• Category
  • Length Range
    24.7-43.8 µm
  • Width Range
    4.6-6.3 µm
  • Striae in 10 µm
    10-12 at the valve center, 12-14 at the headpole, 14-15 at the footpole

Identification

Description

Valves are linear-clavate to clavate. The apices are acutely rounded, markedly so in the footpole. The axial area is variable; linear-clavate valves have a narrowly lanceolate axial area, while clavate valves have a more broadly lanceolate axial area. Striae are weakly radiate at the valve center, becoming parallel toward the apices. The raphe is filiform and weakly undulate. The proximal raphe ends are deflected to the same side as the stigmoid. The distal raphe ends at the headpole is deflected to the opposite of the stigmoid.

Kociolek and Stoermer (1990) considered this taxon to be highly variable. The isotype slide (ANSP GC 55687a) showed two distinct morphologies of G. germanii. (see autecology section for additional images). One morphology is linear-clavate, with a narrow axial area. The second morphology is clavate, with a wide axial area. Comparisons to similar taxa were based on Lange-Bertalot (1986).

Autecology

Gomphonema germanii has been reported from epilithic habitats of Lake Huron, Lake Michigan, and Lake Superior (Kociolek and Stoermer 1990).

Gogermanii M1
Credit: Academy of Natural Sciences of Drexel University GC 55687a
Gomphonema germanii morphological group 1
Gogermanii M2
Credit: Academy of Natural Sciences of Drexel University GC 55687a
Gomphonema germanii morphological group 2

Original Description

Valves linear-clavate to lanceolate clavate with headpole apiculate and footpole narrow. The striae are punctate, radiate, 9-11|10 µm. The central area has the median stria approaching the isolated stigma. The axial area of variable width. Length 20-28 µm. Breadth 4.5-7.0 µm. The raphe is undulate and lateral and has prominent internal proximal raphe ends.

  • Author
    Kociolek and Stoermer 1990
  • Length Range
    20-58 µm
  • Width
    4.5-7.0 µm
  • Striae in 10µm
    9-11

Original Images

Gogermanii  Orimage
Gogermanii  Ordesc

Cite This Page

Burge, D. (2016). Gomphonema germainii. In Diatoms of North America. Retrieved August 19, 2018, from https://diatoms.org/species/gomphonema_germanii

Responses

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