Growth, microcystins synthesis, and cell viability of Microcystis aeruginosa FACHB905 to dissolved organic matter originated from cattle manure

- Cattle manure DOM (CM-DOM) increases the cell viability of Microcysris aeruginosa.
- CM-DOM increases the synthesis and secretion of microcystins.
- CM-DOM inhibits the activity of extracellular alkaline phosphatase.
- Lignin originated phenol and benzene derivatives are the primary constituents in the CM-DOM.

Discharge of livestock effluents and poor management of livestock manures are important reasons for the eutrophication of water bodies. Dissolved organic matter (DOM) originated from livestock manure is ubiquitous in water, but the effects of such DOM and the organic substances on the growth and cyanotoxins synthesis of bloom-forming cyanobacteria are still unknown. In order to elucidate these issues, the growth, microcystins synthesis, and cell viability of Microcystis aeruginosa exposed to cattle manure originated DOM (CM-DOM) were investigated in this study. The results indicated that the growth of M. aeruginosa FACHB905 was slightly improved by CM-DOM at a concentration of 90 mg l −1 (TOC). CM-DOM slightly decreased the electron transfer efficiency of photosystem II (PS II) of M. aeruginosa FACHB905. The synthesis and secretion of microcystins were promoted by CM-DOM. The cell viability (TTC test) increased in response to CM-DOM addition. Results presented in this study suggested that CM-DOM may increase the ecological and public health risks of M. aeruginosa when poor management of livestock manure is anticipated.

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