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Researcher Behind “Fake Grouper” Sensor Creates “Red Tide” Detector

John Paul, PhD, USF distinguished professor at the College of Marine Science, is lead inventor of Red Tide Chek, the first hand-held device to detect red tide in the field



John Paul, PhD, USF distinguished professor, is lead inventor of Red Tide Chek, the first hand-held device that can detect red tide in the field.

Red tide is one of Florida’s greatest environmental, ecological and economic threats. These harmful algal blooms can cause human health problems and hamper the economy in lost tourism dollars and damaged fisheries.

“The Florida red tide organism produces a toxin called brevetoxin that can be released in the air as an aerosol. Thus, this toxin is particularly troublesome for people with asthma or other respiratory conditions and causes them to cough and choke. Brevetoxin is particularly lethal to fish, manatees, dolphins and sea birds,” said John Paul, distinguished professor at the University of South Florida College of Marine Science.

Following his successful creation of GrouperChek, a sensor that catches fake grouper, Paul is lead inventor of Red Tide Chek. It’s the first hand-held device that can detect red tide in the field, providing results directly to end users such as government agencies and businesses. This technology speeds up the decision-making process in closing beaches and shellfish harvesting beds, along with determining the cause of a fish kill.

Red Tide Chek can speed up the process of detecting red tide, harmful algal blooms producing toxins that can kill fish and cause respiratory irritation in people.

Red Tide Chek
 runs on batteries and can measure as many as eight samples at once. It doesn’t require special training, allowing volunteers to regularly take and test samples along Florida’s Gulf Coast. Currently, very highly trained technicians are required to count red tide cells and differentiate them from similar, nontoxic cells using microscopy. 

“Red Tide Chek is relatively inexpensive. The assay is extremely quantitative and that’s because we use an internal control called IC RNA and it’s very rapid, usually within 20 minutes we have an answer,” Paul said.



John Paul, PhD uses Red Tide Chek to identify the Florida red tide organism.


Paul has a patent through USF to use nucleic acid amplification to detect red tide. 
Red Tide Chek works by extracting ribonucleic acid (RNA) from cells, targeting the carbon fixation gene, which is specific to Karenia brevis, the organism that causes red tide. The carbon fixation gene is amplified to better understand cell growth and concentration, helping determine the presence of Karenia brevis.

Paul collaborated with Kathrine Hubbard of the Florida Fish and Wildlife Conservation Commission on a grant from the National Oceanic and Atmospheric Administration (NOAA) for genetic detection of red tide in the southeastern Gulf of Mexico.

Story by Tina Meketa, Photos and video by Vjollca Hysenlika and Sandra C. Roa, University Communications & Marketing

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