Cyanobacteria-Grazer Interactions: Consequences of toxicity, morphology, and genetic diversity
Interactions between cyanobacteria and herbivorous grazers play an important role in mediating the responses of freshwater phytoplankton assemblages to nutrient enrichment and top-down manipulation. Negative consequences associated with these interactions include dangerous blooms of harmful blue-green algae that have been implicated in the sickness and death of fishes, livestock, and, in extreme cases, humans. Frequently cited mechanisms influencing the interactions between grazers and cyanobacteria include cyanobacterial toxicity and morphology. To tease apart the importance of these mechanisms, I used meta-analysis to quantitatively synthesize the available literature on this topic. In addition, I conducted several experiments using novel techniques to determine the effect that cyanobacterial secondary metabolites from the bloom-forming cyanobacterium, Microcystis aeruginosa, have on the fitness of the common, lake-dwelling zooplankter, Daphnia pulicaria. Together, results from these studies suggested that cyanobacterial toxicity and morphology can influence the fitness of grazers, however conclusions drawn from these studies were heavily influenced by which herbivore or cyanobacteria genotype was considered. Thus, genetic variation within aquatic communities can have significant ecological implications on the promotion and/or control of harmful cyanobacterial blooms in nature.
Advisor:Klausmeier, Christopher; Montoya, Joseph; Snell, Terry; Sarnelle, Orlando; Hay, Mark
School:Georgia Institute of Technology
School Location:USA - Georgia
Source Type:Master's Thesis
Date of Publication:04/11/2006