Aulacoseira canadensis | Species - Diatoms of North America

Category

Centric
Diameter

5-16 µm
Width Range

13-22 µm
Striae in 10 µm

6-11

Contributor

Loren Bahls - Mar 2012
Reviewer

Sarah Spaulding - Mar 2012

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Identification

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Description

Frustules are cylindrical and form colonies. Valves are 5-16 µm in diameter, with a mantle height of 13-22 µm. The ratio of mantle height to valve diameter is >1. The mantle has straight sides, but sides may be curved in smaller diameter cells. Rows of mantle areolae are straight, 6-11 in 10 µm, with 5-10 very large blocky or oblong areolae in 10 µm. In smaller diameter cells areolae may be disorganized and more widely spaced. The height of the collum varies between 1/3 and 1/10 of the mantle height. The valve face is usually covered by areolae, but in some specimens there are areolae only at the periphery of the valve face. Linking spines are present. The ringleiste is solid and located on the border between the collum and the part of the mantle containing areolae.

Autecology

When found in abundance, Aulacoseira canadensis is associated with freshwater lacustrine deposits of Miocene age, and none of the preserved material that we have examined contains protoplasm or plastids (Bahls et al. 2009). We therefore conclude that this taxon is probably extinct. Geological processes have redistributed fossil material throughout much of the interior Northwest (map), where occasional cells may appear in a wide variety of habitats.

Size Range, µm3

101-1000
Motility

Non-motile
Attachment

Unattached
Habitat

Planktonic
Extinct

Yes
Waterbody

Inland
Distribution

California coastal rivers 2017
Learn more about this

Credit: Bahls et al. 2009.

Distribution of Aulacoseira canadensis in western North America. "Q" marks the type locality at Quesnel, British Columbia. Other letters represent known fossil deposits.

Original Description

Basionym

Melosira canadensis
Author

Hust. 1952

Original Images

Citations & Links

Citations

Cite This Page

Bahls, L. (2012). Aulacoseira canadensis. In Diatoms of North America. Retrieved December 16, 2024, from https://diatoms.org/species/48479/aulacoseira_canadensis

Responses

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