Ice cores describe our past and provide clues about our future. Scientists collect an ice core by drilling a long tube into ice, then capping the tube and pulling it up with the ice inside.
They’re like closed, chronological history books sitting upside down on a table: the layers at the bottom were formed first. We read them in reverse. Slicing the core and studying it from top to bottom allows scientists to “read” about the environment, from when that ice was formed to now.
There’s more recorded in the ice than you might think. Temperature, precipitation, chemical conditions in the atmosphere, solar variability, and human-caused emissions are just some of the chemical and physical properties that leave their signatures in the ice. The ice also preserves biological materials like seeds, pollen, and fungal spores.
We’re collaborating with other scientists to study organic matter in ice cores, or biological molecules from living and decaying organisms. Organic matter is a hodgepodge of leftovers from living. If you’re walking through the woods, the trees and leaves are organic materials because they’re naturally-made biological structures. But, someone who studies organic matter would want to collect samples of the wet, gunky materials decayed beyond recognition and accumulating under the fallen leaves on the forest floor.
Organic matter in ice cores tells us what the environment and biological communities were like when that matter accumulated. In addition, our warming climate is melting ice worldwide, changing the role that this organic material plays. As ice melts, this material gets incorporated into current biological systems instead of being trapped in the ice. The amount of organic material being mobilized may have global impacts.
Our team have been some of the first to characterize organic matter in deep ice cores. Our research enhances understanding of past environmental conditions. We’re also describing organic matter signatures that may match particular climate conditions. Any future study that finds these signatures will gain information on what the climate was like when those signatures were created.