Washington: Researchers have found proof for catastrophic oceanographic events linked with climate change and a mass extinction 375 million years ago that devastated tropical marine ecosystems.
Professor Johnny Waters, who is a co-leader of the five-year, UN International Geoscience Programme project that began in 2011, said that the Late Devonian mass extinction was one of the five largest mass extinction events in the history of life.
The research team, which includes Assistant Professor Sarah Carmichael , is examining the relationship between climate change and changes in the ecosystems in the Devonian period, from 419 to 359 million years ago.
In the Devonian period, Waters explained, the world was experiencing super greenhouse climate conditions. This means that it was very warm, there probably were no ice caps, there was a lot carbon dioxide in the atmosphere (with estimates of 4,000 parts per million).
Waters said that as plant communities expanded onto land to form the first forests, they depleted the carbon dioxide (CO2) that was in the atmosphere, asserting that CO2 levels dropped to 400 ppm toward the end of the Devonian.
He explained that it got colder and that there were glaciation events and the rapid change in the climate caused severe extinction in the tropics and the existing coral reefs became extinct, saying that by comparison, the world`s current CO2 level is very close to 400 ppm.
Answers about the earth`s climate during and after this mass extinction are contained within rock samples from these new field sites, which were once part of the ocean floor, as geochemical signals preserved in the rocks record devastating climate change.
The paleogeography of the field sites indicate that Devonian climate change not only had environmental impacts on life associated with large land masses, but also on life in the open ocean.