Modelling the consequence of glacier retreat on mixotrophic nanoflagellate bacterivory: a Bayesian approach

SCHENONE, LUCA; BALSEIRO, ESTEBAN G.; BASTIDAS NAVARRO, MARCELA; MODENUTTI, BEATRIZ E.

OIKOS

WILEY-BLACKWELL PUBLISHING, INC

Año: 2020

0030-1299

Mixotrophic nanoflagellate bacterivory is affected by light; however, in glacially influencedlakes, glacial clay may also interfere with prey uptake. Mechanistic models basedon prior quantitative hypotheses and tested with field data are useful for predictingthese predator?prey interactions under a changing climate. We modelled the effect ofglacial particles on the bacterivory of mixotrophic nanoflagellates, the dominant phytoplanktonin mountain lakes in the North Patagonian Andes. Our model equation isbased on the classical Michaelis?Menten formulation and Platt?s photosynthesis?irradiancecurve to account for the interference by glacial particles and the effect of lightintensity, respectively. Bayesian inference was applied to estimate model parametersusing data from field bacterivory experiments. Light experiments (LE) were performedin lakes with different levels of light penetration without clay particles, while clayexperiments (CE) were performed with an experimental gradient of glacial clay concentrationat constant light intensity. The LE showed a non-monotonic effect of lightintensity and the CE revealed an exponential negative effect of clay concentration. Theobtained model was tested with two independent experiments carried out in a turbidproglacial lake. Our proposed mechanistic model successfully predicted the combinedeffect of light availability and particle interference on the mixotrophic nanoflagellate?bacteria relationship. The model demonstrated that the effect of light is dampened asclay concentration increases.