Effects of UV on carbon assimilation of phytoplankton in a mixed water column   总被引：1，自引：0，他引：1  

Jan Köhler  Mechthild Schmitt  Hartwig Krumbeck  Maria Kapfer  Elena Litchman  Patrick J. Neale 《Aquatic Sciences - Research Across Boundaries》2001,63(3):294-309

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Xixth International Congress of Photogrammetry and Remote Sensing     

Roger P. Kirby  George Joseph  Ian J. Doqman  Yi Dong Huang  Gordan Petrie  Stuart Robson  Tania Maria Sausen  Ian D. Downey  & A. Stewart Walker 《The Photogrammetric Record》2001,17(97):119-155

The XIXth International Congress of Photogrammetry and Remote Sensing was held at the Amsterdam RAI International Exhibition and Congress Centre, the Netherlands, from 16th to 23rd July 2000. Reports are given on the Congress as a whole, including the General Assembly, some Technical Commission activities and the Congress Exhibition. Papers from the Congress are published in the International Archives of Photogrammetry and Remote Sensing, 33.  相似文献   

Water balance of basins in central Greece: Comparison with other circum-Mediterranean basins and validity of empirical methods   总被引：1，自引：0，他引：1  

George Soulios  Maria Toubektsi  George Tzevelekis  Haniel Ezeigbo 《Environmental Geology》1991,18(2):85-94

The geological and physicogeographical elements of the neighboring basins of Xyniada and Sofaditi in central Greece are given. The average annual and monthly amounts of precipitation that each basin receives for a nineyear period (1972–1981) are estimated by analyzing the data of eight rain gauges. The average annual value of total runoff is also obtained by frequent discharge measurements at the basin outlets during the same period of record, and the water balance of the basins is thus estimated. The examined basins are compared to others in the circum-Mediterranean region. Finally, various empirical methods of estimating components of water balance are applied, and opinions are expressed about the correspondence of these methods to reality and the way they are applied.  相似文献   

Book reviews     

Kacper R. Rybicki  Vernon F. Cormier  Manfred Koch  B. Ducarme  Gary Mavko  Maria Jeleńska  Frazer Tabeart  Yu. N. Korenkov 《Pure and Applied Geophysics》1992,138(3):507-527

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The seasonal variation of streamwater chemistry in three forested Mediterranean catchments     

Josep Pi  ol  Anna   vila  Ferran Rod 《Journal of Hydrology》1992,140(1-4):119-141

Streamwater chemistry is described for three streams draining undisturbed, evergreen broad-leaved forested catchments on phyllites in NE Spain: two streams with no or negligible flow in summer are located in the Prades massif, and one perennial stream is in the wetter Montseny mountains. Weekly data for a study period of 2–4 years are provided to (1) describe the seasonal variations in streamwater chemistry, (2) analyse the relationship between stream discharge and solute concentrations using a two-component mixing model and (3) search for patterns of temporal variation in stream solute concentrations after discounting the effects of discharge. At Prades, concentrations of all analysed ions, except NO⁻₃, showed marked seasonal variations in stream water, whereas at Montseny only ions related to mineral weathering (HCO⁻₃, Na⁺, Ca²⁺ and Mg²⁺) showed strong seasonality. Ion concentrations were more closely dependent on instantaneous discharge at Montseny than at Prades. The residuals of the relationship between solute concentrations and discharge retained a strong seasonality at Prades, but not at Montseny. These differences are related to the major hydrochemical processes that determine the streamwater chemistry at each site. The same processes are probably operative in the three catchments, but are of varying relative importance. At Montseny, the mixing of waters of different chemical composition seems to be the major process controlling streamwater chemistry, although the soilwater end-member composition predicted by the mixing model applied did not match the measured soilwater chemistry. In the drier Prades catchments, the two major hydrochemical processes determining the seasonal variation of streamwater chemistry are (1) the restart of flow after the summer drought, which flushes out the solutes accumulated during the dry period, and (2) the seasonal changes in groundwater chemistry that result from the interplay of water residence time, temperature and CO₂ partial pressure. In Mediterranean catchments with relatively high precipitation, such as Montseny, the seasonal variation in the streamwater chemistry is largely determined by the same processes as at humid-temperate sites, whereas in drier Mediterranean catchments, such as Prades, the major hydrochemical processes are clearly distinct.  相似文献   

Stable hydrogen and oxygen isotope studies of rainfall and streamwaters for two contrasting holm oak areas of Catalonia, northeastern Spain     

Colin Neal  Margaret Neal  Anita Warrington  Anna   vila  Josep Pi  ol  Ferran Rod 《Journal of Hydrology》1992,140(1-4):163-178

Results are presented of a study of stable hydrogen and oxygen isotopes in rainfall and streamwaters for the Montseny and Prades areas in northeastern Spain: results cover the full year of 1991. The isotopic pattern for rainfall is similar for both areas: there is a wide range in isotopic contents and the results show a strong, near-linear trend, δ²H = 7.9 × δ¹⁸O + 9.8 (N = 59; r² = 0.952), the ‘local meteoric line’. There is slight curvature to the data which may be related to the sources of water vapour forming the rainfall. Within the streams, the isotopic variability is much less than that of the rainfall although the data lie on, or very near to, the meteoric line. Data for detailed collections during storm events show more scatter than those collected regularly on a fortnightly basis. The event data show a linear feature that conforms to the local meteoric line. These results indicate that: (1) the main supply of water to the stream stormflow comes from water stored in the catchment prior to the event; (2) waters of more than one isotopic composition reside within the catchment and are transferable to the stream during storm events; (3) the main process of water transfer from the catchment back to the atmosphere comes from transpiration by the trees and (possibly) complete evaporation from the near-surface soil horizons and the tree canopy; (4) the isotopic technique cannot be used for quantitative hydrograph separation in this instance — at least two water types can be present within the catchment at any given time.  相似文献   

A new method of cubature using spline functions     

Dr. Ing. Paul Dierckx  Dr. Ing. Eduard Smets  Prof. Dr. Ing. Robert Piessens  Ing. Maria Temmerman 《Ocean Dynamics》1981,34(2):61-79

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Paleoclimatic record of a long deep sea core from the eastern Mediterranean     

Maria Bianca Cita  Colette Vergnaud-Grazzini  Christian Robert  Hervé Chamley  Neri Ciaranfi  Sara d&#x;Onofrio 《Quaternary Research》1977,8(2):205-235

A deep-sea core over 16 m long from the crestal area of the Mediterranean Ridge has been investigated with different techniques, including quantitative micropaleontology, stable isotopes (measured on the epipelagic species Globigerinoides ruber and on the mesopelagic species Globorotalia inflata), and clay mineralogy. The resulting record of climatic fluctuations can be cross correlated to other Mediterranean cores by means of isochronous lithologies (tephra layers and sapropels). The climatic record of the Mediterranean is similar in character, phase, and chronology to the records investigated in the equatorial Pacific and in the Caribbean. Isotope stages 1 to 17 have been recognized. Cyclically repeated stagnant cycles resulting in sapropel deposition complicate both the isotopic and the faunal signal. The isotopic investigations reveal that the temperature change in the surface layers of the eastern Mediterranean was no greater than 8°C in the late “glacial” Pleistocene. The chronostratigraphic and biostratigraphic interpretation of Core KS09 indicate that the mean sedimentation rate was 2.4 cm/1000 years, a value very close to the 2.5 cm/1000 years calculated for the entire Quaternary section at DSDP Site 125, also located in the crestal area of the Mediterranean Ridge in the Ionian Basin. The base of KS09 is likely to be very close to the Brunhes/Matuyama boundary dated at 0.7 my.  相似文献   

Use of ²³⁴U/²³⁸U disequilibrium in measuring chemical weathering rate of rocks     

Lycia Maria Moreira-Nordemann 《Geochimica et cosmochimica acta》1980,44(1):103-108

The rate of chemical weathering of rocks has been determined by using uranium as a natural isotopic tracer. The concentration of uranium and ²³⁴U/²³⁸U ratio in natural waters, rocks, and soils of the Preto river basin (Bahia State, Brazil) was measured by alpha-ray spectroscopy.The activity ratio U234/U238 measured in the various samples indicates the uranium fraction which is dissolved from rocks during the weathering process. The results obtained show that 1 m of rock needs 25,000 yr to be weathered in this region under present climatic conditions.  相似文献   

Heavy metals in ionian and tyrrhenian waters from a section of the sicilian coast     

Maria Alpha  Corrado Caristi  Guiseppe Cimino  Marisa Ziino 《Marine pollution bulletin》1982,13(11):399-400

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