Tool for Microscopic Identification Home

 

Show UniqueIdentification

Id 79
Identification Type Algae
Name Diatom
Distinguishing Features Isotropic
Patterned
Description Transparent colorless to slightly brown or red tinted. Nonpleochroic. Isotropic. Many different shapes; in two-dimensional view these may appear as circles, rectangles of varying aspect ratios, canoe-shapes, banana-shapes, etc. moderate relief. Occur in essentially all lakes and rivers, but may not be preserved in sediments due to high- or low-pH conditions or silica undersaturation of bottom waters.
Tags circular
transparent
colorless
rice-shape
External Resources Diatoms of the US
TMI diatoms overview
Imposters Sponge
Isotropic, elongate, and sometimes textured, sponge spicules can superficially resemble diatoms. However, they are typically much larger (up to ~1mm long) and solid rather than hollow and porous.
Images
Unique Identification: Diatom
Site name: Twin
Light type: Plane-Polarized Light
Magnification: not specified
Submitted by: not specified
Notes: monospecific bloom; mixed with calcite
Image Tags: none
Unique Identification: Diatom
Site name: Twin
Light type: Cross-Polarized Light
Magnification: not specified
Submitted by: not specified
Notes: monospecific bloom; mixed with calcite
Image Tags: none
Unique Identification: Diatom
Site name: Twin Lake
Light type: not specified
Magnification: not specified
Submitted by: Mark Edlund
Notes: An assemblage of freshwater diatoms including planktonic and benthic forms.
Image Tags: transparent siliceous colorless many-shaped diatom benthic planktonic
Unique Identification: Diatom
Site name: Twin Lake
Light type: not specified
Magnification: not specified
Submitted by: Mark Edlund
Notes: An assemblage of freshwater diatoms including planktonic and benthic forms.
Image Tags: transparent siliceous colorless many-shaped diatom benthic planktonic
Unique Identification: Diatom
Site name: Twin Lake
Light type: not specified
Magnification: not specified
Submitted by: Mark Edlund
Notes: An assemblage of freshwater diatomsshowing benthic forms.
Image Tags: transparent siliceous colorless many-shaped long curved diatom benthic
Unique Identification: Diatom
Site name: Twin Lake
Light type: not specified
Magnification: not specified
Submitted by: Mark Edlund
Notes: These split rings or circular structures are diatom girdle bands from centric diatoms
Image Tags: transparent siliceous colorless circular ring-shaped diatom girdle-bands
Unique Identification: Diatom
Taxon: Puncticulata lemanica
Site name: Kekakabic Lake
Light type: not specified
Magnification: not specified
Submitted by: Mark Edlund
Notes: This is a diatom prep that shows two Puncticulata lemanica specimens (the round diatoms) and many specimens of Tabellaria. Note that many of the specimens of Tabellaria are only the empty girdle bands.
Image Tags: transparent siliceous colorless circular ring-shaped round diatoms girdle-bands
Unique Identification: Diatom
Site name: Malawi
Light type: Plane-Polarized Light
Magnification: not specified
Submitted by: Andy Cohen
Notes: Aulacoseira ooze with charcoal fragment
Image Tags: none
Unique Identification: Diatom
Site name: AuSable River
Light type: not specified
Magnification: not specified
Submitted by: Mark Edlund
Notes: Prominent in this image are two colonies of benthic chain-forming diatoms
Image Tags: transparent siliceous colorless ribbon-like chains diatom
Unique Identification: Diatom
Taxon: Campylodiscus sp.
Site name: AuSable River
Light type: not specified
Magnification: not specified
Submitted by: Mark Edlund
Notes: This diatom is the saddle-shaped genus Campylodiscus. There are different Campylodiscus species in freshwater compared to saline lakes
Image Tags: transparent siliceous colorless many-shaped saddle-shaped Pringle's diatom
Unique Identification: Diatom
Site name: Spectacle Lake
Light type: Plane-Polarized Light
Magnification: not specified
Submitted by: Andy Cohen
Notes: diverse diatom assemblage (littoral?)
Image Tags: none
Unique Identification: Diatom
Taxon: Chaetoceras elmorei
Site name: Devils Lake ND
Light type: not specified
Magnification: 100x
Submitted by: Mark Edlund
Notes: This group of images shows various views of spores from the diatom Chaetoceros elmorei. Spores are produced by few inland diatoms. Spores are more heavily silicified than the vegetative cells and are often the only part of the diatom that is preserved in lake sediments. Chaetoceros spores are usually an indicator of saline conditions.
Image Tags: siliceous army-helmet transparent colorless oval saline spore heavily-silicified diatom
Unique Identification: Diatom
Site name: Mono
Light type: Plane-Polarized Light
Magnification: 100
Submitted by: Joe Smoot
Notes: elongate translucent grains are isotropic, algal bloom
Image Tags: none
Unique Identification: Diatom
Taxon: Aulacoseira ambigua
Site name: Harriet
Light type: not specified
Magnification: 400.0
Submitted by: Hedy Kling
Notes: cell of A. ambigua appears to be making a spore
Image Tags: cylindrical chambered
Unique Identification: Diatom
Taxon: Urosolenia sp.
Site name: Spirit Lake, Iowa
Light type: not specified
Magnification: 100x
Submitted by: Mark Edlund
Notes: These are resting spores produced by the freshwater diatom Urosolenia. They look very similar to chrysophyte cysts but are bipartite. The heavily silicified spores can be found in sediments; usually the lightly silicified vegetative valves of this diatom are not present. For more information see Edlund & Stoermer (1993. JOPL 9:55-61).
Image Tags: siliceous transparent cyst spore heavily-silicified rounded bipartite diatom
Unique Identification: Diatom
Taxon: Acanthoceras sp.
Site name: Spirit Lake, Iowa
Light type: not specified
Magnification: 100x
Submitted by: Mark Edlund
Notes: These are resting spores produced by the freshwater diatom Acanthoceras. The heavily silicified spores can be found in sediments; usually the lightly silicified vegetative valves of this diatom are not present. For more information see Edlund & Stoermer (1993. JOPL 9:55-61).
Image Tags: siliceous transparent cyst spore heavily-silicified diatom comma-shaped scalloped bipartite
Unique Identification: Diatom
Site name: Miscanti
Light type: Plane-Polarized Light
Magnification: not specified
Submitted by: Andy Breckenridge
Notes: diatom
Image Tags: none
Unique Identification: Diatom
Site name: Lake Malawi
Light type: Plane-Polarized Light
Magnification: not specified
Submitted by: Andy Breckenridge
Notes: diatom, Aulacoseira
Image Tags: none
Unique Identification: Diatom
Site name: Miscanti
Light type: Plane-Polarized Light
Magnification: not specified
Submitted by: Andy Breckenridge
Notes: diatom
Image Tags: none