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  • 1
    Online Resource
    Online Resource
    The Ecology of Cyanobacteria : Their Diversity in Time and Space. (2000)
    Dordrecht :Springer Netherlands,
    Details
    Keywords: Cyanobacteria-Ecology. ; Electronic books.
    Type of Medium: Online Resource
    Pages: 1 online resource (718 pages)
    Edition: 1st ed.
    ISBN: 9780306468551
    URL: https://ebookcentral.proquest.com/lib/geomar/detail.action?docID=6700441
    DDC: 579.3/917
    Language: English
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    GEOMAR EBL
  • 2
    Electronic Resource
    Electronic Resource
    A differential absorption spectrometer for bremsstrahlung diode voltage measurement : Proceedings of the 9th topical conference on high temperature plasma diagnostics (1992)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 63 (1992), S. 4792-4794 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: An indirect voltage measurement of a relativistic electron beam diode can be deduced from the high energy tail of its bremsstrahlung spectrum. Our spectrometer contains seven silicon pin diode detectors with filters optimized to cover the 0.5–2 MV range. Theoretical response functions were calculated using the CYLTRAN Monte Carlo transport code with the next event estimator method. Diode voltage measurements performed with the spectrometer on the PITHON x-ray simulator are in good agreement with the standard electrical measurement.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1143565
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Influence of zinc on lotic plants (1977)
    Oxford, UK : Blackwell Publishing Ltd
    Freshwater biology 7 (1977), S. 0 
    Details
    ISSN: 1365-2427
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: SUMMARY. The toxicity of zinc to Hormidium rivulare Kütz. in laboratory culture media is decreased by rises in the levels of magnesium, calcium and phosphate, and increased by rises in pH and cadmium. The effects of all these are sufficiently marked that they may be expected to have considerable importance in the field. In contrast, assays with sodium, chloride and sulphate showed no detectable influence of these ions on zinc toxicity.When applied at higher concentrations, calcium was always more effective than magnesium, but the reverse was sometimes true at lower concentrations. Both magnesium and phosphate were more effective in reducing zinc toxicity with zinc-tolerant populations than with zinc-sensitive ones. Cadmium was highly toxic, either alone or in combination with zinc; however, calcium had a proportionately greater effect in reducing cadmium toxicity than zinc toxicity. The toxic effects of zinc and cadmium were synergistic, and it seems probable that the presence of cadmium at levels of 0.01 mgl−1 and above will usually lead to a significant increase in the toxicity of any zinc also present. Cadmium (in the absence of zinc) was 34 times more toxic than zinc to a zinc + cadmium sensitive population, and 15.5 times more toxic to a zinc + cadmium tolerant population. Because of the synergistic response, cadmium had an even greater effect in the presence of zinc.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2427.1977.tb01685.x
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  • 4
    Electronic Resource
    Electronic Resource
    Influence of zinc on lotic plants (1977)
    Oxford, UK : Blackwell Publishing Ltd
    Freshwater biology 7 (1977), S. 0 
    Details
    ISSN: 1365-2427
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: SUMMARY. Field and laboratory studies have been carried out on the tolerance to zinc of the filamentous green algae Hormidium rivulare Kütz., H. flaccidum Kütz. and H. fluitans (Gay) Heering growing in flowing waters. Forty-seven different sites in England, France, Germany and Ireland were included, the majority of them chosen to represent examples of zinc pollution resulting from past or present mining activities. All three species were widespread both in waters free of zinc pollution and waters with zinc pollution, and H. rivulare and H. flaccidum were frequent at a site with the highest zinc level included in the survey (mean of 22.8 mg l−1, maximum of 30.2 mg l−1 Zn passing through a filter). At sites with higher zinc levels, populations showed increased resistance to zinc of the filamentous green algae Hormidium rivulare Kütz., H. flaccidum creased resistance being largely, if not entirely, the result of genetic adaptation. An increased frequency of geniculations can occur both as an environmental and a genetic response to very high zinc levels. The application of various statistical analyses to the data suggests that two groups of chemical factors may be influencing the toxicity of zinc in the field. The first group which appears to increase the toxicity of zinc includes cadmium and lead, while the second group, which decreases the toxicity of zinc, includes magnesium, calcium and various hardness factors. As the occurrence of zinc, cadmium and lead in the field are all strongly intercorrelated, it is not possible to distinguish clearly the effects of one from the other, although the data do suggest that cadmium is more likely than lead to influence zinc toxicity. The ‘amelioration’ factors are also strongly intercorrelated in the field, so it is difficult to comment on their relative importance. There is some indication for H. rivulare at least, that an increase in PO4-P and a decrease in pH may also reduce zinc toxicity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2427.1977.tb01684.x
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  • 5
    Electronic Resource
    Electronic Resource
    The macrophytic vegetation of the River Tees in 1975: observed and predicted changes (1977)
    Oxford, UK : Blackwell Publishing Ltd
    Freshwater biology 7 (1977), S. 0 
    Details
    ISSN: 1365-2427
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: SUMMARY. An account is given of the distribution of macrophytes in the River Tees and its tributaries, north-east England, together with a critical discussion of the problems involved in recording data in a form which can be used for monitoring long-term changes of vegetation in rivers. Among the conventions and methods adopted in the present study are an attempt to define the vertical limits of the river sensu strictu as opposed to the bank, the extension of the term macrophyte to include as many visually obvious photosynthetic organisms as possible, the use of a check-list prepared in advance which contains a wider range of species than are actually expected for the river, and the collection of two different types of standard record for each 0.5 km length of river. The Tees has been the subject of intermittent observations on its vegetation for some 45 years. The most obvious change has taken place since 1965, with a substantial upstream spread of four submerged angiosperm species. Potamogeton crispus, Zannichellia palustris and Myriophyllum spicatum were previously present only in the lower reaches of the Tees, and have spread 25, 9.5 and 4.5 km respectively upstream from their previously known most upstream localities. Ranunculus penicillatus var. calcareus is an apparent invader to the river. It seems probable that these changes have taken place since 1971 as a result of regulation of the Tees by Cow Green Reservoir. Further changes are predicted with the advent of water transfer from the Tyne to Tees around 1980, because at least twenty-six macrophytes are known to be present in the former river that are either absent or confined to the lowest stretches of the latter.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2427.1977.tb01656.x
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  • 6
    Electronic Resource
    Electronic Resource
    Chemistry and vegetation of highly acidic streams (1975)
    Oxford, UK : Blackwell Publishing Ltd
    Freshwater biology 5 (1975), S. 0 
    Details
    ISSN: 1365-2427
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: An account is given of the water chemistry and photosynthetic flora of waters in England with a pH value of 3.0 or less. Of the fifteen sites found, thirteen were associated with coal-mining, one with a barytes mine and one was an industrial effluent. Flowing waters predominated, but in some cases pools in direct contact with the streams were also present. All waters carried high levels of heavy metals and silicate, and most carried moderately high levels of phosphate and combined inorganic nitrogen. The total flora consisted of twenty-four algae, two mosses and two flowering plants. Of these, three algae and one flowering plant were found in pools only. Euglena mutabilis was both the most widespread species, and often also the most abundant. The number of species present in a reach showed a positive correlation with pH during late summer, and a negative correlation with total acidity in winter. Only four of the algal species found in England are certainly included in the U.S.A. literature. Some, but not all, the apparent differences between the two floras are very probably due simply to taxonomic problems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2427.1975.tb00156.x
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  • 7
    Electronic Resource
    Electronic Resource
    Phytobenthos of the River Tees and its tributaries (1981)
    Oxford, UK : Blackwell Publishing Ltd
    Freshwater biology 11 (1981), S. 0 
    Details
    ISSN: 1365-2427
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: SUMMARY. A standard method is given for describing plant communities in fast-flowing streams and rivers. This involves the selection of a representative 10-m length of stream (termed a reach) which can be re-located exactly. Various estimates of the relative areas covered by different physiognomic forms and the relative proportions of species present are then combined to give a ‘semi-quantitative’ account, which can be compared with data collected at other sites or times. The method has been applied to six sites on the River Tees system. A site below Cow Green reservoir with markedly regulated flows, differs from the others in various ways. Bryophytes show a greater cover here than elsewhere throughout the year and a conspicuous cover of Phormidium occurs in autumn. Filamentous green algae of many different species are abundant at this site in late summer and early autumn. At the most downstream site where such seasonal growths also occur, a single species, Cladophora glomerata, is dominant. Conspicuous spring diatom ‘bursts’ occurred at the two upstream sites and a month later at the two downstream sites.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2427.1981.tb01250.x
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  • 8
    Electronic Resource
    Electronic Resource
    Macrophytic vegetation of the River Swale, Yorkshire (1977)
    Oxford, UK : Blackwell Publishing Ltd
    Freshwater biology 7 (1977), S. 0 
    Details
    ISSN: 1365-2427
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: SUMMARY. An account is given of the distribution down the River Swale in summer 1976 of 132 species of photosynthetic plants which are recognizable macroscopically. Some environmental data are included. The river may be regarded as falling into three zones, both with regard to its physical features and its type of vegetation. The upper zone has rocky substrata, fast flows and a macrophytic vegetation largely of bryophytes; the middle zone has unconsolidated substrata and the macrophytic vegetation is relatively sparse; the lower zone is silted and the macrophytic vegetation consists largely of angiosperms. The flora of the Swale is compared with that of the Tees, since eventually the former is likely to receive water from the latter as part of a major water transfer scheme. Eleven species of ‘river’ angiosperm which are present in the Tees above the projected abstraction point are absent from the Swale above the inflow point.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2427.1977.tb01706.x
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  • 9
    Electronic Resource
    Electronic Resource
    Growth rate of the aquatic moss Rhynchostegium riparioidesin Northern England (1987)
    Oxford, UK : Blackwell Publishing Ltd
    Freshwater biology 18 (1987), S. 0 
    Details
    ISSN: 1365-2427
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: SUMMARY 1. The rale of shoot growth in Rhynchostegium riparioideswas measured at monthly intervals over a 12-month period at four upland sites in the Northern Pennines. Changes were recorded by observations attached pieces of cotton. Detectable growth was found in each month, with the maximum in spring (up to 2.31 mm week−1) and minimum in winter (1.12 mm week−1); there was a second smaller peak in the autumn.2. Growth rate was related strongly to several environmental variables, including spot measurements of water temperature (positive) and mean monthly precipitation (negative). A regression equation based on these two variables accounted for 5% of the variation recorded.3. Total shoot growth over the 12-month period ranged from 33.4 to 73.3 mm, corresponding to an increase in mass of 22.9 and 120.8 mg, respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2427.1987.tb01331.x
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  • 10
    Electronic Resource
    Electronic Resource
    Characterization of the phosphatase activities of mosses in relation to their environment (2001)
    Oxford, UK : Blackwell Science, Ltd
    Plant, cell & environment 24 (2001), S. 0 
    Details
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Phosphatase activities and environmental features were characterized for 12 terrestrial and aquatic mosses in upland northern England, along with four species sampled from subarctic Sweden. Phosphomonoesterase (PMEase) and phosphodiesterase (PDEase) activities of shoot tips were measured using para-nitrophenyl phosphate (p-NPP) and bis-pNPP. All species showed PMEase activity, but not all showed PDEase activity. The mean pH optimum was 5·0 for PMEase and 5·7 for PDEase. The kinetic parameters Km and Vmax were calculated from three linear transformations of the Michaelis–Menten equation. The mean Km values of the mosses ranged between 77 and 468 µm for PMEase and 26 and 414 µm for PDEase. The corresponding Vmax values were 0·6–205 µmol pNP g−1 DW h−1 for PMEase and 1·4–110 µmol pNP g−1 DW h−1 for PDEase. Mosses from Sweden displayed greater Km and smaller Vmax values than those from England. The aquatics Fontinalis antipyretica and Rhynchostegium riparioides displayed two-phase kinetics for PMEase and PDEase, with Km and Vmax being dependent on substrate concentration. Staining suggested that PMEase activity was located in the cell wall of most mosses. Phosphatase assays provide a rapid method for screening environmental nutrient status and a standard procedure is recommended.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-3040.2001.00767.x
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