Comparison of production computation methods in a Southeastern North CarolinaSpartina alterniflora salt marsh     

Dale M. Shew  Rick A. Linthurst  Ernest D. Seneca 《Estuaries and Coasts》1981,4(2):97-109

Tagging studies ofSpartina alterniflora Loisel showed no significant differences in stem longevity of short, medium, and tall height forms. Mean stem longevity was 7.9 months, and the experimental turnover rate was 1.5 crops per yr. Five methods to measure productivity (peak standing crop, Milner and Hughes, Smalley, Wiegert and Evans, and Lomnicki, et al.) yielded annual net aerial primary production (NAPP) estimates ranging from 214 to 1,038 g dry wt per m² per yr in a stand of shortSpartina. Turnover rates were computed for each of the methods by dividing the respective production value by the peak standing crop (242 g dry wt per m² per yr). Each computed turnover rate was compared with the experimental value of 1.5 crops per yr to ultimately determine that the methods of peak standing crop, Milner and Hughes, and Smalley were underestimates and that the Wiegert and Evans method was an overestimate of NAPP in tidal marsh systems. Based on its calculated turnover rate of 1.9 crops per yr, a modified Lomnicki, et al. method provided the best NAPP estimate (454 g dry wt per m² per yr).  相似文献   

Decomposition ofSpartina alterniflora in different seasons and habitats of a Northern Massachusetts salt marsh,and a comparison with other Atlantic regions     

Paul A. Montagna  Ernest Ruber 《Estuaries and Coasts》1980,3(1):61-64

Packets of freshly harvested liveSpartina alterniflora were placed on the marsh surface, in a tidal ditch, in a pool contacting sides and bottom, and in the center-bottom of the same pool in September 1972. Rates of loss were the same for all four sites through day 242. After that packets on the marsh surface decomposed slower. A second experiment was begun in July only at the marsh surface and pool side sites. These lost dry weight much more rapidly than packets started in September. Populations of bacteria, fungi, diatoms, flagellates, ciliates and nematodes within the packets peaked within 60 days then decreased proportionately with the loss of dry weight in packets through day 242. After this, bacterial numbers decreased more rapidly presumably in response to a qualitative change in the packet material. Populations of flagellates and ciliates also declined rapidly after day 300. This decline occurred in new packets at around this date as well. In a limited set of samples 12 taxa were analyzed for date or detritus-age dependent occurrence. Of these, eight were data dependent, two were dependent on packet age, and two could not be determined from the data.  相似文献   

Further paleomagnetic results for the San Juan volcanic field of southern Colorado     

Myrl E. Beck  Steven D. Sheriff  Jimmy F. Diehl  Ernest A. Hailwood  Peter W. Lipman 《Earth and Planetary Science Letters》1977,37(1):124-130

Combining paleomagnetic data for 17 new sites from the northwest portion of the (Oligocene) San Juan volcanic field of southern Colorado with data for 29 sites previously published yields a paleomagnetic pole at 85°N, 114°E (with a 95% confidence circle of 7.5° radius). A further combination of the San Juan data with the results of other studies on rocks of Oligocene age from tectonically stable parts of North America gives a mid-Tertiary reference pole located at 81°N, 132.5°E, with a confidence circle of approximately 4°. Mid-Tertiary paleomagnetic poles for the western edge of the continent diverge markedly from this reference pole.  相似文献   

Chemical speciation of Cd,Cu, Pb,and Zn in mixed freshwater,seawater, and brine solutions     

David T. Long  Ernest E. Angino 《Geochimica et cosmochimica acta》1977,41(9):1183-1191

A theoretical model was developed to study the chemical speciation of the trace elements Zn, Cd, Cu and Pb aqueous solutions and their responses to variations in ionic strength and complexation. Two mixing solutions were investigated, a freshwater-seawater system and a freshwater-brine system. The brine was a calcium, sodium-chloride solution with a molal ionic strength of two. Trace element associations with the ligands OH^?, Cl^?, CO^2?₃, SO^2?₄, and HCO^?₃ were considered at pHs from 3.5 to 11.0 at 25°C. In general, the relative importance of the various ligand-trace element complexes can be predicted from a comparison of their stability constants. However, the effect of pH on the importance of a given complex is not readily apparent from the stability constants. Freshwater-seawater mixtures, as might be found in a totally mixed estuary, show that seawater composition is the dominant control on chemical complexing. Chloride complexing is similar for lead and zinc in the freshwater-brine mixtures. This similarity may account in part for the association of lead and zinc in strata-bound ore deposits.  相似文献   

Conversion of abandoned collieries in southern Belgium into low-pressure gas storage units, with description of special plugging of the various shafts     

Ernest F.J. Buttiens 《Engineering Geology》1979,13(1-4):531-539

In the southern part of Belgium, in the province of Hainaut, several collieries have been dismantled and closed over the last ten years. Geological conditions in this part of the country are advantageous for the construction of large storage units in the mine galleries which remained open. It is therefore necessary to evaluate this possibility, and also to plug the old mine shafts. The construction of gastight shaft-plugs able to withstand demolition charges, was carried out with maximum safety precautions by artificially freezing the roof and floor above and beneath the plug. The application of this unique method in the concession of “Bois de la Haye” is described, a storage capacity of > 100.10⁶Nm³ being formed at reasonable cost.  相似文献   

The influence of interstitial water on the rheological behaviour of calcite rocks     

Ernest H. Rutter 《Tectonophysics》1972

The effects of pore water on the mechanical behaviour of Solnhofen Limestone and Carrara Marble at various temperatures and confining pressures at constant strain-rate have been experimentally investigated. It is shown that water affects the strength and ductility of calcite rocks through

1.

(1) physico-chemical action at grain boundaries, and  相似文献   

Atomic absorption spectrometry,vol. 5: Techniques and instrumentation in analytical chemistry: Edited by John Edward Cantle,Elsevier, New York, 1982, 448 pp + XXVI,U.S. $97.75.     

Ernest E. Angino 《Geochimica et cosmochimica acta》1983,47(8):1546-1547

  相似文献   

Determination of Thorium-230 in CCRMP Reference Samples by Alpha Spectroscopy     

Richard J. PETERS  Ernest S. GLADNEY 《Geostandards and Geoanalytical Research》1983,7(2):319-320

Thorium-230 concentrations have been determined in 11 CCRMP (Canadian Certified Reference Materials Project) reference rock and ore samples using alpha spectroscopy following a chemical separation of the thorium. Literature data are available for only one of these 11 reference samples.  相似文献   

Regional hydrogeochemical patterns in ground water of Northwestern Ohio and their relation to Mississippi valley—type mineral occurrences     

Mark F. Deering  Eileen T. Mohr  Bruce F. Sypniewski  Ernest H. Carlson 《Journal of Geochemical Exploration》1983,19(1-3)

A cluster of minor Mississippi Valley-type deposits occurs in northwestern Ohio. The district, which forms a northeasterly trending belt that cuts across the Findlay Arch, extends from the Indiana border to the Lake Erie Islands. The minerals of the deposits — chiefly celestite, fluorite and sphalerite with lesser amounts of barite and galena — show variation in both geographic and stratigraphic distribution. Dolomites of Middle Silurian to Middle Devonian age, which are the host rocks, also form an important aquifer system. The deposits are of interest because they might be indicators of economic mineralization at depth.Through a reconnaissance study, one-hundred ground-water samples from shallow wells (less than 50 m deep) were collected across an area of approximately 19 000 km². Recharge takes place in the southern part of the area while ground-water flow is northward towards Lake Erie. The majority of the samples are high in sulfate with the source being evaporites within the carbonate sequence. The remainder of the water samples are rich in bicarbonate. Trend surface maps for the major constituents indicate that the ground-water chemistry for the region is established chiefly by the lithology and the flow system. Trend surface maps for F⁻, Sr and Ba reflect the geographic distribution of the minerals in the deposits. Correlations are weakened, however, due to the influence of geochemical barriers such as SO₄²⁻ on Ba and Sr, and Ca on F⁻. The map for Pb follows the trends of the major constituents instead of the mineralization.In a detailed study across northwestern Sandusky County, which lies near the center of the district, 46 samples were collected in an area of 78 km². Trend surface maps for Ca, Mg, SO₄²⁻ and total dissolved solids reflect the chemistry of the bedrock and display concentrations that increase along the local flow path. Maps for F⁻, Sr and Ba correlate with mineralization in the vicinity, the first of these displaying a local trend and the last two correlating with regional trends.  相似文献   

1987 Compilation of Elemental Concentration Data for USGS BHVO-1, MAG-1, QLO-1, RGM-1, SCo-1, SDC-1, SGR-1 and STM-1   总被引：2，自引：0，他引：2  

Ernest S. GLADNEY  Iwan ROELANDTS 《Geostandards and Geoanalytical Research》1988,12(2):253-362

Elemental concentration data on up to 84 individual constituents in BHVO-1, MAG-1, QLO-1, RGM-1, SCo-1, SDC-1, SGR-1 and STM-1 have been collected from 311 journal articles and technical reports. These data are summarized in consensus (mean) values with uncertainties expressed as one standard deviation. Mean values are also calculated as a function of analytical procedure and all raw data are given in the tables.
Ce rapport rassemble des données analytiques parues dans 311 articles scientifiques ou rapports techniques sur 84 éléments dans huit échantillons du Service Géologique des Etats-Unis: BHVO-1, MAG-1, QLO-1, RGM-1, SCo-1, SDC-1, SGR-1 et STM-1. Quand cela a été possible, les valeurs de consensus (moyenne) sont présentées pour chaque élément avec l'incertitude exprimée en un écart-type. Des valeurs moyennes en fonction des procédures analytiques sont également présentées.  相似文献