Modelling the Consequence of Glacier Retreat on Mixotrophic Nanoflagellate Bacterivory: A Bayesian Approach

SCHENONE L.; E. BALSEIRO; M. BASTIDAS NAVARRO; B. MODENUTTI

OIKOS

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2020 vol. 847 p. 1479 - 1489

0030-1299

Mixotrophic nanoflagellate bacterivory is affected by light; however, inglacially influenced lakes, glacial clay may also interfere with preyuptake. Mechanistic models based on prior quantitative hypotheses andtested with field data are useful for predicting these predator-preyinteractions under a changing climate. We modelled the effect of glacialparticles on the bacterivory of mixotrophic nanoflagellates, the dominantphytoplankton in mountain lakes in the North Patagonian Andes. Ourmodel equation is based on the classical Michaelis?Menten formulationand Platt?s photosynthesis?irradiance curve to account for theinterference by glacial particles and the effect of light intensity,respectively. Bayesian inference was applied to estimate modelparameters using data from field bacterivory experiments. Lightexperiments (LE) were performed in lakes with different levels of lightpenetration without clay particles, while clay experiments (CE) wereperformed with an experimental gradient of glacial clay concentration atconstant light intensity. The LE showed a non-monotonic effect of lightintensity and the CE revealed an exponential negative effect of clayconcentration. The obtained model was tested with two independentexperiments carried out in a turbid proglacial lake. Our proposedmechanistic model successfully predicted the combined effect of lightavailability and particle interference on the mixotrophic nanoflagellate?bacteria relationship. The model demonstrated that the effect of light isdampened as clay concentration increases.