Making the best of a bad red tide year
A bloom of Florida red tide algae (Karenia brevis) formed in December 2020 and continued along parts of the Gulf of Mexico Coast beyond the end of this fiscal year, bringing more than 2,000 reports of dead fish to the State of Florida’s fish kill hotline. The bloom killed at least 34 manatees and is the suspected cause of death for 16 more. Mote Marine Laboratory’s wildlife rescue and rehabilitation staff responded to more than 180 deceased or stranded sea turtles as red tide affected the region between late July and late October.
The bloom overlapped in time and space with several unusual and complex environmental events, whose possible influences can be untangled only by science. These include rain and runoff from Hurricane Elsa, unusual wind patterns that kept red tide algae near shore, drought-related increases in salinity that helped move the bloom further up into Tampa Bay than normal, large amounts of nutrients released from dead fish, and the 215 million gallons of nutrient-polluted wastewater released into Tampa Bay from the former phosphate processing facility at Piney Point.
Mote scientists, who are leading major studies on red tide dynamics, helped the public separate fact from fiction this year: The events above didn’t start the bloom of native K. brevis algae, but they probably worsened it or strengthened its impacts on coastal communities—fish kills along shore and in the estuaries, and respiratory irritation in people who inhaled red tide toxins (brevetoxins).
Such impacts can be fought directly—a vision fortified with hard evidence this year by the Florida Red Tide Mitigation & Technology Development Initiative led by Mote in partnership with the Florida Fish and Wildlife Conservation Commission (FWC). This summer, Governor Ron DeSantis cut the ribbon for Mote’s new Florida Red Tide Mitigation & Technology Development Facility, where Mote and partners from across the country conducted six experiments advancing promising mitigation technologies through the second tier of a three-tiered testing process. All together, this year the Initiative supported more than 25 research projects to find and test the best mitigation compounds and technologies among more than 125 examined to date.
MITIGATION: WHAT’S WORKING
Mote, FWC and partners from more than 20 private businesses, academic institutions, and federal and state agencies are pleased to report that the Florida Red Tide Mitigation & Technology Development Initiative has:
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Provided the best and brightest scientists nearly 29,000 square feet of new research facilities to safely test the most promising red tide mitigation tools and technologies in large experimental systems that help us predict environmental effects. Mote’s new Florida Red Tide Mitigation & Technology Development Facility, located at Mote Aquaculture Research Park in eastern Sarasota County, offers:
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12 raceway tanks, each 450 gallons
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Two labs featuring a total of 24 mesocosms measuring 5 feet in diameter. Mesocosms are tank systems that help scientists test mitigation compounds under conditions that simulate the real world better than smaller-scale lab systems.
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One lab featuring 12 mesocosms measuring 10 feet in diameter.
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K. brevis culture room where Mote scientists have produced tens of billions of active red tide algae cells to support Initiative research in this controlled setting
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Chemistry and water quality lab
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160,000 gallons of treated and recirculated seawater storage
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Advanced four mitigation technologies from tier 1 (small-scale lab tests) to tier 2 (larger-scale tests in mesocosm systems that help mimic real-world conditions). Those projects are:hose projects are: patented OZONIX® water purification technology; a robot called EVIE designed to find and harvest red tide algae to produce biofuels; a type of ultraviolet light (UVC) that is widely used to kill other microscopic organisms; and kaolinite clay intended to “grab,” sink and remove red tide cells and toxins from the water.
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Enabled two mitigation technologies to begin moving into the third tier of experiments—pilot tests in the environment:
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OZONIX® technology studies by Prescott Clean Water Technologies and Mote:
The researchers tested a 53-foot OZONIX® Mobile Water Treatment Unit using water from the ongoing red tide bloom pumped from Sarasota Bay at Mote’s City Island research facility, along with red tide culture in the mesocosm systems at Mote’s new facility. The system worked well for destroying red tide and its toxins and reducing the nutrients that tend to arise as a side effect of those processes. The system—using processes called hydrodynamic cavitation, ozone injection, ultrasonic acoustic cavitation, and electrochemical oxidation—is designed to clean and reoxygenate water in hard-hit red tide areas such as canals where many marine species have been impacted by red tide. This year’s tests examined how the OZONIX®-treated water affected grass shrimp, finding no toxicity to the shrimp when the technology was applied at levels expected in red tide treatment. -
Kaolinite clay studies led by Woods Hole Oceanographic Institution with partners from Mote and University of Central Florida:
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The researchers made the best of this year’s bloom by conducting a rapid, small-scale, field test of the kaolinite clay technology in a curtain-bound canal near Mote’s Sarasota campus and the Sarasota Outboard Club on City Island, Sarasota.
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The researchers also found that the clay was effective at removing red tide cells and toxins in mesocosms at Mote’s new facility. There, project partners have continued to investigate how the clay performs and how it affects water chemistry and local bottom-dwelling animals, such as urchins and clams. Now, the researchers are analyzing their results and planning new mesocosm experiments focused on emerging questions—for example, can the cells and toxins that sank with the clay re-enter the water later, if the clay is stirred back up?
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Project partners leveraged their discoveries so far to secure a competitive grant from the National Oceanic and Atmospheric Administration (NOAA) for more mesocosm research and government-permitted field tests to assess the clay’s effectiveness and safety, along with further research on its socio-economic costs and benefits. Mote scientists also secured support from Florida Sea Grant to study how the clay affects microscopic life.
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Discovered that at least six other types of mitigation compounds have great potential to reduce K. brevis cells, toxins or both, through small-scale lab experiments in tier 1 of the Initiative’s research process.
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Seaweed compounds: Mote scientists have identified six compounds from seaweed that reduce Florida red tide algae (K. brevis) cells by nearly 100% during small-scale, tier-1 studies. Some of the compounds took just an hour to achieve this effect.
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Quaternary ammonium compounds (“QUATs”): Mote research demonstrated that QUAT-coated fiberglass strips reduced red tide cells in small-scale lab tests by 100% within two hours. Within 48 hours,the red tide toxins were reduced 50% and 63% in water with high and low doses of quats, compared with 20% and 24% in water by itself and with untreated fiberglass strips, respectively. These strips have the advantage of being easily removed from the water when the desired effects are achieved.
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Other compounds showing promise in studies by initiative partners include:
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An environmentally benign shroud called a “metal phenolic network” combined with curcumin, a natural compound found in turmeric.
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A slow release oxidant product designed to kill red tide cells and degrade toxins.
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Two amino acids that enhance the algae-killing effects of a type of bacteria called Shewanella.
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Magnetic, polymer-coated nanoparticles designed to attract both brevetoxins and K. brevis cells and remove them from the water.
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Put 500 pounds of dead fish from Pinellas County Beaches to good use—in a red tide mitigation study by Florida Gulf Coast University (FGCU) and Mote scientists. The study examined potential benefits of removing dead fish killed by red tide—so the nutrients in those fish are no longer available to feed red tide–and recycling the fish to produce viable fertilizer. FGCU scientists used special compounds to help the collected fish decompose faster, and Mote scientists, monitoring the resulting composting fish material, found that red tide toxins were gone in three weeks.
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Improved technology for detecting red tide, which is necessary for reducing its impacts:
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Handheld biosensor for toxins in shellfish: Mote scientists have identified 12 synthetic antibodies that are potential key components needed to make a handheld red tide toxin sensor for shellfish and water. The goal is to make it easier for the shellfish farmers and natural resource managers to monitor red tide toxin concentrations so that both economic and public health are protected.
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Shellfish detox studies: More than 1,200 shellfish from three species (hard clams, sunray venus clams and oysters) have been used by Mote scientists to test different strategies for quickly, effectively, and inexpensively flushing red tide toxins from exposed shellfish. The team is investigating techniques that farmers might use to help the shellfish clear these toxins faster, allowing them to be safe to eat sooner after they encounter red tide.
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Mote’s Beach Conditions Reporting System (BCRS, visitbeaches.org) expanded and upgraded its public website and app this year, including adding 17 new shoreline monitoring sites. Two new sites are in Alabama—the first BCRS sites outside Florida.
The BCRS—which allows trained volunteers and the public to report observed impacts of red tide—grew in multiple other ways this year while rising to meet the public information demands of the ongoing bloom:-
The BCRS website and app were upgraded with a new look and a more user-friendly interface, more detailed conditions reports and the new community portal where the public can share their own observations (a service formerly offered through a separate Mote app, now conveniently located in our popular BCRS).
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The BCRS website had a user base of 615,895 and total pageviews of 1,378,998 from October 2020 through September 2021.
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Mote's BCRS-focused staff communicated with 497 members of the public to provide red tide resources, assist in BCRS usage and translate reports to stakeholders from October 2020 through September 2021.
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310 Community Reports were made by the public via the BCRS Community Portal since the relaunch of the site in March 2021.
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48 reporting locations monitored by 164 trained Beach Ambassador reporters were providing condition updates to the BCRS at the end of this fiscal year.
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Mote’s new “BloomZoom” smartphone-microscope tool is in development with the goal of providing a widely usable, simple method to detect the levels of red tide in water samples right from the beach with greater sensitivity to lower levels of red tide than other emerging tools.
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Drone projects took flight this year. Mote scientists have been examining how to use programmable flying drones with specialized (multispectral) cameras to capture meaningful data on red tide blooms at higher resolution than commonly used satellite imagery can provide. Starting in June 2021, Mote launched routine drone surveys of Sarasota-area waters. Drone-collected data are being analyzed now so Mote scientists can continue to adjust how data are collected and processed, and so they can compare results from drones and satellites—which are currently the primary tools for large-scale imaging of harmful algal blooms at the ocean surface.
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Visit the Initiative website redtidemtdi.org for a complete list of projects.
MAJOR STUDIES: WHAT WE’RE LEARNING
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An ongoing, Mote-led study supported by a competitive grant from NOAA’s ECOHAB program is shedding new light on how K. brevis red tide blooms change over time, respond to extreme events like storms that wash nutrients into the water and climate change, which may increase storm severity, and ultimately terminate (die and/or break apart)—the least understood bloom stage. Mote and partners at Bigelow Laboratory for Ocean Sciences, the Florida Fish and Wildlife Conservation Commission (FWC), New York University-Abu Dhabi, University of Maryland, and the University of South Florida are learning that:
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Karenia brevis red tide blooms in the eastern Gulf of Mexico have four major patterns of termination, which project scientists identified by analyzing bloom data from 1998-2021. The researchers are describing these patterns in detail for an upcoming scientific publication. Understanding what drives these patterns could improve bloom prediction and monitoring.
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The K. brevis bloom that started in December 2020 might have been strengthened later by nutrient-polluted waters from the spring 2021 Piney Point wastewater spill as well as nutrients from extensive fish kills. Mote scientists and their University of Maryland collaborators conducted lab experiments comparing and combining water samples from the spill area in Tampa Bay with samples of the concurrent red tide bloom. Overall, the spill area has been monitored over time by FWC, Tampa Bay Estuary Program and others, while Mote scientists collected a limited set of samples in April 2021 for experimental studies. Those spill-affected water samples contained abundant micro-organisms called picocyanobacteria. When those samples were combined with the K. brevis bloom samples in various concentrations in the lab study, picocyanobacteria disappeared—one hint that the red tide bloom was able to consume picocyanobacterial cells as a nutrient source and may have strengthened in the Piney Point water.
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K. brevis may be able to handle hotter water temperatures than scientists previously realized. While peer-reviewed scientific papers suggested Florida red tide would fare best in water temperatures of 20-28 degrees Celsius (68-82.4 degrees Fahrenheit), and some lab studies concluded the algae became stressed at 30 Celsius (86 Fahrenheit), project partners point out that some of the most severe recent blooms (2005-2006 and 2017-2019) and this year’s bad bloom lasted through summer months with temperatures exceeding those limits and reaching up to 34 Celsius (93.2 Fahrenheit). Establishing the temperature range of red tide is important for predicting the impacts of climate change on red tide.
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Together, project partners are building improved mathematical models to help explain and predict the behavior of Florida red tide blooms and conditions that affect them, such as extreme weather events expected to increase with climate change. This means gathering better data on bloom dynamics that are little understood—for instance, when do K. brevis algae feed on other microscopic organisms, rather than just making their own food through photosynthesis powered by the sun?
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Mote scientists authored a scientific review paper about red tide risks amid climate change. Read the paper.
This paper “Florida’s Harmful Algal Bloom Problem: Escalating Risks to Human, Environmental and Economic Health With Climate Change” was published this year in the scientific journal Frontiers in Ecology and Evolution. It shares critical discoveries from Mote scientists and many others in their field, raising awareness of growing risks that multiple species of harmful algae in Florida could pose to our growing population. Mote is dedicated to informing societal decisions with sound science—including decisions about the response to harmful algal blooms that can greatly impact public health, economies, ecosystems and our quality of life. -
A new report on harmful algal blooms and ocean acidification (OA) is now available, based on a national workshop with invited participants from Mote. Read the report.
The report focuses on defining the research agenda for this important topic—one that Mote scientists are investigating actively already. As leaders in this field, Mote scientists were invited by NOAA to prepare a future peer-reviewed research paper on harmful algal blooms and OA, providing perspective from the U.S. southeast and helping provide perspective on the Gulf of Mexico.
A MASSIVE EFFORT: SCIENCE IN SERVICE OF THE GULF COAST
Mote and FWC scientists work together in the longstanding Cooperative Red Tide Program—a year-round source of reliable data on Florida red tide (Karenia brevis) presence, absence, concentrations and related environmental conditions—part of a massive monitoring partnership along the Gulf of Mexico Coast that informs the public and societal leaders.
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In the last year, Mote and FWC scientists conducted 28 surveys of the marine environment to study and track Florida red tide and the conditions that can affect it. We also supported the response effort to the Piney Point spill by analyzing samples collected by other institutions from five stations in the Tampa Bay Area.
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Through all our activities this year, the Mote-FWC team analyzed 2,552 samples for Florida red tide algae—including samples from their surveys and from partner projects such as beach sampling by the Florida Department of Health. Many samples were also analyzed for other algae and for chemical and physical features that have the potential to influence Florida red tide. Mote’s data on red tide abundance goes into FWC’s database that supports vital bloom updates for the public.
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Mote’s underwater robotic gliders spent 98 days at sea collecting data with onboard, ocean sensing instruments.
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The Mote-FWC Cooperative Red Tide Program is the only group regularly gathering data on K. brevis and carbonate chemistry together in the natural environment on Florida’s west coast. Carbonate chemistry is important for studying climate change—increased temperature and ocean acidification from excess carbon dioxide in the atmosphere—impacts on marine species, including harmful algae. Their efforts include regular Cooperative surveys and NOAA’s Atlantic Oceanographic and Meteorological Laboratory cruises with funding from Mote-FWC Cooperative and the Southeast Coastal Ocean Observing Regional Association.
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Key questions in this effort include: How will acidification affect Karenia itself, and how might Karenia blooms affect regional or local carbonate chemistry?
In general, the Cooperative Program’s data collected so far drive home that acidification isn’t just global—it can vary locally with coastal conditions. The team has observed seasonal differences in carbonate chemistry in surveyed areas, and differences between surveyed estuaries along Florida’s Gulf Coast.
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Research on clams and brevetoxins advances: Mote scientists have been studying how long it takes for clams to clear brevetoxins, the Florida red tide toxins that can cause neurotoxic shellfish poisoning in people who eat contaminated shellfish. This year Mote expanded our tests to use greater concentrations of red tide, to better understand how long the toxins from a severe bloom might persist in clams. At the same time, we’re examining what physiological processes might allow the clams to clear the toxins, while looking for evidence of any subtler damage the toxins might cause—for example, affecting the clams’ health, reproductive capacity or ability to clear toxins in future exposures.