Electromagnetic stratagem to control predator population in algal open pond cultivation

• Published in: Algal research (Amsterdam) 2019-01, Vol.37, p.133-137
• Main Authors: Venkata Subhash, G., Rangappa, Manjuladevi, Raninga, Sagarkumar, Prasad, Venkatesh, Dasgupta, Santanu, Raja Krishna Kumar, G.
• Format: Article
• Language: English
• Subjects: Algal cultivation; Ciliates; Crop protection; Current and voltage; Dinoflagellates; Electrode
• ISSN: 2211-9264; 2211-9264
• DOI: 10.1016/j.algal.2018.11.014

Large scale cultivation of algae is becoming a major challenge due to the impact of biotic (grazers and predators) and abiotic (salinity, light, temperature and pH) stress factors on growth and biomass productivity. Historically, to control grazers and predators, various physical, chemical and biological methods have been used which have had detrimental effects on algae growth and environment. Continuous usage of chemicals on grazers or predators is indirectly or directly encourage the biotics to resist against the applied chemicals leads to crashing of algae by enhancing their growth. To overcome such drawbacks on the usage of chemicals in the present investigation we have demonstrated an electrocution technology (physical strategy) to control grazer population without affecting algal growth and biomass productivity. Initially under lab studies different parameters like current (A)/voltage (V) were optimized to kill grazers and algal sensitivity towards the applied current and voltage. Our results reveal that the bacteria and protozoans were more sensitive to applied current at 5–10 mA compared to algal cells which are able to tolerate lower applied current dosages. Successfully, same technology with best optimum operating conditions is translated in 1 m2 and 20 m2 open ponds with unique multi electrode assembly units. Large scale cultivation of algae is becoming a major challenge due to the impact of biotic (grazers and predators) and abiotic (salinity, light, temperature and pH) stress factors on growth and biomass productivity. Historically, various physical, chemical, and biological methods have been used to control grazers and predators, which have had detrimental effects on algae growth and environment. Continuous usage of chemicals on grazers or predators directly or indirectly encourages resistance against the same chemicals, leading to frequent algae culture crashes. To overcome these drawbacks on the usage of chemicals, in the present investigation we have demonstrated the use of an electrocution technology (physical strategy) to control grazer population without affecting algal growth and biomass productivity. Initially at the lab scale level different parameters like current (A)/voltage (V) were optimized to kill grazers and algal sensitivity towards the applied current and voltage was determined. Our results reveal that the bacteria and protozoans are more sensitive to applied current at 5–10 mA compared to algal cells which are able to toler