Diatoms Resources

Online Databases


Our online database includes approximately 63,000 diatom slides and 12,000 samples.

Click here to access our online database for the Diatom Herbarium.

Ongoing Projects

Diatoms as environmental indicators in mid-Atlantic coastal wetlands

Nutrients and climate change are leading causes of water quality deterioration in coastal wetlands. The goal of this research is to test applicability of diatoms as indicators of human impacts using analysis of surface sediments and sediment cores. This study generated a wealth of information about diatom flora and ecological preferences of coastal diatoms. We found that diatom assemblages in the New Jersey marshes shifted over time towards increased abundance of nitrogen-tolerant species. Our analysis revealed composition of diatom assemblages before these dramatic changes took place and the sets of diatom taxa were established that we recommend using as indicators of the “reference” or eutrophic conditions. This work has been supported by grants from New Jersey DEP, EPA and USGS.

Diatoms of the United States (DOTUS)

Diatom species composition and abundance are well known to reflect the biotic condition of streams and lakes. Together with aquatic invertebrates and fish, diatoms are an indispensable component of Federal and State monitoring programs. Unfortunately the existing taxonomic keys for the North American diatoms are incomplete or out of date and diatom analysts routinely use European taxonomic keys to identify American diatoms. Not only has this practice led to misidentification of species, but perhaps more important, there is a lack of taxonomic consistency within analyses and across programs. This project was initiated to provide free online access to accurate taxonomic and nomenclatural information on North American diatoms. This collaborative project involves many diatom scholars from North America and has been supported by the USGS and EPA. ANSP Diatom Herbarium is an important resource for developing DOTUS: we hosted several workshops bringing together experts and students working on DOTUS taxa pages and support the work by providing research material and data (See westerndiatoms.colorado.edu.)

Diatom DNA-metabarcoding for biomonitoring of New Jersey streams

Various protists, especially diatoms and other groups of microscopic algae possessing distinct morphological characters, have been traditionally used as water quality indicators. This type of assessment is based on morphological identification under light and electron microscopes and on the knowledge of their indicative properties. Many diatom taxa are known to be good indicators of specific environmental conditions, while their assemblage diversity has been shown to decline in particularly stressful conditions. The drawbacks of these morphology-based methods are inconsistencies in identification, lack of clear boundaries among morphologically-defined taxa, and, therefore, considerable uncertainties in environmental inferences. DNA-metabarcoding is a relatively new method of diatom biomonitoring, which allows for an automated identification of organisms from environmental samples but has inadequate taxonomic coverage in DNA reference databases. In this pilot study, we are comparing high-throughput DNA-metabarcoding methods against morphology-based assessments in characterizing high- vs. low-quality New Jersey streams. This project is currently supported by the New Jersey Department of Environmental Protection.

Digitization of the Diatom New Taxon File

The Diatom New Taxon File ("DNTF") was initiated by Dr. Ruth Patrick in the early 1950s as a centralized resource of all diatom names. For many years, Diatom Herbarium staff diligently maintained and updated this card catalog file, which today contains over 100,000 cards. In 2013, an external review committee recommended digitization and online posting of the DNTF, which has since been an ongoing effort. Since 2003, the DNTF has been supported by the Frank and Ruth Patrick Fund.

Renovation and computerization of ANSP Diatom Herbarium

The goal of this project is to make the resources of ANSP Diatom Herbarium easily accessible to scientists. We are reorganizing the Herbarium to facilitate the retrieval of materials and are developing a new online Herbarium database. The project has been supported by NSF grant DBI-0840406.

Diatoms of the North-Eastern Asia

In cooperation with scientists from the Russian Academy of Sciences we study diatoms of the North-Eastern Asia. Our collections from Kamchatka, Commander Islands, and the Magadan District provide an essential baseline for biogeographic studies and for studying the impacts of climate change in the North. This research has been supported by the Trust for Mutual Understanding for collaborative research on ecosystem monitoring in the Russian North-East.

Links of Interest

Diatom New Taxon File

Diatoms of the United States web project