Andy Baker, nominated in 2021 for sustained excellence in water and
climate science, especially the use of chemical tracers including
applications to speleothem palaeoclimatology
Abstract
My earth science focused PhD research included the analysis of annual
fluorescent laminae in cave stalagmites, under the supervision of karst
hydrologist Peter Smart (Bristol, UK). At the time, the source of this
fluorescence was uncertain, opening new research opportunities
characterizing what is now understood to be soil-derived, water-soluble
fluorescent dissolved and colloidal organic matter that is transported
to the cave by vadose zone percolation waters. Aquatic organic matter
fluorescence research benefitted at this time from significant
laboratory analytical advances that were commercially driven, including
Sony’s Blu-ray technology and the use of fluorescent labelling in the
biomedical sciences. Faster analyses at increasingly higher energy
excitation energies opened opportunities for novel fingerprinting of
organic matter in hydrological science, including landfill leachates and
sewage contamination. Today, hand-held fluorescence sensors can
instantaneously determine microbial water quality. And back in the field
of speleothem (cave deposit) science, annual geochemical laminae are now
recognized to be widely preserved in regions where there is a
seasonality in recharge, providing a precise chronology for the
stalagmite paleoenvironmental archive. Currently, we are utilizing this
precise chronology to generate high-resolution fire history records,
where the fire proxy is water-soluble ash-derived elements transported
from soil to cave by vadose zone percolation waters.