When tides collide: Harmful cyanobacterial and microalgal blooms in Florida and implications for risk assessment Cyanobacterial blooms are a regular occurrence in southern Florida. Water releases from Lake Okeechobee to maintain the water level in this large lake regularly occur along the St. Lucie Canal to the eastern seaboard or along the Caloosahatchee to Fort Myers and the Gulf of Mexico (Fig. 1). Due to increased nutrient loading in Lake Okeechobee, cyanobacterial blooms, frequently composed of Microcystis aeruginosa are released from the lake and contaminate both these waterways. This results in large, microcystin-containing cyanobacterial blooms that can affect tourism and fisheries (Fig. 2). Press reports cataloguing these economic and health impacts in Florida are common. In summer 2018, the situation on the west coast of Florida was exacerbated by the appearance of a bloom of Karenia brevis in the Gulf of Mexico. This brevetoxin-producing algal bloom resulted in the deaths of marine mammals and fish with numbers in the thousands reported on the beaches around southwest Florida. Due to the large discharge of water from Lake Okeechobee, pulses of freshwater ended up in the estuarine and coastal environments. Sampling of the Caloosahatchee in 2018 showed high concentrations of Microcystis aeruginosa and microcystin-LR according to microscopy, UPLCPDA and UPLC-MS [1]. BMAA was also detected by triple quadrupole mass spectrometry at much lower concentration. Although such blooms dominated the freshwater environment of the river, visually intact Microcystis colonies were observed in brackish water in the sound and estuary past the tide line. Conversely, although diatoms and dinoflagellates could not be observed in freshwater samples, ELISA analysis for brevetoxins showed low positive concentrations in the Caloosahatchee and large concentrations in the brackish and marine environment. The findings of the crossing-over of blooms raise questions concerning the risk assessment of cyanobacterial and dinoflagellate toxins in estuarine environments. First, how far can toxins Fig. 1. Location of Lake Okeechobee and Caloosahatchee River in Southern Florida, USA where a bloom of Microcystis aeruginosa released from the lake collided with a red tide of brevetoxin-producing Karenia brevis near Sannibel Island. Bottom left Insert, a colony of Microcystis aeruginosa (approx. 500 m width) from Caloosahatchee River 4 produced by freshwater cyanobacterial blooms be found in saline environments? Conversely, can marine diatom and dinoflagellate toxins be routinely found in freshwater environments, most likely through navigation and tidal flows? Our data indicate that both are possible, although a greater understanding of the effect of salinity on the growth of Microcystis is required, building upon previous work that has shown that e.g. microcystin concentrations can be increased after salt shock [2]. Furthermore, in other estuarine environments a wide range of marine and freshwater toxins have been identified [3]. If the particular toxin(s) are known within freshwater or marine blooms, then adequate risk assessment is possible to protect human and animal health. However, when multiple blooms occur at the same location, then toxicity assessment and risk assessment are necessary to determine whether there are interactions between the toxicants that may change the toxicological outcome. Communication is also essential in order to alert the public to potential issues that may arise from exposure to one or more classes of aquatic toxin(s), whether from harmful cyanobacterial and/or algal blooms. Further communication may be necessary as, depending on the country, marine and freshwaters may be under the jurisdiction of different agencies with different accountabilities and responsibilities. The presence of such multiple blooms may also have effects upstream as, in the case of Florida, changes to discharges from Lake Okeechobee may have to occur when marine blooms are present. When tides collide, procedures need to be in place to determine the potential risk, communicate with relevant parties and perform toxicity assessments when necessary. In addition, collection of autopsy materials can also determine what toxicants may be causing adverse health effects, whether to wild or domestic animals or humans. Ultimately, legislation and good stewardship of waters and relevant contingencies can minimise the potential risk of adverse health effects from occurring. Acknowledgements We are grateful to Dr. John Cassini, Jason HARMFUL ALGAE NEWS NO. 65 / 2020 Harmful Algae News An IOC Newsletter on Toxic Algae and Algal Blooms No. 65 - September 2020 www.ioc-unesco.org/hab Genomic resources for the domoic acid-producing diatom Pseudo-nitzschia multistriata Species responsible for Harmful Algal Blooms (HABs) are among the best studied unicellular microa Fig. 2. Schematic drawing of the life cycle of the pennate diatom Pseudo-nitzschia multistriata. The vegetative phase is characterized by progressive cell size reduction of the population. When cells reach the sexual size threshold (SST), they can either keep decreasing in size until they die, or un Fig. 3. The genome browser available on the SZN BioInforma platform. The genome could be sequenced exploiting inbred strains, obtained from the cross of a first generation of sibling strains [7]. Because of the lower polymorphism of inbreds, it was possible to reconstruct long fragments of DNA from When tides collide: Harmful cyanobacterial and microalgal blooms in Florida and implications for risk assessment Cyanobacterial blooms are a regular occurrence in southern Florida. Water releases from Lake Okeechobee to maintain the water level in this large lake regularly occur along the St. Lucie Pim and Calusa Waterkeepers for assistance in sampling. References 1. Metcalf JS et al (in press). Neurotox Res 2. Matthiensen et al 2000. In: de Koe WJ et al (eds), Mycotoxins and Phycotoxins in Perspective at the Turn of the Millenium. Proc Xth Int IUPAC symposium on Mycotoxins and Phycotoxins, Gu Record levels of Dinophysistoxin-2 in clams from Douarnenez Bay, France, after an unusual bloom of Dinophysis acuta Fig. 1. Location of Douarnenez Bay (48 5 29 North; 4 19 51 West), Western French Atlantic coast. The official monitoring network for phytoplankton and algal toxins in French shellfis Fig. 4. Weekly lipophilic toxin concentrations in Donax spp. in 2019 and 2020. Fig. 3. (A) Percentage of Dinophysis species in Douarnenez Bay water samples between 2010 and August 2020. (B) Mean percentage of DSP toxins in Douarnenez Bay in Donax spp. between 2010 and August 2020. recorded in Dona New insights on the diversity of the dinoflagellate genus Ostreopsis in lagoons of French Polynesia, South Pacific Ocean French Polynesia is a vast territory in the South Pacific Ocean, stretching over an expanse of more than 1,200 miles with a surface area as large as Europe. It is composed of 118 health hazards posed by the proliferation of this species in French Polynesian lagoons. Future studies should aim at developing a better understanding the biogeographic distribution of this species, as well as assessing the impacts of its associated toxins on coral reef ecosystems and/or putative ac Toxin profiles of Gambierdiscus lapillus from the Cook Islands Species of the dinoflagellate genus Gambierdiscus produce the toxins responsible for ciguatera fish poisoning (CFP), an illness that has been prevalent throughout the Pacific and particularly in the Cook Islands [1]. The illness is cause Fig. 3. Phylogenetic analysis of partial large subunit ribosomal DNA sequences (D8D10 region) from the Gambierdiscus strains isolated in this study (in bold font) using Bayesian analyses. Values at nodes represent Bayesian posterior probability support. Scale bar is substitutions per site. lus was Unusual bloom of the red alga Ceramium sp. (Ceramiales, Rhodophyta) in Cartagena, Colombia, SW Caribbean Sea Fig. 1. Map of the study site. Macroalgal blooms are frequently associated with eutrophication of coastal waters [1]. These blooms are mainly composed of ephemeral and opportunistic green a ported as bloom forming species, and this finding adds another genus to the group of harmful bloom-forming macroalgae. Furthermore, this report highlights the potential introduction of a new species which has passed undetected until now. This would not be the first case of a potentially introduced b Distribution of the fish-killing dinoflagellate Karlodinium (Dinophyceae) in the Johor Strait, Malaysia Fig. 1. Sampling sites in the Johor Strait Species of Karlodinium are naked dinoflagellates. More than one third of the named species have been known to cause fish mortality. Toxigenic Karlod- Bloom of a red tide species Akashiwo sanguinea in Semerak Lagoon, Kelantan, Malaysia March 2016: i.e. Pseudo-nitzschia spp. (potentially toxic species), Chaetoceros, Skeletonema, and Blixaea quinquecornis (red tides, fish kills) [3]. In this survey, we confirmed the blooming species as the dinoflag Fig. 3 Bayesian trees of Akashiwo sanguinea inferred from (A) LSU rDNA and (B) ITS datasets. Values on nodes represent bootstrap supports of MP, ML, and posterior probabilities of BI Continued from page 14 sulcus extension invading the epicone is visible (Fig. 3B). Cells are slightly pigmented, wi CLEFSA project identifies Harmful Algal Blooms as a threat to food safety resulting from climate change Fig. 1. Organizations involved in the CLEFSA project Climate change is one of the key drivers of emerging risks for food and feed safety, plant and animal health (including terrestrial and aquat Fig. 3. CLEFSA Multi-Criteria strategy which several directly related to toxins produced by harmful algal blooms (HABs). These include: ciguatoxin, domoic acid, okadaic acid, saxitoxin, pinnatoxin, tetrodotoxin, beta-methylamino-L-alanine (BMAA) and palytoxin analogues. The analysis indicates that Blooming Buddies: MSc Research Projects Extend our Knowledge on Bloom-Forming Freshwater Cyanobacteria Freshwater cyanobacteria blooms are an increasing problem globally and much work is focussing on understanding bloom dynamics and toxin production in order to better manage the inherent health risk Fig. 2. Confocal microscopy images of Planktothrix sp. CAWBG59 (A), Microcystis aeruginosa CAWBG617 (B) and Nodularia spumigena CAWBG21 (C) stained with SYTOXTM green so that lysed cells fluoresce green, whilst intact cells are detected by red chlorophyll autofluorescence. bacterium interfering wit 25 years of service enhancing the capacity to monitor and manage HABs Fig. 1. Participants from the first course held at the IOC Centre in Copenhagen in 1995 The IOC Science and Communication Centre on Harmful Algae opened in May 1995 at the University of Copenhagen, Denmark. It was a new concept International Phytoplankton Intercomparison (IPI) exercise in abundance and composition of marine microalgae Dear participants of the annual IPI (International Phytoplankton Intercomparison) exercise in abundance and composition of marine microalgae: This note is to confirm that due to the ongoing p Canadian review: Marine harmful algal blooms and phycotoxins of concern to Canada As has been reinforced all too well in recent months with the COVID-19 pandemic, the world is indeed interconnected. The international harmful algal bloom community recognized this early on, with a series of internatio Fig. 2. Maps showing the location of selected phycotoxins on the Canadian east (left) and west (right) coast. Symbols represent domoic acid and okadaic acid group toxins above (closed symbols) and below (open symbols) the regulatory action level. The green shaded areas show the distribution of saxit Terri Wells (DFO-NAFC, St. Johns, NL); Michel Poulin (Canadian Museum of Nature, Ottawa, ON); Wade A. Rourke (CFIA, Dartmouth, NS). Fig. 4. Heterosigma akashiwo bloom in Kyuquot, British Columbia, 1996 (Photo courtesy of Nicky Haigh, Microthalassia Consultants Inc., Nanaimo, BC) References 1. LoCi ISSHAs Corner CHA 2021 Hybrid Conference, NEW DATE!! Dear ISSHA members and colleagues: Due to the COVID-19 pandemic and following recommendations of the World Health Organization and National Health Authorities, the 19th International Conference on Harmful Algae has been postponed to October 10-15 HAN Subscription To subscribe to Harmful Algae News anyone can send a mail to sympa@sympa. iode.org with the subject subscribe han do not write any text at all in the mail message itself. The system will send back a mail to you with subject similar to auth 22d6dcd9 subscribe han and with instructio