摘要:

AbstractTheoretical analyses and experiments have been performed for rapid detection of dissolved humic substances in surface waters. The fluorescence has been generated by a nitrogen laser in a laboratory. An optical model has been developed, which has been applied to eutrophic waters around Berlin. The model is based on the assumption, that humic substances and phytoplankton dominate the fluorescence behaviour of the investigated waters. To verify the results of the model, regression analyses between fluorescence data of natural samples and the chemical oxygen demand of filtrates have been conducted. When green and red fluorescence values and the green fluorescence decay time were considered, a maximum squared correlation coefficient of typically 0.85 occurred.

ISSN:0020-9309    

DOI:10.1002/iroh.19960810102

出版商:Akademie Verlag, Berlin    

年代:1996

数据来源: WILEY

摘要:

AbstractUnicellular autofluorescent picoplankton ranging from 0.6 to 0.9 ym in diameter were isolated from Lake Maggiore and from Lake Balaton. The cyanobacterial isolates contain two accessory pigments: phycoerythrin (PE) and phycocyanin (PC) respectively. Thein vivospectral properties of the two clones were compared to identify characteristics of the pigments.In vivofluorescence excitation and emission spectra revealed that clones with PE are composed only of phycoerythrobilin chromophores and lack phycourobilin. Glycerol treatment enhances the fluorescence yield up to 3 times and improves the detection sensitivity of PE particularly at 436 and 520 nm and of PC at 600 nm. The vertical profiles of the underwater irradiance at different wavelengths were measured in both lakes to study the light quality of the natural environment of the two strains. Growth rates of both clones growing at different light intensities and wavelengths, selected by the same filters used for vertical profiles, were estimated. The results showed a difference in growth rate of phycoerythrin and phycocyanin containing cells exposed to an equal quantum flux of preferential illumination. In particular the maximum growth rate was reached by PE cells exposed to green light and by PC cells exposed to red light.

ISSN:0020-9309    

DOI:10.1002/iroh.19960810103

出版商:Akademie Verlag, Berlin    

年代:1996

数据来源: WILEY

ISSN:0020-9309    

DOI:10.1002/iroh.19960810104

出版商:Akademie Verlag, Berlin    

年代:1996

数据来源: WILEY

ISSN:0020-9309    

DOI:10.1002/iroh.19960810105

出版商:Akademie Verlag, Berlin    

年代:1996

数据来源: WILEY

ISSN:0020-9309    

DOI:10.1002/iroh.19960810106

出版商:Akademie Verlag, Berlin    

年代:1996

数据来源: WILEY

摘要:

AbstractA total of 1136 Ephemeroptera, Plecoptera and Trichoptera were caught from March 1993 to March 1994 at the Weidlingbach, a first to fourth order forest brook near Vienna. Austria, using pyramid‐type emergence traps at tree sampling stations (390, 360 and 260 m above sea level). Five species comprised 67.1 % of the catch: the ephemeropteransParaleptophlebia submarginata(Stephens),Habroleptoides confusaSartori and Jacob andHabrophlebia lautaEaton, and the plecopteransNemoura flexuosaAubert andLeuctra hippopusKempny. Most taxa emerged from April to August, but the plecopteransLeuctra primaKempny andCapnia bifrons(Newman) were caught early in the year (January to April), andLeuctra digitataKempny (Plecoptera),Chaetopteryx fuscaBrauer andChaetopteryx majorMcLachlan (Trichoptera) emerged in September and October. In Ephemeroptera and Trichoptera, similarities between species groups were highest at the two upstream sampling stations; in Plecoptera and in pooled taxa, however, similarities were highest at the middle and downstream sites. Except in Trichoptera, diversity was highest at the middle station situated at 360 m above sea leve

ISSN:0020-9309    

DOI:10.1002/iroh.19960810107

出版商:Akademie Verlag, Berlin    

年代:1996

数据来源: WILEY

ISSN:0020-9309    

DOI:10.1002/iroh.19960810108

出版商:Akademie Verlag, Berlin    

年代:1996

数据来源: WILEY

摘要:

AbstractMacroinvertebrate communities were studied in relation to food (particulate organic matter and periphyton) availability and hydrologic regime in two reaches (autotrophic and heterotrophic) of the Agüera stream (Northern Spain). The structure of macroinvertebrate community reflected the trophic characteristics (main food sources) at each site. From a temporal point of view, both food availability and hydrologic regime seem to be the main factors that determine the dynamics and structure of the community. In the autotrophic reach, shredder density showed significant relationship with CPOM, and scrapers with periphyton both in terms of density and biomass

ISSN:0020-9309    

DOI:10.1002/iroh.19960810109

出版商:Akademie Verlag, Berlin    

年代:1996

数据来源: WILEY

ISSN:0020-9309    

DOI:10.1002/iroh.19960810110

出版商:Akademie Verlag, Berlin    

年代:1996

数据来源: WILEY

摘要:

AbstractFive species of the genusMesocyclopsfrom various waterbodies of Uzbekistan are described. Some data on the variability and distribution of these species are given. The synonym ofM. aequatorialis similisvan de Velde andM. thermocyclopoides acutusDussart et Fernando is proposed. A key to females ofMesocyclopsspecies occuring in Uzbekistan is presented.

ISSN:0020-9309    

DOI:10.1002/iroh.19960810111

出版商:Akademie Verlag, Berlin    

年代:1996

数据来源: WILEY