Diatoms of North AmericaDiatoms of North America

Encyonema kamtschaticum var. parvum

Krammer 1997

Encyonema kamtschaticum parvum guide2
  • Category
    Asymmetric Biraphid
  • Length Range
    23.3-55.7 µm
  • Width Range
    7.9-12.7 µm
  • Striae in 10 µm
    11-14 dorsal at valve center; 12-15 dorsal at valve apices; 9-11 ventral at valve center; 12-16 ventral at valve apices

Identification

Encyonema kamtschaticum parvum LM1 Encyonema kamtschaticum parvum LM2 Encyonema kamtschaticum parvum LM3 Encyonema kamtschaticum parvum LM4 Encyonema kamtschaticum parvum LM5 Encyonema kamtschaticum parvum LM6 Encyonema kamtschaticum parvum LM7
View image metadata

Description

Valves are dorsiventral, with narrow apices. The dorsal margin is moderately arched. The ventral margin is weakly concave, with a tumid center. The axial area is narrow and the central area is slightly wider than the axial area. The raphe is lateral, narrowing near the proximal and distal ends. Proximal raphe ends are deflected, with weakly inflated pores. The distal raphe ends are comma-shaped and ventrally deflected. Dorsal striae are radiate. Ventral striae are radiate at the valve center and less than 1/4 the valve width, transitioning to convergent near the apices. Areolae number 18-24 in 10 µm.

Stria and areola densities were measured following the method of Spaulding et al. (2010): A: 11-14; B: 6-7.5; C: 9-11; D: 6-8; E: 9-12.

This taxon is a member of a diverse and poorly known group. The group seems to have its greatest diversity in the western and northwestern US, and has yet to be adequately described.

Autecology

Encyonema kamtschaticum var. parvum is widely distributed in rivers and creeks from western Montana to western Oregon, including the Snake River on the Idaho/Oregon border. The pH of these waters ranges from 7.2 to 8.6 and specific conductance ranges from 27 to 154 µS/cm. Krammer (1997) reports that the variety parva occurs in Mexico and the nominate variety in Colorado.

Two populations of E. kamtscaticum var. parvum are shown below alongside populations of the nominate variety. Variety parvum was a dominant taxon in Rock Creek, Montana, where it was found with the less common nominate variety. The other plate shows taxa in the Encyonema temperei group (formerly the "muelleri" group) from the western United States, including Encyonema kamtschaticum var. parvum and Encyonema kamtschaticum.

Snow Creek Or Orsnw1010 2191
Credit: Kirsten Gallo, Siuslaw National Forest
Snow Creek, Deschutes County, Oregon.
Encyonema Kamtschaticum Parvum
Credit: Loren Bahls
Two populations of Encyonema kamtschaticum var. parvum from Montana and Oregon (figs 13-25) compared to populations of the nominate variety (figs 1-12).
Encyonema reimeri Sensu Lato Copy
Credit: Loren Bahls
Taxa in the Encyonema reimeri group from the western United States.

Original Description

  • Author
    Krammer 1997
  • Length Range
    26-56 µm
  • Width
    10-15.4 µm
  • Striae in 10µm
    10-11

Original Images

Encyonema kamtschaticum var. parva orig illus
Encyonema Kamtschaticum Parva Origdesc001

Cite This Page

Bahls, L. (2016). Encyonema kamtschaticum var. parvum. In Diatoms of North America. Retrieved December 16, 2024, from https://diatoms.org/species/51636/encyonema_kamtschaticum_parvum

Responses

The 15 response plots show an environmental variable (x axis) against the relative abundance (y axis) of Encyonema kamtschaticum var. parvum 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.

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