Diatoms are single-celled algae that are an important component of plankton in both fresh and saltwater environments. These microscopic organisms have a unique cell wall made of silica, which distinguishes them from other types of algae. Some synonyms for diatoms include: - Frustules - Bacillariophyta - Microalgae - Silicon algae - Phytoplankton - Microscopic algae - Glassworts - Diatomaceous microalgae - Siliceous microorganisms Each of these synonyms describes different aspects of diatoms, including their physical characteristics, taxonomic classification, and ecological role. Regardless of what they are called, diatoms are incredibly important for aquatic ecosystems and play a critical role in the global carbon cycle.