摘要:

AbstractThe phosphate removal in small, completely mixed storage reservoirs (preimpoundment basins) mainly is a function of the production of biomass by the phytoplankton. The knowledge of the critical detention time of the water is the most important premise to the prediction. The critical detention time t̄ is computed from the equation:\documentclass{article}\pagestyle{empty}\begin{document}$ \overline t _c = \frac{1}{{\mu ^* - 0,1}} $\end{document}and the growth rate μ* at a given combination of the light intensity J, temperatureTand phosphate concentrationPis computed from:\documentclass{article}\pagestyle{empty}\begin{document}$ \mu ^* = \frac{{\mu T \cdot \mu J \cdot \mu P}}{{\mu \max ^2 }}\mu \max \cdot \frac{P}{{K_p + P}}\frac{J}{{K_j + J}}\frac{T}{{T_{opt} }}, $\end{document}(μmax = maximum possible growth rate of the dominant species;Kp, KjandToptare constants computed from batch cultures).The quotient\documentclass{article}\pagestyle{empty}\begin{document}$ \frac{{\bar t_{act.} }}{{\bar t_c }}(\bar t_{act.} = {\rm actual detention time in the water body)} $\end{document}enables prediction of the phosphate removal.A comparison of the predicted results from semicontinuous cultures and from the preimpoundment basin of the Weida reservoir revealed a satisfactory degree of conformi

ISSN:0020-9309    

DOI:10.1002/iroh.19730580102

出版商:Akademie Verlag, Berlin    

年代:1973

数据来源: WILEY

摘要:

AbstractThe water mossFontinalis antipyreticaL. is well suited for measuring CO2exchange by infrared gas analysis (IRGA), as only CO2is used for assimilation. Both in a state of full activity and of reduced activity in the course of a toxical charge the ratio of net primary productivity to respiration related to intermittent illumination is used as a bioassay. Three types regarding the proportion of net assimilation (AN) to respiration (RD) are refered to the toxical charge (phenol, HgCl2, CuSO4, CdCl2). In the case of displacing the balance ofAN/RDin the diurnal cycle to the side of respiration, photosynthetic oxygenation in the water ecosystem decreases. The combination of measuring CO2exchange by IRGA with a cyto‐physiological investigation by determining the time of deplasmolysis of leaves is used for the prediction of vitality long before damage including lethal effects are to be recognizend morphologicall

ISSN:0020-9309    

DOI:10.1002/iroh.19730580103

出版商:Akademie Verlag, Berlin    

年代:1973

数据来源: WILEY

摘要:

AbstractFour mountain lakes were studied. Two are eutrophic, one is mesotrophic and one is oligotrophic. The first three have a well‐developed phyto‐ and zooplankton, with a relatively high diversity index. There are differences between the faunas that may be ascribed to differences in surface, depth, altitude and also to biological phenomena such as interspecies competition. The Ifni Lake is a genuine high‐mountain lake, subject to severe environmental conditions. It has a very simple food chain: there is only one species of algae, an unicellular blue‐green, one copepod species, one rotifer and one fish. In general some features of a definite interest for fundamental limnology were found: the presence of a pelagic Rhabdocoelid in Dayat Ifrah, some particularities in the vertical distribution of a number of plankton species, the existence of a layer of relatively warm water near the bottom of Lake Ifni. The latter is explained by a strong bottom current which flows through the lake between its phreatic in‐ and outlets.Finally, stress is laid on the under‐exploitment of Moroccon inland waters with respect to a freshwater fishery.Yet, perspectives are good and some suggestions ar

ISSN:0020-9309    

DOI:10.1002/iroh.19730580104

出版商:Akademie Verlag, Berlin    

年代:1973

数据来源: WILEY

摘要:

AbstractA few of Tasmania's several thousand lakes and rivers have been sampled in a preliminary survey of water chemistry. They range in concentration from extremely dilute glacial lakes (TDS85%), the majority being dilute (TDS<50 ppm). The 3 mechanisms controlling water chemistry proposed by GIBBS (1970) are seen to operate and the 3 terminal water types showing precipitation‐dominance, rock‐dominance and solubility‐limited composition are found, together with a range of intermediates. The majority of waters have seawater ionic composition or moderate geochemical modification of

ISSN:0020-9309    

DOI:10.1002/iroh.19730580105

出版商:Akademie Verlag, Berlin    

年代:1973

数据来源: WILEY

摘要:

AbstractThe seasonal cycles of the zooplankton in 1967–1969 in Lakes Rotorua and Rotoiti in the North Island of New Zealand are outlined.Bosmina meridionalishad several peaks in abundance during the summer and low winter numbers, whilstCeriodaphnia dubiagenerally had only a single period of real abundance during the summer. The rotiferAsplanchna priodontawas present throughout the year in low numbers except for two brief but striking peaks in the spring‐summer period. The only cyclopoid copepod present wasMacrocyclops albiduswhich was never abundant.The annual cycles of the calanoid copepodCalamoecia lucasiwere studied in some detail. Total numbers were high but very variable during spring‐autumn and low in winter, the seasonal cycles being very similar in both lakes. Breeding was continuous although egg clutches were small (1.1–6.6), and the development of at least 5 cohorts per year could be followed from data on breeding intensity, population age‐structure and adult size. Laboratory determined egg development rates were used to calculate birth rates in the populations so that production and losses could be estimated. Survival rates appeared to be higher in Rotoiti than in Rotorua. Birth and death rates were low, the annual means for both linear and exponential rates ranging from around 0.04 to 0.07, giving turnover times for individuals of 12–18 days in Rotorua and 18–24 days in Rotoiti. Population turnover rates were higher in Rotorua (19–28 days), which had a similar mean population per square metre but higher clutch sizes, than in Ro

ISSN:0020-9309    

DOI:10.1002/iroh.19730580106

出版商:Akademie Verlag, Berlin    

年代:1973

数据来源: WILEY

摘要:

AbstractIn continuation of a series of papers describing new representatives of the phylum Gnathostomulida from the east coast of North America, the monotypic genusNanognathiais presented. It is distinguished by small size, grouped epidermal inclusions on the ventral body surface, and flattened basket‐type jaws with long teeth of which one is developed as a terminal tooth. Together with the structure of the reproductive system, these characteristics placeNanognathiawithin the suborder Scleroperalia, family Onychognathiida

ISSN:0020-9309    

DOI:10.1002/iroh.19730580107

出版商:Akademie Verlag, Berlin    

年代:1973

数据来源: WILEY

摘要:

AbstractThe mucilages of this alga contain acid polysaccharides, some of which are Ca binding. After deproteinization and gel filtration the residue of the aqueous algal extract has the composition: 2% complexed protein, 3–4% Ca, 0.4–0.5% SiO2, 0.03–0.04% Al, ∼ 0.005% Fe, rest: polysaccharide. The molecular weights of the major and minor polysaccharide fractions are approximately 5000 and 200000 respectively (Sephadex). Uronic acid and O‐ester sulfate give a total of 0.25 μequiv. H+/mg polysaccharide whereas the Ca binding capacity is 2.1 μequiv./mg polysaccharide. Ca complexing of the dibasic polyacid is restricted to the low molecular species and involves the 2 acidic and unidentified nonacidic groups. The complexing strength of the polysaccharide for Ca is similar to succinate. These Ca binding polysaccharides may play a role in algal ca

ISSN:0020-9309    

DOI:10.1002/iroh.19730580108

出版商:Akademie Verlag, Berlin    

年代:1973

数据来源: WILEY

摘要:

AbstractThe paper describes a year‐round limnoplanktonic study of a freshwater pond in West Bengal, India. Always predominant over zooplankton, phytoplankton demonstrates three peaks. The relationships between pH and phytoplankton, between phosphate and green algae and between rotifers and diatoms are significant. The role of physico‐chemical factors in determining different planktonic population is discussed. The multiple correlation between several physico‐chemical factors and phytoplankton percentage is not signif

ISSN:0020-9309    

DOI:10.1002/iroh.19730580109

出版商:Akademie Verlag, Berlin    

年代:1973

数据来源: WILEY

ISSN:0020-9309    

DOI:10.1002/iroh.19730580110

出版商:Akademie Verlag, Berlin    

年代:1973

数据来源: WILEY

ISSN:0020-9309    

DOI:10.1002/iroh.19730580112

出版商:Akademie Verlag, Berlin    

年代:1973

数据来源: WILEY