By Marc Suddleson, Manager, Monitoring and Event Response for Harmful Algal Bloom (MERHAB) Program, Center for Sponsored Coastal Ocean Research (CSCOR), National Centers for Coastal Ocean Science (NCCOS)
This article is one in a periodic series regarding CSCOR activities and sponsored research. You can also see the blog for other articles about the work being done by CSCOR.
A NOAA funded research team recently reported that an autonomous sensor, deployed on a special mooring in the Atlantic about five nautical miles off Portsmouth, New Hampshire has successfully detected the presence of toxic Alexandrium fundyense cells and relayed its data to scientists in a lab onshore. The sensor, an Environmental Sample Processor (ESP) nicknamed “Chris” after its inventor Chris Scholin of the Monterey Bay Aquarium Research Institute, is off to a strong start in what will be a challenging, 45 day test of its ability to provide an automated, early warning of toxic blooms of Alexandrium fundyense or New England ‘red tides.’
Early warnings help state managers and the shellfish industry protect human health and minimize economic impacts from the toxic ‘red tides’ which threaten New England’s shellfish industry every spring and summer. Total costs of the severe 2005 Alexandrium bloom were estimated at nearly $50 million for Massachusetts and $23 million for Maine.
Onboard ESPChris, Alexandrium detection is accomplished via a miniaturized and fully automated molecular probe assay. After collecting a water sample, the ESP can test it for the presence of five different harmful algal species. A tiny set of species-specific probes that react to nucleic acids are bound to a HAB filter array, or small disk, at pre-determined positions prior to deployment. Positive assay results yield spots of varying size and intensity in the pre-determined positions indicate each species that is present. An onboard camera that digitally images the results and a transmitter sends it to the scientists onshore. Raw data from an ESPChris sample taken in early May (image left) shows three large intense control spots that verify that the assay is functioning properly. The small spots with weak intensity represents a positive signal from the binding of Alexandrium fundyese nucleic acids in the sample to a complementary set of specific molecular probes. The spot intensity in this case represented about 100-200 cells per liter of sea water. ESPChris had successfully provided an early signal of what may become a ‘red tide’ leading to shellfish toxicity along the New England coastline.
But ESPChris must continue to operate over the next two months, withstanding heavy seas, storms, and other open ocean hazards because researchers are counting on the sensor to continue returning results from its daily sampling. Prior to the start of the 2012 ‘red tide’ season, NOAA funded scientists at the Woods Hole Oceanographic Institution and North Carolina State University issued an outlook for a “Moderate” New England ‘Red Tide.’ Information from ESPChris will be provided to managers in weekly updates the Northeast PSP website.
Armed with these weekly updates, state managers will know in advance where and when shellfish may become toxic. Currently, they can only measure toxins in shellfish nearshore, and have no way to know the number of toxic cells that are “upstream” in coastal waters, waiting to be carried to shore by favorable winds. Information from in situ sensors, like ESPChris, can help them determine when increased biotoxin testing is warranted for decisions to close shellfish beds and determining when harvesting can safely resume. Advance warnings help states marshal limited resources available for operating mandatory shellfish monitoring programs which enable public health protection and the safeguarding of important economic resources.
This mission is the first of several planned ESP deployments during a five year NOAA NCCOS MERHAB funded project led by Woods Hole Oceanographic Institution (WHOI) scientist Dr. Donald Anderson to demonstrate the feasibility and value of the ESP to routine HAB monitoring and forecasting. Future ESP deployments will test an added capability for sensing algal toxins in water samples. NOAA, state agencies, and the shellfish industry are eager to see multiple ESPs incorporated into an operational ocean observing capability to remotely detect and transmit to shore a stream of continuous, near-real time data on toxic Alexandrium populations. Real-time data on toxic cell abundance and eventually toxicity will be used to improve the accuracy of red tide forecasts, much like meteorological observations are used to improve weather forecasts. This deployment represents a significant step toward realizing this vision.
Learn more about the recent Gulf of Maine ESP deployment from a Phys.Org article, “Robot Monitors Red Tide”.