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Making Waves: Episode 87 (November 10, 2011)

You’re listening to Making Waves from NOAA’s National Ocean Service. I’m Troy Kitch. It’s hard to believe that tiny little aquatic plants can wreak human-scale economic havoc, but it’s happened again and again in recent history in the Gulf of Maine. 

In 2005, harvesting closures caused by red tide resulted in $23 million dollars in lost shellfish sales in Massachusetts and Maine alone.

Again in 2008, red tide shut down shellfish beds for months in the waters off Massachusetts, New Hampshire, and Maine. 

And in 2009, red tide resulted in the closure of 97 percent of Maine’s coastal shellfish beds and 100 percent of offshore beds in the Gulf of Maine’s federal waters during peak-harvesting season. New England red tide is caused by an algal species called Alexandrium. At times when Alexandrium blooms out of control, these tiny plants can produce toxins that lead to serious illnesses in people who eat poisoned shellfish – one of the most well-known illnesses is paralytic shellfish poisoning.  Since these potent neurotoxins readily accumulate in clams, mussels, oysters, and other shellfish that filter ocean water through their gills as they gather food, red tide outbreaks routinely lead to the closure of shellfish harvesting until the algal blooms go away … and until toxin levels dissipate in the tissues of affected shellfish.  

Now for some backstory. Most algae are harmless … They’re actually really important because they form the base of the entire marine food web. But at times when they bloom out of control, some types of algae discolor the water or produce powerful toxins that kill fish and make shellfish dangerous to eat. As the name ‘red tide’ suggests, some blooms of algae turn the water a deep red color. A classic example is the Florida red tide. But blooms aren’t always red. –they come in many forms and many colors … and some have no color at all. To make it even more confusing not all blooms that discolor the water produce toxins and not all toxic algae discolor the water. That’s why scientists prefer the term harmful algal bloom, or HAB, so we focus on the harm rather than the color.

Once algae turn toxic they can wreak havoc. They threaten marine ecosystems, they’re bad for human health, and they cost local and regional economies millions of dollars every year through fishery closures, and recreation and tourism losses because vast swaths of water have to be closed off until the threat passes.

Now back to the Gulf of Maine, where one of the most damaging harmful algal bloom varieties is caused by a species called Alexandrium. The full name is Alexandrium fundyense.  Over the years, scientists have made great strides in bloom prediction and monitoring in this region, but what’s clear is the red tide problem is here to stay and it seems to be growing in magnitude in recent years.   So while we can’t control these large outbreaks of toxic algae, we can try to create better early warning and detection systems. 

Last week, scientists at the University of Maine were awarded a little over $200 thousand dollars from NOAA for the first year of what is expected to be a three-year project to investigate methods to provide early warning detection of red tide blooms in the Gulf of Maine.

The goal of this project is to use inexpensive monitoring devices to pinpoint areas for targeted closures of shellfish harvests, so smaller areas can be closed off to harvesting. Without a system like this in place, huge swaths – and sometimes nearly all harvesting areas – have to be closed down until the threat passes, because we don’t know exactly where those areas are where Paralytic Shellfish Poisoning is a direct threat.

This research effort is part of a larger package of NOAA grants totaling over $1.6 million dollars to create seasonal and weekly toxic algal bloom forecasts that are more accurate and provide better early warning of toxic blooms in the Gulf of Maine. 

There are two additional components to this larger package of grants. The first is focused on preventing, controlling, or mitigating the effect red tides have in the Gulf.  Over the next four years, the goal of this effort is to transfer to NOAA seasonal and weekly bloom forecast models, developed by scientists at Woods Hole Oceanographic Institute and North Carolina State University with earlier NOAA funding. NOAA will then issue red tide forecasts for the Gulf of Maine similar to how we issue weather forecasts. 

The other part of this funding package is focused on monitoring and event response for red tides. This project will deploy state of the art sensors for Alexandrium cells and toxins in the Gulf of Maine over five years to improve the accuracy of red tide predictions and provide better early warning. These sensors will robotically sample the water, analyze those samples for red tide cells and toxins, and send these data to shore, giving the shellfish industry and public health and resource managers near real-time information to guide their decisions and actions. 

The research for all of these projects will be carried out at Woods Hole Oceanographic Institution with research partners at North Carolina State University, the University of Maine, and the Monterey Bay Aquarium Research Institute. More than 40 percent of the funding directly supports university and private sector jobs for people working to protect New England fisheries from these devastating blooms. Funding will also open new markets for ocean observing technologies manufactured in Massachusetts. 

NOAA’s investment in these two projects is aimed at creating more-accurate forecasting of red tide to help better protect public health and jobs and coastal economies in New England. State and local shellfish managers and the shellfish industry use these warnings to prepare for severe seasons, to protect human health, and to lessen economic losses.

These research projects were selected for funding through national peer-reviewed competitions run by NOAA’s National Centers for Coastal Ocean Science. Congress provides NOAA the authority to run these programs through the Harmful Algal Bloom and Hypoxia Research and Control Act. We’ll have links to more information in our show notes.

Now let’s wrap it up with an Ocean Fact. Why do harmful algal blooms occur? While we know of many factors that may contribute to the formation of harmful algal blooms - commonly called red tides – how these factors come together to create a ‘toxic bloom’ of algae are not well understood which is why further research is needed.

Studies indicate that many algal species flourish when environmental conditions, such as salinity, temperature, nutrients, lack of algae-eating animals, are favorable. In other cases, red tides may be linked to nutrient over enrichment or eutrophication. This occurs when phosphorus and nitrogen) from sources such as sewage, lawns and farmlands flow downriver to the sea and build up at a rate that ‘overfeeds’ the algae that exist normally in the environment.

Some harmful algal blooms have also been reported in the aftermath of natural phenomena like sluggish water circulation, unusually high water temperatures, and extreme weather events such as hurricanes, floods, and drought.

Rigorous state monitoring prevents people from getting sick by eating shellfish containing toxins produced by these algae, although occasionally people harvest shellfish in areas that are not monitored or are closed and get sick or die.
In the case of the Florida red tide, which is a different species than the red tide in Maine, airborne algal toxins may also cause breathing problems and, in some cases, trigger asthma attacks in some people.

Red tides also pack a huge economic punch. By some estimates, harmful algal blooms cause about $82 million dollars a year in due to commercial fisheries losses, public health costs, recreation and tourism impacts and coastal monitoring and management.. 

NOAA continues to provide funding and conduct research to monitor and study harmful algal blooms around the country to better detect and forecast the location of these natural phenomena to provide coastal communities advance warning.

And that’s the NOS news for this week. But before we go, I want to tell you about one more thing. One of the challenges we face in the National Ocean Service is telling people like you what we do. And that’s because we do so many different things. It’s hard to sum up in a sentence or two.  Here’s the big picture: the work that people at the National Ocean Service do is about protecting our ocean and coasts. And it’s about providing services and tools that keep commerce moving safely and efficiently around our waterways.  Why devote so much time and energy to our coasts and coastal ocean areas? Because that’s where about half of us live, and it’s the area where about 57 percent of our nation’s Gross Domestic Product is generated.  

So how about some specific examples. Well, as it turns out, we just released our annual round-up of all the big things we did in Fiscal Year 2011. You’ll find it a link to it at It’s a great snapshot of the kinds of science, tools, and services that NOS delivers to the nation. I hope you check it out.

If you have any questions about this week’s podcast, about the National Ocean Service, or about our ocean, send us an email at

This is Making Waves from NOAA’s National Ocean Service.  See you in two weeks.