Warming trends
Scientists look at climate change past, present and future
Archived article from Jan 28, 2000
By Sandra Lanman
An ancient 'belch'
Great science can spring from humble beginnings. Just ask Miriam Katz.
Katz, a doctoral candidate in geological sciences on the New Brunswick campus, recently made a splash in the world of paleo-oceanography and beyond when she discovered hard evidence of an ancient global-warming event that triggered a mass extinction of sea life and the rise of many of today's mammals.
Her breakthrough started with cocktail napkins in a Secaucus sports bar in July 1997.
Katz and fellow scientists had just debarked from the international Ocean Drilling Program's (ODP) research ship, on which she had been studying tiny, salt-grain-sized microfossils known as foraminifera, recovered in sediment cores from the ocean floor. At the bar, she chatted with Gerald Dickens, a paleo-oceanographer at James Cook University in Australia, who had been among the 25 scientists aboard the ship.
Dickens grabbed cocktail napkins and began diagramming his theory about a massive global-warming event millions of years ago. Scientists have long speculated on the cause of this "late Paleocene thermal maximum," which killed off sea life but raised temperatures in frigid areas of the Earth enough to allow new mammalian species, including primates, to thrive.
Dickens believed the cause could be traced to a giant "belch" of methane gas from the ocean floor 55.5 million years ago. He hypothesized that some 15 trillion tons of methane hydrate -- a combination of ice and methane -- beneath the ocean floor had warmed enough to decompose, sending tons of methane into the sea. It eventually reached the atmosphere as carbon dioxide, causing a greenhouse effect much like today's burning of fossil fuels.
The problem with Dickens' theory was that he had very little proof.
"So I stuffed all these cocktail napkins into my pocket, said goodbye and left," recalls Katz, who was then working at Columbia University's Lamont-Doherty Earth Observatory. "The next day, I found them and thumbtacked them to my bulletin board at work. Every so often, I'd look at the napkins and think, 'What the heck was he talking about?'"
By then, Katz was already one of the world's experts on the taxonomy and distribution through time of foraminifera, says her adviser, Kenneth Miller, a professor of geological sciences who first met Katz in 1982 and later encouraged her to pursue a Ph.D. at Rutgers.
The "forams," as Katz calls them, especially the extinct varieties, have long intrigued her. There have been about 30,000 species of these non-descript "amoebas with shells" resembling minuscule snails and clams under the microscope.
"I really don't look at their biology at all," she says. "I look at how the fauna and their geochemistry have changed over time, and through that I can reconstruct changing ocean and climate conditions."
One day, as she gazed at the crumpled cocktail napkins, a light went on in her head: She realized that the "forams" and other materials she had collected on an ODP cruise from an area called the Blake Nose off the northeast Florida coast held the clues that could prove Dickens' theory.
The missing pieces of the puzzle were in the isotopic, or chemical, analysis of the organisms and her ability to date their demise to the same period Dickens was talking about -- 55.5 million years ago. The analysis showed the presence of isotopically distinctive carbon consistent with methane gas in the microfossils. Telltale deposits of carbonic acid dissolution also were found in the sediments. In addition, Katz's work turned up previously undiscovered physical evidence of the methane release in that area. In short, she had the evidence to shore up Dickens' hypothesis.
With Miller, Dickens and Dorothy Pak of the University of California-Santa Barbara as co-authors, Katz published her findings in the November issue of the journal Science. The paper, which will be part of Katz's dissertation, recently was nominated for best student paper at the annual meeting of the American Geophysical Union.
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