Achnanthidium rivulare

Potapova et Ponader 2004      Category: Monoraphid
BASIONYM: Achnanthidium rivulare Potapova et Ponader 2004

Achnanthidium reimeri

 

Actinella punctata

LM scalebar = 10 µm = 80 pixels.



Observations

Contributor: Marina Potapova - May 2009
Length Range: 5.4-23.8 µm
Width Range: 2.6-4.4 µm
Striae in 10 µm: 19-25 in the middle of raphe valve, 19-28 in the middle of the rapheless valve

Description

Valves are linear-elliptical, with rounded or slightly protracted apices. Valve length is 5.4-23.8 µm and width is 2.6-4.4 µm. The raphe valve is concave with a linear-lanceolate axial area, widening slightly in the middle portion of the valve. Externally, the terminal raphe fissures are hooked toward the same side of the valve. The central raphe endings are teardrop-shaped externally, while internally, they curve to opposite sides of the valve. The rapheless valve is convex with a narrow, linear axial area widening slightly in the middle portion of the valve. Striae are parallel throughout most of both valves, becoming slightly convergent or parallel near apices of the raphe valve and slightly radiate near apices of the rapheless valve. Striae density is 19-25 in 10 µm at valve center and up to 55 in 10 µm near the apices of rapheless valve. Areolae have small round or slightly transversely elongated external openings and transversely elliptical internal openings occluded by hymenes. Each stria in the middle part of the valve contains 5-6 (occasionally 7) areolae on the valve face and one areola on the mantle.



Original Description

Basionym: Achnanthidium rivulare
Author: Potapova et Ponader 2004
Length Range: 5.4-21.3 µm
Width Range: 2.6-4.4 µm
Striae in 10 µm: 19-25 in the center raphe valve, 19-28 in the center of the rapheless valve

Original Description

Valves linear-elliptical, 5.4-21.3 µm long, 2.6-4.4 µm wide, with rounded or slightly protracted apices. Raphe valve concave with linear-lanceolate sternum widening slightly only in the middle portion of the valve. Terminal raphe fissures externally hooked toward the same side of the valve. Central raphe endings teardrop-shaped externally, curved to opposite sides internally. Rapheless valve convex, with narrow linear sternum widening slightly in the middle. Striae parallel throughout most of both valves, slightly radiate near apices of rapheless valve and slightly convergent or parallel near apices of raphe valve. Striae density 19-25 in 10 µm at valve center and up to 55 in 10 µm near apices of rapheless valve. Areolae have small round or slightly transversely elongated external openings and transversely elliptical internal openings occluded by hymenes. Each stria in the middle part of the valve contains 5-6 (occasionally 7) areolae on the valve face and one areola on the mantle.

Original Images

Original text and images reproduced with permission by Biopress Ltd..


Cite This Page:
Potapova, M. (2009). Achnanthidium rivulare. In Diatoms of the United States. Retrieved April 16, 2014, from http://westerndiatoms.colorado.edu/taxa/species/Achnanthidium_rivulare

Species: Achnanthidium rivulare

Contributor: Marina Potapova

Reviewer: Sarah Spaulding

Citations

Potapova, M. and Ponader, K.C. (2004). Two common North American diatoms, Achnanthidium rivulare sp. nov. and A. deflexum (Reimer) Kingston: morphology, ecology and comparison with related species. Diatom Research 19(1): 33-57.

Links & ID's

Index Nominum Algarum (INA)

Original INA

California Academy of Sciences (CAS)

Achnanthidium rivulare CAS

North American Diatom Ecological Database (NADED)

NADED ID: 1036

Autecology Discussion

Although formation of mucilaginous stalks was never observed in A. rivulare, this species might be able to produce stalk as other Achnanthidium species.

In the Appalachian region of the US (Ponader and Potapova 2007), A. rivulare was widespread and had a pH optimum of around 7.3, although in previous analysis carried out on the scale of continental US, its pH optimum was around 6 (Potapova and Ponader 2004) . Compared to other species of Achnanthidium in Appalachia, A. rivulare has a greater tolerance for elevated nutrient concentrations. Modeling results indicate that the distribution of this species is related to ionic composition. For example, A. rivulare has an affinity for relatively low calcium and high chloride concentrations.

EMAP Assessment

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.


EMAP Distribution

Achnanthidium rivulare


EMAP Response Plots

Achnanthidium rivulare


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.