Navicula aitchelbee | Species - Diatoms of North America

Category

Symmetric Biraphid
Length Range

20-36 µm
Width Range

4.8-7.0 µm
Striae in 10 µm

14-16

Contributor

Loren Bahls - Mar 2012
Reviewer

Mark Edlund - May 2012

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Identification

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Description

Valves are narrowly lanceolate with subcapitate apices. Raphe branches are filiform with proximal endings deflected to the primary side. Distal raphe fissures are hooked to the secondary side. The axial area is very narrow and widens somewhat near the small, asymmetric central area. Striae are radiate and become convergent at the ends. Areolae number approximately 32 in 10 μm and are usually visible in LM.

Autecology

Navicula aitchelbee is widely distributed in soft-bottomed streams of the Northwestern Great Plains (eastern Montana and Wyoming, western North Dakota and South Dakota) where it may be locally abundant. In these streams the mean pH is 8.5 and the mean specific conductance is 3627 µS/cm. The most frequently co-occurring diatom associates of N. aitchelbee are also salt-loving, epipelic taxa: Nitzschia frustulum var. subsalina, Cylindrotheca gracilis, Entomoneis paludosa, Nitzschia nana, Synedra famelica, Navicula salinicola, Hippodonta hungarica, Ctenophora pulchella, Navicymbula pusilla, and Navicula eidrigiana.

Size Range, µm3

101-1000
Motility

Moderately motile
Attachment

Unattached
Habitat

Benthic
Colony

Solitary
Waterbody

Inland
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Credit: Montana Diatom Database

Abundance-weighted mean values for selected water quality variables measured concurrently with the collection of samples containing Navicula aitchelbee.

Original Description

Valves narrowly lanceolate with subcapitate ends, 20–36 μm long, 4.8–7.0 μm wide. Raphe filiform, proximal endings deflected to the primary side, distal raphe fissures hooked, opening to the secondary side. Axial area very narrow, widening somewhat near the small, asymmetric central area. Striae radiate, convergent at the ends, 14 –16 in 10 μm, lineolae about 32 in 10 μm, visible in LM. For measurements, n = 40 valves. SEM (Figs 23 – 25): External raphe fissures filiform, proximal endings deflected slightly to the primary side. Distal raphe endings hooked, the hooks opening toward the secondary side (the side with the Voigt faults).

Author

Bahls 2012
Length Range

20-36 µm
Width

4.8-7.0 µm
Striae in 10µm

14-16

Original Images

Citations & Links

Citations

Bahls, L.L. (2012) Seven new species in Navicula sensu stricto from the Northern Great Plains and Northern Rocky Mountains Nova Hedwigia, Beiheft 141: 19–38

Cite This Page

Bahls, L. (2012). Navicula aitchelbee. In Diatoms of North America. Retrieved December 16, 2024, from https://diatoms.org/species/48333/navicula_aitchelbee

Responses

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