Taxonomy, ultrastructure and distribution of Gomphonemoid diatoms (Bacillariophyceae) from Great Smoky Mountains National Park (USA)

The All Taxa Biodiversity Inventory (ATBI) of the Great Smoky Mountains National Park (GSMNP) is an ambitious effort to catalogue the entire biota of the park. As a part of this effort we are examining diversity and microhabitat affinities of microalgae. The focus of this paper is to better understand the morphology and ultrastructure of the genera Gomphonema, Gomphoneis, and Gomphosphenia in the GSMNP, which have traditionally been confusing from a taxonomic point of view. Over 300 collections have been studied with light and scanning electron microscopy. Collections have come from all aquatic habitats in the park from streams to ponds to wet rock walls. In the present study a total of 30 species have been identified; 27 were members of the genus Gomphonema, 2 of the genus Gomphoneis and I species of the genus Gomphosphenia. Twenty percent of the taxa identified are new to science, including five species of Gomphonema and the one species of Gomphosphenia. The present list of taxa is compared to past reports for the Park, and the geographic distributions of the taxa considered. This survey provides for a better understanding of species diversity of these genera, and offers insight into the possibility of finding new members of other genera in the Park and worldwide.