Credit: USGS BioData
Distribution of Gomphonema sarcophagus in rivers of the continental U.S. based on the National Water Quality Assessment program. Retrieved 10 June 2016.
Gomphonema sarcophagus
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Category
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Length Range27-38 µm
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Width Range5-7 µm
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Striae in 10 µmCoarse valve: 6-8, Fine valve: 11-14
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SynonymsGomphonema angustatum var. sarcophagus (W.Greg.) Grunow
Gomphonema angustatum f. sarcophagus (W.Greg.) Hust.
Gomphonema angustatum var. sarcophagus (W.Greg.) Cleve
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Reported AsGomphonema angustatum (Reavie and Smol 1998, p. 49, Pl. 20, Fig. 14)
Gomphonema angustatum (McBride and Edgar 1998)
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ContributorJeremy Walls - Jun 2016
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ReviewerMark Edlund - Jun 2016
Identification
Description
Valves are linear- to elliptic-lanceolate, with rostrate to truncate apices. Valves are asymmetric to the transapical axis, with the footpole slightly more tapered than the headpole. The axial area is distinctly linear. A stigma is present in the central area, in line with a stria. The raphe is undulate with slightly expanded proximal ends. Striae are slightly radiate to parallel, bending inward at the center of the valve. There are typically 1-2 shortened striae at the central area. Areolae are not easily visible in the light microscope, but appear larger at the center of the valve along the axial area.
The appearance of enlarged areolae in LM is due to biseriate striae, which are visible by SEM (Reichardt 1999).
Valve morphology of specimens within populations of G. sarcophagus may vary considerably, including that irregular undulations may be present along the valve margin. Additionally, the presence of Janus cells was observed with this species. Janus cells are frustules that have two morphologically different valves, often of differing stria densities. A few species of Gomphonema have been documented to produce Janus cells, including G. parvulum and G. sarcophagus (McBride and Edgar 1998, Reichardt 1999). In this study, two valve types were observed: valves with low stria densities (coarse striae) and valves with higher stria densities (fine striae). Valves with coarse striae were more commonly observed, but over 25% of examined valves (n=55) had fine striae.
Note that G. sarcophagus and G. angustatum are very similar taxa and further investigation may show that they are environmental variants and conspecific. A lectotype was designated for G. sarcophagus (Reichardt 1999).
Autecology
Gomphonema sarcophagus was found in periphytic samples from a kettle hole at the Freda Haffner Kettlehole State Preserve in Dickinson County, Iowa, and epiphytic samples from a small stream in Cayler Prairie, Dickinson County, Iowa. Both sampling locations had pHs near 7 and temperature near 20°C. Conductivity was 190 μS/cm in the kettle hole and 489 μS/cm in the prairie stream.
Gomphonema sarcophagus has also been found in eutrophic ponds across Europe (Hofmann et al. 2011), as well as the San River in the upper San basin of Poland (Noga et al. 2014). The species has also been found in a stream in the Dolina Kobylanska valley, Poland, which has moderate conductivity and neutral pH. It has also been recorded across Germany (Reichardt 1999). In the United States, it has been reported to inhabit primarily mesotrophic waters with moderate conductivity (Patrick and Reimer 1975).
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Size Range, µm3
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Habitat
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Colony
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BCG
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Waterbody
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Distribution
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Credit: USGS BioData
Distribution of Gomphonema sarcophagus in rivers of Alaska based on the National Water Quality Assessment program. Retrieved 10 June 2016.
Credit: Image by Sylvia Lee
Photo of the Kettlehole, Dickinson Co., Iowa, United States in June of 2016.
Original Description
Gomphonema Sarcophagus, W. G. - This species occurs abundantly in the Lochleven gatherings, but it occurs also in several gatherings made near Edinburgh, and in others from Fife, Stirlingshire, Lanarkshire, and elsewhere. Indeed it would seem not to be uncommon. In form it is linear, rather narrow, the sides gently curved, so as to form a sort of shoulder at the widest part, after which it contracts a little, and again expands to a somewhat truncate extremity. The opposite end is narrower, and, with the exception of a trifling expansion at the apex, becomes continuously narrower. These things give to it very nearly the shape of a coffin. The F. V. is, as usual in this genus, cuneate. Length about .0014 inch. Striae 20 to 22 in .001".
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AuthorW.Greg. 1856
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Length Range35.6 µm
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Striae in 10µm8-9
Original Images
Citations & Links
Citations
Links
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Index Nominum Algarum
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North American Diatom Ecological DatabaseNADED ID: 37152
Cite This Page
Walls, J. (2016). Gomphonema sarcophagus. In Diatoms of North America. Retrieved December 26, 2024, from https://diatoms.org/species/51552/gomphonema_sarcophagus
Responses
The 15 response plots show an environmental variable (x axis) against the relative abundance (y axis) of Gomphonema sarcophagus 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.
Gomphonema sarcophagus
- Valve linear- to elliptic-lanceolate
- Headpole rostrate
- Striae slightly radiate
- Stigma present
- Forms Janus cells
Valves are linear- to elliptic-lanceolate. The headpole is rostrate. Striae are slightly radiate and irregularly spaced. Janus cells may be present, frustules that have valves of differing morphologies, often of differing stria densities. One to two shortened striae are present in the central area. A single stigma is present.