• Category
  • Length Range
    28-50.5 µm
  • Width Range
    5.8-8.4 µm
  • Striae in 10 µm
    10-12

Identification

Description

Valves are dorsiventral, with protracted, acute apices. The dorsal margin is convex. The ventral margin is slightly convex to markedly gibbous in the center of the ventral side. The axial area is nearly lanceolate. The central area is absent, to weakly rounded on the dorsal side. The raphe is lateral. The proximal raphe ends are expanded and curved to the dorsal side. The distal raphe ends are close to the ventral margin. Striae are radiate, except near ventral ends where they become convergent. Areolae within a central, dorsal stria number 22-28 in 10 μm.

NOTE: We observed valves larger in length (30.7-50.5 μm) than the range provided in the original description (28-44 μm) (Krammer 1997). We also observed valves much more narrow (5.8-7.4 μm) than the original description (7.5-8.8 μm). Our observed population, therefore, has a slightly larger length to width ratio (5) than the type population. The expanded length and width ranges (our measured range and Krammer's range) are reported above.

Autecology

This taxon was described from the Florida Everglades (Krammer 1997). It has been reported from freshwater and, sometimes, coastal brackish water throughout the Florida Coastal Everglades (FCE). The FCE is described as a karstic wetland, known wetlands dominant limestone bedrock, low phosphorous concentrations, high calcium carbonate concentrations, and calcareous periphyton mats. The FCE comprises an area of about 5000 km2 and as one of the largest wetland systems in North America, it provides drinking water to over eight million people.

Encyonema silesiacum var. elegans is frequently found in calcareous mats at the FCE Long-term Ecological Research site and within Comprehensive Everglades Comprehensive Plan (CERP) sites. This taxon may be a biological indicator for aquatic systems similar to the FCE.

An interactive map of the species' distribution is available the projects Southeast Florida Coastal Mangroves,
Florida Bay Paleo Project, Dosing Project, and Transect Project: https://fce-lter.fiu.edu/data/... .

Florida Everglades
Credit: Evelyn Gaiser
Typical habitat of Gomphonema vibriodes in the Florida Everglages.
Thumbnail IMG 1132
FCE LTE Rmap 600dpi
Credit: Evelyn Gaiser
Long-term Ecological Research site map

Original Description

Differt a varietate nominata habitu elongato, apicibus acuminatis, margine ventralis magis convexa et area axialis fere lanceolata.

Locus typicus: Everglades, Florida, coll. Bierhals 9.1986.

Typus: praep.1042C IOK.

  • Author
    Krammer 1997
  • Length Range
    28-44 µm
  • Width
    7.5-8.8 µm
  • Striae in 10µm
    10-12

Original Images

Encyonema Krammer orig illus
Encyonema Krammer orig illus2
Encyonema Krammer orig desc

Cite This Page

Johnson, K., Gaiser, E., Tobias, F. (2022). Encyonema silesiacum var. elegans. In Diatoms of North America. Retrieved April 21, 2024, from https://diatoms.org/species/encyonema-silesiacum-var-elegans

Responses

The 15 response plots show an environmental variable (x axis) against the relative abundance (y axis) of Encyonema silesiacum var. elegans 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.