Valves are dorsiventral and lanceolate, with rounded apices. The dorsal margin is strongly arched; the ventral margin is convex, sometimes with a slightly tumid center. The central area is a somewhat wider continuation of the axial area. The raphe is distinctly lateral. The raphe is filiform to weakly reverse-lateral and ventrally deflected. Proximal raphe ends terminate in slightly inflated pores. Distal raphe fissures are deflected dorsally. Striae are radiate, becoming more strongly radiate near the apices. Areolae are distinct in LM and number 24-28 in 10 µm. A stigma is absent.
The images of C. hustedtii shown on this web page are from the Redwater River, a prairie stream in Montana (photo below). Measured pH values in the Redwater River range from 7.76 to 8.40 and specific conductance values range from 944 to 4652 µS/cm. Krammer (2002) reports this species as widespread in the temperate zone in oligotrophic waters with low to average electrolyte content.
Bahls, L. (2016). Cymbella hustedtii. In Diatoms of North America. Retrieved December 21, 2024, from https://diatoms.org/species/49961/cymbella_hustedtii
The 15 response plots show an environmental variable (x axis) against the relative abundance (y axis) of Cymbella hustedtii 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.
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