CHRYSOWEB – The effect of mixotrophic chrysophytes on secondary productivity in pelagic food webs

Funding: EU Horizon 2020 Marie Skłodowska-Curie Actions Individual Fellowship for Csaba Vad

Project leaders: Csaba Vad, Robert Ptacnik

project chrysoweb
2016-2018: ChrysoWeb project – The effect of mixotrophic chrysophytes on secondary productivity in pelagic food webs

Project summary:

Global change is expected to have far reaching consequences on hydrological processes at the catchment level. For lakes in the temperate zone, it is expected to enhance the intensity and duration of thermal stratification, as well as the input of allochthonous carbon from the catchment into the lakes (‘brownification’). While changes in the plankton of eutrophic lakes (e.g. increased dominance of cyanobacteria) are a widely discussed topic in the current literature, the consequences of global change for oligotrophic lakes receives little attention.

Plankton occupy a key position in aquatic trophic webs and today, a highly relevant topic lies ahead in assessing the global change-mediated shifts in aquatic trophic webs, with implications for the functioning of aquatic systems. Mixotrophic chrysophytes are important elements of phytoplankton in oligo- and mesotrophic lakes and their contribution is predicted to increase with global change-associated phenomena (brownification and enhanced thermal stratification). Current knowledge suggests that chrysophytes may impair zooplankton secondary production, which imply serious consequences for pelagic trophic efficiency and ecosystem services e.g. fish production. However, our understanding on the nutritional quality and bottom-up effects of chrysophytes on zooplankton is insufficient.

ChrysoWeb aims to quantify the effects of chrysophytes on zooplankton secondary production and diversity. Laboratory feeding experiments are be combined with field observations, and the underlying mechanisms are explored biochemically. Altogether ChrysoWeb will significantly contribute to the understanding of carbon flow and nutrient cycling in alpine lakes under global change.