• Category
  • Diameter
    5-7.5 µm
  • Striae in 10 µm



Cyclotella atomus has a flat valve face with short striae arranged around the margin on the valve. A fultoportula can be seen toward the center of the valve (but slightly off center) appearing as a dark dot. Marginal fultoportulae occur on every fourth to fifth costa and can be seen in deep focus as dark spots.


Common in warm nutrient-rich rivers.

Original Description

  • Author
    Hust. 1937
  • Length Range
    4-5 µm
  • Striae in 10µm

Original Images

Cyclotella atomus orig illus
Cyclotella atomus orig illus

Cite This Page

Lowe, R. (2015). Cyclotella atomus. In Diatoms of North America. Retrieved April 16, 2024, from https://diatoms.org/species/cyclotella_atomus


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