Diatoms as a tool for reconstructing sedimentary environments in coastal wetlands; methodological aspects

This paper presents a method for reconstructing sedimentary environments on the basis of diatoms in clastic deposits of coastal wetlands. The method includes improvements and updates of previously described approaches of coding ecological data on diatom species for computer utilization and of combining diatom species into ecological groups, which are related to specific environments.The assessment of autochthonous and allochthonous diatoms is the major problem in the palaeoenvironmental diatom research in tide-influenced coastal areas, because the allochthonous influx by tidal currents (mainly marine planktonic and tychoplanktonic diatoms) is significant. In tidal deposits, the allochthonous diatoms often outnumber the autochthonous assemblage. Criteria for the assessment regarding which diatoms are in or out of place are discussed.