This story is a highlight from our 2020 Annual Report.


As Gulf of Mexico communities recovered from the Florida red tide bloom of 2017-19—and its devastating impact on our environment, economy and quality of life—Mote Marine Laboratory ramped up a new, unprecedented effort to fight the impacts of Florida red tide with science.

The Florida Red Tide Mitigation & Technology Development Initiative—led by Mote in partnership with the Florida Fish and Wildlife Conservation Commission (FWC)—began uniting the best and brightest scientists focused on reducing Florida red tide impacts when the Initiative was signed into law by Governor Ron DeSantis (379.2273 Florida Statutes) in June 2019. The Florida Legislature made a significant commitment of $18 million over six years for the Initiative to implement the development of red tide mitigation technologies that are both effective and ecologically sound, along with novel systems that support emergency response and implementation of bloom-control strategies to protect public and environmental health.

Researchers have sought to battle blooms of Florida red tide algae since at least the 1950s, after centuries of observed impacts and the 1947 scientific documentation of Florida red tide alga, Karenia brevis, which is native to the Gulf. Unfortunately, K. brevis red tides proved too complex for early mitigation attempts—such as adding copper sulfate to ocean water—due to their environmentally damaging side effects. Over the decades, scientists at federal, state and independent institutions including Mote—a longtime leader in the field—have primarily protected public health by monitoring and studying blooms to help communities avoid the worst impacts and inform seafood providers, health authorities and others as they adapt their practices.


During this fiscal year and in the weeks after it concluded on Sept. 30, 2020, the Florida Red Tide Mitigation & Technology Development Initiative has provided support for more than 20 projects by Mote and partners, advancing promising mitigation technologies along the three-tiered testing approach that Mote developed. Technologies must graduate from lab studies to larger “mesocosm” systems and then to government-permitted pilot tests in coastal waters.

Before the Initiative was in full swing, Mote’s existing research programs—including its Red Tide Institute supported by the Andrew and Judith Economos Charitable Foundation and Charles & Margery Barancik Foundation—were already screening more than 100 compounds in the scientific literature for bloom-mitigation potential.

This year, Initiative funding allowed Mote and partners to test promising compounds more extensively, including seaweeds that naturally produce chemicals that are algicidal (algae-killing) against K. brevis, new formulations of clay that can remove K. brevis and its toxins from the water, and QUATs—quaternary ammonium compounds adsorbed to pieces of concrete or fiberglass—that reduced K. brevis cells and toxins in preliminary experiments. The Initiative also allowed testing of new mitigation technologies such as ultraviolet light and nanobubbles designed to physically affect red tide. Initiative projects are also exploring unique and exciting angles on Florida red tide mitigation—such as utilizing spent grain from beer breweries or removing and composting fish killed by red tide to take this natural nutrient source away from K. brevis and potentially repurpose it in fertilizer.

Also thanks to Initiative support, Mote and partners are developing better technologies to detect K. brevis and its toxins. As the fiscal year ended, Mote was taking early steps toward developing a biosensor that will detect red tide toxins rapidly in commercially important shellfish and seawater, to give shellfish industry regulators timelier updates on when shellfish harvest areas should or shouldn’t close to protect seafood consumers. Another Mote-led project, with additional support from Florida Sea Grant, aims to train volunteer citizen scientists to operate user-friendly DNA technology that can identify and count the cells of K. brevis to boost bloom detection efforts. In addition, successful technologies will improve further. For example, Mote’s Programmable Hyperspectral Seawater Scanner (PHYSS) not only detects red tide but also is being upgraded to provide more data on environmental conditions and other species of algae that may influence red tide.


This year, the Initiative has supported more than 20 projects conducted by Mote scientists and partners from 15 institutions supported by competitive grants.

  • Read summaries of all projects led by Mote and partners.
  • Read ongoing progress updates from the Florida Red Tide Mitigation & Technology Development Initiative, including meeting minutes from the Initiative’s Technology Advisory Council. The Council, first convened in 2020, is chaired by Mote President & CEO Dr. Michael P. Crosby and comprises members appointed by FWC, the Florida Department of Environmental Protection and the president of the Florida Senate and the speaker of the Florida House of Representatives.

As this annual report went to press, Initiative partners were working closely with Mote scientists and leveraging Mote’s laboratory facilities, and Mote had nearly finished creating a new, cutting-edge red tide mitigation and technology development testing facility at the 200-acre Mote Aquaculture Research Park in Sarasota County. The facility includes 5-foot and 10-foot mesocosms—large experimental systems needed to safely test coastal ecosystem components with mitigation compounds—and other systems needed for diverse red tide research efforts. The facility, and the unprecedented quantities of cultured K. brevis cells it will produce, will be free for Initiative participants, accelerating their progress toward fighting red tide impacts with science. Read more about the growth of Mote in our “Looking Ahead” section.


This year, Mote scientists deepened our understanding of how Florida red tides work. Their new discoveries will inform diverse red tide response efforts from novel mitigation strategies to improved forecasting, detection and public information to safeguard human health against the impacts of these harmful algal blooms.

Encapsulating some of their latest discoveries, Mote scientists presented or co-presented 20 research sessions or posters during the 10th U.S. Harmful Algal Bloom Symposium held in November 2019 in Orange Beach, Alabama.

Mote highlights from the Symposium:

  • Mote and the Florida Department of Health discovered that Florida red tide toxins in the air can move further inland than previously known. The team deployed air samplers during 2018 in Pinellas and Sarasota counties and found detectable amounts of these toxins (called brevetoxins), with very small amounts traveling up to 9.7 miles inland. Previous research detected brevetoxins up to just 2.6 miles inland, but those sampling efforts were concentrated nearer to shore. More research is needed to determine if the levels measured in this study have implications for human health. On and near the shore, brevetoxins in the air are known to cause respiratory irritation in people, usually having stronger impacts on people with chronic respiratory conditions such as asthma.
  • Scientists know that Florida red tide can use at least 12 sources of nitrogen and phosphorous nutrients—most occurring naturally and some influenced by human activity. During the 2017-19 Florida red tide bloom, many people asked: Did the freshwater blue-green algae Microcystis aeruginosa, released from the Lake Okeechobee system, provide another source of nutrients that “fed” Florida red tide? Research by Mote and Everglades Foundation found that nutrients recycled from dying blue-green algae in the lower river could have provided some nutrients to red tide cells at the river mouth, but not enough to be the main fuel source for this bloom. This is the first research showing M. aeruginosa can be a nutrient source for Florida red tide—the 13th source known to science—but suggests that it can provide far less nitrogen (two orders of magnitude less) than other known sources such as dead fish, waste from small animals called zooplankton, and the “nitrogen fixing” activity of saltwater blue-green algae known as Trichodesmium.
  • Mote and FWC scientists have been investigating the nutrient chemistry patterns before, during and after Florida red tides form, using sample data from five years of surveys in offshore waters in the Gulf of Mexico, these blooms typically originate. Their research is slated for future scientific publication and is focused on providing critical insight for predicting Florida red tide dynamics across seasons or years.
  • Mote scientists are investigating a major modern mystery: How will climate change affect Florida red tide? This year, they demonstrated an experimental approach that allows cultured cells of Florida red tide algae, Karenia brevis, to experience a continuous flow of water with climate-change conditions: elevated temperature and carbon dioxide. In this system, designed to mimic real-world conditions, Mote’s preliminary results showed that K. brevis’ growth rate slowed in warmer water but didn’t change with increased carbon dioxide. With increased temperature and carbon dioxide combined, the K. brevis had higher rates of photosynthesis (using light energy to build certain molecules needed for survival).
  • Another study by Mote scientists and the Maryland Department of Natural Resources examined how different Karenia species, including Florida red tide algae, Karenia brevis, co-occur during severe blooms, such as in 2004-06 and 2017-19. K. brevis was present in much higher concentrations and occurred in warmer water temperatures than the seven other Karenia species found in these blooms, suggesting it tolerated a wider range of temperatures than other Karenia species—one possible factor helping it dominate during blooms.
  • In the lab, Mote scientists found that filter-feeding animals called tunicates from City Island in Sarasota, Florida, could remove two strains of cultured Florida red tide cells from seawater. Other filter-feeding animals are known to remove red tide cells and toxins as well. Based on this knowledge, Mote undertook a community science (citizen science) project to test a new tool for red tide reduction in local environments: “living docks” (artificial reef structures designed to attract filter feeders). Volunteers helped Mote to test these structures along canals in Boca Grande, Florida, providing data that will be analyzed to further understand the potential of this tool as part of a red tide response framework


Millions of residents and visitors on Florida’s Gulf Coast rely upon red tide condition updates and short-term forecasts from a partnership of government, nonprofit and academic institutions that monitor west Florida waters year ‘round. Central to that partnership is the Red Tide Cooperative Research Program led by Mote and FWC scientists.

  • In 2020, Mote and FWC scientists completed a five-year red tide research and monitoring effort—the latest in their decades of partnership—as part of the Red Tide Cooperative Program. As that chapter ended, they charted a new course for the next five years.The five-year Cooperative Program that culminated in 2020 produced a wellspring of data:
    • Routine boat surveys in southwest Florida waters yielded 2,500 water samples used to count Florida red tide algae and 1,700 samples analyzed for algal pigments to identify the community of microscopic algae, or phytoplankton.
    • Mote analyzed 8,050 water samples collected from shore by Mote scientists, the Florida Department of Health in Sarasota County and other local sampling programs—an essential effort to help communities and individuals avoid the worst bloom impacts.
    • In the Florida Keys, 1,830 water samples were collected by scientists and volunteers to monitor for red tide.
    • Mote scientists participated in two major research cruises led by the National Oceanic and Atmospheric Administration to collect data on nutrients and carbonate chemistry conditions that may influence Florida red tide.
    • Mote conducted 24 deployments of robotic gliders (or autonomous underwater vehicles, AUVs) that can help detect hotspots of chlorophyll, a sign of microscopic algae that must be sampled by scientists to determine if they are the Florida red tide species, K. brevis.
    • Two real-time Florida red tide detectors called Programmable Hyperspectral Seawater Scanners (PHYSS) were deployed continuously for months in southwest Florida waters.
    • As of 2020, Mote-trained volunteers are monitoring 40 beaches through Mote’s Beach Conditions Reporting System (BCRS,, including two new sites added in the past fiscal year—Jacksonville Beach and Indian Shores. Over the five year project period, trained BCRS volunteers reported 49,865 sightings of dead fish and 49,910 instances of respiratory irritation in beachgoers—two potential impacts of Florida red tide. Daily online updates from Mote’s BCRS include multiple conditions such as wave height, water temperature, and crowds, helping beachgoers avoid red tide impacts when they occur and find the best beach on a given day, year ‘round. In the past five years, the BCRS website had more than five million page views by more than 1 million unique users.
    • Mote led multiple experiments elucidating how Florida red tide brevetoxins persist in shellfish. Hard clams, a farmed species worth more than $35 million to Florida’s economy, are known to retain Florida red brevetoxins for periods of time after being exposed. If enough toxins are retained, they can cause neurotoxic shellfish poisoning (NSP) in people who eat the clams. For that reason, shellfish harvest areas close when Florida red tides reach specific concentrations. In the five years of research recently completed, Mote scientists:
      • Deepened knowledge of how red tide toxins persist, change, and are cleared by hard clams—information needed by government agencies that manage commercial production of this species.
      • Documented that a newly farmed shellfish species—sunray venus clams—can temporarily pose risks of NSP after encountering certain red tide concentrations. They ultimately clear the toxins in the lab study, but more research is needed on how long they retain the toxins in the field.
      • Led the first study to determine how long lightning whelks—a wild shellfish species that people eat—retain brevetoxins that they accumulate by feeding on hard clams and oysters.Notably, the whelks could retain brevetoxins for at least eight months in their viscera, meaning they can pose a risk of NSP to members of the public who harvest wild whelks and consume the viscera. The whelk muscle (meat) did not contain enough toxins to cause NSP.
  • In summer 2020, Mote and FWC launched the next five-year phase of the Red Tide Cooperative Research Program, adding new priorities to meet the needs of decision makers and communities:
    • Enhanced sampling in estuaries, where rivers meet the Gulf of Mexico.
      Florida red tides normally form 10-40 miles offshore, far from coastal and estuarine influences. However, red tides that reach the coast can be influenced by coastal nutrients, changes in water salinity (saltiness), other local algae species and additional features of estuaries. Recognizing the need to understand these influences better, Mote and FWC scientists have planned enhanced estuarine surveys in the outlets of Charlotte Harbor, the Caloosahatchee River and Tampa Bay four times each year.
    • Expanded water chemistry sampling to enable studies of climate change and Florida red tide. Climate change includes temperature increases and ocean acidification driven by human-contributed carbon dioxide entering the atmosphere and oceans. As ocean carbonate chemistry changes, scientists suspect that microscopic algae may experience changes in physiology. What that means for Florida red tide algae, Karenia brevis, is a key topic for ongoing research.
    • A better Beach Conditions Reporting System (BCRS). The vital public information provided by Mote’s BCRS—daily updates on conditions at dozens of Florida beaches, including red tide impacts—will expand over the next five years. During and after the current fiscal year, Mote has been preparing to roll out an expanded, redeveloped BCRS, improved using results of surveys Mote distributed to users, beach ambassador volunteers and stakeholders in 2020. Expected to launch in 2021 and continue evolving over the next five years, the redeveloped BCRS will monitor more beach conditions and locations, have a more user-friendly interface and more informational resources on its smartphone app and website (, provide three-day synopses of data alongside daily updates, share more of its data with other organizations, and offer a new Community Science Portal where beachgoers can submit their own observations and validate others’ submissions with a thumbs-up or thumbs-down. Some recommendations from survey responders will be implemented now—such as uploading daily beach images via the Community Science Portal and reported UV index and sunrise/sunset times—and others such as tide tables will be added through later updates. Over time, the BCRS will also launch an education portal where people of all ages can learn about our beach environments.
    • Evolving technology to detect harmful algae.
      • Mote’s next-generation instrument for detecting harmful algae—the Programmable Hyperspectral Seawater Scanner (PHYSS)—will be upgraded to provide richer data and more ways to analyze it for red tide scientists at multiple institutions. Mote scientists and engineers have been working to enhance PHYSS’s battery life, its cost effectiveness, its data library that allows PHYSS readings to be compared with multiple algal species including Florida red tide, its ability to sense chemical and physical conditions, and its flexibility to be deployed on both stationary platforms and ultimately, mobile robotic gliders.
      • In 2020, Mote added a new robotic glider—nicknamed “Dora” in a social-media naming contest—to its suite of red-tide-detection technology. This year, Dora completed one of the longest ocean-sensing missions Mote gliders have achieved, collecting data at sea for 29 days. After this year wrapped up, Mote’s other glider, “Genie,” completed a similarly successful, 27 day mission. Mote’s two gliders will continue playing a vital role in Mote’s harmful algal bloom surveys in the next five years. Mote glider missions contribute vital data to, and receive funding support from, FWC and the Gulf of Mexico Coastal Ocean Observing System (GCOOS).
    • New shellfish investigations to protect public health and economies: Mote scientists will continue studying Florida red tide toxins in hard clams as well as oysters—seeking a more exact threshold for how concentrated these brevetoxins must be to make the shellfish toxic, and how long the shellfish retain brevetoxins after experiencing severe bloom conditions. Additionally, they’ll launch new research investigating how clams’ and oysters’ body functions are affected by red tide exposure. This “sublethal” exposure (not enough to kill the animal) has the potential to cause impairment over time—for example, scientists want to know if one exposure will alter the shellfish’s ability to clear toxins from the next exposure.
    • Expanding what our data can do: Red tide surveys by Mote, FWC, NOAA, GCOOS and academic institutions such as University of South Florida have supported government decisions and public health recommendations for decades. Now, Mote is spearheading a new data leadership team to combine the findings from multiple red tide research partners in more powerful ways—including a multi-institution data repository focused on Florida red tide and other species in the microscopic algae community, nutrient data, physical data and toxin data: information that must be interpreted together across long time-scales to improve bloom prediction and forecasting. The data leadership team will also expand efforts to publish Florida red tide science—and in turn, provide even more actionable insights for societal leaders.


The Mote-led project “Life and death of Karenia blooms in the eastern Gulf of Mexico” has continued to move forward despite delays from reduced travel and lab access due to COVID-19. Since fall 2019, Mote scientists have been leading monthly field sampling of 28 stations between Tampa Bay and Sanibel Island out to 120 feet depth, as well as sampling the 2020-21 bloom of Karenia brevis red tide that began after the current fiscal year ended.

The project examines how red tides vary from year to year in their magnitude, what factors cause a bloom to expand and spread, and what influences bloom decline. It is funded by NOAA’s ECOHAB program and includes collaborators from Bigelow Laboratory for Ocean Sciences, FWC, New York University-Abu Dhabi, University of Maryland, and the University of South Florida.

In addition to enhanced sampling of southwest Florida waters, project scientists are also analyzing the State of Florida’s historical database for trends in red tide bloom expansion and termination over the past 30 years and conducting experiments examining the potential influence of climate change on red tide by investigating the impacts of changing temperature on K. brevis growth, nutrient acquisition, and photosynthesis.