Valves are linear-elliptic with slightly set-off broadly rounded apices. Raphe is straight, filiform. Axial area is narrow, linear, and expands into large, transversely eliiptic or rectangular central area. Striae are weakly radiate in the valve center and become parallel or weakly convergent towards valve ends. Striae are interrupted by four hyaline areas, one on each half and each side of the valve. Note that the hyaline areas might not be distinct, especially in smaller or weakly silicified specimens.
Chamaepinnularia witkowskii is fairly common in soft-water lakes of the Northeastern United States, but is usually not abundant. The specimens shown here were collected from lakes in Maine, Rhode Island, and Vermont.
Potapova, M. (2021). Chamaepinnularia witkowskii. In Diatoms of North America. Retrieved November 10, 2024, from https://diatoms.org/species/chamaepinnularia-witkowskii
The 15 response plots show an environmental variable (x axis) against the relative abundance (y axis) of Chamaepinnularia witkowskii 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.