Search Results - (Author, Cooperation:P. Burkill)

Showing 1 - 5 results of 5, query time: 0.15s Refine Results
  1. 1
    Staff View
    Publication Date:
    2015-03-15
    Publisher:
    American Association for the Advancement of Science (AAAS)
    Print ISSN:
    0036-8075
    Electronic ISSN:
    1095-9203
    Topics:
    Biology
    Chemistry and Pharmacology
    Computer Science
    Medicine
    Natural Sciences in General
    Physics
    Keywords:
    *Conservation of Natural Resources/economics ; *Ecosystem ; *Environment ; Guidelines as Topic ; Policy
    Published by:
    http://www.aaas.org/

    Latest Papers from Table of Contents or Articles in Press
  2. 2
    Owens, N. J. P. ; Law, C. S. ; Mantoura, R. F. C. ; Burkill, P. H. ; Llewellyn, C. A.

    [s.l.] : Nature Publishing Group
    Published 1991
    Staff View
    ISSN:
    1476-4687
    Source:
    Nature Archives 1869 - 2009
    Topics:
    Biology
    Chemistry and Pharmacology
    Medicine
    Natural Sciences in General
    Physics
    Notes:
    [Auszug] A transect was followed from close to the Equator to the Gulf of Oman during September and October 1986, and dissolved methane was measured in the atmosphere, and from the sea surface to the bottom at 13 stations. Figure 1 shows that methane concentrations varied considerably with depth, being ...
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1038/354293a0

    Articles: DFG German National Licenses
  3. 3
    Leakey, R. J. G. ; Burkill, P. H. ; Sleigh, M. A.
    Springer
    Published 1992
    Staff View
    ISSN:
    1432-1793
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Biology
    Notes:
    Abstract The abundance and biomass of marine planktonic ciliates were determined at monthly intervals at two stations in Southampton Water between June 1986 and June 1987. The two stations, an outer one at Calshot and an inner one at N. W. Netley, were subject to differing marine and terrestrial influences. The potential ciliate production at cach station on each visit was estimated from these data. Enumeration of ciliates and measurements of biovolume were performed on Lugol's iodinepreserved samples and potential production was calculated using a predictive relationship based on temperature and cell volume. Heterotrophic ciliate abundance and biomass were greatest at both stations during spring and summer months, with respective maxima of 16x103 organisms 1-1 and 219 μg Cl-1 recorded at N. W. Netley. Estimates of the potential production of the ciliate community ranged from 〈1 to 18 μg Cl-1 d-1 at Calshot and 〈1 to 141 μg Cl-1 at N. W. Netley, with annual values of 2 and 9 mg Cl-1 yr-1, respectively. Abundances, biomass and potential production estimates were generally greater at N. W. Netley than at Calshot. Carbon flow through the ciliate community was assessed using annual production values from both this study and the literature. The annual ciliate carbon requirement was equivalent to 9 and 11% of annual primary production at Calshot and N. W. Netley, and potential annual ciliate production was equivalent to 34% and 〉100% of the energy requirements of metazoan zooplankton at these locations, although comprising only 8 and 10% of their available food.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1007/BF00350857

    Articles: DFG German National Licenses
  4. 4
    Staff View
    ISSN:
    1432-1793
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Biology
    Notes:
    Abstract The results from a series of five cruises (August 1979–January 1981) to examine rates of primary production, nitrogen assimilation and regeneration in Carmarthen Bay, S. Wales, are presented. Chlorophyll, primary production and regeneration were distributed irregularly throughout the bay, with the highest concentrations and rates being found around the shallow periphery. Nitrate was the dominant form of nitrogen assimilated by the phytoplankton, apart from periods of high biomass during the summer when ammonium assumed a more important role. The rates of ammonium regeneration from microheterotrophs were greater than the ammonium demand over much of the year, indicating that the bay was a net exporter of ammonium and was a physically dominated “open” system. During the summer, the rates of ammonium regeneration and assimilation were similar, indicating efficient recycling of nutrients.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1007/BF00401100

    Articles: DFG German National Licenses
  5. 5
    Staff View
    ISSN:
    1432-1793
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Biology
    Notes:
    Abstract Microzooplankton grazing activity in the Celtic Sea and Carmarthen Bay in summer 1983 and autumn 1984 was investigated by applying a dilution technique to high-performance liquid chromatographic (HPLC) analysis of photosynthetic pigments in phytoplankton present within natural microplankton communities. Specific grazing rates on phytoplankton, as measured by the utilisation of chlorophyll a, were high and varied seasonally. In surface waters during the autumn, grazing varied between 0.4 d-1 in the bay and 1.0 d-1 in the Celtic Sea, indicating that 30 and 65% of the algal standing stocks, respectively, were grazed daily. Grazing rates by microzooplankton within the thermocline in summer suggest that 13 to 42% of the crop was grazed each day. Microzooplankton showed selection for algae containing chlorophyll b, in spite of a predominance of chlorophyll c within the phytoplankton community. Changes in taxon-specific carotenoids indicated strong selection for peridinin, lutein and alloxanthin and selection against fucoxanthin and diadinoxanthin. This indicates a trophic preference by microzooplankton for dinoflagellates, cryptophytes, chlorophytes and prasinophytes and selection against diatoms, even when the latter group forms the largest crop within the phytoplankton. Interestingly, those algal taxa preferentially grazed also showed the highest specific growth-rates, suggesting a dynamic feed-back between microzooplankton and phytoplankton. Conversion of grazing rates on each pigment into chlorophyll a equivalents suggests firstly, that in only one experiment could all the grazed chlorophyll a be accounted for by the attrition of other chlorophylls and carotenoids, and secondly that in spite of negative selection, a greater mass of diatoms could be grazed by microzooplankton than any other algal taxon. The former may be due either to a fundamental difference in the break-down rates of chlorophyll a compared to other pigments, or to cyanobacteria forming a significant food source for microzooplankton. In either case, chlorophyll a is considered to be a good measure of grazing activity by microzooplankton.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1007/BF00392796

    Articles: DFG German National Licenses