Valves bluntly acuminate, with the headpole protracted and bluntly rounded. Valve biconstricted, broadest near the headpole, but tumid at the center of the valve. The footpole is rounded. The axial area is straight and distinct, but the central area is barely differentiated. The raphe is lateral and undulate. The striae are radiate about the center, become parallel towards the headpole, and may become convergent at the apex. Striae are parallel becoming strongly radiate at the footpole. About the center of the valve the central striae on either side of the axial area are separated more from those next to them. One of the central striae terminate next to an isolated stigma. Apical pore fields are distinct at the footpole.
Kociolek, P. (2011). Gomphonema brebissonii. In Diatoms of North America. Retrieved November 23, 2024, from https://diatoms.org/species/gomphonema_brebissonii
The 15 response plots show an environmental variable (x axis) against the relative abundance (y axis) of Gomphonema brebissonii 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.