Biostratigraphic and palaeoenvironmental applications of testate amoebae

Abstract

Testate amoebae (also referred to as rhizopods, thecamoebians and arcellaceans) are single-celled organisms in which the cytoplasm is enclosed within an external shell (the test). They live in a wide range of terrestrial and aquatic habitats, including wet soils, lakes and saltmarshes, and fossil tests have been recovered from sediments from all these environments. This paper reviews existing and recently developed applications of testate amoebae analysis to biostratigraphic description of Quaternary sediments and palaeoenvironmental reconstruction. Advances in testate amoebae analysis are discussed for three key areas of Quaternary research and the potential for the further exploration and use of the technique is emphasised. These areas are: (1) Peatlands and palaeoclimates: Testate amoebae have been used as a new method of reconstructing palaeoclimates from ombrotrophic peats; (2) lake sediments: Testate amoebae respond to acidity levels in lakes but they may also be useful as indicators of pollution and temperature; (3) saltmarshes and sea-level change: Testate amoebae can now be added to diatoms and foraminifera as potential indicators of sea-level change. The paper concludes with an examination of future developments in testate amoebae research and highlights the need for further work to explore their full range of occurrence in Quaternary sediments.