Ecosystem Effects

What the HAB? Florida Red Tide 2018

(Karenia brevis)

Ecosystem Effects • Could impact larvae dispersal • Bioaccumulation

• K. brevis<Inverts<Fish< dolphins • Dissolved O2 depletion • Increases turbidity- eutrophication • All creates stress on benthic communities

Harmful Algal Bloom • Algae that produce toxins (Neurotoxin) • Dinoflagellates

• Single celled Eukaryote (Protist) • Phytoplankton

• Florida Red Tide Bloom • Naturally occurring • No direct evidence of

anthropogenic causes • Correct water chemistry, physical

conditions, and ecology to bloom. • Develops off-shore

Symptoms of inhalation and Neurotoxic Shellfish Poisoning(NSP) • NSP Symptoms appear within a few minutes after eating contaminated

Shellfish. • Nausea, vomiting, diarrhea, loss of motor control, numbness and stomach pain. • Not usually fatal.

• Skin and respiratory irritation: Coughing, sneezing, watery eyes, trouble breathing.

What Happened? • Started Fall 2017 and lasted 16

months: Peaked Fall 2018 • Caused $130 million in damage

and killed 850,000 pounds of marine life.

• 150 dolphins, 400 sea turtles, and 100 manatees died.

• Harmful at 10,000 cells/liter but they were recording 1 million cells/liter.

 

 

The Role of Brevetoxins Toxin Function: • Lipid-soluble polyether compounds: Why they produce these toxins is not fully

understood. • Thought to be a major role in organism, because they are produced in the cell and

retained.

• Could be for osmoregulation, but Dinoflagellate osmoregulation is not understood.

• Toxin production changes based on salinity in the environment. Low salinity= High Toxin production

• In other Dinoflagellate species (ones that cannot photosynthesize) toxin production could relieve grazing pressures and help prey capture.

Toxin Release: • Released when the cell dies.

• Selective activation of voltage-sensitive Na+ channels.

• Affects neurons in other organisms. Brevetoxin disrupts and binds to sodium channel and depolarizes the cell. There is a massive influx on sodium and the cell cannot repolarize itself. The neuron doesn’t know what to do and creates loss of motor control.

• Harms other organisms but could allow K. brevis to outcompete other phytoplankton. Questions:

1. What is Florida Red Tide, and what needs to happen for a bloom to occur?

2. Can nutrient runoff worsen Florida Red Tide that moves in-shore? How?

3. Why is K. brevis harmful to humans and marine life? What are symptoms?

4. What are some ways to monitor K. brevis in the water and give an example on how we could filter it out of the water column.

Sources: • Carty, A., M.W. Parrow. 2015. Chapter 17-Dinoflagellates. In Freshwater Algae of North America 2nd edition. Ecology and Classification

Aquatic Ecology: 773-807. https://doi.org/10.1016/B978-0-12-385876-4.00017-7

• Collins, A. (2019, August 29). Tips for Tracking Red Tide. Retrieved May 2, 2020, from http://blogs.ifas.ufl.edu/manateeco/2018/09/04/tips-for-tracking-red-tide/

• Eck, A. (2019, July 19). A year ago, toxic red tide took over Florida’s Gulf Coast. What would it take to stop it next time? Retrieved May 2, 2020, from https://www.pbs.org/wgbh/nova/article/florida-red-tide-gulf-coast/

• Errera, R. and L. Campbell. 2011. Osmotic Stress Triggers Toxin Production by the Dinoflagellate Karenia brevis. Proceedings of the National Academy of Sciences 108(26):10597-10691

• Hollenbeck, S. (2019, October 31). FWC: Very low level of red tide detected in Pinellas County. Retrieved May 2, 2020, from https://www.abcactionnews.com/news/red-tide/fwc-very-low-level-of-red-tide-detected-in-pinellas-county

• https://myfwc.com/research/redtide/statewide/

• Watkins, S.M., A. Reich, L.E. Fleming, and R. Hammond. 2008. Neurotoxic Shellfish Poisoning. Mar Drugs 6:431-455.

 

 

Answers

1. Florida Red tide is caused by a marine dinoflagellate K. brevis.

Items needed for a bloom to occur:

• Correct water chemistry: Temperature, salinity, and nutrients (nitrogen and phosphorus

• Right physical conditions : Wave action, storms, tides to bring K. brevis inshore

• Ecology of the ecosystem: Other phytoplankton that try to out compete K. brevis.

2. There is no direct evidence that nutrient run off increases K. brevis blooms, but the extra nutrients help make them persistent. The excess nutrients are food for the organism. The extra source of nitrogen and phosphorus could allow the organism out complete other phytoplankton as they grow.

3. K. brevis is harmful to humans and marine life, because it releases a neurotoxin called Brevetoxins when the cell dies. It can cause skin and respiratory irritation if it gets inhaled and can also cause Neurotoxic Shellfish Poisoning.

• NSP symptoms include vomiting, diarrhea, loss of motor control, and stomach pain. It happens when you eat contaminated shellfish.

• Respiratory symptoms include coughing, sneezing, watery eyes, and trouble breathing.

4. Taking routine water samples at sites along the gulf, and as soon as cell count become high alert the public. Mote Marine is making a cell phone app that allows people to turn their phone into a mini-microscope to look for species. Making sure public is aware and make a data base where people can check regularly.

• You could filter it from the water column by bio-filtration. We could use mussels, oysters, and tunicates to help filter out the species from the water. We could make more artificial reefs that are designed for bivalves.