Coring involves cylindrical canisters (left) which are dropped through the bottom of the lake so sediment can be collected and analyzed.

WHAT IS IT

Coring involves a tall cylindrical canister that has an opening on the bottom. It is used to collect sediment samples from beneath the lake bottom.

HOW IS IT USED

A winch lowers the canister to a depth ranging from 10 to 20 meters above the bottom of the lake. The canister is then allowed to free fall into the lake bottom where the force of the fall burrows the canister a few meters beneath the lake bottom.

The winch then pulls the canister back to surface where a cap is placed into the hole on the bottom to prevent sediment from leaking out. Back in the sediment is analyzed.

WHY IS IT USED

Lake sediments are perfect for investigating past environments and climate change. Over time the lake bottom is slowly covered over with new sediment and the sediment beneath the new layer provides a snapshot of what life was like.

Coring provides a way to collect a sediment sample while also protecting it from exposure to air which will oxidize some of the chemicals, contaminating them and making them scientifically unusable.