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North Carolina and Washington Sea Grant Programs Join Forces
to Curb Unwanted Introductions of Ballast Water Organisms
Imagine this...Bathed in early morning
light, the Caspian Prince, a 900-foot freighter leaves Antwerp,
Belgium, bound for the Port of Wilmington, N.C., to fill its
cargo hold with tobacco. For this leg of its journey, the
ship is empty... or so it seems.
Within the Caspian Prince’s hold
and ballast tanks are millions of gallons of seawater, drawn
from the northern European harbor to lend stability and trim
to the vessel during its two-week ocean crossing.
The ballast water contains a mini-menagerie
of aquatic organisms — minute jellyfish, larval mussels
and barnacles, marine worms, tiny shrimp-like copepods and
juvenile fish. These creatures share their confines with an
assortment of single-celled plants and even smaller bacteria
and viruses. Many of these organisms can withstand the hardships
of a journey across the Atlantic Ocean.
When the ship docks in Wilmington and
empties its ballast tanks before loading its cargo, the plants,
animals and microbes are unintentionally released into the
Cape Fear River. Freed from their confines, the ballast water
organisms may multiply and thrive.
This scenario may be imaginary — but
the concern is real.
It is likely how the zebra mussel, a fingernail-sized
mollusk from the Black, Caspian and Azov seas entered the
Great Lakes in the late 1980s. Since their introduction, zebra
mussels have spread rapidly to all of the Great Lakes and
to waterways in many states, as well as the Canadian provinces
of Ontario and Quebec. Growing in dense clumps, the mussels
can encrust and foul facilities at power plants, fish ladders
and industrial sites. To date, natural resource managers have
been powerless to stop the mussels’ spread.
“Thousands of species of marine life
are currently being transported in ballast water,” says
William Cooper, a Sea Grant researcher at the University of
North Carolina at Wilmington. “It’s unclear what
long-term effects such large-scale introductions will have,
but the evidence to date suggests there could be serious trouble
ahead,” he adds.
LITTLE CRITTERS, LARGE WOES
Releases of ships’ ballast water have
been blamed for the spread of the bacteria known to cause
cholera. In the Chesapeake Bay, for example, researchers have
identified a new strain of Vibrio cholerae, the organism that
causes cholera, with origins in the Mediterranean or North
seas. Health officials in Delaware, Maryland and Virginia
must remain vigilant to prevent outbreaks of the disease caused
by this particular strain.Introductions of exotic plankton
species can shift the balance of aquatic ecosystems. First
sighted in Cape May County, N.J., in 1988, the non-indigenous
Asian shore crab (Hemigrapsus sanguineus) has rapidly expanded
its range. This small (1.5-inch) but highly adaptable crustacean
now occupies coastal niches from Maine to North Carolina.
Researchers anticipate that the crab will continue to proliferate,
edging out native species that share its habitats.
The problem of unwanted ballast water organisms
is hardly limited to the East Coast. In San Francisco Bay,
for example, more than 230 non-native aquatic shore-dwelling
species already have taken over in mudflats, shoals and along
the coast.
On the lower Columbia River, a natural boundary
between the states of Oregon and Washington, at least 61 of
the 292 known plant and animal species are non-native. Some,
such as the Asian clam (Corbicula flumine, so thoroughly dominate
the sediment in some stretches of the Columbia that little
else can survive. If that’s not bad enough, these introduced
pests can proliferate to such a degree that, like zebra mussels,
they will eventually clog irrigation ditches and fish screens.
With funding from a National Sea Grant initiative
and other sources, Cooper and his West Coast counterpart,
Russ Herwig, with the Washington Sea Grant Program in Seattle,
are looking at ways to curb future introductions of ballast
water organisms along the nation’s coasts.
For the past three years, Cooper has been
working with a team of scientists to develop the technology
to treat ballast water before it is dumped. For nearly two
years, Herwig’s crew has been testing the new equipment
in the field, working aboard the oil tanker S/T Tonsina. It
is one of a fleet of tankers that carries oil — and
ballast water — from the Port of Valdez in Southeast
Alaska, to Long Beach, Calif., Puget Sound, Wash., and other
destinations along the Pacific Ocean coast.
This collaborative project began several
years ago, when the Tonsina’s principal owner, British
Petroleum, recruited Nutech O3, Inc. of MacLean, Va., to develop
and design a shipboard ballast water treatment system, using
ozone as the active ingredient. Nutech recruited Cooper to
oversee the ozone chemistry at play.
In turn, Cooper contacted Herwig and his
colleagues at the University of Washington, asking them to
conduct field tests of the system. Cooper and Herwig saw the
national and international importance of applied research
on ballast water — and the Tonsina would provide a demonstration
opportunity to evaluate how the ozone theories would translate
to real shipboard experiences.
HARMLESS, HIGH-TECH FIX
Ozone gas is produced when an electrical
impulse is shot through air that is rich in oxygen.
“When you smell the air after a lightning
storm, you’re smelling ozone,” Cooper explains.
Ozone has been used for decades to disinfect drinking water,
swimming pools and aquariums. It is incredibly effective at
killing bacteria and viruses in water. Because it degrades
quickly, reverting back to oxygen, it is safe for these freshwater
applications.
Today, the Tonsina is equipped with almost
seven kilometers of stainless steel tubing through which ozone
gas is conveyed to the ship’s ballast water. The process
is relatively simple, and there is no need to bring potentially
harmful chemicals on board ship. “All you need is electricity
and air,” Cooper notes.
A stream of oxygen-rich air is sent through
an electrode, exposing the gas to 10,000 volts of electricity.
The ozone gas that emerges is then sent to the 15 ballast
tanks on board through a system of 1,200 diffusers, which
Cooper compares to aerators in fish tanks. The gas bubbles
through the ballast water continuously while the ship is in
transit. Ozone oxidizes the tissues of any ballast water organisms
inside, destroying them.
According to Cooper, the ideal ballast water
treatment system would kill organisms of all sizes, a requirement
that many potential technologies have failed to meet. “We’re
looking at every trophic level in the water system, from viruses
and bacteria all the way up to fish,” the UNC-W chemist
says.
While ozone kills microorganisms like bacteria
and viruses almost immediately, larger organisms often escape
treatment. However, when ozone reacts with bromide naturally
present in seawater, bromine is formed. Bromine extends the
effects of ozone treatment because it also can disinfect —
and bromine does not degrade as rapidly as ozone.
This combination of ozone and bromine has
the potential to eliminate entire populations of microbes
and planktonic organisms within the ballast water tanks. Initial
tests, conducted in Long Beach, Calif., and Port Angeles,
Wash., have shown that the ozone treatments can kill up to
99.99 percent of the bacteria and phyto-plankton in ballast
water.
The system was somewhat less effective at
destroying zooplankton, but the success rate was still above
90 percent.
TESTING THE WATERS
As one group of scientists monitors the effectiveness
of the Tonsina’s ozone treatment technology, another
gathers samples of ballast water organisms. This means gaining
access to each ballast tank through a service hatch, or manway
— an access secured with many bolts, some rusted in
place since last time the ship was serviced. “The ship’s
crew has been extremely cooperative and very interested in
watching our sampling efforts,” Herwig says.
Once the crusty hatches are cracked open,
the team collects plankton samples, pulling a small plankton
net, or “tow,” through the tank. One tow will
amass about 5,000 planktonic organisms in its stocking-shaped
sieve. Microbe-laden water samples also were collected in
five-liter Niskin bottles for subsequent lab analysis.“
Collecting samples is the fun part,”
Herwig says with a wry grin. “After that comes many
hours spent processing samples and sorting those tiny planktonic
organisms by genus and species.”
While sorting the plankton, the researchers
seek to distinguish foreign species from those native to North
America’s West Coast waters. They also try to recognize
species associated with coastal and open ocean habitats.
That latter distinction is especially valuable
in gauging the effectiveness of what scientists call mid-oceanic
exchange — an international voluntary ballast water
management measure.
To reduce the possibility of introducing
exotic aquatic organisms, the Washington State Legislature
recently approved a bill requiring transoceanic vessels to
empty and refill their ballast tanks in the open ocean. Vessels
entering U.S. ports are required to report these activities
to the U.S. Coast Guard.
Legislatures in California, Hawaii, Maryland,
Oregon and Virginia have enacted similar laws. Though not
legislated in North Carolina, Erik Stromberg, North Carolina
Ports Authority executive director, spearheaded efforts in
1998 to ensure that vessels en route to state ports engage
in ballast water exchange before entering the U.S. Exclusive
Economic Zone.
Ballast water exchange on the high seas greatly
reduces the chances of ships ferrying planktonic aquatic organisms
from one nearshore area to another.Alas, seawater swapping
is probably not sufficient to eliminate the threats from ballast
water releases. The designs of most ballast tanks make it
difficult to drain every drop of water or replace all of the
living organisms in a ballast tank, says Herwig. Sediments
also may accumulate in the nooks and crannies of a ballast
tank. Living organisms and resting stages of organisms may
accumulate in the sediments.
Furthermore, Washington’s ballast water
regulation has a loophole. A ship’s crew can be exempted
from making mid-ocean exchanges if stormy seas or other conditions
would present insurmountable safety hazards.
FINE-TUNING AND TEAM-BUILDING
Ozone treatment may sound great in principle,
but there’s still work to be done. That’s because
the extended life of bromine can raise environmental concern.
Ozone’s quick decay rate means it is unlikely to threaten
native life when the ballast water is poured out.
Longer-lived bromine, however, still may
be present in the released water, so scientists must make
sure that bromine will not harm the aquatic systems into which
it is released. For this reason, researchers are trying to
pin down the lowest concentration of ozone that will get the
job done.
Lower concentrations of ozone also will reduce
operational costs — an important consideration in getting
the shipping industry to adopt this technology. The Tonsina’s
formidable network of stainless steel pipes almost certainly
would be too expensive for most ships to install, so the experimenters
also are exploring a less costly alternative system. Instead
of bubbling ozone gas through a maze of tubes for the entire
voyage, the new streamlined set-up simply will inject ozone
into the seawater on its way to the ship’s ballast tanks.
Herwig suspects that employing a combination
of ballast water treatment technologies — ozone, ultra-violet
light, chemical additives and fine-meshed filters —
ultimately may be the best way to tackle the invasive species
problem. Perhaps different technologies will be appropriate
for different types of vessels, he suggests. There also may
be sequential treatments developed.
Many researchers, says Herwig, believe that
a filtration step could be used first to remove larger organisms
and then a second step, perhaps ozone treatment, would follow
to remove the smaller life. For now, though, there is no consensus
about which methods are most likely to pay off.
One thing is certain, however: industry approval
is key. “Wherever our research takes us, it’s
essential that we work closely with the shipping industry,”
Herwig notes. “There’s no point in coming up with
measures that are too impractical to be implemented. What
shipping company would be eager to adopt a technology that
took up three-fourths of a cargo hold? Understanding and solving
the problems associated with ballast water also requires a
multidisciplinary approach, teams of scientists, engineers
and representatives from the shipping and regulatory communities.
”Cooper agrees with Herwig’s
assessment. “The industrial component of this is very
large and very cooperative,” he says. “This particular
project is an example of multi-institution academic and private
industry cooperation and collaboration, which has led to some
astounding results that we would not have been able to obtain
if this cooperation wasn’t in place.”
Collaborators on this project currently include
Gregory Ruiz from the Smithsonian Environmental Research Center,
Robert Gensemer from Parametrix, Inc., Paul Dinnel from Western
Washington University, and Jeffery Cordell from the University
of Washington.
Industry partners come from BP Oil Shipping
Company, the Alaska Tanker Company, Nutech O3, Inc., and Northeast
Technical Services Company, Inc. of Olmstead Falls, Ohio.
Each Thursday, a conference call connects
scientists and executives from all of the participating institutions.
“No one is left out,” Cooper says. “Everybody
has an equal say. We all decide where we’re going and
how we’re going to get there most efficiently, and then
we charge off.
”Cooper also emphasizes that, though
cost is of course a consideration, the group holds its work
to high scientific standards.
“The most important thing is that we
do research that’s scientifically defensible. That’s
been the philosophy of our collective group ever since we
started,” he says.
“We’re doing it because we want
to get answers to solve real problems.”
David G. Gordon is a science writer with
Washington Sea Grant, where Melissa Lee Phillips is a communications
intern.
BALLAST WATER MANAGEMENT INFORMATION
In 1990, Congress directed the U.S. Coast
Guard, then under the Department of Transportation, to establish
a mandatory national ballast water management program for
vessels entering the Great Lakes.
Then, in 1996, Congress directed the Coast
Guard to establish a national ballast water management program
that included a voluntary mid-ocean exchange initiative for
transoceanic vessels — with mandatory reporting. However,
compliance is sketchy at best. When the Coast Guard was transferred
to the Department of Homeland Security in 2003, ballast water
management became a priority.
At the urging of both the Coast Guard and
the American Association of Ports Authorities, the department
published a “Notice of Proposed Rulemaking” in
the National Register: “The Coast Guard proposes mandatory
ballast water management practices for all vessels equipped
with ballast tanks bound for ports or places within the U.S.
and/or entering U.S. Waters. The Great Lakes (mandatory) ballast
water management program would remain unchanged. The proposed
rulemaking would increase the Coast Guard’s ability
to protect U.S. waters against the introduction of NIS (nonindigenous
species) via ballast water discharges.
”Currently the Department of Homeland
Security is reviewing comments and is expected to develop
the final rule in 2004.
Along with mid-ocean ballast water exchange
and reporting, the rules would approve alternative “environmentally
sound” methods of ballast water management as they are
developed and tested for effectiveness.
In addition, the International Maritime Organization
currently is negotiating a binding international agreement
for mandatory ballast water management by member nations.
Adoption is expected in 2004, with ratification and implementation
by 2006.
For a complete overview of the ballast water
issue, here are a few resources:
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