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Ferren MacIntyre 《Marine Chemistry》1976,4(3):205-224
The four scales considered are molal (m, γ, mol/kg-water), molar (c, y, mol/dm3), mole fraction (x, f, mol/total-moles), and the uniquely oceanographic scale - for which nomenclature is proposed - ‘mokal’ (k, v, mol/kg-seawater). Conversion ratios are given in tabular form for multi-component ionic mixtures and as functions of salinity. Conversion of concentrations, activity coefficients, activities, Debye-Hückel ‘constants’, and ionization functions is treated. The advantages of the molal scale are noted, and suggestion made that the ‘mokal’ scale be used only when there is insufficient information to convert oceanographic data to the molal scale. 相似文献
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The microphytobenthos form an important component of all shallow-water ecosystems where enough light reaches the sediment surface to support appreciable primary production. Although less conspicuous than macroalgae or vascular plants, the microphytobenthos can contribute significantly to primary production and can modify habitat characteristics. The microphytobenthos alter sediment properties (e.g., erodibility) both directly, in the extreme forming a mat or scum on the sediment surface, and indirectly by modifying the activities of benthic infauna (e.g., pelletization, burrowing, tube building, and sediment tracking). Carbon dioxide fixed by the microphytobenthos supports higher, grazing trophic levels. These include deposit-feeding and suspension-feeding macrofauna as well as meiofauna and microfauna. Quantitative relations between the feeding and growth rates of macrofauna and the abundance of microphytobenthos and suspended organic matter (i.e., functional responses) are reviewed. Given the current state of knowledge of the direct and indirect interactions involving trophic dynamics, sediment properties, and benthic microalgae, we argue for reductionist studies of particular interactions as distinct entities. This is a prerequisite for the emergence of a comprehensive picture of unvegetated ecosystems and the ability to predict their responses to man’s activities. *** DIRECT SUPPORT *** A01BY074 00005 相似文献
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Ferren MacIntyre 《Marine Chemistry》1978,6(2):187-192
Lyman's 30-year-old seawater titration is sufficiently precise to reveal a 4 micromolar discrepancy (theoretically supported) between observed end point and zero-alkalinity equivalence point. Accurate measure of alkalinity requires correction for the difference, either by assuming the constancy of relative proportions and multiplying the end-point alkalinity by 1.002, or by careful fitting of data far from the end point. 相似文献
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Evelyn Lawrenz James L. Pinckney Melissa L. Ranhofer Hugh L. MacIntyre Tammi L. Richardson 《Estuaries and Coasts》2010,33(5):1186-1201
We investigated spatial and temporal relationships between spectral irradiance and phytoplankton community composition in
the blackwater-influenced estuary Winyah Bay, South Carolina. Upstream, high concentrations of chromophoric dissolved organic
matter (CDOM) absorbed blue wavelengths, resulting in a predominantly red light field. Green light prevailed downstream near
the lower-CDOM coastal ocean, and phytoplankton community composition was distinct from upstream and mid-estuarine communities.
Diatoms were abundant throughout the estuary in January, August, and October, cryptophytes dominated in July, and chlorophytes
were abundant in December 2006. Only diatoms and chlorophytes showed significant covariation with the spectral attenuation
coefficient (k(λ)): Chlorophytes showed positive relationships with k(442) (blue light) while diatoms were negatively correlated with k(442) and k(490) (violet to blue). Phytoplankton community composition in Winyah Bay appears to be driven by strong horizontal flow rather
than gradients in spectral irradiance, but results indicate that water color is likely to play a greater role in blackwater-influenced
estuaries with longer residence times. 相似文献
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Ferren MacIntyre 《Climatic change》1978,1(4):349-354
The commonly reported temperature coefficient of P. the equilibrium partial pressure of CO2, is (P/T)
A,C
,which is about 15 ppm/°C, or 5% of the atmospheric partial pressure of CO2. This coefficient, however, applies only to deep water, not to surface water which can exchange CO2 with the atmosphere. The coefficient (P/T)
A,C
,, where designates constancy of the sum of atmospheric and surface-ocean CO2, is the appropriate value for air-sea exchange. Numerical values are mass-dependent because the depth of the exchanging ocean layer must be specified. For a 100-m surface layer, the value is ca. 1.5 ppm/°C, or 0.5% of ambient CO2.
Editor's Note:In view of the interdisciplinary importance of the carbon dioxide-climate problem, this note on seawater chemistry should be of interest to specialists beyond the discipline of ocean chemistry. 相似文献
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Summary Electrum, hessite, petzite and sylvanite have been recorded from veins at Tyndrum, Scotland. Electron probe micro-analyses have also revealed two un-named Ag-Te-S phases. Fluid inclusion studies suggest that the mineralising fluids responsible for the precious metal mineralization contained 7.0 mol % CO2 and 7 wt % NaCl. TH (temperature of homogenisation) determinations were in the range 295°C to 325°C and a depth of vein formation 4 km is indicated. Mineral precipitation was probably caused by cooling and adsorption of gold onto pyrite. 34S values of + 1.8%o for galena from the Au + Ag + Te veins suggest a different (possibly igneous) sulphur source to that producing the Pb +Zn vein mineralization in the Tyndrum area. Although an age of 380 Ma was obtained using K-feldspar in the veins the data are not conclusive. It is argued that the Au + Ag mineralization at Tyndrum is due to hydrothermal activity related to Cu +Mo mineralization associated with the Late Caledonian granites.
With 5 Figures 相似文献
Die Gold-Silber-Gang-Vererzung von Tyndrum, Schottland
Zusammenfassung In der Gang-Vererzung von Tyndrum, Schottland, kommen eine Gold-Silber-Legierung, Hessit, Petzit und Sylvanit vor. Außerdem ergaben Mikrosondenanalysen das Vorhandensein von zwei unbekannten Ag-Te-S Phasen. Die Untersuchungen von Flüssigkeitseinschlüssen zeigen, daß die für die frühe Mineralisation verantwortlichen Lösungen 7.0% Mol.% CO2 und 7 Gew.% NaCl enthalten haben. Die Homogenisie-rungstemperaturen liegen im Bereich von 295-325°C und weisen auf eine Tiefe der Gangentstehung von 4 km hin. Die Au-Ag-Te Mineralbildung kam vermutlich durch Abkühlung und Adsorption von Gold auf Pyrit zustande. 34S-Werte von + 1.8%0, gemessen an Bleiglanz aus Au-Ag-Te-Gängen deuten eine magmatische Schwefelherkunft an, während die Pb-Zn-Gangmineralisation eine andere Schwefelquelle vermuten läßt. Die Altersdatierung der Gänge von 380 Mio. Jahren läßt sich derzeit noch nicht sinnvoll interpretieren. Es wird angenommen, daß die Au-Ag-Vererzung von Tyndrum durch hydrothermale Aktivität im Zusammenhang mit einer an spätkaledonische Granite gebundenen Cu-Mo-Vererzung entstanden ist.
With 5 Figures 相似文献
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