Diatoms of North AmericaDiatoms of North America

Diatoma problematica

Lange-Bert. 1993

Diatoma problematica guide
  • Category
    Araphid
  • Length Range
    6.6-43.4 µm
  • Width Range
    3-5 µm
  • Striae in 10 µm
    >40

Identification

Diatoma problematica LM3 Diatoma problematica LM2 Diatoma problematica LM4 Diatoma problematica LM1 Diatoma problematica LM7 Diatoma problematica LM6 Diatoma problematica LM5
View image metadata

Description

Frustules are rectangular in girdle view. Valves are elliptic to linear-elliptic, with rounded or slightly set-off apices. Striae are uniseriate and composed of small poroid areolae. Transapical ribs number 6-8 in 10 µm. The axial area is linear and very narrow. One rimoportula is positioned within a transapical rib near one of the valve apices.

The specimens shown here are from material of Patrick and Freese (1961). Note that these Alaskan specimens are more narrow than those from the type locality in Bavaria (Wörth am Main, a town in the Miltenberg district of Lower Franconia (Unterfranken)) and other Eurasian populations.

A single valve from the Canadian High Arctic (Antoniades et al. (2008) and designated as Diatoma cf. problematica) is more narrow (4 µm) than Eurasian specimens. It remains to be determined whether North American populations belong to a separate species or represent geographic variability within D. problematica.

Autecology

Lange-Bertalot (1993) stated that Diatoma problematica has been found in eutrophic and beta-mesosaprobic European rivers. Since the time this species was established, it has been most commonly reported from fresh and slightly brackish waters of colder regions of Northern Hemisphere , such as northern Baltic Sea (Snoejis & Potapova, 1998), Franz Josef Land (Pla-Rabés et al., 2016), Kamchatka (Kezlya et al., 2024), and Canadian Arctic (Antoniades et al., 2008, as D. cf. problematica). Specimens in this page are from the Point Barrow area, Northern Alaska.

Original Description

Frustula fere rectangularia cingulari aspectu, Diatoma vulgari similia sed semper angustiora, atque etiam similia Diatoma tenui et Diatoma moniliformi sed semper latiora. Valvae lineari-ellipticae finibus late rotundatis, saepe paulo protractis,20-50 µm longae, 5-7 µm latae. Area axialis (sternum) angustissima. Costae transapicales incrassatae eaedem sunt paries separantes interni (alias striae transapicales falsae!) irregulariter positae, nonnullae abbreviatae, 6-8/10 µm. Striae verae non aspectabiles (in LM), 40-48 (in REM). Una rimoportula in positione subpolare in utraque valva frustulorum, inclausa in costa est nec inter costas posita. Valvocopula et copulae D. vulgari valde similes sed subtiliores constructae.

  • Author
    Lange-Bert. 1993
  • Length Range
    20-50 µm
  • Width
    5-7 µm
  • Striae in 10µm
    6-8

Original Images

Diatoma problematica orig illus3
Diatoma problematica orig illus2
Diatoma problematica orig illus1
Diatoma problematica orig desc

Cite This Page

Leppik, S., Potapova, M. (2025). Diatoma problematica. In Diatoms of North America. Retrieved June 20, 2025, from https://diatoms.org/species/339572/diatoma-problematica

Responses

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