Ellen Thomas, research professor of earth and environmental science, holds two samples of microfossils that were printed on a 3-D printer at the University of Iowa. The printed fossil models are about 8,000 times bigger than the actual limestone fossils. These planktonic forms lived closer to the surface of the water. At left is Hantkenina alabamensis, which lived when the world was warm, and went extinct at the time of formation of the Antarctic ice cap about 33.7 million years ago. At right is Globigerinella siphonifera. It lives in the subtropics today, in open ocean. “When it’s alive, it has spines and protoplasm inside and along the spines,” she said. (Photos by Olivia Drake)
This slide contains more than 300 microfossil specimens from an ocean drilling site in the eastern Indian Ocean. These are estimated to be 55.8 millions years old, and lived during a period of extreme global warming with a duration of 170,000 years. At the beginning of this warm period, there was a mass extinction of deep-sea benthic foraminifera, which may have been caused by the rapid global warming and ocean acidification.
Research Professor Ellen Thomas grasps a glass-enclosed sample of hundreds of microfossils, each a white fleck of limestone barely visible to the human eye.
“The first time students look at these they say, ‘they all look the same to me,’ but in reality, they are all have very different shapes,” Thomas says. “Even under a microscope, it can be difficult for a new eye to see the differences, but each species has its own shape; some have a much more open, light structure because they lived floating in the oceans close to the surface. Others have denser shells and lived on the bottom of the ocean, or within the mud. And each one can tell us, in its chemical make up, what the environmental conditions were like at the time that they lived and built their shells.”
By studying and analyzing microfossils, Thomas and fellow scientists are able to explore aspects of climate change on a variety of timescales,
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