In the Northeast, the microscopic algae, Alexandrium (inset), does not harm clams but it can sicken or kill humans who eat shellfish contaminated by its toxin.
Fluorescent signals from an optical fiber bundle. Each point of light is from one bead at the end of a fiber. The amount of light is proportional to the number of HAB cells in the sample. Different colors could represent different species.
Keeping Tabs on HABs
Fiber-optic technology promises to monitor Harmful Algal Blooms (HABs) in the water and in real time.
Challenge
Harmful algal blooms (HABs), commonly called “red tides,” are a bit like hurricanes—they can do a lot of damage in a short period of time, and early warning is key to minimizing damage. And like hurricanes, HABs appear to be on the rise. The worst bloom of toxin-generating algae in several decades hit the Northeast in 2005, closing shellfish beds along most of the New England coast, and leaving shell-fishermen without income for almost two months.
Balancing the protection of human and economic health requires robust tools to detect both the early warning signs that precede a bloom and the conditions that signal the coast is clear. However, traditional methods used by state and local monitoring programs, in which shellfish are tested manually for toxins, are time consuming, expensive, and can’t deliver the rapid detection capability that managers need.
Response
CICEET-sponsored researchers at Woods Hole Oceanographic Institution and Tufts University are developing a HAB detection device that uses fiber optics to identify multiple HAB species, and other microorganisms in the water column. Leveraging technology created for the Department of Defense and the National Institutes of Health, they are creating a microarray that can process a “macro” amount of information.
The microarray is made up of tiny optical fiber bundles—each no thicker than a thread—consisting of up to 50,000 separate fibers. The ends of the fibers are etched to form wells to which the researchers insert a bead covered with DNA probes. Since each probe binds to complementary DNA from a specific kind of algae, a single array could test for hundreds of species simultaneously. The fiber optic bundles can easily be cleaned and re-used, hundreds of times.
Impact
The technology is currently being tested in the lab, where researchers have attached a fiber-optic bundle to a microscope and successfully identified the type and number of HAB species in the samples tested.
Since the DNA probes for this technology can be adapted to test different species of HABs and other microorganisms, this technology has the potential for broad geographic distribution. Researchers speculate that it could be used to monitor coastal oceans and freshwater areas around the globe for HABs, microbial pathogens, and toxic chemicals.
Project investigators are collaborating with engineers from the Monterey Bay Aquarium Research Institute, who are developing a water-processing device into which the microarray can be integrated. This device, or a similar one, could be deployed on buoys or other monitoring stations to provide continuous monitoring of HABs, and transmit real-time data, thereby providing advance warning of outbreaks and their status over time.
Learn More
Dr. Donald Anderson
Woods Hole Oceanographic Institution
T: 508.289.2351
E: danderson@whoi.edu
Website: http://www.whoi.edu/redtide/labweb/projects.html
Dr. David Walt
Tufts University
T: 617.627.3470
E: david.walt@tufts.edu
Website: http://ase.tufts.edu/chemistry/walt/
Related Projects
In Situ Nutrient Monitoring in Estuaries [Bulletin]
Application of an Inexpensive Microarray for Assessment of Microbiological Contaminants in Water Quality Control [Progress Report]
High-throughput Quantitative Detection of Microbial Contaminants [Progress Report]
Developing and Applying a New In Situ Technology for the Investigation of Episodic Contaminant Transport Events within Estuaries [Bulletin]
Direct Incorporation of Poultry Litter into No-till Soils to Minimize Nutrient Runoff to Chesapeake Bay [Progress Report]
Development of microfluidic technologies for the detection and quantification of toxins from harmful algal blooms [Progress Report]
Improved Characterization of Microalgal Abundance and Taxonomic Status through Laser-Induced Fluorescence (LIF) [Progress Report]
Automated Imaging and Classification System for Harmful Algal Bloom Detection [Progress Report]
Multichannel Handheld Sensor for Microbial Contaminants [Progress Report]