Eucocconeis flexella

(Kützing) Meister 1912      Category: Monoraphid
BASIONYM: Cymbella flexella Kützing 1844
SYNONYM(S): Achnanthes flexella (Kützing) Brun 

Eucocconeis americana

 

Eucocconeis laevis
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LM scalebar = 10 µm = 40 pixels.

Observations

Contributor: Marina Potapova - October 2010
Length Range: 18-40 µm
Width Range: 9-20 µm
Striae in 10 µm: 22-24 in center valve

Description

Frustules are strongly bent in girdle view with concave raphe valve and convex rapheless valve. Valves are elliptical-lanceolate with slightly drawn-out ends and deep mantles. Valve face has depressions along the margins. The raphe valve has a narrow axial area and a lanceolate-rhomboid central area. The raphe is straight or slightly sigmoid with terminal ends sharply turned to opposite directions. Rapheless valve has a narrow linear or slightly sigmoid axial area and a large rectangular or hexagonal central area. The striae are punctate, strongly radiate on raphe valve and slightly radiate on rapheless valve, 22-24 in 10 μm.

Original Description

Basionym: Cymbella flexella
Author: Kützing 1844
Length Range: 41 µm
Striae in 10 µm:

Original Description

CYMBELLA? FLEXELLA. Taf. 4. Fig. XIV, Taf. 6. Fig. VIII. (420/1). C. laevissima, mi¬nor, a latere secundario elliptica, subsigmoidea, apicibus parum productis obtusis, altero latere cur-vata, (genuflexa) dorso convexo, ventre concavo exciso, apice truncato. In Quellwasser bei Thun in der Schweiz! — Länge 1/55"'.

Original Images

Cite This Page:
Potapova, M. (2010). Eucocconeis flexella. In Diatoms of the United States. Retrieved May 23, 2013, from http://westerndiatoms.colorado.edu/taxa/species/eucocconeis_flexella

Species: Eucocconeis flexella

Contributor: Marina Potapova

Reviewer: Mark Edlund

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Image Credit: Marina Potapova

  1. Frustules large, 18-40 μm long
  2. Frustules strongly bent
  3. Striae 22-24 in 10 μm

Frustules are large and strongly bent. Valves are elliptical-lanceolate with slightly drawn-out ends and deep mantles. The raphe valve has lanceolate-rhomboid central area. The rapheless valve has a large rectangular or hexagonal central area. The striae are strongly radiate on raphe valve and slightly radiate on rapheless valve, 22-24 in 10 μm.

Compare

Eucocconeis flexella is easily distinguished from other species of Eucocconeis by its large and strongly bent frustules. Eucocconeis alpestris is smaller and has parallelogram-shaped, often twisted, frustules.

Eucocconeis alpestris

Citations

Kützing, F.T. (1844). Die kieselschaligen Bacillarien oder Diatomeen. Nordhausen. 152 pp., 30 pls.

Meister, F. (1912). Die Kieselalgen der Schweiz. Beiträge zur Kryptogamenflora der Schweiz, 4/1, 1–254.

Links & ID's

Index Nominum Algarum (INA)

Original INA

California Academy of Sciences (CAS)

Eucocconeis flexella CAS

North American Diatom Ecological Database (NADED)

NADED ID: 187001

Autecology Discussion

Habits

Size Range

1001-10,000 µm3 (ie Diatoma vulgaris)

Motility

slightly motile (e.g. Cocconeis)

Attachment

prostrate (e.g. mucilage pad)

Habitat

benthic

Colony

solitary

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

Eucocconeis flexella

Distribution

The distribution map represents the relative abundance of this Eucocconeis flexella 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 Eucocconeis flexella was not recorded, or with a red circle indicating the relative abundance of Eucocconeis flexella.

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

Eucocconeis flexella

Responses

The 15 response plots show an environmental variable (x axis) against the relative abundance (y axis) of Eucocconeis flexella from all the stream reaches where it was present. Note that the relative abundance scale is the same on each plot. Explanation of each environmental variable and units are as follows:

ELEVATION = stream reach elevation (meters)
STRAHLER = distribution plot of the Strahler Stream Order
SLOPE = stream reach gradient (degrees)
W1_HALL = an index that is a measure of streamside (riparian) human activity that ranges from 0 - 10, with a value of 0 indicating of minimal disturbance to a value of 10 indicating severe disturbance.
PHSTVL = pH measured in a sealed syringe sample (pH units)
log_COND = log concentration of specific conductivity (µS/cm)
log_PTL = log concentration of total phosphorus (µg/L)
log_NO3 = log concentration of nitrate (µeq/L)
log_DOC = log concentration of dissolved organic carbon (mg/L)
log_SIO2 = log concentration of silicon (mg/L)
log_NA = log concentration of sodium (µeq/L)
log_HCO3 = log concentration of the bicarbonate ion (µeq/L)
EMBED = percent of the stream substrate that is embedded by sand and fine sediment
log_TURBIDITY = log of turbidity, a measure of cloudiness of water, in nephelometric turbidity units (NTU).
DISTOT = an index of total human disturbance in the watershed that ranges from 1 - 100, with a value of 0 indicating of minimal disturbance to a value of 100 indicating severe disturbance.

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.