Cocconeis pediculus

Cocconeis pediculus was found in an epilithon sample from the Bronx River, southeastern New York state (early April); in plankton, epiphyton, epipelon, and epilithic samples from Lake Okoboji, Dickinson County, Iowa (late May); and in high abundance in a epilithon sample from Grove Lake, Antelope County, Nebraska (late May). The Reimer Collection at Iowa Lakeside Lab contains C. pediculus specimens collected from late May to early August from planktonic, epiphytic, epilithic, and benthic habitats in various aquatic systems in Dickinson County, Iowa. In addition, the collection has specimens of C. pediculus from a dry epilithic sample at Skunk River, Story County, Iowa taken in late July; Brewer’s Creek, Hamilton County, Iowa taken in late October; and an epilithic sample at Shell Rock River, Cerro Gordo County taken in late May.

Patrick and Reimer (1966) noted that Cocconeis pediculus is sometimes considered a pollution tolerant species, while Lange-Bertalot classified C. pediculus as pollution intolerant (Brown and Olive 1995). The EMAP assessment shows that C. pediculus can be found in a relatively wide range of environmental conditions.

Cocconeis pediculus has also been reported in periphyton samples from the upper reaches of the Cuyahoga River, which flows into Lake Erie (Brown and Olive 1995). In a study of Cladophora epiphyton in Lake Ontario, C. pediculus dominated the diatom community, which the authors hypothesized may be due to stronger attachment to the substrate or to greater resource use efficiency (Malkin et al. 2009). Other reports of C. pediculus include southern California in the Salton Sea, which C. pediculus likely entered via inflow from freshwater streams (Lange and Tiffany 2002), and the Colorado River, where C. pediculus was particularly abundant in the upstream regions of this reach near Lees Ferry and Nankoweap Creek (Hardwick et al. 1992).