• Category
  • Length Range
    23-41 µm
  • Width Range
    7.9-9.9 µm
  • Striae in 10 µm
    11-14

Identification

Description

Valves are broadly lanceolate with rounded, rostrate apices. Raphe branches are weakly lateral. Proximal raphe ends are straight or deflected slightly to the secondary side. Distal raphe fissures are hooked to the secondary side. The axial area is narrow and linear, widening slightly toward the central area. The central area is large, rounded, and asymmetric, always smaller on the secondary side of the valve. Striae are evenly spaced throughout, radiate in the center and becoming parallel to slightly convergent at the apices. Areolae number 24–28 in 10 μm and are visible in LM.

Autecology

Navicula caroliniae has been collected from 17 lakes, ponds, and slow-moving streams in the Canadian Rockies (“Crown of the Continent”) Ecoregion of Montana and Alberta, where it is present in low numbers. It prefers waters with circumneutral to somewhat alkaline pH (range 6.5-8.6) and low to moderate levels of electrolytes (range 92-332 μS/cm).

Bowman  Lake 1
Credit: Loren Bahls
Bowman Lake, Glacier National Park, Montana: type locality of Navicula caroliniae.

Original Description

Valves broadly lanceolate with protracted, obtusely rounded to subcapitate ends, 23–40 μm long, 7.9–9.9 μm wide. Raphe weakly lateral, proximal raphe endings straight or deflected slightly to the secondary side, distal fissures hooked to the secondary side. Axial area narrow, linear, widening slightly toward the central area. Central area large, rounded, and asymmetric. Striae radiate, becoming parallel to slightly convergent at the ends, 11–14 in 10 μm, lineolae 24 – 28 in 10 μm, visible in LM. For measurements, n = 30 valves. SEM (Figs 42 – 44): External raphe fissures weakly lateral, proximal endings defl ected slightly to the secondary side. Distal raphe endings hooked, the hooks opening toward the secondary side (the side with the Voigt faults). Other external features unremarkable for Navicula species.

  • Author
    L.L.Bahls 2012
  • Length Range
    23-40 µm
  • Width
    7.9-9.9 µm
  • Striae in 10µm
    11-14

Original Images

Ncaroliniae Origimag1
Ncaroliniae Origimag2
Ncaroliniae Origdesc

Cite This Page

Bahls, L. (2012). Navicula caroliniae. In Diatoms of North America. Retrieved June 22, 2018, from https://diatoms.org/species/navicula_caroliniae

Responses

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