Key
to the Dominant Diatom Species of the Great Lakes
![Stephanodiscus alpinus. Courtesy of the University of Michigan](Diatoms/Images/UMStephalpinus1189-1.1_small.gif)
Radially symmetric and circular in valve view - Eucentric
diatoms (2) |
![Pleurosira laevis. Courtesy of Bowling Green State University](https://webarchive.library.unt.edu/eot2008/20090514235514im_/http://www.glerl.noaa.gov/seagrant/GLWL/Algae/Diatoms/Images/BGSUPleuLae1_small.GIF)
Radially symmetric, Bipolar or multipolar - Eccentric diatoms
- Not Dominant in the Great Lakes |
![Nitschia lauenbergiana. Courtesy of the University of Michigan](Diatoms/Images/UMNitzlauenberg1189-1.0.gif)
Bilaterally symmetric or asymmetric with a thick sternum
running longitudinally along both valves (8) |
2. Eucentric diatoms
![Stephanodiscus sp. Courtesy of Michigan Tech](https://webarchive.library.unt.edu/eot2008/20090514235514im_/http://www.glerl.noaa.gov/seagrant/GLWL/Algae/Diatoms/Images/Stephanodiscus_girdle.jpg)
Cell length < 2x diameter (3)
|
|
3. Short eucentric diatoms
![Cyclotella sp. Courtesy pf Bowling Green State University](Diatoms/Images/BGSUCyclotellasp2.gif)
Valve with an intramarginal zone of costae encircling
the cell - Cyclotella spp. |
![Coscinodiscus sp. EPA](Diatoms/Images/EPAcoscinodiscussp_vsm.jpg)
Valve evenly ornamented with punctae - Thalassiosira
spp. and Coscinodiscus spp. (Coscinodiscus not
dominant in the Great Lakes) |
![Stephanodiscus hantzschii. Courtesy of "Life in Lake Myvatn"](Diatoms/Images/MYstephanodiscushantzschii_small.gif)
Valve ornamented with radiating rows of punctae which
are separated by smooth zones - Stephanodiscus
spp. |
4. Cyclotella spp.
- Cyclotella comensis
- Cyclotella comta
- Cyclotella delicatula
- Cyclotella ocellata
5. Stephanodiscus spp.
- Stephanodiscus alpinus
- Stephanodiscus binderanus
- Stephanodiscus hantzschii f. tenuis
- Stephanodiscus niagarae
- Stephanodiscus parvus
- Stephanodiscus subtransylvanicus
6. Thalassiosira spp. and/or Coscinodiscus
spp.
7. Aulacoseira spp.
- Aulacoseira islandica
- Aulacoseira subarctica
8. Bilaterally symmetric or
asymmetric with a thick sternum running longitudinally along both
valves
![Ctenophora sp. Courtesy of University of Michigan](https://webarchive.library.unt.edu/eot2008/20090514235514im_/http://www.glerl.noaa.gov/seagrant/GLWL/Algae/Diatoms/Images/Ctenophorapulchella1407a.gif)
Bilaterally symmetric; neither sternum modified to form
a raphe - Araphid Diatoms (9) |
![Nitzschia sp. Courtesy of Bowling Green State University.](Diatoms/Images/BGSUNitzschia3.gif)
Raphe (on both valves) raised in a keel; raphes central
or displaced toward one side - Nitzschioid
Diatoms (10) |
![Amphora ovalis. Courtesy of Bowling Green State University](Diatoms/Images/BGSUAmphoraovalispediculus.gif)
Raphe otherwise (e.g., on only one valve, reduced to the
ends, asymmetric, wrapped around the margin forming a wing,
etc) - Not Dominant in the Great Lakes |
9. Araphid Diatoms
![Tabellaria fenestrata. Courtesy of Michigan Tech](Diatoms/Images/MTUTabellaria_fenestrata_small.jpg)
Colony a zig-zag chain - Tabellaria
sp.
Tabellaria fenestrata, Tabellaria flocculosa, Fragilaria
crotonensis |
![Fragilaria crotenensis. Courtesy of Michigan Tech](Diatoms/Images/MTUFragilaria_crotonensis.jpg)
Colony a ribbon of rectangular cells with prominent costae
- Fragilaria
sp. |
![Asterionella sp. Courtesy of Ohio University](https://webarchive.library.unt.edu/eot2008/20090514235514im_/http://www.glerl.noaa.gov/seagrant/GLWL/Algae/Diatoms/Images/OUAsterionella_small.JPG)
Colony otherwise (e.g., wheel, spokes, fan, radiating,
etc.) or solitary - Not Dominant in the Great Lakes |
10. Nitzschiod Diatoms
Key
to the Dominant Chrysophyte Species of the Great Lakes
Browse Dominant Chrysophyte
Photos
1.
![Chrysosphaerella longispina. Courtesy of Michigan Tech](Chrysophyta/Images/MTUChrysosphaerella_longispina_small.jpg)
1 flagella, no lorica - SubOrder
Chromulineae (2) |
![Dinobryon divergens. Courtesy of Fitoplancton.](Chrysophyta/Images/FPDinobryon_divergens_small.JPG)
2 flagella of unequal length (or non-motile vegetative),
with lorica lacking transverse growth scars - Dinobryon
sp. (3) |
![Chrysochrumulina sp. Courtesy of micro*scope](https://webarchive.library.unt.edu/eot2008/20090514235514im_/http://www.glerl.noaa.gov/seagrant/GLWL/Algae/Chrysophyta/Images/chrysochromulina282_bgw.jpg)
2 apical flagella and a haptonema (looks like a third
flagella, but while it is flexible, it does not beat with
the typical flagellar movement and is usually straight);
unicellular - Haptophyceae |
![Synura sp. Courtesy of Ohio University](https://webarchive.library.unt.edu/eot2008/20090514235514im_/http://www.glerl.noaa.gov/seagrant/GLWL/Algae/Chrysophyta/Images/OUSynura.jpg)
Flagella - lorica combination otherwise - Not Dominant
in the Great Lakes |
2. SubOrder Chromulineae
![Chrysosphaerella longispina. Courtesy of Michigan Tech](Chrysophyta/Images/MTUChrysosphaerella_longispina_small.jpg)
Globose colony, each cell with 2 long anterior rods set
in basal cups to either side of the flagellum, 2 parietal
golden-brown chromatophores, cells 9umx15um, colony to 250um
- Chrysosphaerella
longispina |
Otherwise - Not Dominant in the Great Lakes |
3. Dinobryon sp.
![Dinobryon divergens. Courtesy of Fitoplancton.](Chrysophyta/Images/FPDinobryon_divergens_small.JPG)
Tree-like colony in which the loricas are nearly parallel
and in which the upper portion of the individual lorica is
smooth but the lower portion undulates, base of the lorica
bent and blunt, lorica 7-8 um diameter by 35-50um long - Dinobryon
divergens |
![Dinobryon sociale. Courtesy of MiljoLare.](Chrysophyta/Images/MLdinobryon_sociale_small.jpg)
Tree-like colony, individual loricas flared and smooth with
blunt bases (bent or straight), lorica 7-8 um diameter by
30-70 um long - Dinobryon
sociale |
![Dinobryon bavaricum. Courtesy of MiljoLare](Chrysophyta/Images/MLdinobryon_bavaricum.jpg)
Tree-like colony in which the individual loricas are slightly
flaring and undulate with a sharply pointed base, lorica
6-9 um diameter by 45-100um long - Dinobryon
bavaricum |
![Dinobryon sp. Courtesy of Ohio University](Chrysophyta/Images/OUDinobryon.JPG)
Solitary and epiphytic or lorica otherwise - Dinobryon
sp. (Not Dominant in the Great Lakes) |
4. Haptophyceae
![Chrysochrumulina sp. Courtesy of micro*scope](https://webarchive.library.unt.edu/eot2008/20090514235514im_/http://www.glerl.noaa.gov/seagrant/GLWL/Algae/Chrysophyta/Images/chrysochromulina282_bgw.jpg)
*The EPA study on which the list of dominant species is
based did not identify the dominant haptophyte to species.
It was likely Chrysochromulina
parva. |
Key
to the Dominant Dinoflagellate Species of the Great Lakes
Browse Dominant Dinoflagellate
Photos
1.
![Gymnodinium sp. Courtesy of Michigan Tech.](https://webarchive.library.unt.edu/eot2008/20090514235514im_/http://www.glerl.noaa.gov/seagrant/GLWL/Algae/Pyrrophyta/Images/Gymnodinium_s60_dollarbaytow13_402.jpg)
Motile unicells with an undivided envelope (without walls
or plates) - Order Gymnodiniales
(2) |
![Peridinium sp. Courtesy of Michigan Tech.](https://webarchive.library.unt.edu/eot2008/20090514235514im_/http://www.glerl.noaa.gov/seagrant/GLWL/Algae/Pyrrophyta/Images/Peridinium_jason6_hfallspond3ab_402.jpg)
Motile unicells with walls and a membrane divided into conspicuous
plates, anterior and posterior portions divided by a deep
groove - Order Peridiniales (3) |
![Tetradinium javanicum. Courtesy of Freshwater Dinoflagellates of Ohio](Pyrrophyta/Images/AVESTetradiniumjavanicum.jpg)
Non-motile - Not Dominant in the Great Lakes |
2. Order Gymnodiniales
-
There is only one Great Lakes genus in this order, relatively
large ovoid cells (30-120um) - Gymnodinium
sp.
3. Order Peridiniales
-
![Peridinium sp. Courtesy of Michigan Tech.](https://webarchive.library.unt.edu/eot2008/20090514235514im_/http://www.glerl.noaa.gov/seagrant/GLWL/Algae/Pyrrophyta/Images/Peridinium_jason6_hfallspond3ab_402.jpg)
Globose cells, anterior rounded or conical
- Peridinium
sp. |
![Ceratium hirundinella. Courtesy of Michigan Tech](Pyrrophyta/Images/MTUCeratium_hirundinella_small.jpg)
Long cells, anterior extended into a long
horn, posterior with 2-3 horns- Ceratium
sp. |
4. Ceratium spp.
![Ceratium hirundinella. Courtesy of Michigan Tech](Pyrrophyta/Images/MTUCeratium_hirundinella_small.jpg)
Anterior horn longer than the rest of the body (including
posterior horns) - Ceratium
hirundinella |
![Ceratium cornutum. Courtesy of Ralf Wagner](https://webarchive.library.unt.edu/eot2008/20090514235514im_/http://www.glerl.noaa.gov/seagrant/GLWL/Algae/Pyrrophyta/Images/Ceratium_cornutum_K.jpg)
Anterior horn shorter and curved or angled - Ceratiun sp.
(Not Dominant in the Great Lakes) |
Key
to the Dominant Cryptophyte Species of the Great Lakes
Browse Dominant Cryptophyte
Photos
1.
2. Family Cryptomonadaceae
3. Family Cryptochysidaceae
Key
to the Dominant Green Algae Species of the Great Lakes
Browse Dominant Green
Algae Photos
1.
![Tetraedron minimum. Courtesy of Protist Information Server](Chlorophyta/Images/PISTetraedron_minimum_3_small.jpg)
Non-motile solitary cells (2) |
![Staurastrum gracile. Courtesy of Ohio University](https://webarchive.library.unt.edu/eot2008/20090514235514im_/http://www.glerl.noaa.gov/seagrant/GLWL/Algae/Chlorophyta/Images/OUStaurastrum_small.JPG)
Unicell divided into 2 hemicells - desmids (4) |
![Oocystis sp. Courtesy of Michigan Tech](Chlorophyta/Images/MTYOocystis_sp_small.jpg)
Globose colony of 2-8 globose cells enclosed in an enlarged
mother cell wall, gelatinous investment or gelatinized mother
cell (5) |
![Pediastrum simplex. Courtesy of Fitoplancton](Chlorophyta/Images/FPPediastrum_simplex_small.JPG)
A flat circular plate of polygonal cells (8) |
![Planktonema lauterbornii. Courtesy of the Baltic Sea Portal](https://webarchive.library.unt.edu/eot2008/20090514235514im_/http://www.glerl.noaa.gov/seagrant/GLWL/Algae/Chlorophyta/Images/Planktonemalauterbornii.jpg)
Unbranched filament (9) |
![Ankistrodesmus sp. Courtesy of Ohio University](Chlorophyta/Images/OUankistrodesmus1.JPG)
Cells or colonies otherwise - Not Dominant in the Great
Lakes |
2. Non-motile solitary cells
Flat quadrangular cells (3) |
Cells shaped otherwise: spindles, crescents, round, cruciate,
polyhedral (3D - e.g., pyramidal), triangular, pentagonal.
- Not Dominant in Great Lakes. |
3. Flat quadrangular cells
![Tetraedron minimum. Courtesy of Protist Information Server](Chlorophyta/Images/PISTetraedron_minimum_3_small.jpg)
Flat quadrangular cells without spines and with a distinct
cell body. Sides concave (frequently one side incised). Tetraedron
minimum |
Flat quadrangular cells with a tuft of spines at each
corner. Polyedriopsis sp. (Not Dominant in Great Lakes) |
Flat quadrangular cells in which the cell body is extended
into processes at the corners (without spines) such that
the cell body itself is not evident. Cerasterias sp. (Not
Dominant in Great Lakes) |
4. Desmids
![Staurastrum gracile. Courtesy of Ohio University](https://webarchive.library.unt.edu/eot2008/20090514235514im_/http://www.glerl.noaa.gov/seagrant/GLWL/Algae/Chlorophyta/Images/OUStaurastrum_small.JPG)
Unicell divided into 2 hemicells by a median incision but
without an apical notch. Star-shaped or triangular in both
the vertical and end views (not flat in one plane). Cell
length less than twice the diameter. - Genus Staurastrum (Staurastrum
gracile) |
Cells otherwise - (Not Dominant in Great Lakes) |
5. Globose colony of 2-8 globose cells held
together by an enlarged mother cell wall or gelatinous investment
(~15 known Great Lakes genera have species in this category)
Cells Small (9-20um) (6) |
Cells Larger (>20um) - Not Dominant in the
Great Lakes |
6. Globose colony of 2-8 globose
cells held together by an enlarged mother cell wall or gelatinous
investment - Cells <20um.
![Oocystis sp. Courtesy of Michigan Tech](Chlorophyta/Images/MTYOocystis_sp_small.jpg)
Cells without flagella in families of 2-6 each surrounded
by complete mother cell wall(s) - (mother cell shape may
be distorted, but remains firm/rigid). Oocystis spp. (7) |
Cells arranged otherwise: reticulate, branching,
hollow sphere, fragmented mother cell walls, in clusters without
mother cell walls, gelatinous investment irregular or amorphous
in outline, concentric layers of mucilage, dark zones within
the mucilage, etc. - Not Dominant in the Great Lakes |
7. Oocystis spp.
Cells ellipsoid, broad with round poles and regularly
thin walls. 1-4 chloroplasts (laminate discs). Cell 9-13um
diameter by 9-19um long. - Oocystis
borgei |
Cells otherwise - Oocystis sp. (Not dominant
in Great Lakes) |
8. Colony a flat circular plate
of polygonal cells - Pediastrum
sp.
9.Unbranched filament
![Planktonema lauterbornii. Courtesy of the Baltic Sea Portal](https://webarchive.library.unt.edu/eot2008/20090514235514im_/http://www.glerl.noaa.gov/seagrant/GLWL/Algae/Chlorophyta/Images/Planktonemalauterbornii.jpg)
Unbranched filament of disjointed cells in a sheath - Planktonema
lauterborni |
Cells or colonies otherwise - Not Dominant in the Great Lakes |
Key
to the Dominant Blue-Green Algae Species of the Great Lakes
Browse Dominant Cyanophyte
Photos
1.
![Oscillatoria sp. Courtesy of Ohio University](Cyanophyta/Images/OUOsc1.jpg)
Filamentous - Order Hormogonales (2) |
![Chroococcus sp. Courtesy of Ohio University](Cyanophyta/Images/OUChroococcus.JPG)
Round cells, solitary or colonial - Order Chroococcales (5)
|
Club-shaped attached solitary
or gregarious cells - Chamaesiphonales (Not Dominant in Great
Lakes) |
2. Filamentous Blue-Green Algae
![Oscillatoria sp. Courtesy of Michigan Tech](Cyanophyta/Images/MTUOscillatoria_sp_small.jpg)
No heterocysts - Family Oscillatoriaceae (3)
|
![Anabaena sp. Courtesy of Hawaii Botany](Cyanophyta/Images/HIAnabaena.jpg)
Heterocysts - Not Dominant in Great Lakes |
3. Filamentous Blue-green Algae
without heterocysts
![Oscillatoria sp. Courtesy of Michigan Tech](Cyanophyta/Images/MTUOscillatoria_sp_small.jpg)
Straight, bent or tangled filaments (multicellular with
clear cross walls) without an evident sheath - Genus Oscillatoria (4) |
Filaments with a sheath or coiled and lacking cross-walls
(Not Dominant in Great Lakes) |
4. Genus Oscillatoria
Cells 2um diameter by 5-6um long, filament slightly coiled
or spiral and golden color - Oscillatoria
minima |
![Oscillatoria tennuis. Courtesy of Protist Information Server.](Cyanophyta/Images/PISOscillatoria_tenuis_small.jpg)
Short cells 4-10um diameter by 2-5um long; filament straight
or flexed but not coiled, neither tapering nor capitate,
slightly constricted which have rows of granules; blue-green
in color; may be aggregate mass but not arranged in parallel
bundles - Oscillatoria
tenuis
|
Cells and filaments otherwise (e.g., thinner, red or purple,
tapering or capitate, arranged in bundles, etc.) - Oscillatoria
sp. (Not Dominant in Great Lakes) |
5. Order Chroococcales
Many cells embedded in copious mucilage forming an irregular
or spherical (but not hollow) 3-dimensional colony (6) |
Colony otherwise (e.g., unicellular, aggregates of 2-8, rectangular
plate, or hollow sphere) - Not Dominant in Great Lakes |
6. Rounded cells in an irregular
or spherical colony with copious mucilage
Cells spherical or globose (not longer than wide) (7) |
![Anacystis sp. Courtesy of Hawaii Botany](Cyanophyta/Images/HIAnacystis_small.jpg)
Cells oblong or short-cylindric with rounded ends (but length
much less than 10x width) - Anacystis
sp. |
Cell shape otherwise (e.g., length more than 10 times diameter,
cylindric) - Not Dominant in Great Lakes |
7. Spherical or globose cells
in an irregular or spherical colony with copious mucilage
![Microcystis sp. Courtesy of Cyanosite](Cyanophyta/Images/PurdueMICROC2_small.JPG)
Cells densely and unevenly arranged in an
irregularly shaped colony; pseudovacuoles usually present
-Microcystis
sp. |
![Aphanocapsa sp. Courtesy of Michigan Tech](Cyanophyta/Images/MTUAphanocapsa_sp_small.jpg)
Cells remotely and evenly arranged in a globular
colony - Aphanocapsa
spp. |
8. Aphanocapsa spp.
![Aphanocapsa delicatissima. Courtesy of Leibniz-Institut fur Ostseeforschung Warnemunde](https://webarchive.library.unt.edu/eot2008/20090514235514im_/http://www.glerl.noaa.gov/seagrant/GLWL/Algae/Cyanophyta/Images/aphanocapsa_delicatissima.jpg)
Cells <1um diameter and evenly distributed
- Aphanocapsa
delicatissima |
![Aphanocapsa sp. Courtesy of Michigan Tech](Cyanophyta/Images/MTUAphanocapsa_sp_small.jpg)
Cells larger (>1.5um diameter) or in pairs - Aphanocapsa
sp. (Not Dominant in the Great Lakes) |
|