Nutrient transports in a Swedish estuary

Himmerfjärd is a Swedish estuary bordering on the Baltic. The estuary lacks astronomical tides and its circulation is driven by winds and freshwater runoff. Because of a tertiary sewage treatment plant located at its inner end, the estuary is becoming increasingly eutrophic. A field study was carried out for a 78-day period in late summer and early fall of 1977 to determine rates of nutrient transport and to construct nutrient budgets. Since physical parameters (current velocity, temperature, salinity, winds and water level changes) were measured more frequently than nutrients (phosphate, nitrate, nitrite and ammonium) it was necessary to develop a suitable method to calculate nutrient flux time series and net nutrient fluxes. Over the study period, Himmerfjärd imported phosphorus and exported nitrogen. Direction of nutrient fluxes and changes in flux direction were consistent with the structure of the baroclinic currents.     

Sources and sinks of sea salt in a newfoundland blanket bog

Over an oceanic peatland, the concentration of Na in fog averaged 38.1 mgl^?1 compared with 1.8 mgl^?1 in rain, resulting in a significant flux of mineral elements to the surface. Between 16 May and 20 June 1990 the average mass flux of Na to the bog surface by fog, rain, and dry deposition was 21.9, 10.4 and 7.0 mg m^?2 d^?1. There was little long-term storage of Na within the peatland system, where Na losses measured in stream runoff averaged 34.8 mg m² d^?1, and deep groundwater losses 4 mg m^?2 d^?1. Calcium and Mg were preferentially retained in the organic soil, whereas K was relatively mobile. Potassium tended to become concentrated in the unsaturated zone. Stream runoff had a consistently higher pH than groundwater, corresponding to higher Ca and Mg concentrations, which may have been from mineral sources in the headwater ponds. Otherwise, the stream water chemistry was closely related to groundwater in the upper layers of the peat deposit.     

Deformation styles as a key for interpreting glacial depositional environments

Lithostratigraphical and lithofacies approaches used to interpret glacial sediments often ignore deformation structures that can provide the key to environment of formation. We propose a classification of deformation styles based on the geometry of structures rather than inferred environment of formation. Five styles are recognised: pure shear (P), simple shear (S), compressional (C), vertical (V) and undeformed (U). These dictate the first letter of the codes; the remaining letters conveying the evidence. This information can be used to reconstruct palaeostress fields and to infer physical properties of sediments when they deformed. Individual structures are not diagnostic of particular environments but the suite of structures, their relative scale, stratigraphical relationships, and orientation relative to palaeoslopes and to palaeoice‐flow directions can be used to infer the environment in which they formed. This scheme is applied at five sites in west Wales. The typical succession is interpreted as subglacial sediments overlain by meltout tills, flow tills and sediment flows. Paraglacial redistribution of glacial sediments is widespread. Large‐scale compressional deformation is restricted to sites where glaciers readvanced. Large‐scale vertical deformation occurs where water was locally ponded near the ice margin. There is no evidence for glaciomarine conditions. Copyright © 2003 John Wiley & Sons, Ltd.     

The Statistical Analysis of Migration of Strong Earthquakes-Taking the North China Region as an Example

The migration of strong earthquakes is an important research topic because the migration phenomena reflect partly the seismic mechanism and involve the prediction of tendency of seismic activity. Research on migration of strong earthquakes has mostly focused on finding the phenomena. Some attempts on getting regularity were comparatively subjective. This paper suggests that there should be indices of migration in earthquake dataset and the indexes should have statistical meaning if there is regularity in the migration of strong earthquakes. In this study, three derivative attributes of migration, i.e., migration orientation, migration distance and migration time interval, were statistically analyzed. Results in the North China region show that the migration of strong earthquakes has statistical meaning. There is a dominant migration orientation (W by S to E by N), a dominant distance (≤100km and on the confines of 300～700km), and a dominant time interval (≤1a and on the confines of 3～4a). The results also show that the migration will differ slightly with different magnitude range or earthquake activity phase.     

The Upper Pleistocene to Holocene sediments on the Mediterranean island of Lampedusa (Italy)

The island of Lampedusa lies on the northern edge of the African continental shelf, but during some Quaternary marine lowstands it was joined to the African continent. The study and dating of the aeolian, alluvial, detrital sediments, calcareous crusts and speleothems have established that the climatic–environmental variations recorded on the island can be related chronologically to those known for northern Libya, Tunisia and the Italian peninsula. During the Last Glacial Maximum, phases of Saharan dust accumulation on Lampedusa occurred, and were coeval with dust accumulation in crater lakes and on high mountains in central‐southern Italy, and with phases of glacial advance in the Apennines and in the Alps. During the late Holocene, accumulation of Saharan dust on Lampedusa occurred but there was little accumulation of dust on the northern side of the Mediterranean Sea. With the new data from Lampedusa, it is possible to envisage two different scenarios of atmospheric circulation relating to the Last Glacial Maximum and to the late Holocene. During the Last Glacial Maximum, southerly atmospheric circulation brought rainfall to the southern slopes of the Alps and to the Apennines. During the late Holocene, a prevalent westerly atmospheric circulation became established in the northern Mediterranean. Copyright © 2004 John Wiley & Sons, Ltd.     

Water transport from the North-east Irish Sea to western Scottish coastal waters: Further observations from time-trend matching of Sellafield radiocaesium

Radiocaesium isotopes, discharged into the North-east Irish Sea from the Sellafield (formerly Windscale) nuclear fuel reprocessing plant in Cumbria, have been employed as flow monitors to update and extend the record of coastal water movement from the Irish Sea to the Clyde Sea area and, further north, to Loch Etive. The temporal trends in radiocaesium levels have been used to determine the extent of water mixing en route and to define mean advection rates. Flow conditions from the Irish Sea have changed considerably since the mid-1970s, the residence time of northern Irish Sea waters being ～12 months during 1978–1980 inclusive. Average transport times of four and six months are estimated for the Sellafield to Clyde and Sellafield to Etive transects respectively. Sellafield ¹³⁷Cs levels in seawater were diluted by factors of 27 and 50 respectively during current movement to the Clyde and Etive areas. The decrease in salinity-corrected ¹³⁷Cs concentrations between the Clyde and Etive suggests that dilution by Atlantic water occurs, the latter mainly entering the Firth of Lorne from the west. The majority (～94%) of the radiocaesium supply to Loch Etive enters the Firth of Lorne via the portion of the coastal current circulating west of Islay, only ～6% arriving via the Sound of Jura.     

公共行政监督的"经济解释"及其启示

行政腐败和行政作弊现象使政府行政的合法性受到人们的置疑 ,深入推行的廉政建设责任制反映了政府在这一问题上理论认识的巨大进步与从严治政的重大决心。公共选择理论认为 ,官僚的经济人属性不会因其成为政府官僚而改变 ,其目标不是公共利益也不是机构效率 ,而是个人效用 ;西方国家的“三权分立”学说及其实践对于公共行政的监督具有重大的历史进步意义 ,但其精致架构的私有制基础决定了这种民主可能只具有形式主义的性质 ,它只是一种富人之间的游戏规则与表现形式。毛泽东的“双平行制约”理论与方法是中国共产党人对公共行政理论与实践的巨大贡献 ,效果奇特却存在着一系列致命的弊端。对上述理论与实践的比较研究 ,为我国当前广泛展开的廉政建设提出了一些深层次的启发性思考     

NEMERTEANS OF ZHOUSHAN ISLANDS, EAST CHINA SEA COAST,CHINA Ⅰ.ENOPLA: DISTROMATOPHYNCHOCOELA: MONOSTILIFERA: EMPLECTONEMERTIDAE

Two nemerteans of the Zhoushan Islands, Paranemertes sinensis sp. nov. and P. peregrina, are reportedin this paper. P. sinensis sp. nov. has the body wall longitudinal musculature anteriorly divided,numerous eyes grouped into four clusters, two pairs of cephalic furrows, rhynchocoel 1/3 to 1/2 of fullbody length, cephalic glands well developed and posteriorly extending beyond the cerebral ganglia.precerebral septum absent, cerebral sense organs situated in front of brain, three pairs of nephridiopores,and 17-18 proboscis nerves.     

加强技术创新服务地质调查——庆祝探矿工艺研究所成立30周年

为加强地质探矿技术力量,改变地质装备落后现状,经国务院批准,1978年8月8日成立了探矿工艺研究所。30年来,经过新老两代工艺所人的艰苦奋斗、刻苦钻研、勇于创新,在科研攻关、成果转化、基地建设和管理等方面都取得了可喜的成绩,为国家的地质科学事业做出了贡献,目前已成为一个“以勘查技术为基础,以承担地质调查任务和科研项目、提供勘查与监测技术方法和技术服务为手段,以服务国家经济建设、社会发展和地质工作为目标,以探矿工艺技术和地质灾害监测防治技术研发为主业”的地质调查科研机构。回顾了工艺所艰苦创业、改革进取的发展历程,对科技体制改革、专业结构调整、人事分配制度改革、地质调查和科研工作进行了总结,展示了丰硕的科研成果和强劲的科技实力;指出了工艺所在“十一五”期间地质调查和科研工作的重点领域和优先发展方向。     

Spatial variability in the primary productivity in the East China Sea and its adjacent waters

Primary productivity in the East China Sea and its adjacent area was measured by the¹³C tracer method during winter, summer and fall in 1993 and 1994. The depth-integrated primary productivity in the Kuroshio Current ranged from 220 to 350 mgC m⁻²d⁻¹, and showed little seasonal variability. High primary productivity (above 570 mgC m⁻²d⁻¹) was measured at the center of the continental shelf throughout the observation period. The productivity at the station nearest to the Changjiang estuary exhibited a distinctive seasonal change from 68 to 1,500 mgC m⁻²d⁻¹. Depth-integrated primary productivity was 2.7 times higher in the shelf area than the rates at the Kuroshio Current. High chlorophyll-a specific productivity (mgC mgChl.-a⁻²d⁻¹) throughout the euphotic zone was mainly found in the shelf area rather than off-shelf area, probably due to higher nutrient availability and higher activity of phytoplankton at the subsurface layer in the shelf area.