Kociolek and Kingston 1999 Category: Asymmetrical biraphid
BASIONYM: Gomphonema occidentale var. abbreviate M. Schmidt 1899
Contributor: Pat Kociolek - March 2011
Length Range: 19-45 µm
Width Range: 4-6 µm
Striae in 10 µm: 13-15
Valves are linear-lanceolate, clavate, headpole and footpole are rounded. The axial area is lanceolate. The central area is linear-ellipitic and slightly asymmetric, with the side opposite the stigma larger than the side bearing the stigma. A single, large, distinct stigma is present at the central area. The raphe is lateral and weakly undulate to nearly straight. The external proximal raphe ends terminate close to one another. External distal raphe ends are deflected onto the mantle, to the side of the valve opposite the stigma. Striae are parallel to radiate at the center and towards the headpole, becoming more strongly radiate at the footpole. Striae number 13-15 in 10 µm. The apical pore field is bi-lobed and prominent.
Under SEM, the striae are doubly punctate.
Basionym: Gomphonema occidentale var. abbreviate
Author: M. Schmidt 1899
Length Range: µm
Striae in 10 µm:
Kociolek, J.P. and Kingston, J.C. (1999). Taxonomy, ultrastructure, and distribution of some gomphonemoid diatoms (Bacillariophyceae: Gomphonemataceae) from rivers in the United States. Canadian Journal of Botany 77: 686-705. 10.1139/cjb-77-5-686
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.