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Professor’s research contributes to ‘the climate story’
November 24, 2015Tweet
Tim Lowenstein discussed the changing atmosphere, hydrosphere and biosphere from a geological perspective at the 2015 Harpur College Dean’s Distinguished Lecture.
Lowenstein, a professor of geology, has more than 25 years of experience studying sedimentology and geochemistry. He has examined ancient minerals to determine past levels of greenhouse gases, such as carbon dioxide.
“The greenhouse gases are a very important part of the climate story,” said Lowenstein, who spoke in Old Union Hall on Nov. 20. “As a geologist, we can study past climates and we can try to understand what the carbon dioxide (CO2) was in the atmosphere in the past.”
Lowenstein looked at a carbon dioxide-sensitive mineral, Nahcolite, to study past CO2 levels. Nahcolite forms under conditions with high heat and high levels of CO2.
According to Lowenstein, 50 million years ago there was 1,125 parts per million (ppm) of CO2, three times today’s value. In addition, Earth was about 20 degrees warmer than it is today.
“We extrapolate that there is a causal link between CO2, as a greenhouse gas, and temperature,” he said.
However, recent experiments have shown that Nahcolite can form at CO2 levels as low as 680 ppm, which is significantly lower than was previously thought.
“CO2 is a lot more sensitive to climate change than we might have suspected,” Lowenstein said. “The doubling of carbon dioxide from pre-industrial levels, of 280 to about 560 or higher, that we will see in the next century, may have unexpected feedbacks that could amplify global warming.”
Feedbacks could be shrinking ice sheets, which will affect Earth reflectivity, release frozen methane, melting permafrost.
According to Lowenstein, the data is “humbling” and leads to the further consideration of shrinking ice-sheets, release of frozen methane, another greenhouse gas, and the melting of the permafrost and its effects on global warming.
Lowenstein also presented on the chemical makeup of seawater and how it has changed throughout history. It was previously believed that the chemical makeup of water was relatively stable throughout time. However, Lowenstein has been able to study microscopic water droplets in salt crystals called fluid inclusions. As the salt forms, microscopic droplets of water become trapped within the crystal. By comparing the fluid inclusions from different time periods, Lowenstein has been able to study the change in ocean chemistry over time.
“Unlike what the dogma was for so many decades, we now know that the chemistry of the oceans has changed,” he said. “These systematic chances have influenced the evolution of organisms in the ocean.”
Changes in seawater chemistry have particularly controlled the abundance of shell-building organisms.
Today, reefs are mostly made of corals. Over time, the reef builders have changed in response to change in water chemistry.
One hundred million years ago, clams made reefs as they thrived in an environment high in calcium and low in magnesium. Three hundred million years ago, sponges and algae built reefs.
“As we continue to add CO2 to the atmosphere, about one-third to one-half of it dissolves in the oceans. And that’s changing the pH of the oceans; it’s making them more acidic,” Lowenstein said.
“Ocean acidification, which is the lowering of pH, may impact marine shell-building organisms, especially in the colder parts of the oceans, where the delicate balance of shell builders is most sensitive,” he continued.
Lowenstein not only studied the ancient seawater from the fluid inclusions, but the microbes trapped within them as well. He found algae and prokaryotes, millions of years old.
“[The microbes] are also beautifully preserved,” he said. “Remember that they’re being pickled in salt brine, and so the preservation is astonishing.”
When these microbes get trapped inside the fluid inclusions, they go into hibernation. Lowenstein asked: Were any of these cells alive?
Brian Schubert, who received his doctorate in geology from Binghamton University in 2008, cultured the organisms from these salt crystals. In five cases out of 1,000 he successfully got the 21,000- to 34,000-year-old organisms to grow.
“That was a big discovery!” Lowenstein said. “There are organisms that are 34,000-years-old and they are still alive, trapped inside these salt crystals.”
Lowenstein’s lab was able to prove that these organisms were in fact real and not contaminants. Working with the Anthropology Department at Binghamton University, Lowenstein studied the DNA from the original samples and then compared them with the DNA of the cultured organisms. They were nearly identical.
Lowenstein posited what implications these studies could have on cosmology and for finding life on Mars. He suggested that these fluid inclusions could prove panspermia, the theory that life transfers through the universe and solar system through meteors.
The Monahans meteorite, which fell in Texas in 1998, contained salt with fluid inclusions that dated back to the origin of our solar system, 4.5 billion years ago.
“That water trapped in that fluid inclusion, is the oldest water we know of in our solar system,” Lowenstein said.
He hypothesized that if that if a meteor with fluid inclusions containing microbes crashed onto Earth, the meteor could have brought life to this planet.
According to Lowenstein, in the next 10 years, there will be a sampling mission to Mars, where there are known to be salt deposits.
“I would advocate that we should go to the surface of Mars and collect salt crystals,” he said, “and look for fluid inclusions in those salt crystals and see if they have any microbes.”