摘要:

AbstractThe amount of settling phosphorus was measured in Římov Reservoir using sediment trap technique from April 1986 to April 1987. Sediment traps were placed at three depths near the dam of the reservoir and at the bottom along the reservoir.The highest amount of phosphorus in trapped material was found during the fall turnover in the epilimnion and near the bottom in both spring periods (1986,1997). During the growing season the changes in dry weight and total phosphorus in settling seston were related to changes of phytoplankton biomass in the trophogenic layer. The amount of trapped phosphorus was higher near the bottom than in the upper layers of the reservoir throughout the yea

ISSN:0020-9309    

DOI:10.1002/iroh.19900750302

出版商:Akademie Verlag, Berlin    

年代:1990

数据来源: WILEY

摘要:

AbstractBreakdown rate of terrestrial and aquatic leaves was found to depend on leaf species and on the biotope considered.As the leaves started decaying at different dates and had different breakdown rates, consumable allochthonous or autochthonous organic matter was fed to the aquatic system throughout the year, from one summer to the next.A comparison with former results on the main channel confirms the existence of a transversal gradient in the fluvial network: under the influence of fungal and invertebrate colonization, breakdown was fastest in the channel of the river, slower in an open side‐arm, and slower still in a more lateral and closed side arm, in which organic matter accumulated in hypoxic condition

ISSN:0020-9309    

DOI:10.1002/iroh.19900750303

出版商:Akademie Verlag, Berlin    

年代:1990

数据来源: WILEY

摘要:

AbstractThis paper deals with the abundance and distribution of caddisfly larvae in the River Butron basin. Spatio‐temporal changes in caddisfly community structure, detected by means of correspondence analysis, are related to physico‐chemical changes, mainly conductivity and oxy

ISSN:0020-9309    

DOI:10.1002/iroh.19900750304

出版商:Akademie Verlag, Berlin    

年代:1990

数据来源: WILEY

摘要:

AbstractA study on biological assessment of water pollution using diatom community structure and species distribution was carried out in the Linggi River Basin, Malaysia which was polluted by various urban, industrial and agricultural wastes. A total of 86 diatom taxa belonging to 21 genera were recorded from all eight sampling stations located in the basin, of which 70 species were found on artificial substrates; the remaining 16 species were recorded exclusively on natural substrates. The number of diatom species observed between the stations varied from 22‐47 species. The dominant diatom species in decreasing order of abundance wereEunotia vanheurckii, Nitzschia palea, Achnanthes saxonica, Gomphonema parvulumandAchnanthes minutissima.The most common clean water species wereAchnanthes minutissima, A. linearisandSynedra rumpens.The most tolerant species wereNitzschia paleafollowed byGomphonema parvulumandPinnularia braunii. Eunotia vanheurckiiandNavicula cryptocephalaoccurred in high densities at both unpolluted and polluted stations and can be considered as the common facultative or indifferent species. Although a large number of species were recorded at the unpolluted stations, equivalent number of species were also found at the moderately polluted stations. However, the number of species was reduced at grossly polluted stations. Nevertheless, a marked variation in species association exists between the unpolluted and polluted stations, but not among the polluted stations to distinguish the type and degree of pollutio

ISSN:0020-9309    

DOI:10.1002/iroh.19900750305

出版商:Akademie Verlag, Berlin    

年代:1990

数据来源: WILEY

摘要:

AbstractA limestone outcrop along the north shore of Lake Waccamaw, North Carolina, is found to contain ca. 0.1 % phosphate by weight. Weathering processes have probably driven steady inputs of phosphate from this source throughout the lake's history, accounting for its near eutrophic state. The sediments of Lake Waccamaw are enriched with phosphate, particularly in the littoral zone near the outcrop. Chemical and biological processes apparently remove phosphate from solution rapidly, making detection of a soluble phosphate signal near the outcrop difficult. Management of nutrient inputs and water quality in Lake Waccamaw requires consideration of the effects of this in‐lake source of phosphate. Other sources of phosphate, particularly in the lake's drainage basin, may be less important than previously though

ISSN:0020-9309    

DOI:10.1002/iroh.19900750306

出版商:Akademie Verlag, Berlin    

年代:1990

数据来源: WILEY

摘要:

AbstractThe data obtained during an extensive multidisciplinary investigation of a polluted harbor basin in Hamburg were analyzed in various ways in order to determine which statistical methods are easiest to interpret and permit the most accurate evaluations. The methods analyzed include the species deficit, index of species similarity, and saprobity index, as well as the more complex cluster and gradient analyses, which revealed a variety of relationships among the biotic communities at the various sampling sites and some ecological tolerance limits of various species. The shortcomings of numerical indices for characterizing water bodies are discussed. It is suggested that biostatistical methods are much more valuable for the empirical evaluation of data than for artificially classifying ecosystems.

ISSN:0020-9309    

DOI:10.1002/iroh.19900750307

出版商:Akademie Verlag, Berlin    

年代:1990

数据来源: WILEY

摘要:

AbstractThe distribution of surface and ground waters in Northern Ireland were mapped with respect to pH and total hardness and the distributions discussed in relation to the regional geology and pedology. These waters were grouped into 3 categories depending on their vulnerability to acidification. Three upland areas, the Mournes, the western Sperrins and the northern Glens of Antrim, were identified as being vulnerable to acidification. Concentrations of total and labile aluminium in these areas were high and, in the Mournes and Sperrin areas, exceeded the EC directive on total aluminium in drinking water. However, because of their differing geology and pedology, only the Mournes area had labile aluminium levels which gave cause for concern. A fish survey in a reservoir in the Mournes catchment showed that it supported a small but self‐sustaining population of brown trout (Salmo trutta) which, although small in size, showed no signs of deformit

ISSN:0020-9309    

DOI:10.1002/iroh.19900750308

出版商:Akademie Verlag, Berlin    

年代:1990

数据来源: WILEY

摘要:

AbstractThe planktonic invertebrates found in Lake Volvi are presented. There are 26 species of Rotifera, 1 Bivalve (larva), 13 Cladocera, 5 Copepoda, 1 Branchiura and 1 Diptera (larva). Many of these are new for the Greek fauna, though they are common in Europe. The discovery of some other species extends the knwown bounds of their geographical distribution in Greece.The lack of large‐sized forms is considered to be due to strong predation byAlosa macedonica. (Pisces, Clupeidae). A comparison is given to the planktonic invertebrates of other Balkan lakes. There is a remarkable similarity with the fauna of Lake Doïra

ISSN:0020-9309    

DOI:10.1002/iroh.19900750309

出版商:Akademie Verlag, Berlin    

年代:1990

数据来源: WILEY

摘要:

AbstractThe proximate composition, nutrient and trace elements of the planktonic algal “jellies” of Lake Oguta in Southern Nigeria, are provided as guides to their utilization and control, using flood (rainy) and dry season samples. These “jellies” are an unusual, macroscopic planktonic algal community in the lake, made up mostly of blue‐green algae (Microcystis, Anabaena, Chroococcus) with some green algae (e. g.Spirogyra) and pennate diatoms (e.g.Navicula) rather epiphytic on the mucous jellies of the blue‐green algae. Water content was high (98.2% mean, range 97.5‐99.5%). Ash, protein and fat had values of 41.7 (39.0‐46.2%), 16.9 (15.6‐19.4%), and 2.0 (1.7‐2.1%) respectively. Crude fibre and carbohydrates were high (25.8% and 12.4%). The levels of phosphorus and nitrogen were rather high, so were the major cations whose order of dominance (Ca>K>Mg>Na) differed from that of the lake water. Macronutrients increased in their concentrations during the rainy flood season while the reverse was the case with the micronutrients. Diagenesis of the endogenic minerals rather than anthropogenic factors are thought to be the reason for the seasonal changes in the ionic concentrations. Possible uses of the algal jellies are discussed as well as th

ISSN:0020-9309    

DOI:10.1002/iroh.19900750310

出版商:Akademie Verlag, Berlin    

年代:1990

数据来源: WILEY

ISSN:0020-9309    

DOI:10.1002/iroh.19900750312

出版商:Akademie Verlag, Berlin    

年代:1990

数据来源: WILEY