Harmful Algae News An IOC Newsletter on Toxic Algae and Algal Blooms No. 78 February 2025 https://hab.ioc-unesco.org/ Dinoflagellate Blooms and Spinning Fish Coincide with Sargassum Inundation, Nitrogen Enrichment and Ocean Warming in the Florida Keys, USA Harmful algal blooms (HABs) negative impacts on public health, recreation, tourism, fishery, aquaculture, and ecosystems have increased worldwide over the last decades [1]. In subtropical Florida, blooms of cyanobacteria (Microcystis, Synecchococcus, Lyngbya), red tides (Karenia brevis), brown tides (Aureoumbra lagunensis), golden tides (pelagic Sargassum) and a variety of benthic macroalgae (Laurencia, Gracilaria, Dictyota, Wrightiella, Cladophora, Caulerpa) have increased in severity in the wake of human population growth over decades. This article provides a brief background of the HABs that have developed in the coastal waters of the Florida Keys (the Keys), an island archiplego downstream of the Everglades in southernmost Florida. The coastal waters of the Keys were historically oligotrophic and encompass the majority of the third-longest coral reef in the world, the Florida Reef Tract, which extends 563 kms from the St. Lucie Inlet on the east coast to the Dry Tortugas National Park west of Key West, FL. The sequence of HABs reached a new level of risk in the Lower Keys in 2023/2024 when unprecedented observations of spinning fish and fish kills, most notably the critically endangered smalltooth sawfish (Pristis pectinata), were increasingly reported on social media, local U.S. and national news outlets (https://x.com/NBCNightlyNews/status /1773861243754873069?mx=2). Local nutrient pollution from human waste, mainly from leaking septic systems, was first identified as a driver of excessive phytoplankton and macroalgal HABs in the Keys during the 1980s. The resulting eutrophication contributed to low dissolved oxygen and the early stages of seagrass and coral reef die-off [2]. HAB events increased dramatically in the early and mid-1990s when water managers adopted policies to increase freshwater flows from Lake Okeechobee south to Florida Bay and the Keys to re- Content Feature article Dinoflagellate Blooms, spinning fish, and Sargassum coincides with nitrogen enrichment and ocean warming in the Florida Keys, USA Brian E Lapointe ...................................... 1 HAB events and prediction Tingui: the sickness by exposure to marine aerosols in NE Brazil ....... 6 Calibration and validation of IRMA: an index for predicting fish kills and anoxia ........................................................... 8 A late Dolichospermum bloom in a Nova Scotia lake ................................... 10 HAB Training and Networking Med HAB Net: A network to address Mediterranean HABs ............ 12 GlobalHAB SSC In-person Meeting... 13 HAB Session at the 7th Xiamen Symposium on Marine Environmental Sciences ....................................... 15 Institute of Hydrobiology HAB Training Course under the "Belt and Road" Initiative ............................... 17 Forthcoming Showing the route to ICHA 2025 and qPCR Training course ................... 19 ISSHA Awards: call for nominations. 20 IOC Training Course on HABs Identification and Qualification......... 21 Review Sargassum white paper 2024 ............ 22 Fig. 1. AVHRR reflectance image from March 12 1996 showing a high-turbidity plume from Shark River Slough extending beyond the Lower Florida Keys towards the Dry Tortugas. Interview with Marina Montresor......................... 24 Harmful Algae News An IOC Newsletter on Toxic Algae and Algal Blooms No. 78 February 2025 https://hab.ioc-unesco.org/ Dinoflagellate Blooms and Spinning Fish Coincide with Sargassum Inundation, Nitrogen Enrichment and Ocean Warming in the Florida Keys, USA Harmful algal blooms (HABs) negative imp Fig. 2. Dead brain coral (Pseudodiploria strigosa) overgrown by the green macroalga Cladophora vagabunda in June, 2008 at the Rock Pile, Lower Florida Keys. Photo: Brian E Lapointe. duce salinity. This policy was controversial as there was no scientific evidence that high salinities were causing ei Fig. 4. MODIS/Aqua ERGB satellite imagery showing ENSO-related discharges from the Everglades in the Lower Florida Keys (red circle) on December 5, 2023, February 3, 2024, and March 7, 2024. (Carcharhinus leucas) and many more [7]. Crustaceans were also affected, including blue crab (Callinectes sa and Digenea simplex (4.6 x 103 cells. gDW-1), with lower densities of Ostreopsis (3 x 103 cells.gDW-1) and Gambierdiscus (2.9 x 103 cells.gDW-1) on Digenea simplex. Further sampling was conducted on June 8th 2024 at the Newfound Harbor Reef and Pine Channel sites. TDN, TDP, and TDN:TDP ratios contin Fig. 6. Pelagic Sargassum inundation at Bahia Honda State Park, March, 2023. Photo: B E Lapointe. References 1. Gobler C 2020. Harmful Algae 91:14. 2. Lapointe BE & M Clark 1992. Estuaries 15:465476. 3. Lapointe BE et al 2007. Coral Reefs 26:515. 4. Lapointe BE et al 2019. Mar Biol 166:108. 5. Pew Tingui: the sickness by exposure to marine aerosols in the Northeast of Brazil Fig. 1. Map of Brazil showing the municipalities of Recife, Tamandaré, Barra de São Miguel, Lagoa Azeda, and Porto Seguro in Northeast Brazil. In Tamandaré Bay (84720 S, 350645 W, Fig. 1), on the northeastern coast of B Fig. 3. (A) Coastal area and cliffs of Lagoa Azeda, also known as Lagoa de Jequiá da Praia, in Alagoas. (B) Temporary houses for residents, known as ranchos, used during the tingui period in the municipality. Source: Alagoas Mapa (2022). May 2023, during a tingui event when foam and oily seawater w Calibrating and validating the Aerobic Mortality Risk Index (IRMA): an index for predicting mass mortality of fish due to anoxia. Fig. 1. Location of the Ciénaga Grande de Santa Marta (CGSM), Colombia. Source [4]. Red boxes indicate sampling sites. Mass mortality of marine organisms are frequent e erate and high-risk levels of fish kill events (Fig. 4). The optimized threshold value was 60%. Finally, we classified the risk levels for the occurrence of fish kill events (Table 1). Acknowledgments We express our gratitude to the Marine and Coastal Research Institute INVEMAR for providing the es Unusually late occurrence of a Dolichospermum bloom in a Nova Scotia lake Fig. 1. Map of Sandy Lake. Dolichospermum (formerly Anabaena) is a cosmopolitan buoyant N-fixing cyanobacterial genus found in Canadian lakes. Dolichospermum sp. can be very productive under high-P conditions with prolonged Table 1. Historical trends of total phosphorus for Sandy Lake, Bedford. Data compiled by D. Patriquin. from unpublished consulting reports & HRM Lakewatchers Program datasets. Date Sept 3, 2008 May 24, 2010 August 8, 2011 August 1623 2021 August 22, 2022 August 14, 2023 August 12, 2024 Surface (0. Med HAB Net: A new network addressing Harmful Algal Blooms in the Mediterranean The Mediterranean Sea is a semi-enclosed basin bordered by 23 countries across north Africa, Europe and the Middle-East. It hosts 46 toxin-producing microalgal species harmful to humans and 29 ichthyotoxic species [1], p GlobalHAB Scientific Steering Committee In-person Meeting The IOC-SCOR GlobalHAB Scientific Steering Committee (SSC) members and liaisons convened for an in-person meeting on 24th25th September at Scripps Institution of Oceanography, San Diego, California, USA (Fig. 1). Clarissa Anderson (recently a both sides of the Pacific, China (22 23 October 2024) and PCM-HABs training for South East Asia mariculture stakeholders (111 December 2024). Future activities and deliverables of the current SSC term include: A scientific publication on the monitoring of Ostreopsis during the last decade (20102024 Harmful Algal Bloom (HAB) Session at the 7th Xiamen Symposium on Marine Environmental Sciences The Harmful Algal Bloom (HAB) session, titled Alleviating the Impact of Emerging Harmful Algal Blooms (HABs) on Coastal Ecosystems and Seafood Safety for a Sustainable and Healthy Ocean, was held during th Fig. 2. Invited speakers and oral presentations: Prof. Dr. Mitsunori Iwataki, Prof. Dr. Nansheng Chen, Dr. Chun-kit Kwok and Dr. Kieng Soon Hii. YTX) on the economically significant abalone species, revealing that homoYTX induces oxidative stress, disrupts antioxidant defenses, impairs metabolic an Institute of Hydrobiology successfully conducts the HAB Training Course for Developing Countries Under the Belt and Road Initiative Harmful algal blooms (HABs) represent a pressing global environmental issue, posing significant threats to human health and national security worldwide. To address thes Fig. 2. Laboratory session. CAS HAB Training Course 2024 ed Nations Sustainable Development Goals. The training course brought together an extensive pool of expertise in HAB research, featuring distinguished lecturers (Fig. 1), including: Prof. Joanna Mankiewicz-Boczek (University of Lodz, Poland), Showing the route to ICHA 2025! Welcome Message Dr. Leonardo Guzmán, Chair of the Local Organizing Committee of the International Conference on Harmful Algae (ICHA 2025), welcomes you to this key event on harmful algae and aquatic toxins. Instructions for registration and abstract submission can now tection by using molecular tools To explore the potential application of qPCR for the monitoring and forecasting of harmful algal blooms in (own) monitoring programs To provide guidance for developing own qPCR assays for desired target species This workshop is intended for persons working in or pl IOC Training Course and Identification Qualification in Harmful Marine Microalgae (November 2025) Since 1993 the IOC has conducted training courses on harmful microalgae. The purpose has been to improve the taxonomic and identification skills of the participants for research purposes and for practic Review: Sargassum white paper 2024 In 2011, the scientific community was totally flabbergasted by an unexpected and unprecedented beaching of enormous amounts of pelagic Sargassum along the shores of the Caribbean coasts and tropical West Africa. Before that year, beaching of pelagic Sargassum was a Images of Sargassum overgrowth in Serranilla Cay, San Andrès Archipelago (Colombia), Caribbean Sea. Photos: Brigitte Gabio. Some efforts to fill in these gaps have relied on remote sensing images and citizen science initiatives. To improve forecasting capabilities and support policymakers and stake Interview with Marina Montresor Marina Montresor, a renowned researcher in the field of harmful algal blooms (HABs), has dedicated her career to uncovering the mysteries of these fascinating and sometimes dangerous microorganisms. From her early days studying plankton in Padua to her groundbreaking species concept in Pseudo-nitzschia [7]. Species in this genus are heterothallic - i.e., strains can have mating type plus (+) or minus (-) and we crossed dozens of strains of different species to establish their relationships. Im quite proud of this work, as it was new and groundbreaking. Another Fig. 3-4. Advanced Phytoplankton Course in 2015; Marina Montresor teaching dinoflagellates alongside Karen Steidinger (left) and with Jacob Larsen (right). How have advancements in technology impacted research on harmful algae during your career? What role do you see molecular tools, such as DNA se what causes a bloom. Obviously, phytoplankton needs light and nutrients, but often we do not find relationships between the onset and decay of a bloom and environmental factors. We should focus on the mechanisms that lead to the bloom of the individual species. Is the regulation of growth modulated ing slow science, for reading and thinking. Im also involved in outreach activities and devote some time to volunteer work. Is there a final message or thought youd like to share with the readers of Harmful Algae News? Communicate, discuss, be curious. Dont be afraid of sharing ideas. If you are ope ICHA 2025 Registration opened January 13th 2025 Abstract submission opened January 20th 2025 Abstract Submission deadline June 1st 2025 Late Registration closes September 19th 2025 https://icha2025.org/ Editors-in-chief Beatriz Reguera Kenneth N. Mertens IPHAB Chair Philipp Hess Vice-Chair Mag