Researchers study plants sprouting from century-old seeds after excavation
At a Toronto Port Lands construction site on the city’s waterfront, sharp-eyed workers recently saw plants sprouted from soil recently uncovered by removing tons of soil. The plants were hard bulrush and bulrush, which are common in freshwater swamps.
Because the plants grew on a patch of ground seven meters below the surface for a century, conservationists concluded that they had grown from seeds buried when Ashbridges Bay Marsh at the mouth of the River Don was built in the early 1900s. covered with a landfill.
Now a team of researchers from the University of Toronto, including Sarah Finkelstein and Shelby Riskin, are studying the soil removed from the site to better understand the long-lost natural habitat.
Finkelstein, a paleontologist and associate professor who chairs the Earth Sciences Department at the Faculty of Arts and Sciences, studies paleoenvironmental data to better understand past climates and how ecosystems respond to environmental changes. Mrinmayee Sengupta, a geography student and University College member, will help her analyze the soil of Port Lands.
“Our first goal is to understand what the swamp looked like back then,” Finkelstein says. “We’ll answer questions like, what was the plant community like? What were the food webs like? What role did this swamp play ecologically on a local and regional scale?”
Meanwhile, Riskin, an assistant professor, teaching stream, in the department of ecology and evolutionary biology at the Faculty of Arts & Sciences, will study how land use changes affect ecosystems and how those ecosystems can continue to function in the face of change. Stuart Ralston, an environmental science student and a member of Victoria College, will work with Riskin on the project.
“We will look for evidence of life in the swamp – shells, seeds, pollen – and hopefully get a sense of the biodiversity of those soils 100 years ago and compare it to what we see today in the wetland soils in the area.” find,” Riskin says.
“I’m really curious to see what we’ll find. Whether there will be a viable seed bank of native plants in those soils, or if there’s evidence that it was already a compromised ecosystem 100 years ago.”
Ashbridges Bay Marsh was once a thriving natural ecosystem. But by the late 1800s, it was suffering from sewage and pollution from the cattle yards on Toronto’s waterfront, among other things. As the city grew in the early 20th century, it was covered and more industry moved to the new land.
Today, the port area is undergoing major redevelopment to reduce flooding at the mouth of the River Don and create parks and new wetlands. As city archaeologists dig, workers discover the city’s recent history.
The researchers will also measure the soil’s carbon content to understand whether it comes from a natural source or from human activity, and how well the swamp served to absorb and store carbon.
“Right now my research group is working a lot on carbon uptake and storage in wetlands, which is an important research focus in Ontario, given our abundance of wetlands and their potential role in mitigating climate change,” said Finkelstein. “This work could tell us how well this wetland functioned as a carbon sink. It will also help us learn more about wetland restoration and what we can potentially recreate on Toronto’s waterfront.”
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Quote: Researchers study plants germinating from ancient seeds after excavation (June 2022, June 27) retrieved June 28, 2022 from https://phys.org/news/2022-06-century-old-seeds-excavation.html
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