Harmful algal blooms (HABs) occur all over the world naturally, but with increases in anthropogenic eutrophication, blooms are occurring more frequently, especially in coastal regions. Moreover, there is no indication of bloom occurrences decreasing in the years to come. The consequences of eutrophication often result in shifts in phytoplankton community structure to non-siliceous species, including dinoflagellates. Approximately 75% of known toxic algal species are dinoflagellates. Dinoflagellates are known to bloom to high densities and are often referred to as “red tide”. These blooms can cause significant and even permanent damage to the environment, in addition to posing a human and marine health risk. The economic impacts of HABs are also high, and often cost millions of dollars to the shellfish and recreational fishing industries. As such mitigation of these blooms has long been a priority yet there are currently no measures in place for the rapid response to harmful dinoflagellate blooms.
Previous research at UD in Dr. Kathy Coyne’s lab has demonstrated that the bacterium Shewanella sp. IRI-160 secretes a compound that has negative effects on the growth of dinoflagellates while having no negative effects on other classes of phytoplankton tested (Hare et al., 2005; Pokrzywinski et al. 2012). Further work has demonstrated that that this compound - IRI-160AA (AA for “algicidal agent”) – induces biochemically mediated cell death processes in dinoflagellates causing them to internally degrade without the release of harmful toxins into the water column. Our data suggest a potential treatment for the rapid prevention and mitigation of dinoflagellate blooms without negatively impacting the ecosystem.
Dinoflagellate Karlodinium veneficum morphological changes after addition of the algicide.
While this compound may provide an effective rapid control for monitoring dinoflagellate blooms more work is necessary before it can be safely used in the environment. In this project we continue to characterize the impacts of IRI-160AA on dinoflagellate physiology and metazoan toxicity, along with its impact on whole communities and natural assemblages. We are also currently isolating and elucidating the structure of this compound.
Concentrated dinoflagellate Gyrodinium instriatum after addition of the algicide
Primary investigators: Kathryn J. Coyne (Kcoyne@udel.edu) & Mark E. Warner (Mwarner@udel.edu). Graduate students: Kaytee Pokrzywinski (Kaytee@udel.edu) and Charles Tilney (Ctilney@udel.edu).
Funded by a Prevention Control and Mitigation (PCM) grant by the National Oceanic and Atmospheric Administration (NOAA).