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 - Hairston, Nelson G. A1 - Fussmann, Gregor F. T1 - Lake ecosystems N2 - Lakes are discrete, largely isolated ecosystems in which the interplay between physical, biogeochemical and organismal processes can be studied, understood, and put to use in effective management. Y1 - 2002 ER -