Identification Guide and Ecological Resource for Diatoms of the United States

The Problem

Diatom species composition and abundance are well known to reflect the biotic condition of freshwater streams and lakes. Together with aquatic invertebrates or "bugs" and fish, diatoms are an indispensable component of Federal (U.S. Environmental Protection Agency's (USEPA) Environmental Monitoring and Assessment Program (EMAP), U.S. Geological Survey's (USGS) National Water Quality Assessment (NAWQA) Program) and state monitoring and assessment programs. The USEPA advises state agencies to include attached algae or "periphyton" in biological assessments because diatoms are sensitive to human impacts on watersheds and the condition of diatom populations reflects the aquatic ecosystem response to environmental stress. State agencies have followed the recommendation to use more than one biotic assemblage in bioassessment, and many states now monitor attached algae including diatom assemblages.

Unfortunately, the lack of recent taxonomic and ecologic research on North American diatoms has led to a situation in which the ability of Federal agencies to assess the biological condition of freshwaters using algae is constrained. The existing taxonomic keys for the United States are incomplete or out of date. As a result, diatom analysts routinely use European taxonomic keys to identify North American diatoms. Not only has this practice led to misidentification of species, but perhaps more important, a lack of taxonomic consistency within analyses and across federal programs and state agencies currently exists.

Our Solution

We recognize that analysts need to have access to accurate taxonomic and nomenclatural information on diatoms. By developing a publically accessible resource to provide accurate information on diatoms, analysts will have the ability to create consistent and accurate data in support of Federal and state compliance with the Clean Water Act.

Genesis, Community Support and Collaboration

This project was initiated with a grant from the USEPA Office of Research and Development through the Regional EMAP program in 2007. We set out to produce an innovative website backed by a robust database to accommodate a large number of taxonomic records. In the process of developing and planning the site our vision expanded to incorporate a unique visual key, a means for non-specialists to gain access to understanding of critical diatom species. We began by thinking about a regional database centered on the western United States with the goal of presenting a taxonomic and ecological resource on diatoms. As our vision expanded, we had some delays in finishing the project, but we also gained substantial interest and support from the scientific community of diatomists.

Through this scientific support we were able to expand the number of contributors and scope of the project, before the first version of the site was even launched. With support from the USGS NAWQA Program, in collaboration with contributors from the Academy of Natural Sciences of Drexel University and academic institutions, the database and website have been expanded.

We have also established an Editorial Review Board with a formal process for reviewing the species taxon pages. The content that you see on species pages has been prepared by an expert diatomist and reviewed by at least one member of the review board.

Site FAQ

Our list of Frequently Asked Questions (FAQ) serves as further guide to using the site, specific questions on content, and information on the database and code.