• Category
  • Length Range
    16-19 µm
  • Width Range
    5.8-6.8 µm
  • Striae in 10 µm
  • Synonyms
    Navicula minuscula var. alpestris Hust. 1934
    Navicula detenta Hust. 1943



Valves are elliptic with rostrate to subcapitate apices. The axial area is very narrow, barely wider than the filiform raphe. The central area is narrow to essentially absent, rectangular in the apical axis. Raphe branches are slightly bowed and widen gradually from the apices towards the proximal ends, which are weakly inflated. Distal raphe ends are both curved toward the secondary side of the valve (confirmed under SEM). Striae are radiate near the valve center and become parallel near the apices. A shortened stria sometimes appears next to the central area. Areolae are round, about 35-40 in 10 µm and difficult to resolve in LM.


This taxon is widely distributed in small headwater lakes and streams in the mountains of the Pacific Northwest. Here it prefers cool, slightly alkaline waters with low concentrations of nutrients and dissolved solids (see table below). Krammer and Lange-Bertalot (1986) report it (as N. detenta) as a northern-alpine species in Europe. It was originally described from high mountain lakes in the Swiss Alps (Hustedt 1943).

Paradise  Spring  Brook 1
Credit: Loren Bahls
Paradise Spring Brook, Glacier National Park, Montana.
Adlafia detenta
Credit: Montana Diatom Database
Abundance-weighted means of selected water quality variables measured concurrently with the collection of samples containing Navicula detenta.

Original Description

Originally published without description

  • Basionym
    Navicula minuscula var. alpestris
  • Author
    Hust. in A.Schmidt et al. 1934

Original Images

Navdetenta Origimag1
Navdetenta Origimag2


Apr 07, 2019 - Transfer from Navicula to Adlafia

From October 2012 until 7 April 2019, this taxon appeared as Navicula detenta Hust. 1943. Following the transfer to Adlafia by Heudre et al. 2018, the taxon now appears as Adlafia detenta (Hust.) Heudre et al. 2018.

Cite This Page

Bahls, L. (2012). Adlafia detenta. In Diatoms of North America. Retrieved June 13, 2024, from https://diatoms.org/species/adlafia_detenta


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