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  • 1
    Electronic Resource
    Electronic Resource
    Reactions of phosphorus with sediments in fresh and marine waters (1998)
    Oxford, UK : Blackwell Publishing Ltd
    Soil use and management 14 (1998), S. 0 
    Details
    ISSN: 1475-2743
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. The interactions of P with soils and sediments are examined in the context of transport processes from land, through rivers to estuaries and coastal waters. In soil erosion, selective size fractionation and preferential sorption to finer solids is crucial in the transport of P to water courses. Problems in quantifying the sorption affinity and equilibrium phosphate concentration (EPC) of mixtures of different soils and sediments are identified. Riverine transport of P by suspended solids is usually very important and examples of the changes in the amount and composition of particulate P (PP) concentration during storm events are discussed. Increased P content of solids during the first autumn storms, probably reflect the resuspension of accumulated stream bed-deposits. The fate of P in estuaries and their importance as possible long-term sinks of P are discussed. The relatively high concentrations of dissolved P associated with riverine inputs are to some extent buffered by the relatively high concentrations of suspended sediments resulting from tidal flows. Phosphorus may be released during transport to the sea due to decreases in the EPC, increases in salinity and release from bottom sediments as a result of low oxygen conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1475-2743.1998.tb00632.x
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  • 2
    Electronic Resource
    Electronic Resource
    Major ion and carbonate system chemistry of a navigable freshwater canal (1984)
    Oxford, UK : Blackwell Publishing Ltd
    Freshwater biology 14 (1984), S. 0 
    Details
    ISSN: 1365-2427
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: SUMMARY. 1. An examination has been made of the water quality of a 50 km (Wigan to Litherland) length of the Leeds-Liverpool canal. Regular in situ measurements accompanied by sampling for laboratory analysis were made at seventeen stations over a 15-month period.2. Three principal contributory water types have been recognized, and the observations have allowed estimates to be made of their relative contributions to the total water flux in the lower reaches of the system. Linear flow rates (c. 0.6 km day−1 near Litherland) are consistent with previous reports.3. The combined field and laboratory measurements have been used to obtain estimates of the partial pressure of CO2 in the water (P co2), the degree of saturation of the water with respect to calcite (Ω) and the major ion speciation in the water. Because of the variable ionic compositions of the waters examined, these estimates were made using a program (WATEQ) which took account of ion-pairing.4. Diurnal and annual cycles with respect to pH, P co2 and ω occur, these being most marked in the lower parts of the study length when, for a large proportion of the spring and summer, P co2 was below the atmospheric level and noticeable supersaturation with respect to calcite occurred. In contrast, two of the contributory water types, the River Douglas input and the Creek, showed low pH and Ω values and high P co2 values throughout the year.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2427.1984.tb00172.x
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  • 3
    Electronic Resource
    Electronic Resource
    The effects of biofilms on chemical processes in surficial sediments (1999)
    Oxford, UK : Blackwell Science, Ltd
    Freshwater biology 41 (1999), S. 0 
    Details
    ISSN: 1365-2427
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: 1. The objectives of the present work were: (a) to evaluate the effects of the development and the presence of a photosynthetically active algal biofilm on chemical fluxes and processes at the sediment–water interface; (b) to measure the effects of the biofilm on chemical concentration gradients in the bulk sediment; and (c) to monitor pH and dissolved oxygen concentration in the biofilm, and through the sediment–water interface using microelectrodes.2. Two experiments were performed over a period of 8 weeks using a recirculating fluvarium channel containing river sediments with an exposed surface of 0.2 m2 and 20 dm3 of overlying solution. The first experiment was in darkness with minimal effects of a photosynthetically active biofilm. The second experiment in natural light produced a complex photosynthetic biofilm involving a succession of diatoms, green algae and cyanobacteria.3. The solution overlying the biofilm was monitored continuously for dissolved calcium, silicon, phosphorus, alkalinity and oxygen, as well as conductivity, temperature and pH. The surface of the sediment was also monitored for biological and physical changes as the biofilm developed. The overlying solution was analysed over a period of 48 h at 2-h intervals to examine the effects of a well-developed algal biofilm. At the end of the 48 h, pH and oxygen microelectrodes were used to measure gradients above and through the biofilm, and porewaters were analysed from sediments which had been longitudinally sectioned at a maximum depth resolution of 0.5 mm.4. Biofilm development had a large influence on the composition of the overlying solution and the development of vertical concentration gradients of solutes in the porewater. Once a diatom community was established, the concentration of dissolved silicon was low (〈 40 μm), with all the silicon diffusing from the underlying sediment being consumed in the biofilm (≈ 0.026 μmol m−2 s−1 at the end of the experiment).5. The concentrations of calcium, alkalinity and phosphorus in digested sediment increased near the sediment–water interface. X-ray diffraction analysis showed that calcite was formed at the surface. Estimation of the fluxes of alkalinity and calcium in the overlying solution were consistent with calcite formation during daylight and possible dissolution in darkness. The maximum precipitation flux of calcium was 0.87 μmol m−2 s−1 and the maximum net release flux was 0.89 μmol m−2 s−1.6. The net loss of soluble reactive phosphorus from the overlying solution measured over the intensive sampling period of 48 h is consistent with a coprecipitation mechanism and a surface density of phosphorus included in the lattice of calcite of 0.097 μmol m−2. Processes in the biofilm rather than diffusion from the sediment porewater control chemical fluxes of calcium, alkalinity and phosphorus from the sediment to the overlying water.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2427.1999.00387.x
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  • 4
    Electronic Resource
    Electronic Resource
    A numerical algorithm for the determination of the adsorptive energy distribution function from isotherm data (1978)
    Springer
    Colloid & polymer science 256 (1978), S. 52-61 
    Details
    ISSN: 1435-1536
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Zusammenfassung Es wurde ein numerischer Algorithmus (HILDA) entwickelt und zugänglich gemacht, um die Oberflächenheterogenität eines Pulverpräparates in Termen einer “fleckenweisen” Adsorptionsenergieverteilungsfunktion zu bestimmen. Die Adsorption an einheitlich adsorbierenden “Flecken” kann durch die Wahl geeigneter Modellisothermen beschrieben werden. Als solche dienen die Gleichungen nach Hill-de Boer, Fowler-Guggenheim, Langmuir sowie die zweidimensionale Virialgleichung. Es werden Parameter angegeben, mit deren Hilfe HILDA auf eine Vielzahl von Adsorptionssystemen angewendet werden kann, und es wird gezeigt, wie die Monoschichtkapazität einer Oberfläche bestimmt werden kann. Die Ergebnisse werden mit BET-Werten verglichen. HILDA wird weiterhin verwendet, um Änderungen in der Verteilung der Adsorptionsenergie zu verfolgen, welche beim Tempern eines Kochsalzpräparates mit hoher spezifischer Oberfläche erfolgen.
    Notes: Summary A numerical algorithm (HILDA) is developed and made available for the determination of the surface heterogeneity 'of a powder sample in terms of a ‘patchwise’ adsorptive energy distribution function. Adsorption on unisorptic `patches' may be described by a choice of model isotherm functions. These are the Hill-de Boer equation, Fowler-Guggenheim, Langmuir and the two dimensional virial equation. Parameters are presented to enable HILDA to be applied to a variety of adsorption systems. It is demonstrated how the monolayer capacity of a surface can be determined and the results are compared to BET values. HILDA is also used to follow the changes in the adsorptive energy distribution that occur with annealing a high specific area sodium chloride sample. It is concluded that the method has considerable potential for future applications.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01746691
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  • 5
    Electronic Resource
    Electronic Resource
    Adsorption von inerten Gasen an NaCl. I. Bestimmung der Verteilungen der adsorptiven Energie nach einer neuen numerischen Methode (1979)
    Springer
    Colloid & polymer science 257 (1979), S. 671-671 
    Details
    ISSN: 1435-1536
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01548840
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  • 6
    Electronic Resource
    Electronic Resource
    Die Adsorption von inerten Gasen an NaCl. II. Eine Virialanalyse gasförmig-fest von Argon, das an NaCl adsorbiert ist (1979)
    Springer
    Colloid & polymer science 257 (1979), S. 671-671 
    Details
    ISSN: 1435-1536
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01548841
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  • 7
    Electronic Resource
    Electronic Resource
    Chemical modelling applications to experimental recirculating streams (1989)
    Springer
    Hydrobiologia 178 (1989), S. 93-112 
    Details
    ISSN: 1573-5117
    Keywords: Streams ; carbon dioxide ; oxygen ; calcite ; phosphate coprecipitation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Chemical models describing the precipitation of calcium carbonate, coprecipitation of inorganic phosphate, carbon dioxide and oxygen transfer through the air-water interface have been applied to results from a recirculating experimental stream. The transfer velocities for carbon dioxide and oxygen transfer for the experimental stream were determined as 1.00 × 10−4 m s−1 and 0.0058 m min−1 (at 20°C) respectively. During a 24-hour long experiment the stream, containing a varied biota dominated by the macro-algae Zygnema, was monitored to evaluate changes in the water chemistry. The calcite precipitation rate varied during the experiment reflecting changes in temperature, supersaturation of the water and local variation in the solution chemistry at the growth sites. The rate constant was evaluated from a chemical mechanistic model as 516.7 ± 27.2 mol h−1 at 10 °C. The coprecipitation of inorganic phosphate, which accompanied calcite growth, accounted for 〈 6% of the total phosphorus loss. The constant uptake of phosphorus by plants and algae was estimated as ≃0.22 μmol h−1 g−1 dry weight). The rates of production of oxygen and consumption of inorganic carbon in the experimental stream, after taking account of gas transfer and calcite precipitation, were also computed and found to be in good agreement during the experiment. The maximum rate of production of oxygen was ≃ 3.5 × 10−4 mol h−1 g−1 (dry weight).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00011662
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  • 8
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    Comparison of sample storage protocols for the determination of nutrients in natural waters (2001)
    Elsevier
    In:  Water Research, 35 (15). pp. 3670-3678.
    Details
    Publication Date: 2017-05-30
    Description: There have been several reports on storage protocols for the determination of nutrients in natural waters but each one has been limited to a particular sample matrix and they have reached different, matrix specific conclusions. The aim of this study was therefore to systematically apply the various recommended storage protocols to a range of natural water matrices. Samples from four contrasting sites in the UK, collected in late winter (February, 1999), were filtered and stored under different conditions (-80°C, -20°C, 4°C and at 4°C and -20°C with 0.1 (v/v) chloroform) for up to 247 days prior to analysis. The sites were the River Frome in Dorset (a chalk stream catchment) and three sites from the Tamar Estuary (draining a non-chalk catchment) with salinities of 0.5‰, 10‰ and 34‰. Samples and controls were analysed for total oxidised nitrogen (TON) and filterable reactive phosphorus (FRP) using a segmented flow analyser with spectrophotometric detection. To investigate possible seasonal effects (particularly changes in biological and chemical matrix composition), a second sampling campaign was undertaken in early autumn (October, 1999). The results showed that the optimum storage conditions for the determination of TON and FRP were highly matrix dependent, with significant differences in FRP stability between the Frome and Tamar catchments (due to different calcium concentrations) and between samples of different salinities (due to different bacterial populations and/or dissolved organic matter). General guidelines for sample handling and storage are listed and matrix specific recommendations presented for samples rich in calcium and dissolved organic matter. Copyright © 2001 Elsevier Science Ltd.
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.1016/S0043-1354(01)00088-4
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    OceanRep: Article in a Scientific Journal - peer-reviewed
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