Valves are semi-lanceolate and strongly dorsiventral, with a smoothly arched dorsal margin and a straight to slightly concave ventral margin. Valve ends are rostrate and ventrally curved. The raphe is positioned near the ventral margin, and is straight or with a slight curve dorsally moving from the poles to the central area. Proximal raphe endings are straight or with a slight dorsal deflection. The axial area is narrow, and more prominent on the ventral side. Dorsal and ventral fascia are absent. Dorsal striae are distinctly punctate, more so in the central area, and radiate throughout. Ventral striae are composed of a continuous row of short striae near the valve margin. The ventral striae are often difficult to resolve in the LM depending on the valve angle.
Stepanek, J., Kociolek, P. (2011). Halamphora veneta. In Diatoms of North America. Retrieved November 17, 2024, from https://diatoms.org/species/halamphora_veneta
The 15 response plots show an environmental variable (x axis) against the relative abundance (y axis) of Halamphora veneta 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.