Benthic marine diatoms from tropical environments are still poorly documented, despite their high diversity. Coral reef biotopes of the Mascarene Islands (Western Indian Ocean Archipelago: Réunion, Mauritius, Rodrigues Islands) provide the opportunity to study a large part of their diatom community: the abundant small-sized Achnanthales treated here. Diatoms of other environments of very variable nutrient status were studied in Réunion and Rodrigues Islands and include areas of both low and high anthropogenic impact. This monograph describes taxa of seven genera, upon which Cocconeis Ehrenberg was particularly diverse. Scanning and light microscope investigations document and illustrate a total of 59 taxa, eight of them are new descriptions from these islands. This study serves as a basis for further investigations in the Mascarenes, Réunion the Rodrigues Islands and other tropical areas.weiterlesen