The prevention of saltwater algal pond contamination using the electron transport chain disruptor, rotenone

Caveats on the use of rotenone to estimate mixotrophic grazing in the oceans

“…Additionally, the half-life of rotenone in aquatic environments ranges from hours to weeks 48 and depends on several factors, namely temperature and pH, increases in which quicken degradation 28 . Hence, this information, together with the data gathered in this study for protists, and previous studies on zooplankton 49,50 and rotifers 29,30 suggest that the indiscriminate use of this compound in the past may have had disastrous consequences for aquatic food webs, whose extent is largely unknown. (2020) 10:3899 | https://doi.org/10.1038/s41598-020-60764-2 www.nature.com/scientificreports www.nature.com/scientificreports/ Despite the inability of acting as a deterrent of heterotrophic grazing, rotenone can still be used as a good algal crop protector, especially if the predator is a sensitive organism like a ciliate (present study) or a rotifer 29,30 .…”

“…Hence, this information, together with the data gathered in this study for protists, and previous studies on zooplankton 49,50 and rotifers 29,30 suggest that the indiscriminate use of this compound in the past may have had disastrous consequences for aquatic food webs, whose extent is largely unknown. (2020) 10:3899 | https://doi.org/10.1038/s41598-020-60764-2 www.nature.com/scientificreports www.nature.com/scientificreports/ Despite the inability of acting as a deterrent of heterotrophic grazing, rotenone can still be used as a good algal crop protector, especially if the predator is a sensitive organism like a ciliate (present study) or a rotifer 29,30 . Nevertheless, future measures should always assess the effect of rotenone on the specific organism that is plaguing the algal culture, as differences in the sensitivity towards the compound are expected, as seen in the present study.…”

“…As expected, autotrophs were more resistant to rotenone, with the exception of T. chuii. Other species of the genus Tetraselmis are also reported to be more vulnerable to rotenone than other algae species, such as the marine Nannochloropsis oculata 29 and the freshwater Chlorella kessleri 30 . This observation suggests that there may be a factor that is common to the genus Tetraselmis that enhances cellular susceptibility to this compound, although it is currently unknown.…”

“…Rotenone has already been suggested to eliminate unwanted predation by rotifers in microalgae cultures, as microalgae are seemingly unaffected [28][29][30] . Nevertheless, direct evidence of the effects of rotenone on chloroplast-bearing organisms is scarce despite the common assumption that these organisms are largely unaffected.…”

Hollow Hydrogel Microfiber Encapsulating Microorganisms for Mass-Cultivation in Open Systems

“…Thus, many researchers have proposed open cultivation methods to overcome the problem of animate and inanimate contamination. One approach is to use chemical additives such as quinine sulfate [ 10 , 11 ], rotenone [ 12 ], and ammonium hydroxide [ 13 ]. Yet this method decreases the cell growth rate.…”