Species composition and abundance of diatoms in streams and rivers are a crucial measure of biotic condition as diatoms are sensitive to impacts caused by human activities such as urbanization, flow alteration, and the loading of contaminants, nutrients and sediment. Regional surveys of rivers by the U.S. Geological Survey
(USGS) National Water Quality Assessment Program (NAWQA) were designed to evaluate the effects of these stressors on aquatic organisms, including diatoms.
Algal samples were collected at 108 sites in 2014, from streams representing gradients in chemical and physical alteration across the southeast region. More than 375 taxa were identified during analysis for species composition and abundance. A flora of diatoms in the region was published:
Bishop, I.W., Esposito, R.M., Tyree, M. and Spaulding, S.A. 2017. A diatom voucher flora from selected southeast rivers (USA). Phytotaxa.
A number of taxon pages were developed based on this material. In addition, a workshop on species of Gomphonema was based primarily on specimens from the southeast.