Pinnularia gigas | Species - Diatoms of North America

Category

Symmetric Biraphid
Length Range

172.7-297.0 µm
Width Range

39.3-64.0 µm
Striae in 10 µm

4-5

Reported As

Pinnularia dactylus (Patrick and Reimer 1966, p. 632, plate 62, fig. 4)
Pinnularia dactylus (Krammer and Lange-Bertalot 1986, p. 430, fig. 198: 1)

Contributor

Loren Bahls - Mar 2014
Reviewer

Marina Potapova - Oct 2014

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Identification

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Description

Valves are large and linear-elliptic with slightly convex margins and rounded apices. The post-initial valves are tumid in the center. The central area is asymmetric and rounded. The raphe is distinctly lateral and complex (a raphe with an extremely curved outer fissure). Proximal raphe ends are deflected to one side and terminate in small pores. Terminal raphe fissures are S-shaped, or bayonet-shaped depending on the depth of focus. Striae are radiate at the valve center, becoming parallel near the apices. Striae are crossed by a broad longitudinal line. The proximal edge of this band is distinct.

Autecology

The specimens of P. gigas pictured on this website are from two small ponds and a fen in Glacier National Park, Montana. In these waters, pH ranges from 6.02 to 7.34 and specific conductance from 31 to 71 µS/cm. Krammer (2000) reports this species from nordic-alpine regions in oligotrophic waters with low electrolyte content and low pH.

Size Range, µm3

100001-1000000
Motility

Moderately motile
Attachment

Unattached
Habitat

Benthic
Colony

Solitary
Waterbody

Inland
Learn more about this

Credit: Loren Bahls

Atlantic Pond, Glacier National Park, Montana: home of Pinnularia gigas.

Original Description

Author

Ehrenb. 1843

Citations & Links

Citations

Cite This Page

Bahls, L. (2014). Pinnularia gigas. In Diatoms of North America. Retrieved December 21, 2024, from https://diatoms.org/species/49805/pinnularia_gigas

Responses

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