Blue-green algae and selection in rotifer populations.

Area of Science:

• Ecology
• Toxicology
• Evolutionary Biology

Background:

• Natural populations of rotifers (Asplanchna girodi) showed potential negative impacts from blue-green algae.
• Blue-green algae are common in freshwater ecosystems and can form harmful blooms.

Purpose of the Study:

• To investigate the toxic effects of specific blue-green algae on different genotypes of the rotifer Asplanchna girodi.
• To determine the ecological role of blue-green algae in the natural selection of rotifer populations.

Main Methods:

• Isolation of Anabaena flos-aquae and Lyngbya sp. from a Central Florida pond.
• Testing the effects of isolated algae on the reproductive rates of three A. girodi genotypes.
• Confirmation of algal toxicity using mouse bioassays.

Main Results:

• Anabaena significantly affected rotifer reproductive rates, with genotype-specific responses.
• Lyngbya also depressed rotifer reproduction, but at concentrations an order of magnitude higher than Anabaena.
• Mouse bioassays confirmed the toxicity of the tested blue-green algae.

Conclusions:

• Blue-green algae possess the capability to differentially reduce rotifer reproductive rates across genotypes.
• These algae can act as a significant ecological factor driving natural selection in rotifer populations.
• The findings highlight the complex interactions between cyanobacteria and zooplankton in aquatic environments.