WHOI Scientists Monitor Largest Red Tide Outbreak in 12 Years in Massachusetts Bay


May 26, 2005

With shellfish beds from Maine to the Cape Cod coast closed from the
largest outbreak of red tide in 12 years in Massachusetts Bay,
scientists from the Woods Hole Oceanographic Institution (WHOI) are
studying the algae that causes these “red tides” and providing
information to coastal managers using new molecular techniques and
oceanographic models. 

After a recent research cruise in which the extent of the bloom was
revealed, the WHOI team will head to sea again Memorial Day weekend to
continue monitoring the outbreak and sample areas throughout the Bay,
including waters in Cape Cod Bay that rarely become toxic, but which
are closed to shellfishing in some areas because of this bloom. Their
data will again be shared with state officials and local shellfish
managers given the significant public health concerns from this bloom.
Shellfish contaminated with  the red tide toxin, if eaten in
enough quantity, can cause illness or death – a poisoning syndrome
called paralytic shellfish poisoning, or PSP.

“The nor’easter May 7 and 8 off the New England coast was the perfect
storm in terms of Massachusetts Bay red tide outbreaks,” said WHOI
Biologist and Senior Scientist Don Anderson, who has studied red tides
and other harmful algal blooms for decades and is co-chief scientist of
the current project. “All the conditions were right for a major
outbreak of Alexandrium fundyense,
the predominant red tide species in the Gulf of Maine.  We’ve seen
patches of red tide cells at the entrance to Massachusetts Bay just
south of Cape Ann on other occasions, but often the winds and
circulation patterns take them offshore. This time, we had high cell
concentrations to the north, evidenced by very high levels of toxicity
along the NH coast, and then the unusual winds and currents brought
them into the Bay, where we found them in a broad distribution from
Cape Ann to Stellwagen Bank.”

As luck would have it, a WHOI team headed by Associate Scientist Dennis
McGillicuddy and Anderson had a long-planned research cruise May 9-18
in the Gulf of Maine and Massachusetts Bay as a project for the Woods
Hole Center for Oceans and Human Health (COHH).  The cruise aboard
the Institution’s research vessel Oceanus was the first in a five-year COHH study of harmful algal blooms and their genetic diversity across the Gulf of Maine.

The team on Oceanus began
collecting samples in the Bay about 2 a.m. on May 10 right after the
nor’easter had passed through and immediately saw cells  – more
cells than expected. “The cell counts we’re getting are the highest
they’ve been since the late 1980’s” reported Bruce Keafer, leader of
the at-sea Alexandrium sampling
effort.  Through daily email and cell phone contact with Anderson
and state officials, the team relayed their cells counts so they could
be compared with toxicity readings ashore.  As his colleagues
continued sampling to the north for Alexandrium
cells, eventually reaching the Bay of Fundy, Anderson worked with state
officials who were anxious for information on the nature of the
outbreak, given the need to protect public health through timely
shellfish harvesting closures.  Anderson heads the U.S. National
Office for Marine Biotoxins and Harmful Algal Blooms and is director of
the Institution’s Coastal Ocean Institute.

McGillicuddy, an Associate Scientist in the WHOI Applied Ocean Physics
and Engineering Department, combined the biological observations from
the cruise with ocean conditions into a computer model to help
investigate these events.  As the team measured ocean currents
during the Oceanus cruise and
incorporated that information into the model, other data was being
received from a series of instrumented buoys from the Gulf of Maine
Ocean Observing System (GoMOOS).  By combining the cell counts and
oceanographic and meteorological conditions, McGillicuddy’s team was
able to quickly map the extent of the red tide bloom, continually
updating the model as new data was received.

The Massachusetts Division of Marine Fisheries and other state agencies
monitor Massachusetts Bay shellfish for annual red tide
outbreaks.  This year, these agencies were alerted to the
possibility of Massachusetts Bay toxicity, given the patterns of
toxicity in western Maine and New Hampshire. What they didn’t know
until the WHOI cruise was the extent of the outbreak and how abundant
the toxic cells were.

The WHOI team filled in some of the information gaps by collecting
samples at 160 stations along a series of transects from the coast
offshore from Massachusetts Bay north to the Bay of Fundy, taking
samples at three different water depths at each station. Samples were
then quickly analyzed in the ship’s laboratory under a microscope for
visual identification and live red tide cells were counted.  Using
a novel method called a sandwich hybridization assay to unequivocally
identify and count the Alexandrium fundyense cells, the shipboard team confirmed that toxic cells were indeed present in the Bay, and in waters to the immediate north.

Simultaneously, Anderson and his research team ashore were helping to
map the toxic cell distribution with a different method they had
developed several years ago for rapid cell identification and
enumeration. Funding to develop this method, known as whole cell
hybridization, was provided by the NOAA National Ocean Service’s Center
for Sponsored Coastal Ocean Research (CSCOR).  In the past, it
would have taken weeks or even months to count the many samples that
were coming ashore, but with the new method, the maps of cell abundance
were available in 1-2 days.  This information was of direct value
to health officials, who otherwise would have had to make difficult
decisions about possible shellfish closures based only on the toxin
levels measured in the shellfish.  Knowledge of the widespread
distribution and high abundance of the bloom convinced officials to err
on the safe side and close the shellfish beds quickly and expand their
sampling into areas that are not typically monitored.

“Using the information from sea and this new technique, we were able to map out the distribution of Alexandrium fundyense
within a very short time,” Anderson said. “This is the type of
information shellfish managers need quickly so they can make informed
decisions. “

“The current bloom is big, much larger in fact than the last outbreak
in the Bay 12 years ago, and much more widespread,” added Anderson.
”This is an unusual event.”

The reasons why are unclear.  Both Anderson and McGillicuddy say
the current outbreak could reflect a number of factors. They include
the “perfect storm” idea where all the conditions were right to
introduce cells into the Bay from the north, but also point out that
there may be more “cysts” of Alexandrium
in the western Gulf of Maine sediments than in the past as a result of
a major red tide bloom last fall.  Cysts remain dormant in
sediments until conditions are favorable for germination and growth,
leading to a bloom in subsequent years.  Another possibility is
that there is more freshwater entering the coast of the Gulf of Maine
this year than has been the case for over a decade, reflecting the
abundant rainfall this spring and the heavy snowfall over the
winter.  This freshwater provides the hydrographic conditions that
can lead to optimum growth of Alexandrium cells.

The scientists may get more answers when they head to sea again this
weekend.  This time the WHOI researchers will use the
Institution’s new 60-foot coastal vessel Tioga,
designed for rapid response to such events.  They plan to revisit
some of the same sites and resample, as well as fill in the gaps by
mapping and sampling areas further to the south into Cape Cod Bay to
see how far the bloom has penetrated.  Toxicity has already been
detected in shellfish in Sandwich on Cape Cod for the first time since
the last major red tide outbreak in 1993. The WHOI efforts will be part
of a coordinated sampling program involving the Massachusetts
Department of Marine Fisheries, the Center for Coastal Studies in
Provincetown, and other agencies.

NOAA’s CSCOR program is helping again, this time by providing the rapid
response funds for McGillicuddy and team to get out into the Bay to
sample directly after another nor’easter passes through the
region.  What the next storm will do to the conditions and how it
will affect the bloom is unknown.

Anderson says the ability to respond rapidly to these outbreaks, to
collect and share data quickly with state agencies and local officials,
is the wave of the future. “This project is a great example of how some
of the new technologies we are developing can help these groups work
together to meet a societal need.” He says he expects to see automated
instruments on buoys at sea in the future, collecting information and
relaying it ashore where it can then be used in numerical models to
make forecasts – a huge technological step forward in red tide
research.  The sandwich hybridization technique that they used on
board Oceanus can be run in
automated fashion inside moored instruments in these observatory
arrays, providing early warning of red tide cells and toxins.  

Despite the shellfish closures, “the public should not be afraid to eat
shellfish, as the states have very good monitoring programs,” Anderson
said. “People should just be aware of and observe the signs posted at
areas closed to shell fishing.  If they are going to harvest
shellfish, check with their local officials for the latest information.”

Long after this bloom has dissipated, Anderson and McGillicuddy plan to
conduct a series of sampling cruises in 2007 as part of the five-year
COHH program in the Gulf of Maine and Massachusetts Bay. PSP has long
been a problem in the region, and is not expected to disappear any time
soon.  The Woods Hole COHH, which McGillicuddy serves as deputy
director, is one of four such centers in the nation funded by the
National Science Foundation and the National Institute of Environmental
Health Sciences (NIEHS), one of the National Institutes of Health.
Scientists from the Woods Hole Oceanographic Institution (WHOI), Marine
Biological Laboratory (MBL) and the Massachusetts Institute of
Technology (MIT) formed the Woods Hole Center for Oceans and Human
Health (COHH) in 2003. With administrative offices at WHOI, the Woods
Hole COHH serves as a focal point for research on issues at the
intersection of oceanographic, biological and environmental health
sciences, such as red tides , harmful algal blooms and other organisms
in coastal waters and estuaries that cause human illness and death.