$360k Grant To Support Study Of Climate, Global And Coastal Marine Environmental Change

DARTMOUTH, MASSACHUSETTS - The National Science Foundation has announced a major award to the Isotope Biogeochemistry Laboratory at the UMass Dartmouth School for Marine Science and Technology. The $360,000 grant is designated for the acquisition of a mass spectrometer and associated instrumentation.

DARTMOUTH, MASSACHUSETTS - The National Science Foundation has announced a major award to the Isotope Biogeochemistry Laboratory at the UMass Dartmouth School for Marine Science and Technology. The $360,000 grant is designated for the acquisition of a mass spectrometer and associated instrumentation. 

"This grant is an indication of the scientific community's recognition of this laboratory, both for its current research and for its future potential," noted SMAST Director Brian Rothschild. 

"The 'mass spec' is the central engine of our research," explains Mark Altabet, SMAST professor and director of the Isotope Lab. The spectrometer measures and identifies minute quantities of certain chemicals, and Altabet and company use these chemicals as "tracers" of processes in nature, from coastal eutrophication to past global climate change.

In addition to serving the laboratory's research needs, the new instrument will become part of the educational program of the University of Massachusetts new five-campus Graduate School of Marine Sciences and Technology. It will also support the flow of scholars and graduate students from other institutions and other countries who come to the Isotope Biogeochemistry Lab, to make use of its unique mix of instrumentation and technical expertise. Most recently, a Brazilian researcher spent last semester at Altabet's laboratory using isotope ratios to track the movements of sardines and anchovies along both coasts of South America. 

The lab's current mass spectrometer is nearly 20 years old, and although it has been modified frequently to update its technology, it has become a losing battle. "A mass spec is a high-energy instrument that identifies samples by combustion, draws high voltage, contains a powerful magnet and extreme vacuum conditions," points out Matt Higginson, co-principal investigator with Altabet. "It's a struggle to maintain optimum operation after years of erosive forces." 

The new instrument will be much more compact than the current one and much more sensitive, greater precision. It will also allow investigators to make do with much less sample material. 

The spectrometer allows investigators to take advantage of the fact that a given sample of an element is likely to contain a mixture of isotopes--different forms of the element that are distinguished by their weight. The mass spectrometer enables scientists to determine how much of each isotope is present in the sample. 

This has scientific importance because isotope ratios “record” where a particle sample has been, and scientists are learning to read these records. In September's issue of the journal Nature (vol. 425, p. 366), for example, researchers used methods similar to Altabet's to pinpoint the change from fishing-based to agriculture-based communities in the ancient British Isles. 

The stable isotopes of carbon and nitrogen--the two principal tracers used in Dr. Altabet's lab--are everywhere in nature, including in all living creatures, and have fairly well-known ratios in natural systems. Each deviation from a standard ratio is a clue to the history of the sample. For example, when a cow eats grass, the nitrogen incorporated into the cow becomes measurably different in isotopic composition than the nitrogen in the grass; likewise when a human eats a steak, and so on. And the same kinds of changes occur in the ocean. 

"Mark [Altabet] has spent the past 15 years looking for and studying the processes in the ocean that affect isotope ratios," says Higginson. Through that study, Altabet's group has delved into the history of Earth's biological productivity, marking each change by the variation in isotope ratios at progressive depths in the sediments of the Arabian Sea. As a check on their findings, the group plotted 100,000 years of their reconstruction of climate history against results derived from carbon dioxide bubbles trapped in Antarctic ice. The correspondence was remarkable. 

Dr. Altabet and his research team are just beginning to apply their isotope ratio methodology to a new area: coastal environmental problems. In the past year, they have been part of a team that is reconstructing the environmental history of Long Island Sound over the last millennium by studying its sediments. For most of that time, the Sound "was largely stable," Altabet reported to the NY Times in August ("A History Told by Real Muckrakers," 8/24/03)." But then, beginning in the early 1600's, things began to change drastically. From clearing of the land, you see more sediment deposition; then in the 1800's, you see the first impacts of early industrialization" he said. The group is now planning to focus in on the past 100 years, using much finer resolution. 

Although the lab is extending their methodology to new areas, Dr. Altabet sees their emphasis on earth's climate--both modern and prehistoric--as continuing for the foreseeable future. "There still could be a lot of surprises in store for us," he cautions, "as we perturb the global environment." 


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