of the surrounding soils to the cover of emergent aquaticvegetation.
Black and white aerial photographs from 1947-1963 and colour, mainly infrared aerial photographs from 1996-2000 were used to study quantitative vegetation changes in 7 large lakes : Kemijärvi, Unnukka, Kallavesi, Päijänne, Näsijärvi, Pyhäjärvi
and Vanajavesi. Vegetation changes were evaluated by comparing the situation before large-scale water level regulation and eutrophication to the current situation. The results point out the crucial impact of changing water levels and the significance
during summer and autumn. The morphology of the bend was very stable over the observation period and neither bank erosion nor pool scouring occurred. However, fine sediments accumulate within vegetation patches and in the recirculation zones while
the remaining open areas tend to erode slightly. With the decay of macrophytes in winter, sediment accumulations are mobilised again and the bathymetry levels, supporting cyclic models of morphologic change in vegetated bends. In the second part of the paper
, semi-empirical models for the 3 predominant flow types were tested and discussed; velocity and stress models of vegetated mixing layers and plane turbulent jets, and Rozovskii's model for the transverse flow in bends.
C14 dating ; Evapotranspiration ; Lake level ; Minnesota ; Paleo-environment ; Palynology ; Pollen diagram ; Sedimentology ; United States ; Vegetation
The composition, magnetic characteristics, and pollen content of sediments from two small kettle lakes near the prairie-forest border in west-central Minnesota were used to infer changes in terrestrial vegetation, shoreline erosion, eolian inputs
Chemical pollution ; Ecosystem ; Environment ; Floodplain ; Human impact ; Humid environment ; Netherlands (The) ; Pollution ; Vegetation ; Water pollution
In the Vecht river plain, renown for their great variety of aquatic and fen vegetation, a marked deterioriation of wetland vegetation has been observed. Specific research questions in this thesis are : is the groundwater under the ridge polluted
The relation between hydrology aznd vegetation in the Dutch man-made aquatic polder ecosystems has been investigated at two scales : first this of the direct habitat relations between species and the values of non-biotic variables, and secondly
L'A. étudie l'état actuel de la végétation aquatique supérieure de l'un des lacs artificiels les plus importants d'Europe. A partir de la régionalisation physique et géographique il effectue la régionalisation géobotanique de la zone littorale de
tout le réservoir d'eau. Il distingue 4 régions géobotaniques, qui diffèrent par le degré d'envahissement par la végétation comme par la composition des espèces dominantes.
Ardennes, dépt. ; Biogéographie ; Centrale nucléaire ; Chooz ; Contamination ; Ecosystème ; France ; Géographie de l'Europe ; Meuse, fleuve ; Pollution ; Synécologie fonctionnelle ; Végétation ripicole
An extensive sampling survey of animals and aquatic and ripicolous plants was performed in September 1974 in the Upper Meuse, in order to determine the mean levels of radioactive contamination of the main constituents of the river ecosystem
. In particular, the aquatic mosses remain the most suitable indicators for routine surveillance of the evolution of radioactive contamination in such ecosystems. (LW).
This paper reviews the biological role of Si in higher plants, the impact of vegetation on rates of chemical weathering, the fluxes of Si through catchment ecosystems, lakes and rivers, and the potential contribution of new geochemical and isotopic
tracers to Si biogeochemistry. Multiproxy investigations of lake sediments will provide novel insights into past variations in Si biocycling from terrestrial to aquatic on 10-10 000 000 year time-scales.
Eau ; Eau du sol ; Ecologie ; Ecoulement ; Evapotranspiration ; Feu ; Hydrochimie ; Hydrosystème ; Impact ; Propriétés du sol ; Qualité de l'eau ; Transport sédimentaire ; Utilisation du sol ; Végétation
Ecology ; Evapotranspiration ; Fire ; Hydrochemistry ; Hydrosystem ; Impact ; Land use ; Runoff ; Sediment transport ; Soil properties ; Soil water ; Vegetation ; Water ; Water quality
The aim of this review is to survey recent research used to understand the impact of fire disturbance on hydrological systems : ecophysiology; aquatic biology; soils; water chemistry; seasonal effect of burning; land-use comparisons; experimental
Etablissement de cartes, détermination de la phytomasse et de la production annuelle de la végétation aquatique dans les baies Kurkutskaïa, Bazarnaïa et Tugaïskaïa de ce détroit le long de l'île Olkhon dans le sud-ouest du lac Baïkal. A l'époque des
Ein Optimalprinzip in der Theorie aquatischer Okosysteme. (An optimun principle in the theory of aquatic ecosystems)
In the thermodynamic theory of aquatic ecosystems the non-linear relations between rates and affinities of biological processes, such as primary production, respiration, grazing etc. can be determined using an optimun principle. Especially
partir des conditions de l'eutrophisation anthropique des réservoirs d'eau. Estimation de l'accumulation de substances polluantes dans la végétation aquatique supérieure. Les modifications écologiques des plantes aquatiques servent d'indicateur des