Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Researchers report 'moderately large' potential for red tide outbreak in Gulf of Maine region

24.04.2009
Toxic bloom expected to be smaller than last year, but still significant

The potential for an outbreak of the phenomenon commonly called "red tide" is expected to be "moderately large" this spring and summer, according to researchers with the Woods Hole Oceanographic Institution (WHOI) and North Carolina State University (NCSU).

This advisory is based in part on a regional seafloor survey of quantities of Alexandrium fundyense — the algae notorious for producing a toxin that accumulates in clams, mussels, and other shellfish and can cause paralytic shellfish poisoning (PSP) in humans who consume them. The survey maps are used with computer models that simulate different scenarios of weather and oceanographic conditions to indicate where and in what abundance the toxic cells might be expected in 2009.

The researchers found concentrations of Alexandrium cysts — the dormant seed-like stage of the algae's life cycle — in the Gulf of Maine to be 40 percent lower than the historically high levels observed prior to last year's bloom, but still higher than the level preceding a major regional bloom in spring 2006 that closed shellfish beds from Canada to Massachusetts Bay.

The Alexandrium survey has been conducted each fall since 2004 as part of several research and event response projects funded by the National Oceanic and Atmospheric Administration (NOAA) Center for Sponsored Coastal Ocean Research (CSCOR). Fall concentrations of Alexandrium cysts are one of the indicators of the magnitude of a potential bloom in spring.

In October 2008, a survey team led by Don Anderson, a senior scientist in the WHOI Biology Department and the lead investigator of the Gulf of Maine Toxicity (GOMTOX) study, spent 10 days collecting seafloor sediment samples between Massachusetts Bay and the Bay of Fundy looking for Alexandrium cysts. After the samples were processed and analyzed, the team determined the cyst abundance to be about 40 percent lower than the high levels observed in fall 2007 (see figure).

This is one line of evidence that leads Anderson and his colleagues to believe the bloom this spring won't be as extensive as last year's, which closed shellfish beds from the Canadian border to the Cape Cod Canal, and on the outer portions of Cape Cod as well.

"Last year at this time, we issued an advisory for a very large regional bloom that did in fact occur. In hindsight, that advisory was 'easy' because the cyst concentrations were higher than we had ever seen – 30 percent higher than in 2004 just before the massive 2005 red tide that many people probably remember," said Anderson. "It's more difficult to make a prediction this year because the numbers of cysts we found are not extreme."

The cysts for this year's bloom have been dormant in the seabed since late last summer, when they were formed at the end of the Alexandrium bloom. With the onset of spring and its warm temperatures and increased light, the cysts are already beginning to germinate, liberating cells that swim to the surface waters. Under the right conditions, a single cell can then divide into several hundred cells within a few weeks. But where and when the resulting bloom will make landfall depends on weather events that cannot be predicted months in advance.

That's where computer modeling can help. While cyst abundance gives a general indication of the magnitude of the bloom, oceanographers Dennis McGillicuddy, a senior scientist in the WHOI Applied Ocean Physics and Engineering department, and his colleague Ruoying He of North Carolina State University (NCSU) have been working with Anderson to simulate the resulting growth and transport of the toxic cells using computer models. Working together over the last decade, the team has developed a computer simulation that incorporates weather conditions, river runoff, and various wind and current patterns to predict the intensity and location of blooms of the toxic algae in the Gulf of Maine.

With data from last year's cyst counts, the WHOI and NCSU team ran their computer model through a range of scenarios, using the predominant regional wind patterns and ocean conditions from each year since 2004. (See figure......)

According to He and McGillicuddy, the simulations suggest a moderately large regional bloom of Alexandrium, falling in the mid range of those that have occurred over the last five years. Red tides during those years have ranged from very large ones that stretched from the Canadian border to southern Massachusetts, including Cape Cod and the Islands, to small outbreaks that have only caused limited harvesting closures in Maine, New Hampshire, and northern Massachusetts.

The researchers have found that toxicity in near-shore shellfish is the highest for years in which northeasterly storms occur, which tend to drive Alexandrium cells toward the southern New England coast. When southwesterly winds dominate, the algae tend to remain offshore. So even when there are a lot of cells in the Gulf of Maine, toxicity can be confined to offshore waters if the winds and currents cooperate.

The Alexandrium cells can be expected to appear in surface waters in early April. By the end of that month, cells usually begin to appear in large numbers in the waters off coastal Maine and New Hampshire, which is when and where the first reports of toxicity typically appear. As the coastal bloom is transported to the south, the Massachusetts shoreline can be impacted as well. The severity of this year's outbreak along the coast will depend in large part on the wind patterns in May, June, and July.

The GOMTOX researchers regularly share their results with coastal resource and fisheries managers in six states and at the National Oceanic and Atmospheric Administration, the Environmental Protection Agency, and the Food and Drug Administration (which oversees the safety of offshore shellfish beyond state limits).

"We can only issue an advisory, as opposed to a forecast," says Anderson. "We can estimate how many cells will be in the water from the germination of cysts and potential growth of that population, but not whether those cells and that water will be blown to shore."

These types of red tide or harmful algal bloom (HAB) advisories can help the economy. Advance warning of a potentially troublesome year for algae can give shellfish farmers and fishermen time to make contingency plans for the timing of their harvest or expansion of aquaculture beds; state agencies can make informed staffing decisions to accommodate additional monitoring that might be required to protect public health and the shellfish industry.

The WHOI and NCSU researchers underscore that even when these major red tides occur, shellfish and other seafood products are safe to eat because they are carefully monitored. Shellfish stocks are regularly tested by state and federal agencies, ensuring that contaminated growing areas are closed to harvesting, and that dangerous product does not reach the market.

This research was supported by NOAA's Center for Sponsored Coastal Ocean Research, and the National Institutes of Health and the National Science Foundation (through the Woods Hole Center for Oceans and Human Health). Additional work examining other species of toxic algae in the Gulf and on Georges Bank is supported by the NOAA Oceans and Human Health Initiative (OHHI).

The Woods Hole Oceanographic Institution is a private, independent organization in Falmouth, Mass., dedicated to marine research, engineering, and higher education. Established in 1930 on a recommendation from the National Academy of Sciences, its primary mission is to understand the oceans and their interaction with the Earth as a whole, and to communicate a basic understanding of the oceans' role in the changing global environment.

Media Relations | EurekAlert!
Further information:
http://www.whoi.edu

More articles from Earth Sciences:

nachricht New Study Will Help Find the Best Locations for Thermal Power Stations in Iceland
19.01.2017 | University of Gothenburg

nachricht Water - as the underlying driver of the Earth’s carbon cycle
17.01.2017 | Max-Planck-Institut für Biogeochemie

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

Helmholtz International Fellow Award for Sarah Amalia Teichmann

20.01.2017 | Awards Funding

An innovative high-performance material: biofibers made from green lacewing silk

20.01.2017 | Materials Sciences

Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery

20.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>