The Far-Gone South
Posted on June 27, 2012
Dr Krystyna Saunders explores the bottom of lakes to help piece together the history of our ecosystems.
I am a palaeolimnologist, which means I study past lake environments — or as I often tell friends — I study the layers of sediment that accumulate on the bottom of lakes over time. Each layer represents a particular period of time and contains different biological, chemical and physical information, reflecting what the lake’s ecosystems, surrounding catchment and the climate would have been like at the time that layer was at the sediment surface. By collecting a tube of sediment from the bottom of the lake and analysing each layer, it is possible to piece together the different ecosystems and climates that were present in the past and see how they have developed into what we see today. There are many different ways to collect sediment cores, but the most common practice we use is to take two small rubber boats out into the centre (or deepest part) of a lake and tie them together to create a stable platform. The boats are held in position by ropes that are anchored to the shore. We lower the corer (which is basically a heavy weight with a plastic tube attached to the bottom of it) to the bottom of the lake and hammer or push the tube into the sediment. When the tube is full and/or we cannot hammer it in any further, we pull it back up and the sediment core is contained within the plastic tube. This is transported back to the lab where it is sectioned and analysed.
To read more about Dr Saunders’ work and see some beautiful and fascinating photos from such remote locations, check out Overcoat Issue Two: Work.