Diatoms of North AmericaDiatoms of North America

Encyonopsis subminuta

Krammer and E.Reichardt 1997

Encyonopsis Subminuta Guide
  • Category
    Asymmetric Biraphid
  • Length Range
    10-15 µm
  • Width Range
    3-4 µm
  • Striae in 10 µm
    23-27

Identification

Encyonemopsis Subminuta 002 Encyonemopsis Subminuta 001 Encyonemopsis Subminuta 003 Encyonemopsis Subminuta 006 Encyonemopsis Subminuta 004
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Description

Valves are slightly asymmetrical to the apical axis, with both the dorsal and ventral margins slightly convex. The apices are protracted, relatively narrow and short. The axial area is very narrow, linear. A central area is absent. The raphe is slightly arched, filiform, with external proximal ends dilated slightly. Striae are radiate to nearly parallel.

Autecology

This taxon has been reported with light micrographs from the Rocky mountains, Great Plains, Cascades, Coast Ranges, Sierras, and the California Imperial Valley (Bahls 2021).

In the Great Lakes National Parks (Edlund et al. 2009, 2011, 2012, 2013), this taxon is common (5-25% abundance) in sediment core material from Sleeping Bear Dunes (Florence and Bass lakes), and uncommon (1-5% abundance) to rare (0.1-1% abundance) at Pictured Rocks (Beaver Lake) and Voyageurs (Cruiser, Little Trout, Mukooda, Ek, Locator, Ryan and Brown lakes).

This taxon is reported to occur in rivers, creeks and lakes, with a preference for montane habitats (Bahls 2021). It prefers cool, alkaline waters with moderate conductivity and nutrient content (Bahls 2021).

Several research groups consider this taxon an indicator organism and published regional environmental optima and tolerances including:

Bahls (2021): Conductivity - 389 µS/cm, pH - 8.0, Temperature - 16.4°C, Total Nitrogen - 0.38 mg/L, Total Phosphorus - 33 µg/L for populations from Northwestern North America.

Original Description

  • Author
    Krammer and E.Reichardt 1997
  • Length Range
    10-26 µm
  • Width
    3.4-4.5 µm
  • Striae in 10µm
    23-26

Original Images

Krammer 1997 Tafel 144
Krammer 1997 P96

Citations & Links

Citations

Links

  • Index Nominum Algarum
    Original
  • North American Diatom Ecological Database
    NADED ID: 203008

Updates

Feb 11, 2026 - Addition to Autecology

From 2011 to until 2026, the autecological information on this taxon page was limited. As of this update, information on ecology, biogeography, and environmental optima have been added. - Lane Allen and Mark Edlund

Cite This Page

Kociolek, P., Edlund, M., Allen, L. (2011). Encyonopsis subminuta. In Diatoms of North America. Retrieved March 23, 2026, from https://diatoms.org/species/46361/encyonopsis_subminuta

Responses

The 15 response plots show an environmental variable (x axis) against the relative abundance (y axis) of Encyonopsis subminuta 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.