• Category
  • Length Range
    70-114 (greatest valve dimension) µm
  • Synonyms
    Campylodiscus noricus var. hibernicus (Ehrenb.) Grunow



Cells are solitary, with saddle-shaped valves. Frustules are large with the greatest valve dimension, or diameter, at 70-114 µm. Within a frustule, the valves are oriented perpendicular to one another, that is, the proximal and distal raphe ends are offset from one another by 90 degrees. Furthermore, the valves are curved in both the apical and transapical planes. The raphe is positioned within a marginal canal, raised onto a keel, supported by alar canals. The density of alar canals is 16-20 in 100 µm. The fibula density does not appear to be related to valve diameter. Under SEM, the internal face of the valve is smooth. Externally, numerous short, robust spines cover the valve face and are often more numerous along the radial ridges.

Chloroplast structure has been reported (Round et al. 1990) as “one plastid, divided into two valve-appressed plates with lobed margins, linked by a narrow isthmus.” European floras include a wider range in fibula density, 10-20 in 100 µm (Krammer and Lange-Bertalot 1988).


Campylodiscus hibernicus was found in a benthic dredge sample in a deep location of West Lake Okoboji, Dickinson County, Iowa. In specimens from the Reimer Herbarium, C. hibernicus was found in planktonic, epiphytic and epilithic samples of Lake Okoboji. The genus Campylodiscus is typically associated with the epipelon and can be found in fresh, brackish, and marine waters (Round et al. 1990). Campylodiscus can also be tychoplanktonic, becoming resuspended into the water column during periods of turnover or high turbidity, resulting in its inclusion in samples of other substrata. The large frustules are likely to settle to the lake bottom resulting in relatively high benthic populations.

Other distributional and ecological records include central Italy (Ramrath et al. 1999) and western Tibet (Van Campo and Gasse 1993). In a sediment core taken from Lago di Mezzano, one of the most dominant diatom species was C. hibernicus in both the Pleistocene unit and the Late Glacial/Holocene unit; the presence of C. hibernicus in turbidites within the core indicated that it could have been transported into the lake from the shore (Ramrath et al. 1999). Campylodiscus hibernicus was also one of the dominant diatom species in the uppermost part of a sediment core taken in the Sumxi Co Basin of western Tibet, reflective of the slightly oligosaline status and relatively shallow state of the modern lake (Van Campo and Gasse 1993).

Original Description

  • Author
    Ehrenb. 1845

Original Images

Ec Dr 0221

EMAP Assessment

EMAP Distribution

Campylodiscus Hibernicus 40 Copy
Map 40

Response Plots

Campylodiscus Hibernicus Copy

Cite This Page

Lee, S. (2011). Campylodiscus hibernicus. In Diatoms of North America. Retrieved July 22, 2018, from https://diatoms.org/species/campylodiscus_hibernicus


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