Freshwater Phytoplankton Key for the Northeast By Rachael
Freshwater Phytoplankton Key for the Northeast By: Rachael Brown, Sonya Carlson, and Diana Jackson Under the guidance of Dr. Alan Baker NEXT
Introduction: This photographic key is intended to aid in identification of freshwater algae to the Genus level. Proceed through this key by clicking on the picture that most resembles your organism. Buttons to know: Home: Go to the beginning page at any time Back: Go to the last page viewed Forward: Go to the next page in the key To Start Key Click Here START
Cells with definite chloroplasts and nuclei, not blue-green in color Cells without definite chloroplasts and nuclei, blue-green in color
Vegetative cells usually grass-green in color and with a definite cell wall Vegetative cells not grass-green
Vegetative cells yellow-green with a cell wall Vegetative cells yellowish to brown with a glass-like silica wall of two overlapping halves
Class: Chrysophyceae
Class: Cyanophyceae Common Name: Cyanobacteria, blue-greens Continue to Genus
Is the general contour of the specimen: Elongate strands of cells Oblong, Circular, or Globular Rectangular Sperm shaped Note: A filament is a strand of cells arranged end to end
Elongate filaments of cells Are the filaments: Unbranched Branched
Genus: Microthamnion
Unbranched: Filaments form together in parallel colonies (rafts) Filaments are found alone
Oblong, Circular, or Globular Option A: Oblong Option B: Circular Option C: Globular
Sperm-Shaped Head has thin membrane Head has thick wavy membrane
Genus: Aphanocapsa
Genus: Aphanothece
Genus: Chroococcus
Genus: Coelosphaerium
Genus: Gloeocapsa
Genus: Microcystis
Genus: Merismopedia
Genus: Cylindrospermum
Genus: Gloeotrichia
Genus: Anabaena
Genus: Aphanizomenon
Genus: Calothrix
Genus: Chamaesiphon
Genus: Lyngbya
Genus: Nostoc
Genus: Oscillatoria
Filaments are joined at one end Filaments are parallel and are not joined together at any end
Filaments have elongate cells arranged end to end Filaments have horizontal cells that are stacked on top of each other
Filaments Found Alone Cells are round are arranged in long filaments (like strands of pearls) Elongate unicells are found on a substrate unicells
Cell shape is rectangular Cell shape is oblong
Filaments are spaced apart from each other Filaments are lumped together
Option A: Oblong Cells float freely apart from each other Cells join in even numbers and have a clear membrane around them
Option B: Circular Cells are free floating with thin clear membranes Cells are congregated and encased in a round membrane
Encased Cells are encased by a clear membrane Cells are encased in a thick green membrane
Order: Bacillariophyceae Common Name: Diatoms Continue to Genus
Is the shape of the organism rectangular? Does organism have stalks? Is the shape of the organism circular or oval?
Are there many rectangles joined together? Are the rectangles separate from each other?
Do the rectangles make a line or stairstep formation? Do the rectangles form a star? Do the rectangles form a box?
Genus: Tabellaria
Genus: Asterionella
Genus: Eunotia
Width (W) of individual cells is 1/10 of the length (L) Width (W) of individual cells is 1/5 of the length (L) L L W W
Genus: Fragilaria
Genus: Fragilaria
Are there many small circles within the cells? Is the end of the cell a long spike or is there a few large circles within the cells?
Genus: Melosira
Genus: Rhizosolenia
Is the middle of the cell wider than either end? Is the end of the cell opposite of the stalk the widest section?
Genus: Cymbella
Genus: Gomphonema
Are there smaller circles within the large circle? Are there lines around the edge of the circle? Is the shape of the organism oval?
Genus: Cocconeis
Genus: Cyclotella
Is the cell extremely long and skinny with the length (L) more than 15 times as much the width (W)?
Genus: Synedra
Are the ends of the cell curved (c)? Are the ends of the cell flat (f)? Are the ends of the cell pointed (p) or rounded (r) )?
Genus: Gyrosigma
Genus: Amphora
Is the cell the same width in the middle as it is nearer to the ends? (a is equal to b) Is the cell the wider in the middle than it is nearer to the ends? (a is larger than b)
Is the edge of the oval smooth? Does the edge of the oval have a distinct bump? Smooth Bump
Is there a distinct line down the length of the cell? Distinct Line Is no distinct line visible in the center of the cell?
Is the center area of the middle line is wider than the ends of the middle line with a distinct break in the center? Is the middle line even in width with a distinct break in the center? Is the middle line complete with no distinct break in the center?
Genus: Navicula
Genus: Frustulia
Genus: Opephora
Is the cell long and skinny with the length (L) more than 5 times as much the width (W)? Is the cell short with the length (L) less than 5 times as much the width (W)?
Genus: Diatoma
Genus: Amphipleura
Genus: Surirella
Is the interior of the cell a homogenous color without lines? Are there distinct parallel lines extending from the middle of the cell to the edge? Lines
Genus: Achnanthes
Genus: Rhopalodia
Are the ends distinctly pointed? Are the ends distinctly rounded?
Genus: Nitzschia
Genus: Pinnularia
Actinastrum
Ankistrodesmus
Apiocystis
Arthrodesmus
Bulbochaete
Carteria
Centritractus
Chaetophora
Chaetosphaeridium
Characiopsis
Characium
Chlamydomonas
Chlorella
Chlorococcum
Cladophora
Closterium
Coelastrum
Coelosphaerium
Coleochaete
Cosmarium
Crucigenia
Desmidium
Dictyosphaerium
Dimorphococcus
Docidium
Euastrum
Eudorina
Gloeocystis
Gonium
Haematococcus
Hormidium
Hyalotheca
Hydrodictyon
Kirchneriella
Micractinium
Micrasterias
Microspora
Mougeotia (Conjugating)
Oedogonium
Onychonema
Oocystis
Palmella
Palmellocystis
Pandorina
Pediastrum
Planktosphaeria
Pleurotaenium
Scenedesmus
Selenastrum
Spirogyra
Staurodesmus
Tetraedron
Ulothrix
Volvox
Xanthidium
Zoochlorella
Zygnema
Class: Chlorophycae CELLS ARE ARRANGED IN… FILAMENTS (LINEARLY) COLONIES (GROUPS OF CELLS) SINGLE CELLS
COLONIES ARE… FLAT (2 -D) SPHERICAL (3 -D)
CELLS IN FILAMENTS HAVE… ONE CHLOROPLAST TWO CHLOROPLASTS MANY CHLOROPLASTS
SINGLE CELLS ARE… UNICELLULAR HEMISPHERES
INDIVIDUAL CELL SHAPE IS… SPHERICAL OR ELLIPTICAL SPIKEY LONG OR ROD SHAPED
COLONIES HAVE… TIGHTLY PACKED CELLS SPACE BETWEEN CELLS
FILAMENTS ARE… SINGULAR BRANCHED
HEMICELLS ARE… LONG AND NARROW SEMICIRCULAR
CHLOROPLASTS ARE… CLUMPED SPIRALED
ARE CELLS IN THE FILIMENT… LONG SHORT
Does your algae look like any of these?
Does your algae look like any of these?
Does your algae look like any of these?
Does your algae look like any of these?
Does your algae look like any of these?
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