Free Ammonia Offers Algal Crop Protection from Predators in Dairy Wastewater and Ammonium-Rich Media

Patrick K. Thomas, Gary P. Dunn, Maxine Passero, Kevin P. Feris

Research output: Contribution to journalArticlepeer-review

22 Scopus citations

Abstract

Cost-effective methods for protecting crops from grazing organisms like rotifers are needed to reduce the risk of pond crashes in mass algal cultures. We present a novel strategy to optimize the exposure time to free ammonia, via control of media pH, in both defined media and dairy anaerobic digester effluent to suppress rotifers and maintain algal productivity. We tested five different free ammonia exposure times (0, 1, 2, 6, and 12 h) and found a significant nonlinear effect of exposure time (p < 0.0001) but not pH (p > 0.9) on rotifer survival. In both media types, 6–12 h of elevated free ammonia significantly reduced Brachionus plicatilis rotifer survival with no negative effects on Nannochloropsis oculata , while shorter exposure times were insufficient to inhibit rotifers, leading to severe algal culture crashes. These results suggest that algal crops can be protected from rotifers, without productivity loss, by elevating free ammonia for 6 or more hours.

Original languageAmerican English
JournalBioresource Technology
DOIs
StatePublished - 1 Nov 2017

Keywords

  • ammonia toxicity
  • anaerobic digester effluent
  • axposure time
  • crop protection
  • nanochloropsis oculata
  • rotifers

EGS Disciplines

  • Biology

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