Bayfield Lake is a beautiful long, thin, river-fed lake in the lower Glaven valley. The lake was dug for ornamental purposes in the late eighteenth century and since this time it has slowly been filling up with river-borne mud. But all is changing! Since June 2012 until last month a suction-dredger has been removing mud from the lake as part of a river-floodplain restoration project (see the recent RGCG newsletter for more details).
My main area of research at University College London (UCL) is the field of palaeolimnology. This particular “ology” involves the collection of sediment cores from lakes to reconstruct long-term (100s-1000s of years) changes in their ecology. Species from all parts of the lake food web leave remains in mud cores including fish, invertebrates and minute planktonic algae. By identifying and counting these biological fossils we are able build up a picture of past aquatic ecosystems.
We can also date the different sediment layers by various innovative and maybe surprising means! For example we can usually locate the 1963 layer in cores by a peak in cesium concentrations which represents the global peak in atomic weapons testing! We can also identify the onset of the Industrial Revolution (around 1850) by the first occurrence of “soot” particles in our cores. In fact it is often before this later date that we see more or less undisturbed and very high quality aquatic environments.
This is what we plan to do at Bayfield Lake and on the 3rd of July, 2012 we (Ian Patmore, Tim Grapes, Bernard Cooper and Carl Sayer) collected a 1 metre long sediment core using our “Big Ben” coring system. It was a beauty! In fact the core almost certainly extends back to the formation of the lake and over the coming months and years we hope to work out Bayfields ecological story over the last two centuries. We will provide more news on this work in the near future.
Carl Sayer