A NOVEL IMMOBILIZED ALGICIDAL BACTERIA (DINOSHIELD) FOR CONTROLLING HARMFUL DINOFLAGELLATES: TRANSITIONING RESEARCH TO THE FIELD

Karenia brevis presents a major human health and economic threat to coastal communities in the Gulf of Mexico. Previous research identified an algicidal bacteria, Shewanella sp. IRI-160, having algicidal activity against dinoflagellates, including K. brevis, while having no negative impacts on other phytoplankton tested. Previous research indicated that this bacterium secretes water-soluble algicidal compounds to control the growth of dinoflagellates without the requirement of direct bacteria-algae contact. However, high-dose repeated application of the bacteria or algicidal filtrate may raise concerns about biosafety. Recent research demonstrated the algicidal activity of Shewanella sp. and the algicidal filtrate in retrievable alginate hydrogels (designated as “DinoSHIELDs”) as an effective alternative to direct application of the bacteria or product. Furthermore, at concentrations required to kill K. brevis, DinoSHIELDs were recently demonstrated in in situ mesocosms (2900 L) to have a negligible effect on the microbial community with respect to non-target species. Current research is focused on scaling-up production to conduct a field demonstration on the west coast of Florida, USA. The study will use both turbidity and bubble curtains to confine the trial in the native environment. The overall goal of the field study is to optimize the delivery of the algicide from DinoSHIELDs containing either the immobilized Shewanella sp. IRI-160 or cell-free algicidal product and demonstrate the utility of this technology for continuous red-tide management in the Gulf.

Primary Presenter: Kaytee Pokrzywinski, National Oceanic and Atmospheric Administration National Centers for Coastal Ocean Science (kaytee.pokrzywinski@noaa.gov)

Authors:

Kaytee Pokrzywinski, NOAA's National Centers for Coastal Ocean Science  (kaytee.pokrzywinski@noaa.gov)

Yanfei Wang, University of Delaware  (yfwang@udel.edu)

William Holland, NOAA's National Centers for Coastal Ocean Science  (chris.holland@noaa.gov)

Alexandria Hounshell, NOAA's National Centers for Coastal Ocean Science  (alexandria.hounshell@noaa.gov)

Kathryn Coyne, University of Delaware  (kcoyne@udel.edu)

Alan Kennedy, US Army Corps of Engineers Engineer Research and Development Center  (Alan.J.Kennedy@usace.army.mil)