摘要:

AbstractThe significance of epipsammic microphytobenthos bioproduction in a shallow estuary was investigated by the oxygen method. Bioproduction reached a maximum in May or June. A close correlation was found between the gross production rate and algal biomass at station K. The biomass and production rates were distinctly lower at station B than at station K as station B was more exposed. Circadian variations and depth profiles of the gross production rate correlated best with irradiation intensity. Mean gross production from April to October was 1761 O2.m−2and 75 g C·m

ISSN:0020-9309    

DOI:10.1002/iroh.19860710202

出版商:Akademie Verlag, Berlin    

年代:1986

数据来源: WILEY

摘要:

AbstractThe seasonal changes in the vertical distribution ofTintinnopsis lacustrisandTintinnidium fluviatilewas studied in the Karst Lake Kozjak, one of the group of Plitvice lakes. The question asked was to what extent does the development of these two species‐populations follow the seasonal fluctuations and spatial distributions of the planktonic community or the seasonal changes in environmental condition

ISSN:0020-9309    

DOI:10.1002/iroh.19860710203

出版商:Akademie Verlag, Berlin    

年代:1986

数据来源: WILEY

ISSN:0020-9309    

DOI:10.1002/iroh.19860710206

出版商:Akademie Verlag, Berlin    

年代:1986

数据来源: WILEY

摘要:

AbstractThe ciliates in aufwuchs communities on glass slides exposed to different amounts of salt pollution at several locations in the Weser River system were investigated. The results were compared with those from the study of model ecosystems exposed to salts. A comparison of the ciliate occurrence with a number of physical and chemical parameters showed that it is primarily the amount of salt present that determines which species are dominant. The number of species present decreases in the presence of high salt concentrations and in water flowing at a high velocity. A halobic index was formulated to indicate salt pollution quantitatively but turned out not to be useful due to the euryhaline potency of most of the ciliate species. The saprobic index can be used in rivers polluted with salt only if biological indicator species are present in sufficient number.

ISSN:0020-9309    

DOI:10.1002/iroh.19860710207

出版商:Akademie Verlag, Berlin    

年代:1986

数据来源: WILEY

摘要:

AbstractSix sandy beach stations along the Jordan Gulf of Aqaba were selected for macrofaunal examination during November 1980. Fifteen core samples (0.01 m2to a depth of 10–15 cm) were taken at each station; five at the high tide line, five at the low tide line, and five midway.Twenty‐two taxa were encountered from all stations. Polychaetes were the most diverse group with seven taxa, followed by molluscs and crustaceans with six and five taxa respectively. Animal diversity, using the Shannon‐Wiener Index, was generally low. Based on the biological index value of McCLOSKEY (1970), seven taxa were considered the community dominants. These are: the polychaetes,Glycera tesselata, Pisione remota, Saccocirrussp., andPerinereis nuntia; the isopodEurydice arabica; a nemertean and an oligoc

ISSN:0020-9309    

DOI:10.1002/iroh.19860710208

出版商:Akademie Verlag, Berlin    

年代:1986

数据来源: WILEY

摘要:

AbstractVariations in chlorophyllaconcentration and in qualitative and quantitative counts of Nile phytoplankton were followed at Assiut from September 1980 to September 1982. Chlorophyllaconcentrations usually correlated well with phytoplankton density. The total phytoplankton exhibited higher counts in spring and summer than in autumn and winter. While diatoms exhibited the highest counts, green algae contributed more genera to the phytoplankton community.

ISSN:0020-9309    

DOI:10.1002/iroh.19860710209

出版商:Akademie Verlag, Berlin    

年代:1986

数据来源: WILEY

摘要:

AbstractIn the most productive macrophytes stand lying within the littoral zone of Lake Naini Tal (a Kumaun Himalayan Lake, located 1937 m above sea level) the macrophytic biomass was removed at the time of peak biomass one year, but not during the next. The effect of non‐removal of the macrophytes was apparent in the physical and chemical parameters of the water, viz: thermal stratification, pH, dissolved oxygen, calcium and nitrogen content. The removal of macrophytes increased the plant diversity. Seasonal patterns of ash, calcium and nitrogen content in plant tissues were different for the two years of stud

ISSN:0020-9309    

DOI:10.1002/iroh.19860710210

出版商:Akademie Verlag, Berlin    

年代:1986

数据来源: WILEY

ISSN:0020-9309    

DOI:10.1002/iroh.19860710212

出版商:Akademie Verlag, Berlin    

年代:1986

数据来源: WILEY

摘要:

AbstractPopulation densities of primarily iron precipitating heterotrophs (metal‐precipitating non oxidizing bacteria) were estimated in water and sediments of ponds being used for polyculture, monoculture and traditional systems of fish farming over a period of two and a half years. Spatial differences in microbial density in the ponds were related to the organic loading of the farm site and the type of farming. The highest bacterial populations occurred in November and the lowest in summer. Nitrite concentration was mainly responsible for such seasonal change

ISSN:0020-9309    

DOI:10.1002/iroh.19860710213

出版商:Akademie Verlag, Berlin    

年代:1986

数据来源: WILEY

摘要:

AbstractLaboratory‐based bioassay experiments usingSelenastrum capricornutumPRINTZ as the test organism were conducted to evaluate the potentiality of refinery effluents to sustain algal growth. The raw effluents were remarkably toxic to the test alga, but satisfactory algal growth occurred in (diluted) 0.01 % effluents. The effluents from subsequent treatment stages required much less dilution to eliminate the toxicity. This study implicates oil and phenol in the reduction of algal growth in refinery effluents. A highly significant negative correlation was found between the final yield of the test alga and the concentration of oil or phenol in the culture suspension. The bioassay experiments therefore point to the toxic nature of refinery effluents. On the basis of these findings it is recommended that proper dilution of refinery effluents is necessary before they are discharged into any body of wate

ISSN:0020-9309    

DOI:10.1002/iroh.19860710214

出版商:Akademie Verlag, Berlin    

年代:1986

数据来源: WILEY