• Category
  • Length Range
    26.1-45.6 µm
  • Width Range
    6.0-7.2 at the valve center µm
  • Striae in 10 µm
    9-13
  • Synonyms
    Gomphonema angustatum var. distans (A.Cleve) A.Cleve 1955

Identification

Description

Valves are linear and triundulate. The headpole is subrostrate and the footpole is bluntly rounded. Valves are widest at the center valve. The axial area is narrow. The central area is a rectangular fascia, typically interrupted on one side by a shorter stria with an isolated stigma near the axial area. On some specimens, however, this shorter stria and stigma are absent. The raphe is lateral, becoming filiform near the proximal and terminal ends. Proximal raphe ends are straight. Terminal raphe fissures are deflected in the same direction, at about 45 degrees. Striae near the central area are parallel and curved; elsewhere they are radiate and straight. Areolae are very fine and difficult to distinguish in LM.

Autecology

This taxon was described from material collected in Finnish Lapland (Cleve-Euler 1934) and has been reported from Siberia (Lange-Bertalot and Genkal 1999). The specimens shown on this web page were collected from a lake and a pool in Nunavut, Canada, north of the Arctic Circle. The pH of these waters measured 8.30 and 8.10, respectively.

Sample 7 1
Credit: Beverly Boynton, Adventurers and Scientists for Conservation
September Mountains Lake, Nunavut, Canada.
Sample 7 2
Credit: Beverly Boynton, Adventurers and Scientists for Conservation
September Mountains Lake, Nunavut, Canada.
Sample 5 1
Credit: Beverly Boynton, Adventurers and Scientists for Conservation
Small pool on the tundra of Nunavut, Canada: home of Gomphonema nathorstii

Original Description

  • Basionym
    Gomphonema lagerheimii var. distans
  • Author
    A.Cleve 1934
  • Striae in 10µm
    5-6

Original Images

Gomphonema Distans Origimag001
Gomphonema Distans Origdesc001

Cite This Page

Bahls, L. (2016). Gomphonema distans. In Diatoms of North America. Retrieved July 21, 2018, from https://diatoms.org/species/gomphonema_distans

Responses

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