Kingston, ON Queen's University biologists are part of an international research team whose discovery of a rare sediment core in a remote Arctic lake provides compelling evidence of unprecedented environmental changes occurring over the past few decades.
"Our findings show that the last several decades have been the most ecologically unique in 200,000 years," says Neal Michelutti, a research scientist at the Paleoecological Environmental Assessment and Research Lab (PEARL) at Queen's. With Biology professor John Smol, Canada Research Chair in Environmental Change, and master's student Cheryl Wilson, the Queen's researchers are part of a multidisciplinary team led by University of Colorado scientist Yarrow Axford.
Other members of the team are from the University of Alberta, University of Buffalo and University of Massachusetts.
The sediment core, retrieved from a lake bottom on Baffin Island, predates by about 80,000 years the oldest cores from the Greenland Ice Sheet, capturing two ice ages as well as three interglacial periods. "Lake sediments are natural recorders of climate and environmental changes, as they preserve archives of past geochemical and physical conditions, as well as a diverse record of important biological indicators," Ms Wilson explains. The research team used algae and aquatic insect fossils preserved in the sediment core to reconstruct past climatic and other environmental conditions.
Their analyses show that changes in species, as well as lake-water chemistry, were tightly linked to past shifts in climate. The sediment records have allowed the team to reconstruct climatic and environmental conditions of the past three warm periods between the last two ice ages, and compare them to the human-influenced climate of today.
"The 20th century is the only period during the past 200 millennia in which aquatic indicators reflect increased warming, despite the declining effect of slow changes
|Contact: Nancy Dorrance|