Mixotrophy in Argentina freshwaters
Mixotrophic organisms appeared in photosynthetic and heterotrophic lineages (i. e., algae and ciliates). In this article we will present examples and discuss diverse aspects of the success of this dual nutrition mode in different lakes from Argentina. Factors as nutrients, light, water mixing intensity, mixing depth, and prey abundance have large effects on the ecological dynamics of these organisms. Traditional studies suggested that the growth rate of mixotrophic protists would depend on light intensity and prey abundance allowing the classification of mixotrophs into different groups. We will discuss this scheme in the scenario of protists currently present in Argentina. Additionally, we will examine the results of field and experimental studies in Argentina lakes regarding the different co-occurring factors that determine the success of different mixotrophic species. In particular, we will focus competitive interactions among mixotrophs in nature, evaluating both, photosynthetic efficiency as a result of the niche partitioning along the water column and the ingestion of picoprokaryotes for food niche overlap. Furthermore, we will present other studies on the relative importance of light (intensity and quality) in the autotrophy and phagotrophy balance.