Ehrenberg 1843 Category: Symmetrical biraphid
BASIONYM: Pinnularia borealis Ehrenberg 1843
Contributor: Loren Bahls - March 2014
Length Range: 27-48 µm
Width Range: 8.0-10.2 µm
Striae in 10 µm: 5-6
Valves are linear to linear-elliptic, with parallel to moderately convex margins. Apices are broadly rounded and not protracted. The axial area is narrow. A large transverse central area is formed by one or two shorter striae on each side. The raphe is filiform, to weakly lateral and straight. Proximal raphe ends are deflected to one side and tipped with expanded pores. Distal raphe ends are sickle-shaped. Striae are broad and widely separated, weakly radiate near the valve center and becoming convergent toward the apices.
Pinnularia borealis encompasses a large infraspecific complex. The nominate variety is pictured and described here. This is the most typical and most common form in the complex.
Basionym: Pinnularia borealis
Author: Ehrenberg 1843
Length Range: µm
Striae in 10 µm:
Ehrenberg, C.G. (1843). Verbreitung und Einfluß des mikroskopischen Lebens in Süd- und Nord-Amerika. Abhandlungen der Königlichen Akademie der Wissenschaften zu Berlin, 1841: 291-445, 4 Tafel.
Krammer, K. (1992). Die Gattung Pinnularia in Bayern. Hoppea 52: 1-308.
Krammer, K. (2000). The genus Pinnularia. The Diatoms of Europe. Diatoms of Inland Waters and Comparable Habitats 1: 1-703.
Krammer, K. and Lange-Bertalot, H. (1986). Bacillariophyceae. 1. Teil: Naviculaceae. In: Ettl, H., J. Gerloff, H. Heynig and D. Mollenhauer (eds.) Süsswasserflora von Mitteleuropa, Band 2/1. Gustav Fisher Verlag, Jena. 876 pp.
Patrick, R.M. and Reimer, C.W. (1966). The Diatoms of the United States exclusive of Alaska and Hawaii, V. 1. Monographs of the Academy of Natural Sciences of Philadelphia 13.
Pinnularia borealis is a common cosmopolitan species found in aerial habitats (rocks, walls, soil, moss) and flowing and standing waters (Krammer 2000). The specimens pictured and described on this web page are from a variety of habitats in the Northwest United States.
The Environmental Protection Agency (EPA) western Environmental Monitoring and Assessment Program (EMAP) study was completed during the years 2000-2004 (see citations at bottom of this page). Over 1200 streams and rivers in 12 western states (Arizona, California, Colorado, Idaho, Montana, Nevada, North Dakota, Oregon, South Dakota, Utah, Washington and Wyoming) were selected for sampling based on a stratified randomized design. This type of design insures that ecological resources are sampled in proportion to their actual geographical presence. Stratified randomized design also allows for estimates of stream length with a known confidence in several “condition classes” (good or least-disturbed, intermediately-disturbed, and poor or most-disturbed) for biotic condition, chemistry and habitat.
Results are published in:
Johnson, T., Hermann, K., Spaulding, S., Beyea, B., Theel, C., Sada, R., Bollman, W., Bowman, J., Larsen, A., Vining, K., Ostermiller, J., Petersen, D. Hargett, E. and Zumberge, J. (2009). An ecological assessment of USEPA Region 8 streams and rivers. U.S. Environmental Protection Agency Region 8 Report, 178 p.
Stoddard, J. L., Peck, D. V., Olsen, A. R., Larsen, D. P., Van Sickle, J., Hawkins, C. P., Hughes, R. M., Whittier, T. R., Lomnicky, G. A., Herlihy, A. T., Kaufman, P. R., Peterson, S. A., Ringold, P. L., Paulsen, S. G., and Blair, R. (2005). Environmental Monitoring and Assessment Program (EMAP) western streams and rivers statistical summary. U.S. Environmental Protection Agency Report 620/R-05/006, 1,762 p.
Stoddard, J. L., Peck, D. V., Paulsen, S. G., Van Sickle, J., Hawkins, C. P., Herlihy, A. T., Hughes, R. M., Kaufman, P. R., Larsen, D. P., Lomnicky, G. A., Olsen, A. R., Peterson, S. A., Ringold, P. L., and Whittier, T. R. (2005). An ecological assessment of western streams and rivers. U.S. Environmental Protection Agency Report 620/R-05/005, 49 p.