Harmful Algal Blooms on the Norfolk Broads

Even though Harmful Algal Blooms (HABs) have been studied in detail for many years, practical strategies to mitigate or manage HABs and detailed multi-disciplinary studies of HABs in the environment are limited. Here, we investigate the effects of a harmful bloom of P. parvum on Hickling Broad, England, an area frequently plagued by blooms of this organism. Using molecular genetic approaches, we show that P. parvum dominates the microbial community during a bloom and how the community composition changes in non-bloom conditions. Using biochemical methods, we report for the first time the trace detection of prymnesin toxins in natural water samples and gill cells of a deceased fish. We support these findings by isolating the local strain of P. parvum and using targeted metabolomics to conclusively show production of the B-type prymnesins in these strains. Furthermore, we follow population dynamics of P. parvum and its lytic virus, PpDNAV, over a 2-year period, and finish by showing that hydrogen peroxide provides an effective treatment strategy for instances of Prymnesium blooms. This multi-disciplinary study sheds detailed insight into natural bloom dynamics of an important fish pathogen and provides the basis for understanding and managing future Prymnesium blooms in enclosed waters.