TY - JOUR A1 - Altmann, Thomas A1 - Brandt, Stephan Peter A1 - Kloska, Sebastian A1 - Kehr, Julia T1 - Using array hybridization to monitore gene expression at the single cell level Y1 - 2002 ER - TY - JOUR A1 - Vernesi, C. A1 - Pecchioli, E. A1 - Tiedemann, Ralph A1 - Randi, E. A1 - Bertorelle, G. T1 - The genetic structure of natural and reintroduced roe deer (Capreolus capreolus) populations in the Alps and central Italy, with reference to the mitochondrial DNA phylogeography of Europe Y1 - 2002 SN - 0962-1083 ER - TY - JOUR A1 - Fischer, Markus A1 - Lienert, J. A1 - Schneller, J. A1 - Diemer, M. T1 - Local extinctions of the wetland specialist Swertia perennis : a revistation study based on herbarium records Y1 - 2002 ER - TY - JOUR A1 - Shertzer, Kyle W. A1 - Ellner, Stephen P. A1 - Fussmann, Gregor F. A1 - Hairston, Nelson G. T1 - Predator-prey cycles in an aquatic microcosm : testing hypotheses of mechanism N2 - 1. Fussmann et al. (2000) presented a simple mechanistic model to explore predator-prey dynamics of a rotifer species feeding on green algae. Predictions were tested against experimental data from a chemostat system housing the planktonic rotifer Brachionus calyciflorus and the green alga Chlorella vulgaris. 2. The model accurately predicted qualitative behaviour of the system (extinction, equilibria and limit cycles), but poorly described features of population cycles such as the period and predator-prey phase relationship. These discrepancies indicate that the model lacked some biological mechanism(s) crucial to population cycles. 3. Here candidate hypotheses for the 'missing biology' are quantified as modifications to the existing model and are evaluated for consistency with the chemostat data. The hypotheses are: (1) viability of eggs produced by rotifers increases with food concentration, (2) nutritional value of algae increases with nitrogen availability, (3) algal physiological state varies with the accumulation of toxins in the chemostat and (4) algae evolve in response to predation. 4. Only Hypothesis 4 is compatible with empirical observations and thus may provide important insight into how prey evolution affects predator- prey dynamics. Y1 - 2002 UR - http://www.blackwell-synergy.com/Journals/issuelist.asp?journal=jae ER - TY - JOUR A1 - Fussmann, Gregor F. A1 - Heber, Gerd T1 - Food web complexity and chaotic population dynamics N2 - In mathematical models, very simple communities consisting of three or more species frequently display chaotic dynamics which implies that long-term predictions of the population trajectories in time are impossible. Communities in the wild tend to be more complex, but evidence for chaotic dynamics from such communities is scarce. We used supercomputing power to test the hypothesis that chaotic dynamics become less frequent in model ecosystems when their complexity increases. We determined the dynamical stability of a universe of mathematical, nonlinear food web models with varying degrees of organizational complexity. We found that the frequency of unpredictable, chaotic dynamics increases with the number of trophic levels in a food web but decreases with the degree of complexity. Our results suggest that natural food webs possess architectural properties that may intrinsically lower the likelihood of chaotic community dynamics. Y1 - 2002 UR - http://www.blackwell-synergy.com/Journals/issuelist.asp?journal=ele ER - TY - JOUR A1 - Nistor, C. A1 - Osvik, A. A1 - Davidsson, R. A1 - Rose, Andreas A1 - Wollenberger, Ursula A1 - Pfeiffer, Dorothea A1 - Emneus, J. A1 - Fiksdal, L. T1 - Detection of escherichia coli water by culture-based amperometric and luminometric methods Y1 - 2002 ER - TY - JOUR A1 - Nistor, C. A1 - Rose, Andreas A1 - Farre, M. A1 - Stoica, L. A1 - Wollenberger, Ursula A1 - Ruzgas, T. A1 - Pfeiffer, Dorothea A1 - Barcelo, Damia A1 - Gorton, Lo A1 - Emneus, J. T1 - In-field monitoring of cleaning efficiency in waste water treatment plants using two phenolsensitive biosensors Y1 - 2002 ER - TY - JOUR A1 - Kamjunke, Norbert A1 - Schmidt, Katja A1 - Pflugmacher, Stephan A1 - Mehner, Thomas T1 - Consumption of cyanobacteria by roach (Rutilus rutilus) : useful or harmful to the fish? N2 - 1. The ability of roach to use cyanobacterial food is generally believed to be one reason for the dominance of roach over perch in eutrophic European lakes. The aim of this study was to test whether cyanobacteria really are a suitable food for juvenile roach. Special attention was paid to differences between the two cyanobacteria species Aphanizomenon and Microcystis which are common in eutrophic lakes and are ingested by roach there. 2. We performed growth and behaviour experiments with juvenile roach fed with zooplankton and the different cyanobacteria. Growth rate with Aphanizomenon was lower than with Daphnia but significantly higher than without food, whereas growth rate with Microcystis was as low as without food. 3. In cultivation experiments of roach faeces, Microcystis was found not to have been digested and grew exponentially after passing through the gut whereas Aphanizomenon stayed at low biomass. Differences in growth were not related to the toxin content of cyanobacteria. Investigations of roach motility showed no differences whether fed Aphanizomenon or Microcystis. 4. In contrast to Microcystis, Aphanizomenon can be regarded as a suitable food source for juvenile roach probably due to its better digestability. We conclude that the ability to feed on cyanobacteria is not a general competitive advantage for roach, but the outcome depends on the species composition of the cyanobacteria. Y1 - 2002 ER - TY - JOUR A1 - Kamjunke, Norbert A1 - Mendonca, Rebeca A1 - Hardewig, Iris A1 - Mehner, Thomas T1 - Assimilation of different cyanobacteria as food and the consequences for internal energy stores of juvenile roach N2 - Juvenile roach (Rutilus rutilus L.) fed on the cyanobacterium Aphanizomenon were able to maintain liver glycogen and muscle protein concentrations. In contrast, internal energy stores of fish fed on the cyanobacterium Microcystis were degraded. However, liver glycogen was higher than in starved fish, suggesting that roach was able to obtain some nutrients (probably carbohydrates) from the mucus cover of Microcystis. Weak assimilation of radiolabeled Microcystis by roach was detectable, and assimilation rates increased with increasing proportion of Aphanizomenon in a mixture of both cyanobacteria. We conclude that the incomplete digestion of Microcystis was the main reason for the negative growth rates of roach when fed on this cyanobacterium species. Y1 - 2002 ER - TY - THES A1 - Lesser, Constanze T1 - Lumineszierende Filme durch alternierende Adsorption von CdTe-Nanopartikeln und Polyelektrolyten Y1 - 2002 ER -