Contributor: Marina Potapova - February 2011
Length Range: 35-70 µm
Width Range: 6-7 µm
Striae in 10 µm: 11-12
Valves are linear with slightly protracted ends. Axial area is narrow. Central area is moderately asymmetrical, wedge-shaped or irregularly shaped. The central area is larger on the primary side, and semi-elliptical and smaller on the secondary side, but in some specimens it may be nearly symmetrical. Central raphe endings are slightly expanded. Striae are radiate at the central valve, convergent near the apices. Striae are 11-12 in 10 µm. Areolae are lineolate, with approximately 32 in 10 µm.
Basionym: Navicula angusta
Author: Grunow 1860
Length Range: 43-51 µm
Width Range: 5.1-5.8 µm
Striae in 10 µm: 12.6
Navicula a latere secundo anguste lanceolata, apicibus obsolete productis, nodulo centrali oblongo, striis obscure punctatis radiantibus 32 in 0.001’”. Longitud. 0.0020-0.0017”, latid. 0.0002-0.00023”.
Grunow, A. (1860). Uber neue oder ungenügend gekannte Algen. Verhandlungen der Kaiserlich-Königlichen Zoologisch-Botanischen Gesellschaft in Wein, 10: 503-582.
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.