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Digitale Medien

Comparison of bacterial and algal utilization of orthophosphate in an estuarine environment (1976)

Faust, M. A. ; Correll, D. L.

Springer

Marine biology 34 (1976), S. 151-162

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ISSN: 1432-1793

Quelle: Springer Online Journal Archives 1860-2000

Thema: Biologie

Notizen: Abstract Bacterial utilization of orthophosphate in an estuarine environment has been differentiated from algal utilization by using flow-filters of 5.0, 1.2 and 0.45 μm poresize. Examination by light microscopy showed that most of the bacterial population passed through a 5.0-μm filter, whereas most algae were retained. In all experiments, bacterial and algal cell numbers and biomass were estimated. P-uptake by algae and bacteria was closely correlated with cell biomass. P-uptake by algae was high only in the summer months, whereas P-uptake by bacteria was high throughout the year. Neither algal nor bacterial P-uptake, however, was correlated with temperature or dissolved orthophosphate, total organic phosphate or total phosphate concentrations. Cell biomass of algae at a given time had a high correlation with dissolved organic phosphate levels in 2 weeks prior to sampling (r=0.830) and a low correlation in the 2 weeks following sampling (r=0.0005). Algal cell numbers had a high correlation with bacterial cell numbers (r=0.950). The biomass of algae and bacteria also had a high correlation (r=0.902). The rate of P-uptake from the water by algae and bacteria varied with season and with the species composition of the natural population.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF00390757

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Digitale Medien

Relationship between phytoplankton cell size and the rate of orthophosphate uptake: in situ observations of an estuarine population (1978)

Friebele, E. S. ; Correll, D. L. ; Faust, M. A.

Springer

Marine biology 45 (1978), S. 39-52

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ISSN: 1432-1793

Quelle: Springer Online Journal Archives 1860-2000

Thema: Biologie

Notizen: Abstract Orthophosphate uptake by a natural estuarine phytoplankton population was estimated using two methods: (1) 32P uptake experiments in which filters of different pore sizes were used to separate plankton size-fractions; (2) 33P autoradiography of phytoplankton cells. Results of the first method showed that plankton cells larger than 5 μm were responsible for 2% of the total orthophosphate uptake rate. 98% of the total uptake rate occurred in plankton composed mostly of bacteria, which passed the 5 μm screen and were retained by the 0.45 μm pore-size filter. There was no orthophosphate absorption by particulates in a biologically inhibited control containing iodoacetic acid. Orthophosphate uptake rates of individual phytoplankton species were obtained using 33P autoradiography. The sum of these individual rates was very close to the estimated rate of uptake by particulates larger than 5 μm in the 32P labelling experiment. Generally, smaller cells were found to have a faster uptake rate per μm3 biomass than larger cells. Although the nannoplankton constituted only about 21% of the total algal biomass, the rate of phosphate uptake by the nannoplankton was 75% of the total phytoplankton uptake rate. Results of the plankton autoradiography showed that the phosphate uptake rate per unit biomass is a power function of the surface: volume ratio of a cell; the relationship is expressed by the equation Y=2x10-11 X 1.7, where Y is μgP μm-3 h-1 and X is the surface: volume ratio. These results lend support to the hypothesis that smaller cells have a competitive advantage by having faster nutrient uptake rates.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF00388976

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Digitale Medien

Autoradiographic study to detect metabolically active phytoplankton and bacteria in the Rhode river estuary (1977)

Faust, M. A. ; Correll, D. L.

Springer

Marine biology 41 (1977), S. 293-305

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ISSN: 1432-1793

Quelle: Springer Online Journal Archives 1860-2000

Thema: Biologie

Notizen: Abstract The rate of utilization of inorganic carbon (C) and phosphate (P) by phytoplankton and bacteria in the Rhode River estuary has been estimated using liquid-emulsion autoradiography during four times of the year. Metabolic activity of phytoplankton was estimated by calculating silver grains above individual species. From these counts, the relative C and P uptake rates of individual species per unit of biomass and per volume of water were estimated. Examination of the autoradiograms showed that the metabolically most active, algae were smaller than 10 μm. Both C and P were paken up by these smaller species at a higher rate than their proportion of the total biomass per volume of water would indicate. Uptake of C and P per unit of cell volume varied within a species and among the various phytoplankton at the different seasons of the year. Metabolic activity of planktonic bacteria in safranin-stained autoradiograms was also estimated by counting bacteria with associated grains and cells without grains. The ratio of 33p-labeled to unlabeled bacteria was highest in November. This high metabolic activity of bacteria in November corresponded with high P uptake rates of the phytoplankton at that time. Throughout this study, only 28 to 42% of the total phytoplankton biomass was metabolically active and, 63 to 85% of the bacteria.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF00389096

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Digitale Medien

Morphology and rheology of peel of model adhesives (1978)

Parsons, W. F. ; Faust, M. A. ; Brady, L. E.

New York : Wiley-Blackwell

Journal of Polymer Science: Polymer Physics Edition 16 (1978), S. 775-792

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ISSN: 0098-1273

Schlagwort(e): Physics ; Polymer and Materials Science

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Chemie und Pharmazie , Physik

Notizen: The morphology of surfaces produced during peel experiments was studied to increase the understanding of peel phenomena. Thin films of polystyrenes of narrow molecular-weight distribution and a polydisperse polyester on flexible supports were peeled from rigid substrates at temperatures above their glass transitions with equipment that also permitted quenching and preservation of the peeled surfaces which then could be studied by scanning electron microscopy. The results show many types of cavitation including foams and the coalescence of cavities to form fibers. Cavitation occurred throughout and beyond the region of transition from cohesive to interfacial failure where peel force decreased abruptly; however, cavity growth was abruptly restricted as the failure mode changed. The master curves and shift factors obtained in this work provided strong evidence that the quenching used to preserve the peeled surfaces did not introduce large perturbations in the results. The reason was that failure occurred at or close to the heated substrate.

Zusätzliches Material: 11 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/pol.1978.180160503

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