Part 4 Continued: Scientist Abbey Paulson Breaks Down Cell Walls to Find Answers at Acadia
You don’t know what you’ve got ’til its gone
Thursday, August 11, 2016 5:26 PM
Species are lost daily as a result of increasingly fast environmental change, leaving big gaps in knowledge that could be crucial to the functioning of the planet and to our own lives.
Certainly, the lives of many women with breast cancer would have been cut short if Taxol had not been discovered from the bark of the small Pacific yew tree. As for the economic impact; well, Taxol is one of the best-selling cancer drugs ever manufactured.
But the loss of species, from the big animals to tiny microbes, is occurring at a rate that has left scientists searching for new and more effective tools to capture information.
In the last couple of years environmental DNA has made a splash as a new scientific tool with big potential for measuring changes in biological diversity that connects to landscape-level change.
That’s the research tool used by Dr. Abbey Paulson, the first scientist to be awarded the new Second Century Science Fellowship award from the Schoodic Institute to conduct scientific research at Acadia National Park.
Starting in late August, Paulson will be in the field at Acadia collecting small batches of material. She will use a process that breaks down cell walls and wrings the DNA out of the entire sample before putting it through a sorting and identification process in the lab.
Something like a small cup of stream water can reveal as much as 15 million DNA sequences that can be identified and labeled.
That matters, because if that same area is tested again a month or a year or a century later — or, if an ancient sample is available from a bog or some other material that preserved DNA over a long span of time — it can reveal a whole story of landscape-level change and may be able to point to causes and effects and lead to on-the-ground changes at Acadia National Park.
Take the work Paulson did near Death Valley, where an effort to restore a stream was planned. Paulson took a cup of stream water with thousands of organisms (mostly microbes), put it through a centrifuge, extracted out a pellet of condensed material, broke down the cell walls to extract the DNA, basically used molecular bar codes to label it and put it into a DNA library. Then, she used computer code to analyze it.
She then compared that story of the landscape with another cup of water that went through the same process after invasive crayfish were removed from the stream and native fish and aquatic insects reintroduced.
What she found was a change in the biological community.
“It turns out that the fish are a vital part of the ecosystem,” she said.
The lack of fish was bigger than it seemed. They were vital to the overall health of the stream.
“My research showed that if some species are missing, that has a bigger and more important consequence than just a piece missing from the food chain. When you reintroduced the fish and the aquatic insects it had an effect on the whole community.”
Her environmental DNA also revealed which species are important to reintroduce for ecosystem health.
The importance of microbes to life is just really starting to register beyond scientific circles.
“It’s not just that microbes occur there, but they are involved in freshwater and nutrient cycling, among other things,” said Paulson. “They are important.”
Paulson, who is based at the University of Colorado at Boulder, will use the same methods for extracting environmental DNA from soils, streams, and the intertidal zone during her three field visits to Acadia National Park.
Among her hypotheses are that natural vegetive communities will be correlated with a specific microbial soil community and that streams with culverts will show microbial differences above and below culverts.