The infographic will be published as part of a magazine edited by the Past Global Changes project (PAGES) aimed at teenagers with an interest in environmental science, in order to promote their understanding and appreciation of the palaeosciences. The aim of this infographic is to provide a broad understanding of my PhD research field, giving insight as to why we are interested in the environmental history of tropical crater lakes, and the methods we use to do this.
Over 80 small crater lakes in western Uganda provide water resources for rural communities and a home to wildlife. Unfortunately, the lakes face increasing pressure from human activities, such as deforestation to make room for growing crops, and climate change.
Monitoring of the lakes (temperature, rainfall, and water chemistry) began 30 years ago. To find out about the lakes longer ago we have to use a natural record of the environment. Sediment collects in the bottom of lakes over time, forming a natural record of the lake’s history, which can date back hundreds and even thousands of years. We can collect cores of this sediment to analyse.
Understanding the lakes’ response to past changes helps us predict how they will respond to current and future pressures, and inform sustainable management.
What are environmental proxies?
Proxies are environmental clues to the past, preserved in the lake sediments. They give us information about the lake and wider environment at the time that they were preserved.
Pollen – Pollen can tell us what types of vegetation used to live in the lake catchment.
Diatoms – Diatoms are tiny plants that live in all water bodies. The species present in the sediment tell us about the lake water chemistry when they were alive.
Geochemistry – The chemical fingerprint of the mud can tell us about the lake and the climate when it formed.
Travelling back in time
We work out how old the sediments are by measuring their radioactivity.
Reconstructing the past
By analysing these ‘clues’, we can build up a picture of the lakes’ past environments, and tell a story of their past, like detectives at a crime scene working out what happened from a few clues left behind.
Read about Laura’s experience of fieldwork on Geoblogy: Mud Sweat and Tears: PhD Fieldwork in Uganda
Laura studied Geology at Cardiff University, where she became interested in palaeoenvironmental change and geochemistry before moving to Nottingham to study for her PhD. Laura is based at the British Geological Survey and the University of Nottingham, researching the past hydrological change of tropical crater lakes in Uganda primarily using stable isotopes. Laura is a volunteer for Geology for Global Development and a number of science outreach projects.