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61.
Remineralization Ratios in the Subtropical North Pacific Gyre 总被引:2,自引:0,他引:2
Yuan-Hui Li David M. Karl Christopher D. Winn Fred T. Mackenzie Kathleen Gans 《Aquatic Geochemistry》2000,6(1):65-85
Based on a new mixing model of two end-members, the water column remineralization ratios of P/N/Corg - O2 = 1/13 ± 1/135 ± 18/170 ± 9 are obtained for the Hawaii Ocean Time-series (HOT) data set at station ALOHA. The traditional Redfield ratios of P/N/Corg/–O2 = 1/16/106/138 have standard deviations of more than 50%, when they are based on the average composition of phytoplankton. Apparently, the remineralization processes in the water column have smoothed out the observed large variability of plankton compositions. A new molar formula for the remineralized plankton may be written as 135H280O105N13P or C25(CH2O)101(CH4)9(NH3)13(H3PO4). Oxidation of this formula results inC25(CH2O)101(CH4)9(NH3)13(H3PO4) + 170O2 135CO2 + 132H2O + 13NO3
- + H2PO4
- + 14H+.For comparison, remineralization using Redfield's formula gives:(CH2O)106(NH3)16(H3PO4) + 138O2 106CO2 + 122H2O + 16NO3
-+ H2PO4
- + 17H+ 相似文献
62.
M. Karl H.-P. Dorn F. Holland R. Koppmann D. Poppe L. Rupp A. Schaub A. Wahner 《Journal of Atmospheric Chemistry》2006,55(2):167-187
Atmospheric oxidation of isoprene and its oxidation products methacrolein (MACR) and methyl vinyl ketone (MVK) have an important impact on the photochemical activity in the boundary layer, in particular in forested areas. The oxidation of isoprene by OH radicals was investigated in chamber experiments conducted under tropospheric conditions in the atmosphere simulation chamber SAPHIR at the Research Center Jülich. The aim was to determine the product yield of MVK and MACR in the OH-induced isoprene oxidation and the rate constant of their reaction with OH under real atmospheric conditions. The recently published updated degradation scheme for isoprene from Geiger et al. (2003) was used to determine rate constants and product yields. The fractional yields in the isoprene peroxy radical reaction with NO were found to be 0.41±0.03 for MVK and 0.27±0.03 for MACR. The rate coefficient for MACR with OH was found to be in very good agreement with the recommended value of IUPAC Atkinson (Atkinson et al., 2005). while the rate coefficient for MVK with OH was 27% lower. 相似文献
63.
Economic transition in central and eastern Europe (CEE) has had a particularly strong impact on industrial cities and regions. Following their economic collapse, most of them are now confronted with serious problems such as high unemployment and vast ecological damage. The paper presents findings from a pan European research project that investigated the problems of these cities and regions as well as the strategies being adopted to cope with structural change. It examines the differences in approaches and addresses the question whether existing EU policy is suitable for supporting the redevelopment of old industrial cities and regions in CEE countries. The paper concludes with recommendations for future directions in policy making. 相似文献
64.
The extent to which riverine Os is trapped in a temperate estuary was the aim of this study. The behavior of Os through the Hudson River, East River and the Long Island Sound (LIS) system is addressed using both natural Os and anthropogenically mobilized Os. The Os concentration ([Os]) and isotopic composition (187Os/188Os) of the Mid-Atlantic Bight as inferred from the analysis of a water sample of 31‰ salinity (S) at Vineyard Sound, MA are 46 fM and 1.070, respectively. In comparison, the Hudson River at Newburgh, NY has [Os] = 68 fM and 187Os/188Os = 1.265. The Os concentration of the East River at the Whitestone Bridge is 51 fM and remains essentially constant proceeding eastward in the LIS despite the increase of salinity from 20‰ towards the higher value of the Mid-Atlantic Bight. The 187Os/188Os ratio of water at Whitestone Bridge is 0.945 and increases eastward through the Sound to 0.979 at 7 km and then to 1.019 at 39.6 km. The behavior of Os through LIS appears to be conservative at S > 20‰. On the basis of Os concentration and isotopic composition we infer that anthropogenic Os is being added to the East River through sewers with the likely isotopic ratio of ∼0.13 and that about 24% of riverine Os must be removed at S ? 20‰. There is a net transport of about 0.4-1 mole of anthropogenic Os per year from the East River into the LIS. The residence time of Os in the ocean at present must be about 39,000 years, unless an independent source of supply of Os can be identified. 相似文献
65.
66.
Prof. Dr. Karl Krejci-Graf 《International Journal of Earth Sciences》1981,70(3):1263-1275
Zusammenfassung Die Verfolgung tektonischer Strukturen in die Tiefe ist nur bei kontinuierlicher Verformung einfach. Physikalische oder strukturelle Änderungen innerhalb der sich verformenden Körper, sowie Änderungen in der Richtung der verformenden KrÄfte, bedingungen diskontinuierliche Änderungen in den erzeugten Strukturen, z. B. Scheitelverschiebung, Rückverformung, DurchprÄgung überwÄltigter Strukturen.
To pursue tectonical structures beyond observations is simple only if deformations are continuous. Changes of physical or structural properties of rocks, as well as changes in the direction of transforming forces, create discontinuous alterations within thus generated structures, e. g. displacement of apex, retrograde transformation, penetration of subdued lower structures.
Résumé Le prolongement des structures tectoniques en profondeur n'est simple que dans le cas de déformations continues. Des changements de propriétés physiques ou structurales durant les déformations à l'intérieur des corps tectoniques, ainsi que des modifications dans la direction des forces actives, produisent des transformations discontinues dans les structures engendrées, p. ex. déplacements des sommets des anticlinaux, déformations en retour, rejeu de structures anciennes et leur pénétration dans les structures superposées; etc.
. , : .: , , .相似文献
67.
Prof. Dr. Karl Fuchs 《International Journal of Earth Sciences》1975,64(1):700-716
Specially planned explosion seismic measurements in the oceans provided conclusive evidence that the velocity of Pn-waves depends on the azimuths of the direction of propagation through the upper mantle. The orientation of this azimuthal anisotropy suggests a close connection with the generation of the oceanic lithosphere: in the Pacific the maximum and minimum velocities are measured in a perpendicular and parallel direction to the axis of the oceanic ridges respectively. The observed anisotropy is so strong that a number of models for the generation of anisotropy can be discarded. The most likely cause is a preferred orientation of minerals. The generation of the anisotropy can be simulated in the laboratory under P-T-conditions of the upper mantle. The influence of the rate of deformation can be studied as well. A recent analysis of explosion seismic data in Southern Germany suggests that the continental upper mantle possesses also a velocity anisotropy dependent on azimuth. 相似文献
68.
69.
The fractionation of the oxygen isotopes between water molecules from different sites in CuSO4 · 5H2O has been measured for crystallization temperatures of 25, 40 and 50°C. The temperature dependence found provides a basis for the determination of crystallization temperatures from such intracrystalline oxygen isotope effects; also for hydrated crystals of mineralogical and geological interest. Necessary suppositions for the application of this method are discussed. 相似文献
70.