风沙路基施工技术初探

路基施工中保证路基填筑密实度，通常沙土路基采用水夯；普通路基采用振动碾、羊角碾等重型机具振密夯实。但在缺电、缺水，高气温、大风沙的沙漠气候等恶劣的施工条件下，风沙路基的施工如何保证路基填筑的密实度和施工机械在风沙路基上作业而不陷车的问题，就目前没有合适的经验可借鉴，也没有规范可参考。因此把在包西线神木北至延安北段的铁路工程建设中风沙路基施工所取得的经验和施工技术作一介绍。     

浅析宁波盆地膏盐地层的时代──兼对“宁波盆地北部的长河群”之时代质疑

宁波盆地地下揭示的一套包含暗色膏硝质泥岩、泥质白云岩在内的紫红、灰紫色泥岩、棕褐色砂砾岩、细砂岩和玻屑凝灰岩的地层，均称方岩组，内含膏盐并具油色显示。对其时代有早、晚白垩世和早第三纪之认识，笔者从70～90年代地质工作中所获化石分析认为，虽然宁波盆地这一层位含化石不丰，但从分布及数量上比较，相对占优势的应该是孢粉和植物化石，其时代意见也较为一致，指示为早白垩世。     

A comparative study of the zooplankton in two adjacent embayments,Port Phillip and Westernport Bays,Australia

We report on a year's study of spatial and seasonal patterns of zooplankton abundance in Port Phillip and Westernport Bays, July 1982 to August 1983. These two bays, closely adjacent on the southern coast of Victoria, Australia, differ in several respects: Port Phillip is a nearly landlocked bay with a broad basin, while Westernport is an open tidal embayment with extensive mud and seagrass banks. Both bays have a resident zooplankton fauna distinct from that of Bass Strait. Although these resident communities have many species in common, patterns of abundance and dominance are quite different. We found that the holoplankton of Port Phillip was about half copepods, mostly Paracalanus indicus, with 23% Caldocera and 21% larvaceans. Westernport Bay zooplankton was dominated by Acartia tranteri, with no resident cladoceran fauna. Bass Strait species were more often found in Westernport than in Port Phillip Bay, but the resident community of Port Phillip Bay was more similar to that of Bass Strait than to that of Westernport.Although this study was undertaken in an exceptionally dry year, the available historical data show that the overall patterns found in 1982–1983 are typical for these bays. The differences in community composition probably relate to differences in depth profile, predator abundance, and suspended matter between the bays.     

The middle pleistocene deposits of Waverley Wood Pit,Warwickshire, England

A complex of channels underlying the Baginton-Lillington Gravel (Baginton Formation) at Waverley Wood Quarry, Warwickshire is described. Fossil pollen and plant macrofossils, Coleoptera, Ostracoda, Mollusca and Mammalia are described from the channel-fill deposits. Consideration of all the evidence allows the identification of four separate stages of channel fill which largely occurred under a cool temperate climate. At the top of Channel 2 evidence for a cold, continental climatic episode can be recognised, suggesting that the whole complex was deposited under a fluctuating climate at the end of a temperate stage. At two levels in the channels human artefacts were recovered confirming the presence of Palaeolithic people in Warwickshire during the deposition of the sediments. Amino-acid geochronology suggests an age within the ‘Cromerian Complex’ Stage for the channels. The small vertebrate and molluscan faunas indicate that the deposits are no older than the latter part of the ‘Cromerian Complex’ Stage of East Anglia. The regional stratigraphic significance of the Waverley Wood succession is outlined.     

A taxonomical and ecological survey of rotiffer communities in Krottensee (Austria)

The composition and distribution of benthic, periphytic and planktonic rotifers in different habitats in Krottensee were investigated. Sixty-five rotifer taxa were identified, their relative abundance estimated. Classification of the data set by cluster analysis allowed the recognition of distinct habitat groups confined to acid bog ponds, macrophytes, sediments and open water. Five groups of rotifer taxa were identified on the basis of their habitat preferences and the occurrence of the taxa. Highest diversities were found on macrophytes and in acid bog ponds.     

The influence of macrophyte growth,typical of eutrophic conditions,on river flow velocities and turbulence production

The influence of emergent and submerged macrophytes on flow velocity and turbulence production is demonstrated in a 140 m reach of the River Blackwater in Farnborough, Hampshire, UK. Macrophyte growth occurs in patches and is dominated by Sparganium erectum and Sparganium emersum. In May 2001, patches of S. erectum were already established and occupied 18% of the channel area. The flow adjusted to these (predominantly lateral) patches by being channelled through a narrower cross‐section. The measured velocity profiles showed a logarithmic form, with deviations attributable to topographic control. The channel bed was the main source of turbulence. In September 2001, in‐stream macrophytes occupied 27% of the channel, and overhanging bank vegetation affected 32% of the area. Overall flow resistance, described by Manning's n, showed a threefold increase that could be attributed to the growth of S. emersum in the middle of the channel. Velocity profiles showed different characteristic forms depending on their position relative to plant stems and leaves. The overall velocity field had a three‐dimensional structure. Turbulence intensities were generally higher and turbulence profiles tended to mirror the velocity profiles. Evidence for the generation of coherent eddies was provided by ratios of the root mean square velocities. Spectral analysis identified deviations from the Kolmogorov ?5/3 power law and provided statistical evidence for a spectral short‐cut, indicative of additional turbulence production. This was most marked for the submerged vegetation and, in some instances, the overhanging bank vegetation. The long strap‐like leaves of S. emersum being aligned approximately parallel to the flow and the highly variable velocity field created by the patch arrangement of macrophytes suggest that the dominant mechanism for turbulence production is vortex shedding along shear zones. Wake production around individual stems of S. emersum close to the bed may also be important locally. Copyright © 2006 John Wiley & Sons, Ltd.     

南海大鹏湾夜光藻种群在其生态群落中的地位和功能

分析了１９９１年上半年南海大鹏湾盐田水域夜光菏和浮游动、植物之间的种群动态关系，结果表明，在春季高峰期３月至５月初，调查海域共出现１２个夜光藻和浮游动、植物高峰。其中，以发生４次赤潮的夜光藻种群占主导地位，其次是枝角类的鸟啄尖头蚤，其最高数量高达９６２３８ｉｎｄ／ｍ＾３。相比之下，在夜光藻和枝角类岛啄尖头捕食压力的影响下，浮游植物的春季高峰并不显著。调查结果表明夜光藻的过度繁殖，不但对产浮游性卵的     

Community and Population Responses of the Macroinfauna to Physical Factors over a Range of Exposed Sandy Beaches in South-central Chile

Ten exposed sandy sites covering a range from reflective to dissipative beaches were sampled in south-central Chile to evaluate: (1) spatial changes in species richness, abundance and biomass of the intertidal macroinfauna in response to changes in mean grain size, beach face slope and beach type, and (2) spatial changes in abundance, biomass and body sizes of the most abundant species in response to changes in the physical factors. The number of species, abundance and biomass per beach in general decreased with increasing particle size and beach face slope (steeper beaches) and increased from reflective to dissipative conditions. The best fit for number of species was with Dean's parameter, a measure of beach type, whereas for abundance and biomass the best fits were found with particle size. The isopod Excirolana braziliensis and the anomuran Emerita analoga increased in abundance and biomass towards dissipative conditions, whereas Excirolana hirsuticauda showed the opposite trend in biomass and was significantly larger in beaches with steeper profiles. It is concluded that responses to changes in beach type are more pronounced at community level than within species populations.     

Descriptive Analysis and Classification of Benthic Communities in Some Mediterranean Coastal Lagoons (Central Italy)

Abstract. Benthic samples were taken seasonally at 32 stations in five coastal lagoons of Central Italy (Fogliano, Monaci, Caprolace, Fondi, and Lungo) during a two-year period (1982–1984). Composition and distribution of benthic populations in each lagoon as well as seasonal trends of species richness, density, diversity, and redundancy are presented and discussed.
The faunal differentiation appeared to be mainly due to the different degree of water exchange, both with marine and continental systems.     

Impact of Two "El Niño" Events of Different Intensity on the Hypoxic Soft Bottom Macrobenthos off the Central Peruvian wast

Abstract. Monthly changes in the community structure of hypoxic soft-bottom macrobenthos have been studied at a station at 34 m depth in Ancón Bay (Peru) before and during two El Niño (EN) events. Of these events, 1982-83 is considered the strongest, and 1991–93 one of the most prolonged in the 20th century. On the oceanographic scale, EN 1982–83 ranges as "very strong", whereas EN 1991–93 ranges as "moderate".
The thermal anomalies at the station during EN 1982–83 (+ 7.8 °C) were almost twice those of EN 1991–93 (+ 4.1 °C). However, the community changes were not in all cases proportional to the extent of warming. Species numbers increased in a similar way (up to 24 species from near zero in each of the two events), but maximum faunal density was five times higher, and mean biomass was twice as high in 1982–83 compared with the event a decade later. Species diversity was slightly higher during EN 1982–83, whereas successional and trophic changes occurred on a broader scale during EN 1991–93. On the whole, the impact of the long-lasting event on the small soft-bottom macrofauna was not much weaker than that of the exceptionally strong event.
The authors discuss the mechanisms which may be responsible for the differences and similarities encountered in the benthic community dynamics during these two events. Both in the unusually strong and the unusually long EN, the community revealed a pattern of early biological response several months ahead of the onset of local warming which marks the official begin of EN. The question is addressed to what extent the increase of certain parameters in the benthic community could be used for predictive purposes.