RECONSTRUCTION OF ENVIRONMENTAL CHANGE IN THE TROPICAL WETLANDS OF BELIZE

Leverhulme Trust Research Grant F/158/B Q

This two year project uses evidence from lake sediment cores to reconstruct the past climate in Belize, Central America. Changes in the past climate can be revealed by finding differences in the sediment's geochemistry and in both the species and number of diatoms found at different depths in the cores. Diatoms are microscopic algae, very sensitive indicators of environmental change.

This project continues the Institute of Geography's years of research in Belize.
The work in Belize is one part of a range of Mesoamerican studies.

Aims

The project has two main objectives:

1. To relate observed changes in the past climate to both human activity (social changes) and biological activity in the lake catchment area.

2. To unravel the dynamic changes in Belizean wetland environments through historic time by deciphering local and regional climatic variations.

It combines the results from two dry-season field visits to Belize (in 1999 and 2000) with detailed laboratory analyses.

Methods

Samples have been collected in the field using three different corers: A Livingstone corer, a Kullenberg corer and a percussion corer. Video-footage of team-members coring (suitable for viewing with RealPlayer Version 6 and above) is available below. Each file is available at different compression rates. Select the one most appropriate to your current connection to this server.

After collection, the cores are sealed, brought back to the UK and stored in the dark, close to freezing, to minimise bacterial activity. The cores are then x-rayed and their magnetic susceptibility measured before they are cut up into small pieces. Samples to be used for diatom analysis are pre-treated with a series of hydrochloric acid and hydrogen peroxide washes. This removes organic material and minerals. Diatom identification is carried out by hand under a light microscope. Samples for geochemical analysis are dried and ground. Geochemical analyses include bulk mineral composition determined by x-ray diffraction, measures of carbonate content, organic matter, total carbon, total nitrogen, available p hosphorus and particle size.

Staff

The principal investigator on this project is Professor Peter Furley.

Other investigators include Professor Sarah Metcalfe (diatoms), Dr Andrew Dugmore (tephra) and Dr Sandy Tudhope (carbonate geology and stable isotopes).

Dr Malcolm Murray is employed as a research fellow on this project.
Miss Ann Breen is a NERC-funded postgraduate student whose research complements this work.