Diatom identification guide & ecological resource

for water resource managers, ecologists, taxonomists, analysts, systematists, students, and the public.

To contributors of the Diatoms of the US project:

In anticipation of migration and revision of this site, the last day for data entry and editing on the current system will be FRIDAY MARCH 30, 2018.

The site will continue to function as usual, until it is replaced by the new version later in April. Stay posted!

In the meantime, if you see issues with content or functionality, please let us know.

Halamphora elongata


157 Completed
22 Underway
883 Completed
188 Underway
1071 TOTAL

Getting Started

About this website

What are diatoms?

Identify your taxa

Special News

26 June, 2015

Editorial Review Guidelines

25 March, 2011

Information for contributors


23 March, 2018

Standardization of taxon authorship names

13 February, 2018

Tiny fossils, huge slides

More news...


Ecology and Systematics of Diatoms course, 2014

Ecology and Systematics of Diatoms course, 2015

Taxon pages supported by EPA Office of Water

More projects...