摘要:

AbstractContrary to surface water, groundwaer is mainly anoxic and contains high iron(II) concentrations. Consequently, results of ortho‐phosphate analyses often show a systematical underestimation since phosphate is coprecipitated or adsorbed by precipitating iron(III) hydroxide. This process is caused by aeration during sampling, storing and filtration of groundwater samples. The error of P‐analyses can only be reduced by sampling and filtrating under inert gas and by an immediate addition of the chemicals for the molybdenum blue method. Storage of unfiltered, acidified samples is possible,

ISSN:0323-4320    

DOI:10.1002/aheh.19910190202

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY

ISSN:0323-4320    

DOI:10.1002/aheh.19910190203

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY

摘要:

AbstractIn many biological counting problems it is known that under ideal conditions repeated counts follow a Poisson distribution. This is true, for example, for counts of bacteria in a number of equal volumes from a well‐mixed suspension. In order to indicate whether counts show more variability than can usually be expected from a Poisson distribution it is customary to use the index of dispersion. A BASIC‐program written for personal computers is given which allows a rapid statistical evaluation of count data by means of the dispersion index. The program can be used, moreover, for some other tasks, too, such as the computation of confidence bounds, the testing of hypotheses and the planning of counting proces

ISSN:0323-4320    

DOI:10.1002/aheh.19910190204

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY

ISSN:0323-4320    

DOI:10.1002/aheh.19910190205

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY

摘要:

AbstractMajor cations and anions were investigated in the Damietta branch of the River Nile. The branch is divided into two different regions; the fresh Nile water (Region A) and the mostly marine environment (Region B). The latter region represents the Damietta estuary. The relative abundance of the major ions in the fresh water system was Na>Ca>Mg>K, HCO3>Cl>SO4>CO3, while in the mostly marine area it was Na>Mg>K>Ca, Cl>HCO3>SO4>CO3. Regional and monthly variations of the major ions were related to the duration of the Nile discharge and climatic conditions. The major ions ‐to‐ chloride ratios for Region A were higher than those in the adjacent Mediterranean waters, while those for the mostly marine region were slightly lo

ISSN:0323-4320    

DOI:10.1002/aheh.19910190206

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY

摘要:

AbstractUnder the influence of the wastewaters of the potash industry the Werra river shows considerably varying salt contents (0.47 … 28.2 g/l Cl−, annual means 4.4 … 11.4 g/l Cl−) in dependence on the hydrological situation. Between 1982 and 1988 a total of 112 taxa of diatoms were observed. Of special interest is the occurrence of Stauroneis constricta (EHRENBERG) CLEVE, which is new for the river Werra. Its spreading upstream was observed. Compared with earlier findings as well as within each annual cycle there are observed clear changes in the species present and in the colonization structures in dependence on the salt content. The close relations between the salt content and the diatom communities are truly expressed by the index of halobic organisms. Diversity indices of 1.048 … 3.259 as well as values of 0.074 … 0.817 for evenness verify the imbalance of the colonization, without, however, revealing a relation to the salt content, except for variations of concentration which may be

ISSN:0323-4320    

DOI:10.1002/aheh.19910190207

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY

摘要:

AbstractPhosphorus is considered to be one of the most important factors in the maintenance of an aquatic eco‐system. The study deals with the relation of available inorganic phosphate in water with phytoplankton abundance. The phytoplankton count ranged between 487 and 1711 indiv./l, while phosphate ranged between 0.18 and 1.23 mg/l. A maximum population of phytoplankton was observed in the month of January 1988 and a minimum observed in April 1988. The correlation between the changes in phosphate concentration and phytoplankton abundance revealed an inverse relationship (r= −0.0773, P>0.05), and the regression is expressed by Y = 370 + 755 (x), indicating its link in the cycle of autotrophs though not significan

ISSN:0323-4320    

DOI:10.1002/aheh.19910190208

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY

ISSN:0323-4320    

DOI:10.1002/aheh.19910190209

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY

摘要:

AbstractThe community structure of zooplankton was studied in relation to physico‐chemical characteristics of the river Chambal polluted by industrial effluents and domestic sewage near Nagda. Thirtytwo species of zooplankton of five main groups, viz. Protozoa, Rotifera, Cladocera, Copepoda and Ostracoda were observed at pre‐pollution sampling stations. The abundance, distribution, total population, group percentage and species diversity were studied and correlated with pollution‐indicating parameters. Species diversity values indicated a decrease from the sampling station near a pre‐effluent point to an effluent discharge channel and an increase at a post‐effluent discharge point revealing a slight recovery zone.Keratella tropicaandKellicottiasp. were identified as pollution tole

ISSN:0323-4320    

DOI:10.1002/aheh.19910190210

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY

ISSN:0323-4320    

DOI:10.1002/aheh.19910190211

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY