In this book, the authors present current research in the study of the diversity and distribution, role in biotechnology and environmental impacts of diatoms. Topics discussed in this compilation include the determination of biogenic aluminium and rare earth element composition in diatom opal and its implication for marine chemistry of diatom frustule, an impure entity; diatom flora of fresh and brackish water bodies in the Far East of Russia; paleoceanogaphy since the warm pliocene epoch in the mid-latitudes of the Northwestern Pacific Ocean; the analysis of lake ecosystems transformation by taxonomic structure of diatom assemblages; and microphytobenthic community dynamics in the intertidal flats of the Nakdong River Estuary in South Korea.