• Category
  • Length Range
    39-49 µm
  • Width Range
    7.5-8.6 µm
  • Striae in 10 µm



Valves are lanceolate with short, rostrate apices. Raphe branches are filiform. Proximal raphe ends are straight or deflected slightly to one side. Distal raphe fissures are hooked to the secondary side. The axial area is very narrow. The central area is small and lanceolate and bordered by irregularly shortened striae, often alternating long and short. Striae are radiate and become strongly convergent near the apices. Areolae number 32–36 in 10 μm and are barely visible in LM.


Navicula schweigeri has been found in 18 lakes and streams in western Montana and southern Alberta, where it is present in low numbers. This taxon prefers waters with neutral to somewhat alkaline pH (range = 7.1-8.7) and low to moderate levels of electrolytes (range = 90-201 μS/cm).

Lake  Mc Donald  March 12 2011
Credit: National Park Service webcam photo.
Lake McDonald in winter, Glacier National Park, Montana. Lake McDonald is home to Navicula schweigeri.

Original Description

Valves lanceolate with short protracted and obtusely rounded ends, 39 – 49 μm long, 7.5 – 8.6 μm wide. Raphe filiform, proximal endings straight or deflected slightly to one side, distal raphe fissures hooked to the secondary side. Axial area very narrow. Central area small and lanceolate, bordered by irregularly shortened striae. Striae radiate, becoming strongly convergent toward the ends, 12 –14 in 10 μm, lineolae 32 – 36 in 10 μm, barely visible in LM. For measurements, n = 22 valves.

  • Author
    L.L.Bahls 2012
  • Length Range
    39-49 µm
  • Width
    7.5-8.6 µm
  • Striae in 10µm

Original Images

Nschweigeri Origimag
Nschweigeri Origdesc

Cite This Page

Bahls, L. (2012). Navicula schweigeri. In Diatoms of North America. Retrieved August 19, 2018, from https://diatoms.org/species/navicula_schweigeri


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