Achnanthidium alpestre | Species - Diatoms of North America

Category

Monoraphid
Length Range

10.3-20.4 µm
Width Range

3.7-4.4 µm
Striae in 10 µm

24-28 in the center of raphe valve, 26-32 in the center of rapheless valve, 35-42 at the ends

Contributor

Marina Potapova - Aug 2010
Reviewer

Sarah Spaulding - Aug 2013

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Identification

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Description

Valves are linear-lanceolate with subrostrate ends. The raphe valve is concave with a linear axial area, which widens slightly in the middle portion of the valve. The terminal raphe fissures are hooked towards the same side of the valve. The central raphe ends are teardrop-shaped externally and curve to opposite sides internally. The rapheless valve is convex with a narrow, linear axial area widening slightly in the middle. Striae are parallel or very slightly radiate throughout both valves. Striae 24-28 in 10 µm in the middle and 35-42 in 10 µm at the apices of the raphe valve. Striae 26-32 in 10 µm in the middle and 35-40 in 10 µm at the apices of the rapheless valve. The external openings of the areolae are transapically elongated, appearing as narrow slits. Each stria in the middle part of the valve is composed of 4-5 areolae.

Autecology

Size Range, µm3

11-100 101-1000
Motility

Slightly motile
Attachment

Prostrate
Habitat

Benthic
Colony

Solitary
BCG

BCG 2
Waterbody

Inland
Distribution

Southeast rivers 2014 California coastal rivers 2017
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Original Description

Valves 9-27 μm long, 2.5-5 μm wide, with 19-22 striae in 10 μm at valve center, 29-31 striae in 10 μm at the ends on both the raphe and pseudoraphe valve. Valves linear, with subrostrate ends. Smaller specimens becoming rounded with no distinct ends. Raphe filiform, with distal raphe ends deflecting in the same direction. Differs from the nominate variety in the widely spaced median striae.

Basionym

Achnanthes deflexa var. alpestris
Author

R.L.Lowe and Kociolek 1984
Length Range

9-27 µm
Width

2.5-5 µm
Striae in 10µm

19-22 in the center valve, 29-31 at the ends

Original Images

Citations & Links

Citations

Cite This Page

Potapova, M. (2010). Achnanthidium alpestre. In Diatoms of North America. Retrieved December 16, 2024, from https://diatoms.org/species/44790/achnanthidium_alpestre

Responses

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