A Light in the Fog: Shipboard Genetic Quantification of the Red Tide Alga Karenia brevis

By Alicia Hoeglund, Matt Garrett and Mary Harper

On January 11, on FIO’s new research vessel (R/V) the W. T. Hogarth, FWRI-HAB researchers assisted USF in deploying new infrastructure for oceanographic sensors and took advantage of this opportunity to test hand-held genetic sensors that can detect the red tide alga, Karenia brevis, in water samples collected while onboard. The genetic detection project, funded through a NOAA Prevention Control and Mitigation of HABs (PCMHAB) grant, utilizes a field-friendly approach that can provide genetic quantification of K. brevis in approximately one to three hours from the time of sample collection (see: http://fwcfieldnotes.com/2016/12/on-site-testing-for-red-tide-alga/). Samples collected just west of the Skyway Bridge and off of Pass-a-Grille (Pinellas County) were tested during this trip and provided our researchers with some of the lowest field concentrations of K. brevis observed with this technology to date: approximately 108 cells L-1 and 42 cells L-1, respectively. The limit of detection using our routine light microscopy procedure is 333 cells L-1, making this a very promising find for the development of this project!

Syringes funnel the sampled water into a column that contains the filter to which the RNA binds.

Although this was intended to be a short-day trip, thick sea fog delayed both the departure and the return of the R/V W.T. Hogarth, with researchers spending an unanticipated night at sea. A short reprieve from foggy conditions allowed the port to reopen briefly early in the morning of the 12th, and sea fog continued to impact the area throughout that day. A subsequent trip completed the installation of USF’s oceanographic sensor system, and water current, meteorological, and wave data are now being reported every one to three hours (http://www.ndbc.noaa.gov/).

Deployment of the real-time waves system and meteorological sensor: Once the concrete bottom mount and the Acoustic Doppler Current Profiler was dropped in the water by the ship’s crane, divers descended to remove the deploy cables and ensure the instrument was in the proper location and orientation.