Gomphoneis herculeana var. loweii

Kociolek and Stoermer 1988      Category: Asymmetrical biraphid
BASIONYM: Gomphoneis herculeana var. loweii Kociolek and Stoermer 1988

Gomphoneis herculeana var. abundans

 

Gomphoneis mammilla
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LM scalebar = 10 µm = 40 pixels.

Observations

Contributor: Pat Kociolek - January 2011
Length Range: 47-140 µm
Width Range: 16-25 µm
Striae in 10 µm: 8-12 in the central portion of the valve, 12-14 at the headpole, 13-16 at the footpole

Description

Valves are broadly trullate, with broadly rounded apices. Initial valves are unknown. The axial area is narrow, straight, forming a relatively small, irregularly rounded central area. A single stigma is present in the central area. The raphe is lateral, weakly undulate and with small external proximal ends. The raphe has highly recurved internal proximal ends. Striae are distinctly biseriate, with the areolae arranged alternately. From the central nodule to the head-pole striae are radiate. From the central nodule to the foot pole striae are radiate, become parallel and near the footpole become strongly radiate. Longitudinal lines are positioned approximately one-half the way between the axial area and margin. The apical pore fields are distinctly bi-lobed but reduced in size.

Distribution: To date this species has been confirmed from relatively unimpacted lakes and rivers in the Pacific Northwest.

Original Description

Basionym: Gomphoneis herculeana var. loweii
Author: Kociolek and Stoermer 1988
Length Range: µm
Striae in 10 µm:

Original Description

Original Images

Cite This Page:
Kociolek, P. (2011). Gomphoneis herculeana. In Diatoms of the United States. Retrieved July 31, 2014, from http://westerndiatoms.colorado.edu/taxa/species/gomphoneis_loweii

Species: Gomphoneis herculeana

Contributor: Pat Kociolek

Reviewer: Sam Rushforth

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Image Credit: Pat Kociolek

  1. Vlaves trullate
  2. Apices broadly rounded
  3. Striae count variable across valve

Valves broadly trullate, with broadly rounded apices. Longitudinal lines of are positioned approximately one-half the way between the axial area and margin. The striae density varies across the valve: 8-12 in 10um in the center valve, 12-14 in 10 um at the headpole, 13-16 in 10 um at the footpole.

Compare

Because of its trullate shape, G. herculeana var. loweii might be confused with Gomphoneis trullata. The valves of G. herculeana var. loweii are more robust, have coarser striae and the apices are broadly rounded.

Gomphoneis trullata

Citations

Kociolek, J.P. and Stoermer, E.F. (1988). Taxonomy, ultrastructure and distribution of Gomphoneis herculeana, G. eriense and closely related species (Naviculales: Gomphonemataceae). Proc. Acad. Nat. Sci. Phil. 140: 24-97. http://www.jstor.org/stable/4064935

Links & ID's

Index Nominum Algarum (INA)

California Academy of Sciences (CAS)

Gomphoneis herculeana var. loweii CAS

North American Diatom Ecological Database (NADED)

NADED ID: 36005

Autecology Discussion

Habits

Size Range

1001-10,000 µm3 (ie Diatoma vulgaris)

Motility

moderately motile (e.g. Navicula tripunctata)

Attachment

vertical (e.g. stalks)

Habitat

benthic

Colony

colonies common

EMAP Assessment

The Environmental Protection Agency (EPA) western Environmental Monitoring and Assessment Program (EMAP) study was completed during the years 2000-2004 (see citations at bottom of this page). Over 1200 streams and rivers in 12 western states (Arizona, California, Colorado, Idaho, Montana, Nevada, North Dakota, Oregon, South Dakota, Utah, Washington and Wyoming) were selected for sampling based on a stratified randomized design. This type of design insures that ecological resources are sampled in proportion to their actual geographical presence. Stratified randomized design also allows for estimates of stream length with a known confidence in several “condition classes” (good or least-disturbed, intermediately-disturbed, and poor or most-disturbed) for biotic condition, chemistry and habitat.

EMAP Distribution

Gomphoneis herculeana var. loweii

Distribution

The distribution map represents the relative abundance of this Gomphoneis herculeana var. loweii in the western EMAP study. Relative abundance is a measure of the proportion of cells of this species based on a "fixed count" of 300 total diatom cells counted and identified. Each of the western EMAP sample sites is shown, either with a black dot for sites where Gomphoneis herculeana var. loweii was not recorded, or with a red circle indicating the relative abundance of Gomphoneis herculeana var. loweii.

Note that the size of the proportional symbols varies between species to help show both abundant and rare species.

Scale for the map to the left

EMAP Response Plots

Gomphoneis herculeana var. loweii

Responses

The 15 response plots show an environmental variable (x axis) against the relative abundance (y axis) of Gomphoneis herculeana var. loweii 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.

EMAP citations

Results are published in:

Johnson, T., Hermann, K., Spaulding, S., Beyea, B., Theel, C., Sada, R., Bollman, W., Bowman, J., Larsen, A., Vining, K., Ostermiller, J., Petersen, D. Hargett, E. and Zumberge, J. (2009). An ecological assessment of USEPA Region 8 streams and rivers. U.S. Environmental Protection Agency Region 8 Report, 178 p.

Stoddard, J. L., Peck, D. V., Olsen, A. R., Larsen, D. P., Van Sickle, J., Hawkins, C. P., Hughes, R. M., Whittier, T. R., Lomnicky, G. A., Herlihy, A. T., Kaufman, P. R., Peterson, S. A., Ringold, P. L., Paulsen, S. G., and Blair, R. (2005). Environmental Monitoring and Assessment Program (EMAP) western streams and rivers statistical summary. U.S. Environmental Protection Agency Report 620/R-05/006, 1,762 p.

Stoddard, J. L., Peck, D. V., Paulsen, S. G., Van Sickle, J., Hawkins, C. P., Herlihy, A. T., Hughes, R. M., Kaufman, P. R., Larsen, D. P., Lomnicky, G. A., Olsen, A. R., Peterson, S. A., Ringold, P. L., and Whittier, T. R. (2005). An ecological assessment of western streams and rivers. U.S. Environmental Protection Agency Report 620/R-05/005, 49 p.