Authors: SAVVAS GENITSARIS, NATASA STEFANIDOU, MATINA KATSIAPI, ELISABETH VARDAKA, KONSTANTINOS AR. KORMAS, ULRICH SOMMER, MARIA MOUSTAKA-GOUNI
Abstract: In a literature search, the presence of Haematococcus in phytoplankton communities and its biogeography were investigated. Haematococcus, although showing a wide biogeographical distribution, has been rarely found in phytoplankton communities. Simultaneously, the colonization potential of air-dispersed Haematococcus in ephemeral waters and its interactions with coexisting phytoplankton taxa were examined by microscopy and molecular methods. Haematococcus was a successful colonist, appearing among the first taxa in the experimental containers. According to principal component analysis, Haematococcus growth rate was negatively correlated with the abundance and species richness of the other autotrophs. Furthermore, a negative correlation between Haematococcus and Chlamydomonas and a positive one between Haematococcus and Chlorella were found. Overall, Haematococcus appears to be an effective air-dispersed alga that can successfully colonize and establish populations in small ephemeral water bodies. However, its absence from phytoplankton in larger permanent water bodies could be related to its high light requirements, its competitive disadvantages against other algae, and the grazing pressures from predators. The results of our study suggest a life strategy based on adaptation to higher light intensities in very shallow waters compared with optical dense lakes. Therefore, ephemeral waters are the regular habitat for Haematococcus instead of being "stepping stones" for the colonization of lake phytoplankton.
Keywords: Haematococcus, airborne, colonists, biodiversity, biogeography
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