The Academy's Diatom Herbarium, one of the two largest in the world, is a primary source of taxonomic and ecological information. It includes approximately 220,000 slides (curated and non-curated), of which about 5,000 are types. Materials include both fossil and recent diatoms collected from fresh, brackish, and marine habitats. (See About the Collection for more information.) The online database of the Diatom Herbarium includes approximately 63,000 diatom slides and 12,000 samples, The herbarium has a long history, with many specimens dating from the 19th Century or even earlier. (See History of the Diatom Herbarium for more information.)
In addition to its world coverage and its inclusion of fossil diatoms, the herbarium has an extensive record of materials collected as part of freshwater environmental surveys from throughout the United States. These surveys were the work of the former Department of Limnology, and its successor, the Phycology Section of the Patrick Center for Environmental Research. Often extending over decades, these surveys offer a unique resource for the study of long-term changes in diatom populations and ecology.
The Diatom Herbarium is curated by Dr. Marina Potapova. See Diatom Herbarium Research for more information about current research projects at the Herbarium. See Diatom Herbarium Policies for information on herbarium use and acquisition, and Diatom Herbarium Publications for a list of recent publications based on the collections. You can also view web pages on two former herbarium managers and noted diatomists, Ruth Patrick and Charles W. Reimer (1923-2008).
Written queries should be sent to:
Dr. Marina Potapova or Ms. Alison Minerovic
Academy of Natural Sciences
1900 Benjamin Franklin Parkway
Philadelphia, PA 19103-1195