Isotope hydrological study of mean transit time in the granitic Strengbach catchment (Vosges massif,France): application of the FlowPC model with modified input function

Measurements of ¹⁸O concentrations in precipitation, soil solution, spring and runoff are used to determine water transit time in the small granitic Strengbach catchment (0·8 km²; 883–1146 m above sea level) located in the Vosges Mountains of northeastern France. Water transit times were calculated by applying the exponential, exponential piston and dispersion models of the FlowPC program to isotopic input (rainfall) and output (spring and stream water) data sets during the period 1989–95. The input function of the model was modified compared with the former version of the model and estimated by a deterministic approach based on a simplified hydrological balance. The fit between observed and calculated output data showed marked improvements compared with results obtained using the initial version of the model. An exponential piston version of the model applied to spring water indicates a 38·5 month mean transit time, which suggests that the volume in the aquifer, expressed in water depth, is 2·4 m. A considerable thickness (>45 m) of fractured bedrock may be involved for such a volume of water to be stored in the aquifer. Copyright © 2005 John Wiley & Sons, Ltd.     

Restructuring the export-oriented industrialization in the Pearl River Delta, China: Institutional evolution and emerging tension

The rise of the Pearl River Delta (PRD) as a promising workshop of the “world factory” in China has attributed to the export-oriented industrialization driven by foreign direct investment, particularly Overseas Chinese investment from Hong Kong and Taiwan initiated in the late 1970s. The export-oriented industrialization has embedded in the flexible institutions favourable for foreign investors and local authorities, via the salient entry mode, i.e. processing with supplied materials (lailiaojiagong). Since the mid-2000s, the export-oriented industrialization has undergone dramatic restructuring to cope with the changing business environment at global, national and regional and firm levels. Drawing upon the evolutionary and institutional perspectives in geographical political economy approach, this study argues that the prevailed institutions conducive for the export-oriented processing have evolved into institutional inertia and territorial embeddedness as obstacles for the on-going restructuring, particularly the market reorientation from export to domestic sale. Moreover, difficulties of restructuring through the state-designated relocation have been heightened by the resistance from below and emerging state-firm tension. The institutional evolution of the export-oriented industrialization in the PRD has enriched the literature on industrial restructuring in the context of dynamic global-local interactions, but also provided fundamental implications for formulating well-coordinated restructuring strategies among various institutions and concerned actors.     

闽江河口湿地芦苇和互花米草生物量季节动态研究

通过对闽江河口湿地芦苇(Phragmites australis)和互花米草(Spartina alterniflo-ra)群落特征和生物量的调查,结果表明:2种植物株高和密度呈显著负相关.芦苇地上部各构件生物量最大值出现在夏季,其值为1 524.8±78.85 g.m-2;互花米草最大值出现在秋季,其值为3 037.2±248.78 g.m-2.互花米草地上生物量显著大于芦苇(P<0.05),但立枯量无显著差异(P>0.05).2种植物地下生物量均为0~15 cm>15~30 cm>30~60 cm;芦苇夏季各层生物量极显著大于其他季节(P<0.05),互花米草地下各层生物量在冬季达到最大,生长季节逐渐下降,夏季最小.芦苇和互花米草总生物量积累动态呈典型的单峰值曲线,总生物量互花米草高于芦苇,但二者差异不显著.随着入侵时间推移,互花米草总生物量还要持续增长.     

Sediment records as archives of the Late Pleistocene-Holocene hydrological change in the alluvial Narmada River basin, western India

The rivers of western India are monsoon dominated and have been so throughout the late Quaternary. Sediment accumulation in these river basins has been controlled by climatic and tectonic changes over a time span from the Late Pleistocene to the recent. The lithofacies assemblages associated with the various sediment archives in the Narmada basin range from the boulders of the alluvial fans to overbank fines on the alluvial plains. Estimates, based on clast size, of stream power and competence, bed shear stress and discharge reveal that hydrological conditions during the Late Pleistocene (∼90 ka) were comparable to the present day. The size of the transported clasts and the thickness of the accumulated sediment indicate the influence of basin subsidence rather than an increase in discharge. Discharge estimates based on sedimentary structures preserved in the alluvial-plain facies suggest that the channel had a persistent flow, with a low width-depth ratio and large meander wavelength. The hydrological changes during the Holocene are more pronounced where the early Holocene is marked by a high-intensity hydrological regime that induced erosion and incision of the earlier sediments. The mid-Holocene stream channel was less sinuous and had a higher width-depth ratio and a higher meander amplitude in comparison with the present-day channel. Palaeo-fluvial reconstructions based on the sediment archives in the alluvial reach of the river basin are important tools in understanding the long-term hydrological changes and the intricate fluvial architecture preserved in the Narmada River basin ensures scope for detailed studies to identify phases of weak and enhanced hydrological regimes.     

Spatial variation in river runoff into a coastal area — An ecological approach

Carbon and nitrogen stable isotopes were used to investigate spatial variation in terrestrial particulate organic matter (POM) input to a coastal area off the Tagus river estuary. Isotopic variation in higher trophic level organisms was also examined, along the coast. This study was carried out in late summer, after a period of 3 months of low river flow. The overall aim was to determine if under such conditions the coastal area is enriched by the river plume and, particularly, if lower secondary productivity should be expected in some areas. Spatial variation was detected as a gradient of decreasing terrestrial input with increasing distance from the river. It was concluded that terrestrial carbon input was also incorporated into higher trophic levels and that organisms with lower mobility are more sensitive to the gradient in terrestrial input. Even in low flow conditions the whole fishing area remained under the influence of the river plume, which still accounted for 24% of the total POM 30 km from the river mouth. Additionally, δ¹⁵N values indicated pollution input from the river Tagus.     

Carbon Isotope Geochemistry of the Orinoco Basin

Stable carbon isotope ratios have been used to study the sources of particulate organic carbon (POC) and total dissolved inorganic carbon in the Orinoco Basin. The isotopic composition of total dissolved inorganic carbon shows a range of from -8·1 to -23·0 ppt, an indication of dominance of biological processes. The isotopic composition of POC exhibits a range of from -24·1 to -34·6 ppt with little seasonal variation. The isotopic evidence indicates that the POC is predominantly of terrestrial origin rather than a result of in situ planktonic production. The similarity of isotopic composition of POC and coastal sediments suggests that riverine organic detritus has been transported 30-50 km offshore in a direction parallel to the Orinoco river channel.     

长江口及邻近海域表层水体溶解氧饱和度的季节变化和特征

根据“908”ST04区块调查的夏、冬、春、秋季四个航次和“908”补充调查的8月航次资料对长江口及邻近海区表层水体溶解氧及其饱和度进行了探讨.研究表明东海北部表层水体在夏季和春季以浮游植物光合作用为主要控制过程,特别是7、8月份长江口外、杭州湾外及浙江近海存在大范围的强光合作用区;秋季以有机质氧化分解过程为主,表层溶...     

OBSERVATIONS ON THE HINTEREIS AND VERNAGTFERNER

Abstract

Adequate water resources management at the basin level needs quality downscaling of climate change scenarios for application to impact assessment and adaptation work. This study evaluates the ability of a regional climate model (RegCM3) to simulate the present-day climate and regional water balance over the Niger River Basin (NRB). RegCM3 gives a good simulation of the NRB hydroclimatic features. The mean bias error for monthly temperature is 1.5°C, 0.3 mm d^-1 for rainfall, and 0.4 mm d^-1 for runoff. Moderate to high correlations (0.66–0.95) were found between the modelled and the observed variables. RegCM3-based water cycling indices were not statistically different from the observation. Seasonal moistening efficiency (m) ranges between 19% and 37%; 66% of the available atmospheric moisture over NRB precipitates between June and September, of which 21% originates from local evaporation. The result suggests that the moisture sink period is July to October with very high precipitation efficiency over the basin. The model reproduces the hydroclimatology of the NRB and hence is a suitable tool for further studies relating to the assessment of climate change impacts on river basin water systems.

Editor Z. W. Kundzewicz; Associate editor D. Hughes     

Late Quaternary diatom and sea level changes in estuarine plain of the Jiulong River

TheJiulongRiver,composedoftheWestStream,theNorthStreamandtheSouthStream(seeFig.1)isthesecondlargestriverinFujianProvince.ItsestuarineplainintervenesbetweenthetwqcitiesofXiamenandZhangzhou,withsouthern-subtropicoceanicmonsoonclimate-SofartherehasnotbeensystematicresearchontheLateQuaternarysea1evelchangesinthearea,andthispaperisintendedtodosomethingaboutit.DIAToMZoNESANDBIoFACIESOFZK5BoREHOLETheBoreholeZK5islocatedtothenortheastofHaichengTown,withcoordinateof24"24,32*N,ll7'5…     

Early Paleozoic gabbro-granitoid associations in eastern segment of the Mongolian-Okhotsk foldbelt (Amur River basin): Age and tectonic position

Magmatic rocks of the Pikan and Un’ya massifs situated in eastern segment of the Mongolian-Okhotsk foldbelt are studied using isotopic-geochronological (U-Pb zircon dating) and geochemical methods. Two rock complexes different in age are recognized in the Pikan massif: the high-Al gabbro-tonalite association of the Middle Ordovician (468 ± Ma) and granodiorite-granite association of the Late Silurian-Early Devonian (415 ± 7 Ma). The Late Ordovician age (454 ± 5 Ma) is established for leucocratic granites of the Un’ya massif. As is suggested, the Pikan and Un’ya massifs are “allogenic blocks” detached from continental framework of the Mongolian-Okhotsk foldbelt and tectonically emplaced into the foldbelt structure at the last stage of its development.