LM scalebar = 10 µm = 40 pixels.
Observations
Contributor: Marina Potapova - May 2009
Length Range: 6-30 µm
Width Range: 5-15 µm
Striae in 10 µm:
Description
Cells are cylindrical, forming chains. Frustules are 6-30 µm in diameter with a mantle height of 5-15 µm. The valve face is slightly convex, covered with small spines. The mantle is covered by small granules. The frustule has a loculate structure. Numerous rimoportulae are scattered over valve face and mantle and one row of rimoportulae occurs on the mantle edge.
Original Description
Basionym: Meloseira varians
Author: Agardh 1827
Length Range: µm
Striae in 10 µm:
Original Description
Meloseira varians, caespite fusco fluctuante, filis crassitie variis fragilissimis aureis, articulis diametro aequalibus, geniculis contractis interdum aequalibus et tunc genicula simulantibus.
Original Images
Cite This Page:
Potapova, M. (2009). Melosira varians. In Diatoms of the United States. Retrieved May 23, 2013, from http://westerndiatoms.colorado.edu/taxa/species/Melosira_varians
Species: Melosira varians
Contributor: Marina Potapova
Reviewer: Sam Rushforth
Image Credit: Marina Potapova
- Cells cylindrical, forming filaments of linked cells
- Valve face and margin with little to no ornamentation
Cells cylindrical, often forming long chains. Valve face slightly convex, covered with very small spines. Unlike many Aulacoseira species, valves lack areolae.
Compare
Melosira varians has more lightly silicified cell walls than Melosira lineata. The valve mantle of M. varians is relatively thin and straight, as compared to the thick, curved interior mantle of M. lineata. While M. varians is a very common diatom, M. lineata is restricted to low nutrient waters of the western US.
Melosira lineata
Citations
Agardh, C.A. (1827). Aufzählung einiger in den ostereichischen Ländern gefundenen neuen Gattungen und Arten von Algen nebst ihrer Diagnostik und beigefugten Bemerkungen. Flora oder Botanische Zeitung, Regensburg 2:625-640.
Crawford, R.M. (1978). The taxonomy and classification of the diatom genus Melosira C. A. Agardh. III. Melosira lineata (Dillw.) C.A. Ag. and M. varians C.A.Ag. Phycologia 17(3): 237-250.
Links & ID's
Index Nominum Algarum (INA)
California Academy of Sciences (CAS)
North American Diatom Ecological Database (NADED)
NADED ID: 44073
Autecology Discussion
Benthic and planktonic
Images
Living cells of M. varians grow in long filaments
Credit/Source: Mark Edlund
EMAP Assessment
Sampling for 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). Streams and rivers in 12 western states (Arizona, California, Colorado, Idaho, Montana, Nevada, North Dakota, Oregon, South Dakota, Utah, Washington and Wyoming). Over 1200 sites on 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.
EMAP Distribution
Melosira varians
Distribution
The distribution map represents the relative abundance of this Melosira varians in the western EMAP study. Relative abundance is a measure of the proportion of cells of this species based on a "fixed count" of 300 total diatom cells counted and identified. Each of the western EMAP sample sites is shown, either with a black dot for sites where Melosira varians was not recorded, or with a red circle indicating the relative abundance of Melosira varians.
Note that the size of the proportional symbols varies between species to help show both abundant and rare species.
Scale for the map to the left
EMAP Response Plots
Melosira varians
EMAP citations
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.