Ecotoxicological effects of lithium chloride on Lyngbya wollei
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Authors
Crews, Braxton Grey
Issue Date
2021-07
Type
Thesis
Language
en_US
Keywords
Academic theses , Cyanobacteria , Environmental toxicology , Lithium chloride , Lyngbya , Southern States
Alternative Title
Abstract
Lyngbya wollei is a filamentous cyanobacterium that plagues freshwater environments of the Southeastern United States because it impedes freshwater navigation and recreation, and produces harmful cyanotoxins along with a foul odor. Current treatment plans for L. wollei blooms include numerous biological and mechanical methods, while chemical control is primarily limited to application of copper- and aluminum-based compounds that often have significant negative side effects. Here, we investigate the potential of lithium compounds as control agents for L. wollei. Lithium is not expected to bioaccumulate, has terrific bioremediation potential, and is relatively non-toxic, exhibiting qualities that make it an excellent candidate for an agent of chemical algal control. In this experiment, cultures of L. wollei were exposed to lithium chloride in concentrations increasing up to 400 mg/L. Additionally, filamentous freshwater green algae were also treated with lithium chloride, in order to gain some insight into the specificity of lithium chloride for L. wollei. In a separate set of experiments, L. wollei filaments were exposed to the antibiotics streptomycin, tetracycline, and isoniazid, and to equivalent concentrations of potassium chloride. Filaments were checked for damage using a light microscope, and PAM-fluorometry was used to investigate changes in photosynthetic activity. The effect concentration of lithium chloride was determined to be between 100-200 mg/L for L. wollei and >400 mg/L for freshwater green algae. The antibiotics did not effectively damage the filaments, but the potassium chloride solution produced damage at the effect concentration of lithium, indicating a promising field for further investigation. PAM-fluorometry results suggest that the mechanism by which lithium chloride damages and kills cells in the filaments is unrelated to photosynthesis- the effects observed could be attributed to seasonal variation in L. wollei. In the highest concentration treatment group, freshwater microorganisms were observed, suggesting that lithium chloride may be a safe and effective means of chemical control of freshwater cyanobacteria, pending further experimentation.
Keywords: Lyngbya wollei, lithium chloride, ecotoxicological effects, filamentous cyanobacteria
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This dissertation is protected by the Copyright Laws of the United States (Public Law 94-553, revised in 1976). Consistent with fair use as defined in the Copyright Laws, brief quotations from this material are allowed with proper acknowledgement. Use of the materials for financial gain with the author's expressed written permissions is not allowed.