Diatoms of North AmericaDiatoms of North America

Placoneis abiskoensis

(Hust.) Lange-Bert. and Metzeltin 1996

Placoneis Abiskoensis Guide
  • Category
    Symmetric Biraphid
  • Length Range
    33.3-46.0 µm
  • Width Range
    8.4-11.1 µm
  • Striae in 10 µm
    10-12
  • Reported As
    Navicula abiskoensis (Krammer and Lange-Bertalot 1986)

Identification

Placoneis abiskoensis LM4 Placoneis abiskoensis LM3 Placoneis abiskoensis LM2 Placoneis abiskoensis LM1
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Description

Valves are linear, with parallel or weakly concave margins in the largest specimens. Apices are rostrate to sub-capitate. The axial area is very narrow and widens slightly as it approaches a transversely rectangular central area. The raphe is weakly lateral and somewhat sinuous. Proximal raphe ends are inflated and bent to one side. Distal raphe ends are hooked towards the opposite side of the valve. Striae are strongly curved and radiate except at the ends, where they are straight and parallel. Areolae in the striae number about 26-30 in 10 µm.

Autecology

Placoneis abiskoensis is widely distributed across the Northern Great Plains and Northern Rocky Mountains in streams, lakes, ponds, pools, and wetlands. It is rarely found in large numbers. The species was described from material collected in Swedish Lapland at 68 degrees north latitude (Hustedt 1942) and also reported from Bear Island in Arctic Norway (Metzeltin & Witkowski 1996) and from many other Arctic and Subarctic locations.

Spring Pool On Trail Between Kintla Lakes
Credit: Mike Pasichnyk
Pool on trail near Kintla Lake, Glacier National Park, Montana: home of Placoneis abiskoensis.

Original Description

Navicula abiskoensis n. sp. Schalen linear mit parallelen Seiten und breit un leicht kopfig vorgezogenen Enden, um 45 µ lang, etwa 10 µ breit. Raph gerade, fadenförmig, Polspalten nach derselben Seite abgebogen; Axialarea schmal linear, Zentralarea ziemlich groß, quer-elliptisch. Transapikalstreifen stark radial und leicht gekrümmt (gegen di Enden konvex), an den Polen fast senkrecht zur Mittellinie, nur die äußersten Streifen an der den Polspalten gegenüberliegenden Seite gegen die Enden konvergent; in der Mitte etwa 10-12 in 10 µ, gegen die Pole enger werdend, bis etwa 16 in 10 µ, sämtlich ziemlich grob punktiert, Punkte um 22 in 10 µ. Abb. 36.

  • Basionym
    Navicula abiskoensis
  • Author
    Hust. 1942

Original Images

Navicula Abiskoensis Orig Desc Plate
Placoneis Abiskoensis Origimag001
Navicula Abiskoensis Orig Desc Text

Cite This Page

Bahls, L. (2014). Placoneis abiskoensis. In Diatoms of North America. Retrieved November 17, 2024, from https://diatoms.org/species/placoneis_abiskoensis

Responses

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