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1.
本文对套子湾表层沉积物中的pH、Eh、硫化物、氮、磷、有机质、铜、铅、锌、镉地球化学特征进行了分析研究.并讨论了如下几个关系:①与沉积类型之间的关系;②其相关性与环境的关系。③与矿物的关系;④与水和风等作用的关系;⑤与水化学的关系;⑥重点分析了表层沉积物中化学要素与生物的相互关系。这不仅为该湾的开发治理.生物养殖等提供科学依据.并进一步证明沉积物地球化学.在环境化学和生态学研究等方面的理论意义。 相似文献
2.
秋季东、黄海异养细菌(Heterotrophic Bacteria)的分布特点 总被引:27,自引:1,他引:27
2000年10-11月,乘"北斗号"考察船进行秋季"东、黄海生态系统动力学与生物资源可持续利用"大面调查,研究秋季东、黄海异养细菌的分布.结果表明,异养细菌在黄海和东海的丰度分别在(2.37-13.33)×108 cell/L和(3.05-13.62)×108 cell/L之间.细菌丰度最高值出现在长江口附近,且断面E和断面F各站位的细菌丰度明显高于其他断面.异养细菌丰度大小以长江口为中心向外海依次递减.东、黄海水体异养细菌生物量分别在244.45-1812.90mgC/m2和100.60-940.87mgC/m2之间.东、黄海异养细菌丰度无显著差异,但是东海海域水体异养细菌生物量高于黄海海域.异养细菌空间分布与浮游植物叶绿素在东海有一定的相关性,黄海异养细菌与硝酸盐浓度的相关性极显著. 相似文献
3.
Environmental variables related to wheat yields in the semiarid pampa region of Argentina 总被引:1,自引:0,他引:1
The current paper analyses various environmental parameters in relation to wheat yields in Bordenave, Province of Buenos Aires, Argentina. The variables used are: precipitation (ppt), maximum (Tx) and minimum temperature (Tmi) as well as those obtained by applying the Palmer model. Decadic and phenological scales are used for data corresponding to the period 1977–2000. The stepwise method is used to obtain a multi-variate equation to calculate yield taking into account environmental variables only. For a five variates model the coefficient of determination, R2 equals 95.79% and the standard error of estimation is 129.0 kg ha−1. In the sample yields, the incidence of total variability for thermal variables is 42.7% and for hydrological variables, 53%. The value and sign of the correlation coefficients were analysed throughout the cultivation cycle. The α coefficient is mainly responsible for yield variance during tillering and stem elongation. There is good correlation with the values of Palmer's Drought Severity Index (PDSI) for the flowering and grain filling stages. 相似文献
4.
The Wadi Daya Formation, or the Calcaires crayeux of the older literature, attains a thickness of 10–40 m in the Talerhza Basin of the South Riffian Ridges. Previously, this unit was first dated as “Vraconian” (i.e., late upper Albian), but then reinterpreted as Cenomanian-Turonian and Cenomanian-Coniacian on the basis of foraminiferal and ostracod assemblages, respectively. Here, we record for the first time in the South Riffian Ridges, some typically Turonian ammonoids and a nautiloid species, namely Romaniceras (Yubariceras) cf. ornatissimum (Stoliczka), Spathites (Jeanrogericeras) cf. reveliereanus (Courtiller), Neoptychites cephalotus (Courtiller), Pachydesmoceras linderi (de Grossouvre), Lewesiceras peramplum (Mantell) and Angulithes galea (Fritsch, in Fritsch & Schlönbach). These species are herein described and illustrated. In view of these data, the underlying Marnes et marno-calcaires jaunes Formation, formerly dated as “Vraconian”, could in fact be of a middle to late Cenomanian date, in accordance with the age assignment based on planktonic foraminifera. Deposition of the overlying Marnes jaunes Formation, previously dated as Cenomanian-“Senonian”, probably started during the latest Turonian or earliest Coniacian. 相似文献
5.
M. Franceschelli M. Puxeddu G. Cruciani D. Utzeri 《International Journal of Earth Sciences》2007,96(5):795-815
Metabasites with eclogite facies relics occur in northern Sardinia as massive to strongly foliated lenses or boudins embedded
within low- to medium-grade rocks (Anglona) and migmatites (NE Sardinia). U–Pb zircon dating yielded 453 ± 14, 457 ± 2 and
460 ± 5 Ma as the protolith ages; 400 ± 10 and 403 ± 4 Ma have been interpreted as the ages of the HP event and 352 ± 3 and
327 ± 7 Ma as the ages of the main Variscan retrograde events. A pre-eclogite stage is documented by the occurrence of tschermakite,
zoisite relics within garnet porphyroblasts (Punta de li Tulchi) and an edenite–andesine inclusion within a relict kyanite
porphyroblast (Golfo Aranci). Four main metamorphic stages have been distinguished in the eclogite evolution: (1) eclogite
stage, revealed by the occurrence of armoured omphacite relics within garnet porphyroblasts. The Golfo Aranci eclogites also
include kyanite, Mg-rich garnet and pargasite; (2) granulite stage, producing orthopyroxene and clinopyroxene–plagioclase
symplectites replacing omphacite. At Golfo Aranci, the symplectitic rims around relict kyanite consist of sapphirine, anorthite,
corundum and spinel; (3) amphibolite stage, leading to the formation of amphibole–plagioclase kelyphites between garnet porphyroblasts
and pyroxene–plagioclase symplectites and to the growth of cummingtonite on orthopyroxene. Tschermakite to Mg-hornblende,
plagioclase, cummingtonite, ilmenite, titanite and biotite are coexisting phases; (4) greenschist to sub-greenschist stage,
defined by the appearance of actinolite, chlorite, epidote ss, titanite, sericite and prehnite. The following P–T ranges have been estimated for the different stages. Eclogite stage 550–700°C; 1.3–1.7 GPa; granulite stage 650–900°C; 0.8–1.2 GPa,
clustering in the range 1.0–1.2 GPa; amphibolite stage 550–740°C; 0.3–0.7 GPa; greenschist stage 300–400°C; 0.2–0.3 GPa. Comparable
ranges characterise the other Variscan massifs in Europe; eclogite stage: T = 530–800°C; P from 0.7–1.1 to 1.7 ± 0.3 GPa; granulite stage T = 760–870°C and P from 1.1–1.4 to 7.2–9.9 GPa, clustering around 1.0–1.2 GPa. Whole-rock chemistry: Sardinian eclogites are N- to T-MORB;
European ones N- to E-MORB or calc-alkaline. 相似文献
6.
7.
Osman Sivrikaya 《Environmental Geology》2008,53(7):1585-1595
To prevent the leakage of pollutant liquids into groundwater and sublayers, the compacted fine-grained soils are commonly
utilized as mineral liners or a sealing system constructed under municipal solid waste and other containment hazardous materials.
This study presents the correlation equations of the compaction parameters required for construction of a mineral liner system.
The determination of the characteristic compaction parameters, maximum dry unit weight (γ
dmax) and optimum water content (w
opt) requires considerable time and great effort. In this study, empirical models are described and examined to find which of
the index properties correlate well with the compaction characteristics for estimating γ
dmax and w
opt of fine-grained soils at the standard compactive effort. The compaction data are correlated with different combinations of
gravel content (G), sand content (S), fine-grained content (FC = clay + silt), plasticity index (I
p), liquid limit (w
L) and plastic limit (w
P) by performing multilinear regression (MLR) analyses. The obtained correlations with statistical parameters are presented
and compared with the previous studies. It is found that the maximum dry unit weight and optimum water content have a considerably
good correlation with plastic limit in comparison with liquid limit and plasticity index. 相似文献
8.
lvaro Corral 《Tectonophysics》2006,424(3-4):177
The fulfillment of a scaling law for earthquake recurrence–time distributions is a clear indication of the importance of correlations in the structure of seismicity. In order to characterize these correlations we measure conditional recurrence–time and magnitude distributions for worldwide seismicity as well as for Southern California during stationary periods. Disregarding the spatial structure, we conclude that the relevant correlations in seismicity are those of the recurrence time with previous recurrence times and magnitudes; in the latter case, the conditional distribution verifies a scaling relation depending on the difference between the magnitudes of the two events defining the recurrence time. In contrast, with our present resolution, magnitude seems to be independent on the history contained in the seismic catalogs (except perhaps for Southern California for very short time scales, less than about 30 min for the magnitude ranges analyzed). 相似文献
9.
This paper aims to determine the correlation between Cd, Cu and Pb concentration in the sediment and in five aquatic plants
sampled during wet, normal and dry seasons. Analyses of the sediment showed that concentrations of exchangeable Cd and Cd
after acid reduction were higher during the wet season (October) than on other sampling dates with mean values of 0.18 and
0.29 μg g−1, respectively. The concentration of Cu in the organic oxidation phase was higher in the normal season (January) than on other
sampling dates with a mean value of 11.1 μg g−1. The concentrations of exchangeable Pb and that in the residual phase were higher during the wet season than on other sampling
dates with mean values of 1.05 and 9.18 μg g−1, respectively. Cd and Pb concentrations in the leaves, stems and roots varied between sampling dates with a reduced concentration
during dry season (July) and the highest metal concentrations (Cd and Pb) during wet season. There were positive correlations
between Cd and Cu concentrations in the plant tissues (leaves, stems and roots) of most aquatic plants in the acid reduction
fraction. Conversely, there was no positive correlation between Pb concentration in the plant tissues of all aquatic plants
and the acid reduction fraction of the sediment. 相似文献
10.
An application of Spartan spatial random fields in environmental mapping: focus on automatic mapping capabilities 总被引:4,自引:2,他引:2
Samuel N. Elogne Dionissios T. Hristopulos Emmanouil Varouchakis 《Stochastic Environmental Research and Risk Assessment (SERRA)》2008,22(5):633-646
This paper investigates the potential of Spartan spatial random fields (SSRFs) in real-time mapping applications. The data
set that we study focuses on the distribution of daily gamma dose rates over part of Germany. Our goal is to determine a Spartan
spatial model from the data, and then use it to generate “predictive” maps of the radioactivity. In the SSRF framework, the
spatial dependence is determined from sample functions that focus on short-range correlations. A recently formulated SSRF
predictor is used to derive isolevel contour maps of the dose rates. The SSRF predictor is explicit. Moreover, the adjustments that it requires by the user are reduced compared to classical geostatistical methods. These features
present clear advantages for an automatic mapping system. The performance of the SSRF predictor is evaluated by means of various
cross-validation measures. The values of the performance measures are similar to those obtained by classical geostatistical
methods. Application of the SSRF method to data that simulate a radioactivity release scenario is also discussed. Hot spots
are detected and removed using a heuristic method. The extreme values that appear in the path of the simulated plume are not
captured by the currently used Spartan spatial model. Modeling of the processes leading to extreme values can enhance the
predictive capabilities of the spatial model, by incorporating physical information. 相似文献