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| Enlarge ImagePeter Wiebe, senior scientist in the WHOI Biology Department and chief scientist on the Census of Marine Zooplankton cruise, helps launch the Multiple Opening Closing Net Environment Systems Sampler (MOCNESS) from the deck of the NOAA research vessel Ron Brown, to sample ocean life at several depths. The cruise, part of the Census of Marine Life project, brought international experts together to find Atlantic Ocean animal plankton species and identify them using both taxonomic and molecular DNA methods. (Photo by Larry Madin, Woods Hole Oceanographic Institution) |
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| Enlarge ImageOne of the MOCNESS nets rises out of the ocean, with its multiple net ends trailing. Each separate net samples a different ocean depth and is controlled by computer from the ship. (Photo by Ken Buesseler, Woods Hole Oceanographic Institution) |
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| Enlarge ImageThe large MOCNESS, with a 10-meter-square mouth, a heavy metal frame, and nine separate nets, requires many hands to pull aboard after an hours-long tow through the ocean. (Photo by Larry Madin, Woods Hole Oceanographic Institution) |
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Related Multimedia |
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Sampling plankton with the MOCNESS
Watch the launch and recovery of the MOCNESS net, catching plankton animals in the Atlantic Ocean.
Video by Larry Madin, Woods Hole Oceanographic Institution | » View Video
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Scientists collected more than 1,000 shrimplike creatures, swimming snails and worms, and gelatinous animals, including many species never seen before, on a landmark cruise to take inventory of the ocean's zooplankton.
Woods Hole Oceanographic Institution biologist Peter Wiebe led a team of 28 scientists from 14 nations, who used fine-mesh nets to sample from the sea surface to depths of nearly three miles (five kilometers). The April 2006 cruise across the tropical Atlantic Ocean, funded by the National Oceanic and Atmospheric Administration, was part of the Census of Marine Zooplankton (CMarZ) project—an ambitious global effort to assess the kinds, numbers, ranges, and roles of thousands of tiny animals species that provide the link in the marine food chain between marine plant life and predators from fish to whales.
While still at sea, experts in taxomony (the classification of organisms) identified captured species under microscopes while researchers sequenced their genes to create unique DNA “bar codes.” Future scientists will be able to identify species more easily, even if they didn't study taxonomy themselves.
“Genetic bar codes will be a big step forward,” Wiebe said. “We are trying to provide the stepping-stones so future generations can use the results of this project as a benchmark to measure at a glance how ecosystems are changing in the future.”
The DNA bar codes also reveal genetic variations that allow scientists to differentiate similar-looking species that would otherwise be hard to distinguish by sight, said Ann Bucklin, a University of Connecticut marine scientist who leads CMarZ.
Researchers collected the zooplankton using MOCNESS, or Multiple Opening/Closing Net and Environmental Sensing Systems, designed by Wiebe and WHOI colleagues. The computer-controlled system allowed scientists to open and close separate nets every 3,000 feet (1,000 meters) throughout the ocean and collect corresponding information about water temperature and salinity. To capture the smallest zooplankton, the nets had a mesh size of 333 micrometers (smaller than the period at the end of this sentence). In addition, scuba divers also collected samples during the day and night.
The Net MakersThirty years or so ago, Jackie Halstead was a student at the University
of Washington, pursuing a career in oceanography. Then she met Peter Wiebe, a biologist at Woods Hole
Oceanographic Institution, and a marine
technician named Mike, who worked for one of her professors, Tom English.
Wiebe was visiting Seattle to consult with English, who had developed the tucker trawl, a
mechanical precursor of sorts to an oceanographic sampling system
called MOCNESS: Multiple Opening/Closing Net and Environmental Sensing
Systems.
Her future changed course, drastically. She married Mike, and they soon founded Research Nets, a small business
in Redmond, Wash., that sells nets almost exclusively to universities,
research organizations, and utility companies doing environmental
assessments.
“We saw a need to give scientists what they wanted, and it was a good
opportunity for us to work at home and raise a family,” Halstead said.
“It grew from a backyard effort to a regular shop employing about 10
people.”
Halstead, who has made thousands of nets for Wiebe since the 1970s, says making the MOCNESS nets has been a challenge.
“The MOCNESS nets are unique,” she said. “This last cruise was a
real challenge because the nets were the biggest we have ever made, and
had the smallest mesh size (333 micrometers). I wasn’t sure they would
hold together.”
“There was real skepticism that nets with that
fine mesh on a trawl would work,” Wiebe said. “The net maker and others
thought sure they would blow out. But the nets performed beautifully.”
“We were happy to get the news and see the images of the creatures they
captured,” Halstead said. “It is always nice to know something you made
works and may make a difference in science.”
—Shelley Dawicki
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Posted: July 14, 2006 [top] |
