Navicula margalithii | Species - Diatoms of North America

Category

Symmetric Biraphid
Length Range

35.0-68.0 µm
Width Range

6.5-9.0 µm
Striae in 10 µm

12-13

Contributor

Loren Bahls - Jan 2016
Reviewer

Marina Potapova - Jan 2016

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Identification

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Description

Valves are linear-lanceolate with wedge-shaped ends.The raphe is straight and filiform. The axial area is very narrow and linear. The central area is small and asymmetric. Proximal raphe ends are tear-shaped and straight. Striae are radiate and somewhat sinuous at the valve center, becoming parallel and straight, and then convergent near the apices. Central striae in larger specimens are sometimes alternately long and short. Areolae number about 32 in 10 µm.

This taxon is very similar to Navicula recens and differs mainly in valve size and salinity tolerance. It should not be ruled out that they are conspecific, with the larger size specimens that we call N. margalithii simply a morphological manifestation of the more electrolyte-rich waters in which they are found.

Autecology

This taxon prefers electrolyte-rich waters. The specimens on this page are from a stream in Wyoming that has a specific conductance of 18,100 µS/cm and a chloride content of 60 mg/L. Common diatom associates at this site include Haslea spicula, Mastogloia pumila, and Tryblionella compressa. Lange-Bertalot (2001) reports N. margalithii from saline, electrolyte-rich springs in the Negev Desert of Israel and Tunisia. In contrast, Navicula tripunctata and N. recens prefer fresh to brackish waters.

Size Range, µm3

1001-10000
Motility

Moderately motile
Attachment

Unattached
Habitat

Benthic
Colony

Solitary
BCG

BCG 4
Waterbody

Inland
Distribution

Western rivers 2004 California coastal rivers 2017
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Credit: State of Wyoming DEQ

Stockade Beaver Creek below Salt Creek, Weston County, Wyoming.

Original Description

Author

Lange-Bert. 1985
Length Range

30-70 µm
Width

8-10 µm
Striae in 10µm

9-12

Original Images

Citations & Links

Citations

Cite This Page

Bahls, L. (2016). Navicula margalithii. In Diatoms of North America. Retrieved December 16, 2024, from https://diatoms.org/species/51245/navicula_margalithii

Responses

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