Red Tide Monitoring with Imaging FlowCytobot Instruments

  • Images of Karenia brevis cells, taken by the Imaging Flow CytoBot.

  • Collecting and processing samples using an Imaging Flow Cytobot on a survey, while underway, to help map blooms of Karenia brevis and other harmful algal bloom species. The IFCB is hooked up in parallel with other sensors that can detect changes in temperature, salinity, and chlorophyll a fluorescence (as a proxy for algal biomass).

As far back as the 1800s, a phenomenon known as red tide has been documented along the coast of Florida. Red tide refers to microscopic algae that form harmful algal blooms. In Florida, these blooms are caused by an alga known as Karenia brevis (K. brevis) that produces toxic chemicals that can affect both marine organisms and humans, resulting in fish and wildlife mortalities and human respiratory irritation nearly every year. Innovative approaches and technologies are constantly incorporated to monitor and research this multifaceted, complex phenomenon that vary from year to year with respect to spatial extent and duration.

In 2018, FWRI initiated a project to use in situ measurements to provide additional support to better understand the dynamics of these blooms. The goal of this project is to enhance FWRI’s red tide monitoring capabilities by using a device called an Imaging FlowCytobot (IFCB). IFCBs are automated imaging instruments that can be deployed in the water, on a ship, or in the lab to collect water samples every 20 minutes and then take pictures of all the algal cells in each sample. This generates continuous, near-real time data on K. brevis abundance and behavior and a single instrument can process >400 samples in a week. This allows FWRI Harmful Algal Bloom (HAB) researchers to detect bloom events sooner, provide more timely information about bloom status, and ultimately produce more comprehensive data that will aid in understanding the development, progression, and termination of red tide blooms and the associated drivers.

IFCBs are being used by FWRI in a variety of locations and for several different purposes. They can be deployed at fixed locations like a dock or pier to track bloom conditions at a single site as part of event response or for long periods to generate time series across seasons (and ideally, years, as the program matures). Data is transmitted back to the lab for rapid processing, allowing the instrument to act as an underwater microscope in the sea. The IFCBs are also hooked up to seawater intake systems on research vessels to quickly assess bloom conditions over large areas and generate near real-time maps of red tide concentrations. These instruments are further being used in the laboratory to capture images from water samples collected from the field and red tide cells cultivated as part of targeted experiments to test specific hypotheses. Once data from the IFCB is collected, an automated artificial intelligence (AI) process is then used to classify and count images of cells from a variety of species including K. brevis. This involves first carefully curating libraries of images from species identified by FWRI HAB taxonomists, which are used to develop the automated AI classifiers specific to those different species. Then, once the set of images from a sample is classified, a comprehensive list of the algal species and their abundance in a given sample is available and other parameters within a species can be examined. For example, data from IFCBs are being used to determine the location, both geographically and in the water column, of K. brevis and other algal species; their vertical movement over a 24-hour period, since some species like K. brevis swim up and down in the water column; the progression of their life cycle; and any changes in the cells themselves from environmental stressors.

As this project continues, scientists will continue to upgrade the equipment to deploy these instruments in new ways, to increase the accuracy of identification and the number of algal species that can reliably be identified, and improve capacity for data collection and processing. This will allow research on different types of HAB events to expand. IFCBs have currently been deployed along the coast of southwest Florida, including within Tampa Bay and Sarasota Bay, and offshore along the West Florida shelf, but future efforts will include deployments in different areas and focused on a multitude of HAB issues and research questions focused on understanding how cells respond to their environment, which will give researchers a more inclusive picture of when, where, and why blooms occur and what conditions either promote growth or induce stress. This is critical for advancing FWRI’s ability to predict these blooms and better characterize past events.

Many FWRI scientists on the Ecosystem Assessment and Restoration’s HAB team have been integral in bringing together the different pieces of this innovative research technology, from deployment in diverse field situations, to ensuring that species are characterized properly, to troubleshooting issues that may occur. Other partners have also been involved with this effort, including scientists from Woods Hole Oceanographic Institution, Florida State University, and the National Oceanic and Atmospheric Administration’s Atlantic Oceanographic and Meteorological Laboratory (NOAA-AOML). This project is funded by a NOAA Sea Grant Aquaculture grant and general FWRI HAB funding from the State of Florida.

The data from this project will be invaluable in improving monitoring efforts for red tide and other HABs in Florida and provide new information to researchers and the public about how these species respond to changes in their environment. The more we can learn about K. brevis and other algae in Florida, the better we can prepare for, manage, and mitigate HAB events when they occur.