Lacustrine Diatoms as Paleoclimate Proxies and Their Use in Climate Change Research

Abstract

In this chapter, the potentialities and limitations of using diatoms to infer a range of climate-driven environmental variables are discussed. Given their sensibility and differential distribution along environmental gradients, diatoms have played a significant role in paleoclimatic research. Particularly since the development of statistical inference techniques, diatom-based paleoclimatic reconstructions shifted from strictly qualitative to a quantitative science based on the development of calibration sets and transfer functions. Studies have applied a series of diatom-inferred parameters, such as salinity, conductivity, water level, temperature, pH, and nutrients, to paleoclimatic reconstructions. As the links between salinity, conductivity and climate are more clearly understood, diatom responses to changes in these variables have been successfully linked to past climatic changes, producing a series of robust reconstructions of Holocene paleoclimates. The usefulness of pH, nutrients and temperature inferences is less clear and still under debate, as the links between these variables and climate are often complex and difficult to disentangle from non-climatic controls of lake dynamics. Local and regional conditions can also play a major role in structuring diatom assemblages, signaling the need for more localized studies covering a variety of timescales and waterbodies, particularly in aquatic systems of the Southern Hemisphere, which have received far less attention than their Northern Hemisphere counterparts.