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Michael L. Parsons, Ph.D. - Florida Gulf Coast University. Fort Myers, FL, US

Michael L. Parsons, Ph.D.

Expert in coastal water health | Florida Gulf Coast University


Michael Parsons studies the causes of harmful algal blooms and how their toxins can impact marine and human lives.





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The Water School at FGCU



Michael Parsons is a Professor of Marine Science in the Water School at Florida Gulf Coast University and Director of FGCU's Vester Field Station. In addition to his teaching duties focused on marine ecology, Parsons has built a successful research career, receiving over $20 million of extramural funding to study harmful algal blooms and ecosystem health. His work has been cited over 4,000 times in the scientific literature, demonstrating the quality of his work. In addition to working with other researchers around the state to find solutions to our algal bloom problems, he was appointed to the Blue-Green Algae Task Force by Florida Governor Ron DeSantis in 2019 to work to reduce the impacts of harmful algae in our region.

Areas of Expertise (6)

Coral Reef Ecology

Ciguatera Outbreaks

Coastal Water Health

Plankton Ecosystems

Harmful Algal Blooms

Phytoplankton Ecology

Education (3)

Louisiana Universities Marine Consortium: Post-doctoral Fellow, 1996 - 1999

Louisiana State University: Ph.D., Oceanography and Coastal Sciences 1996

University of Rochester: B.S., Biology - Geology 1990

Affiliations (4)

  • Harmful Algae : Editorial Board
  • Ft. Myers Beach Chamber of Commerce : Board of Directors
  • National Harmful Algal Bloom Committee : Past Member
  • US Harmful Algal Bloom Taxonomy Workshop : Instructor

Selected Media Appearances (23)

Red Tide continues to linger, but how much longer?

Fox 4  tv


Michael Parson talks about a red tide bloom off the coast of Southwest Florida.

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Dead fish washing up on Sanibel’s shore

NBC2  tv


Dead fish are washing up on Sanibel Island and Michael Parsons believes red tide is to blame.

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New technology at FGCU’s Water School addressing water quality issues in SWFL



Michael Parsons talks about research happening inside The Water School at FGCU.

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Florida Gulf Coast University new water school looks to help with red tide

Fox 4  tv


Michael Parsons discusses red tide research happening inside The Water School.

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Englewood beachgoers feel impacts of red tide

Fox 4  


Michael Parsons talks about red tide detected off the coast of Englewood.

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Post-Ian nutrients feeding red tide and other algae blooms along SWFL coastline

Fox 4  tv


Michael Parsons explains how he is looks at past red tide blooms to understand the red tide bloom that happened after Hurricane Ian.

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Sarasota County reimplements red tide warnings at multiple beaches

WTSP  tv


Michael Parsons discusses how red tide blooms move up and down the coast.

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Red tide is blooming in Southwest Florida after Hurricane Ian. Will it reach Tampa Bay?

Tampa Bay Times  print


Michael Parsons discusses the possible impact Hurricane Ian had on red tide.

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Drone captures crimson tide of nutrient-laden stormwater flowing from Caloosahatchee post-Ian

WGCU  tv


Michael Parson explains how correlations between hurricanes and red tides are unclear.

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FGCU project proves removing dead fish can help reduce red tide in the Tampa Bay area

WTSP  tv


Michael Parsons discusses a study that measures the environmental and economic benefits of removing dead fish killed by red tide.

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FGCU researchers say dead fish from red tide can be turned into natural fertilizer

ABC Action News  tv


Michael Parsons discusses a study where researchers are turning dead fish into an eco-friendly fertilizer.

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FGCU scientists unveil new way to continuously track Estero water quality

NBC2  tv


Michael Parsons discusses how his team is tracking water quality in Estero Bay.

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Bonita Springs voting on hiring water steward to analyze community's water quality

NBC2  tv


Michael Parsons discusses how the City of Bonita Springs is considering hiring a water steward to analyze the community's water quality.

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FGCU, Mote Marine Lab project studies if dead fish are feeding red tide

NBC2  tv


Michael Parsons discusses a project that is studying if dead fish feed red tide and if removing them will mitigate the problem.

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DeSantis names FGCU professor to Blue-Green Algae Task Force



Governor of Florida, Ron DeSantis names Michael Parsons to the Blue-Green Algae Task Force.

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Algae toxins are airborne and can reach deep into human lungs, FGCU research shows

News - Press  


Michael Parsons discusses the impacts of airborn toxins inhaled from blue-green algae blooms.

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Exodus: In Bloom

The Weather Channel  


Michael Parsons discusses red tide and blue-green algae blooms on Florida's Gulf Coast. Contains images that some viewers may find distressing.

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A rotten blame-game in Florida

The Washington Post  


Michael Parsons discusses Florida's red tide.

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No, there isn't a brown tide in Florida: Saltwater blue-green algae bloom serves as food for Florida's deadly red tide, scientist explains

The Weather Channel  


Michael Parsons talks about the distinctions between different types of algal blooms, and the resultant impacts on human and marine populations.

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The red tide choking Florida's waters

BBC World Service  


Michael Parson's discusses Florida's red tide.

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Scientists search for 'smoking gun' in the dead zone of Florida's red tide



Michael Parsons is quoted talking about the human influence on Florida's red tide events.

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Toxin taints crabs and kills sea mammals, scientists warn

New York Times  


Michael Parson's discusses the effects of the impact of natural toxins released by algae on marine ecosystems.

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Algae bloom kills record number of Florida manatees



Michael Parsons discusses the impact of Florida's red tide on the manatee population.

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Selected Event Appearances (3)

Invited plenary, “Ciguatera: Will Poisoning Events Increase in the Future?”

15th Symposium on the Natural History of the Bahamas  Gerace Research Centre, San Salvador, Bahamas, June 13-17, 2013

CIGUAHAB: a regional study of ciguatera in the greater Caribbean

GEOHAB Open Science Meeting  Paris, France, April 2013

A simple model capable of simulating the population dynamics of Gambierdiscus, the benthic dinoflagellate responsible for ciguatera fish poisoning

GEOHAB Benthic HABs Open Meeting  Honolulu, Hawaii, June 21 – 24, 2010

Selected Research Grants (7)

Establishment of the Greater Caribbean Center for Ciguatera Research

Centers for Oceans and Human Health (COHH3) NSF and NIH/NIEHS $5.9 million

September 1, 2018 – June 30, 2023 Principal Investigator

Coastal Waters Consortium III

Gulf of Mexico Research Initiative (GOMRI) Research Consortia $4.8 million

January 1, 2018 – December 31, 2020

CIGUATOX: A study of Gambierdiscus "super bugs" and ciguatoxin fate in coral reef food webs

NOAA ECOHAB $749,763

Principal Investigator September 1, 2017 – August 31, 2020

Advancing Global Strategies and Understanding on the Origin of Ciguatera Fish Poisoning in Tropical Oceans

NSF PIRE $4.7 million

Co-Principal Investigator September 1, 2017 – August 31, 2022

Alabama Center for Ecological Resilience

Gulf of Mexico Research Initiative (GOMRI) Selection of Research Consortia II $6.4 Million

Co-Principal Investigator January 1, 2015 – December 31, 2017

Coastal Waters Consortium II

Gulf of Mexico Research Initiative (GOMRI) Selection of Research Consortia II $16.1 Million

Co-Principal Investigator January 1, 2015 – December 31 2017

CiguaHAB: Ciguatera Investigations in the Greater Caribbean Region: Ecophysiology, Population Connectivity, Forecasting, and Toxigenesis

NOAA ECOHAB Regional Grant $4 Million

Principal Investigator September 1, 2011 – August 31, 2016

Selected Articles (9)

CiguaMOD I: A conceptual model of ciguatoxin loading in the Greater Caribbean Region

Harmful Algae

Parsons, Michael L., et al.

2024 Ciguatera poisoning (CP) is the most common form of phycotoxin-borne seafood poisoning globally, affecting thousands of people on an annual basis. It most commonly occurs in residential fish of coral reefs, which consume toxin-laden algae, detritus, and reef animals. The class of toxins that cause CP, ciguatoxins (CTXs), originate in benthic, epiphytic dinoflagellates of the genera, Gambierdiscus and Fukuyoa, which are consumed by herbivores and detritivores that facilitate food web transfer. A number of factors have hindered adequate environmental monitoring and seafood surveillance for ciguatera including the low concentrations in which the toxins are found in seafood causing illness (sub-ppb), a lack of knowledge on the toxicity equivalence of other CTXs and contribution of other benthic algal toxins to the disease, and the limited availability of quantified toxin standards and reference materials. While progress has been made on the identification of the dinoflagellate taxa and toxins responsible for CP, more effort is needed to better understand the dynamics of toxin transfer into reef food webs in order to implement a practical monitoring program for CP.

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Preservation of brevetoxins in Southwest Florida coastal sediments

Harmful Algae

James Javaruski, Puspa L. Adhikari, Joanne Muller, Michael L. Parsons

2022 Florida red tide is a natural phenomenon caused by the dinoflagellate, Karenia brevis. Karenia brevis blooms produce potent toxins (brevetoxins) that can cause neurotoxic and respiratory illness in humans and marine life. Red tides were recorded by Spanish explorers as early as the 17th century, however published red tide studies before 1940 are unavailable. Recent studies have suggested that red tide events may be becoming more frequent, intense, and longer lasting, which may be linked to modern land development and changing water quality. While the scientific record of modern red tides is relatively short, the distributions and concentrations of chemical biomarkers (e.g., brevetoxins produced by K. brevis) in coastal-marine sediments can potentially be used to study historic red tides. This study aims to quantify the concentration and vertical distribution of brevetoxins in coastal Southwest Florida (SWFL) sediment cores in order to determine if downcore brevetoxins may potentially be used to reconstruct historic red tide events.

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Marine phytoplankton responses to oil and dispersant exposures: Knowledge gained since the Deepwater Horizon oil spill

Marine Pollution Bulletin

Parsons, Michael L., et al.

2021 The Deepwater Horizon oil spill of 2010 brought the ecology and health of the Gulf of Mexico to the forefront of the public's and scientific community's attention. Not only did we need a better understanding of how this oil spill impacted the Gulf of Mexico ecosystem, but we also needed to apply this knowledge to help assess impacts from perturbations in the region and guide future response actions. Phytoplankton represent the base of the food web in oceanic systems. As such, alterations of the phytoplankton community propagate to upper trophic levels. This review brings together new insights into the influence of oil and dispersant on phytoplankton. We bring together laboratory, mesocosm and field experiments, including insights into novel observations of harmful algal bloom (HAB) forming species and zooplankton as well as bacteria-phytoplankton interactions. We finish by addressing knowledge gaps and highlighting key topics for research in novel areas.

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Species diversity of phytoplankton along spatial and temporal gradients in the Florida Keys

Journal of Plankton Research

Stanca, E. and M.L. Parsons

2017 Environmental mechanisms that drive changes in phytoplankton community structure remain a remarkably understudied topic in phytoplankton ecology. For this study, two seasons and four sampling sites in the Florida Keys (FK) were selected for phytoplankton analyses to test if environmental constraints select for driving taxonomic diversity. One hundred and twenty-six taxa belonging to 10 classes and 6 phyla were identified, where significant differences in taxonomic composition and biovolume characterized the FK on spatial and temporal scales, with Bacillariophyta being the most representative phylum. A small number of taxa were limited to specific sites or seasons, whereas the majority were present at all sites and in both seasons, albeit in different densities. Canonical correspondence analysis results demonstrated that taxa are distributed along seasonal and spatial gradients defined by temperature, light and waves. The resultant variability in species composition indicates that the phytoplankton community structure is related to changing hydrodynamic conditions, temperature and light availability, which define the temporal and spatial filters for the most important phytoplankton functional groups observed in this study.

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Phytoplankton and the Macondo oil spill: a comparison of the 2010 phytoplankton assemblage to baseline conditions on the Louisiana shelf

Environmental Pollution

Parsons, M.L., Morrison, W., Rabalais, N.N., Turner, R.E., and K.N. Tyre

2015 The Macondo oil spill was likely the largest oil spill to ever occur in United States territorial waters. We report herein our findings comparing the available baseline phytoplankton data from coastal waters west of the Mississippi River, and samples collected monthly from the same sampling stations, during and after the oil spill (May–October, 2010). Our results indicate that overall, the phytoplankton abundance was 85% lower in 2010 versus the baseline, and that the species composition of the phytoplankton community moved towards diatoms and cyanobacteria and away from ciliates and phytoflagellates. The results of this study reaffirm the view that phytoplankton responses will vary by the seasonal timing of the oil spill and the specific composition of the spilled oil. The trophic impacts of the purported lower abundance of phytoplankton in 2010 coupled with the observed assemblage shift remain unknown.

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How were phytoplankton affected by the Deepwater Horizon oil spill


Ozhan, K., M.L. Parsons, and S. Bargu

2014 A literature review demonstrates that crude oil spills can affect phytoplankton, favoring the growth of some while inhibiting the growth of others. Subsequently, the phytoplankton assemblage can change as a result of exposure to crude oil. Studies of phytoplankton responses to the Macondo (Deepwater Horizon) oil spill indicate that the phytoplankton may have been stimulated by the oil spill, although the presence of low-salinity water in the region makes it difficult to discount the importance of riverine-borne nutrients as a factor. A few studies suggest that the oil spill was toxic to some phytoplankton species, whereas others indicate that the degree of tolerance to the oil or to dispersants differs among species. These results generally comply with findings of previous studies, but a lack of published field data analyses prevents further assessment of the impacts of the Deepwater Horizon oil spill on phytoplankton population dynamics in the northern Gulf of Mexico.

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An Assessment of Pseudo-nitzschia Population Dynamics and Domoic Acid Production in Coastal Louisiana

Harmful Algae

Parsons, M.L., Dortch, Q., and G.J. Doucette

2013 Over 1200 samples were collected from Louisiana estuarine and coastal shelf waters between 1989 and 2002, and analyzed to examine the population dynamics of Pseudo-nitzschia and to assess the potential threat posed by domoic acid (DA), a potent neurotoxin produced by some members within this toxigenic diatom genus. Results demonstrated that three species in this region (Pseudo-nitzschia multiseries, P. pseudodelicatissima complex, P. delicatissima) produce DA, and that particulate toxin levels were highest (up to 3.05 μg L−1) during the spring bloom, while cellular concentrations were highest in the winter/early spring when P. multiseries was most abundant (up to 30 pg cell−1). These particulate toxin levels are comparable to those seen in other regions (e.g., United States west coast) where DA poisoning events have occurred in the past. Pseudo-nitzschia were most abundant under dissolved inorganic nitrogen-replete conditions coupled with lower silicate and/or phosphate concentrations, and in the early spring months when temperatures were cooler. Pseudo-nitzschia were occasionally well-represented in the phytoplankton assemblage (≥106 cells L−1 in 14% of samples, over 50% of total phytoplankton in 5% of samples), indicating that planktivores (e.g., Gulf menhaden, Brevoortia patronus) may have little choice but to consume Pseudo-nitzschia cells, thereby providing potential vectors for DA transfer to higher trophic levels. By comparison, eastern oysters (Crassostrea virginica) present in estuarine waters may be more exposed to this toxin when Pseudo-nitzschia cells are part of a mixed assemblage, reducing selective grazing by these bivalves. C. virginica may thus represent the most effective vector for DA exposure in humans.

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Gambierdiscus and Ostreopsis: Reassessment of the state of knowledge of their taxonomy, geography, ecophysiology, and toxicology

Harmful Algae

Parsons, Michael L., et al.

2012 Of the known benthic, toxigenic microalgae, species from the genera, Gambierdiscus and Ostreopsis, present the biggest threats to human and environmental health. Gambierdiscus spp. produce gambiertoxins which are precursors of ciguatoxins, the compounds that cause ciguatera, the most prevalent, phycotoxin-related form of seafood poisoning across the globe, affecting 25,000 to 500,000 people annually. Recent Ostreopsis spp. blooms in the Mediterranean Sea and coastal waters of New Zealand have led to concerns for seafood safety due to the palytoxin analogs produced by these dinoflagellates. Recent advances in molecular genetics have demonstrated that the taxonomy of both genera were in dire need of revision. Subsequently, Gambierdiscus was revised, and efforts to do the same are ongoing for Ostreopsis. The purpose of this review, therefore, is to update the state of knowledge of these genera, with particular emphasis on the validation or dismissal of earlier findings in light of these revisions. The review is divided into four sections (taxonomy, geography, ecophysiology, and toxicology) in an effort to cover all major aspects of study of these genera. A concluding section closes the review with a synthesis of the state of knowledge on these dinoflagellates and identifies gaps as suggested areas for future research efforts.

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Harmful algal blooms and eutrophication: Examples of linkages from selected coastal regions of the United States

Harmful Algae

Anderson, D.M, Burkholder, J.M., Cochlan, W.P., Glibert, P.M., Gobler, C.J., Heil, C.A., Kudela, R., Parsons, M.L., Rensel, J.E., Townsend, D.W., Trainer, V.L., and G.A. Vargo

2008 Coastal waters of the United States (U.S.) are subject to many of the major harmful algal bloom (HAB) poisoning syndromes and impacts. These include paralytic shellfish poisoning (PSP), neurotoxic shellfish poisoning (NSP), amnesic shellfish poisoning (ASP), ciguatera fish poisoning (CFP) and various other HAB phenomena such as fish kills, loss of submerged vegetation, shellfish mortalities, and widespread marine mammal mortalities. Here, the occurrences of selected HABs in a selected set of regions are described in terms of their relationship to eutrophication, illustrating a range of responses. Evidence suggestive of changes in the frequency, extent or magnitude of HABs in these areas is explored in the context of the nutrient sources underlying those blooms, both natural and anthropogenic. In some regions of the U.S., the linkages between HABs and eutrophication are clear and well documented, whereas in others, information is limited, thereby highlighting important areas for further research.

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