochemistry, microbiology and mineralogy were monitored for 4 a. Increases in pore-water concentrations of dissolved organic C (DOC) and decreases in aqueous SO₄ concentrations of >2500 mg L⁻¹ were observed in cells amended with peat + SBG and peat + SBG + MB. Removal of SO₄ was accompanied by shifts in δ³⁴S-SO₄ values of >+30‰, undersaturation of pore water with respect to gypsum [CaSO₄·2H₂O], and increased populations of SO₄-reducing bacteria (SRB). Decreases in aqueous concentrations of Zn, Mn, Ni, Sb and Tl were observed for these cells relative to the control. Organic C introduction also supported growth of Fe-reducing bacteria (IRB) and increases in Fe and As concentrations. Enhanced Fe and As mobility occurred in all cells; however, maximum concentrations were observed in cells amended with MB. Subsequent decreases in Fe and As concentrations were attributed to DSR and metal-sulfide precipitation. The common presence of secondary Zn-S and Fe-S phases was observed by field emission-scanning electron microscopy (FE-SEM) and energy dispersive X-ray (EDS) spectroscopy. Selective extractions indicated that large decreases in water-soluble SO₄ occurred in cells that supported DSR. Furthermore, amendments that supported DSR generally were characterized by slight decreases in solid-phase concentrations of extractable metal(loid)s. Amendment of tailings with organic C amendments that supported ongoing DOC production and DSR was essential for sustained treatment.  相似文献