TY - JOUR

T1 - Functional ecology of aquatic phagotrophic protists–concepts, limitations, and perspectives

AU - Weisse, Thomas

AU - Anderson, Ruth

AU - Arndt, Hartmut

AU - Calbet, Albert

AU - Hansen, Per Juel

AU - Montagnes, David J. S.

PY - 2016

Y1 - 2016

N2 - Functional ecology is a subdiscipline that aims to enable a mechanistic understanding of patterns and processes from the organismic to the ecosystem level. This paper addresses some main aspects of the process-oriented current knowledge on phagotrophic, i.e. heterotrophic and mixotrophic, protists in aquatic food webs. This is not an exhaustive review; rather, we focus on conceptual issues, in particular on the numerical and functional response of these organisms. We discuss the evolution of concepts and define parameters to evaluate predator-prey dynamics ranging from Lotka-Volterra to the Independent Response Model. Since protists have extremely versatilefeeding modes, we explore if there are systematic differences related to their taxonomic affiliation and life strategies. We differentiate between intrinsic factors (nutritional history, acclimatisation) and extrinsic factors (temperature, food, turbulence) affecting feeding, growth, and survival of protist populations. We briefly consider intraspecific variability of some key parameters and constraints inherent in laboratory microcosm experiments. We then upscale the significance of phagotrophic protists in food webs to the ocean level. Finally, we discuss limitations of the mechanistic understanding of protist functional ecology resulting from principal unpredictability of nonlinear dynamics. We conclude by defining open questions and identifying perspectives forfuture research on functional ecology of aquatic phagotrophic protists.

AB - Functional ecology is a subdiscipline that aims to enable a mechanistic understanding of patterns and processes from the organismic to the ecosystem level. This paper addresses some main aspects of the process-oriented current knowledge on phagotrophic, i.e. heterotrophic and mixotrophic, protists in aquatic food webs. This is not an exhaustive review; rather, we focus on conceptual issues, in particular on the numerical and functional response of these organisms. We discuss the evolution of concepts and define parameters to evaluate predator-prey dynamics ranging from Lotka-Volterra to the Independent Response Model. Since protists have extremely versatilefeeding modes, we explore if there are systematic differences related to their taxonomic affiliation and life strategies. We differentiate between intrinsic factors (nutritional history, acclimatisation) and extrinsic factors (temperature, food, turbulence) affecting feeding, growth, and survival of protist populations. We briefly consider intraspecific variability of some key parameters and constraints inherent in laboratory microcosm experiments. We then upscale the significance of phagotrophic protists in food webs to the ocean level. Finally, we discuss limitations of the mechanistic understanding of protist functional ecology resulting from principal unpredictability of nonlinear dynamics. We conclude by defining open questions and identifying perspectives forfuture research on functional ecology of aquatic phagotrophic protists.

U2 - 10.1016/j.ejop.2016.03.003

DO - 10.1016/j.ejop.2016.03.003

M3 - Tidsskriftartikel

C2 - 27094869

VL - 55

SP - 50

EP - 74

JO - European Journal of Protistology

JF - European Journal of Protistology

SN - 0932-4739

IS - Part A

ER -