How to know the freshwater benthic algae

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How to know the freshwater benthic algae

• Maria Kahlert

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freshwater benthic algae

• Check first
• Color
• Bluegreen bluegreen algae
• Green green algae
• Yellowish-Brown brown algae
• Diatoms
• Chrysophytes
• Brown algae
• Red red algae
• Be aware of exceptions!!!

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freshwater benthic algae

• Exceptions in color
• Bluegreen red alga Chroodactylon
• Green brown alga Vaucheria
• Green brown alga diatoms in bad shape
• Red green alga Haematococcus

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freshwater benthic algae

• Check also
• Absence/presence of cell organelles
• Absence bluegreen algae cyanoBACTERIA
• Presence all other algae
• Presence of siliceous cell wall (distinctly
  shaped glass house) diatoms

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freshwater benthic algae

• Check next
• Bluegreen algae
• Organization of thallus
• Coccoid
• Filamentous
• No branches
• False branches
• True branches
• Presence/absence and place of heterocysts (N2
  fixation) (only for the filamentous forms)
• Length of cell

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freshwater benthic algae

• Check next
• Green algae
• Organization of thallus
• Coccoid
• Single cell/colonies/coenobia
• Filamentous
• Not branched/branched
• Chloroplast morphology
• Cup-shaped
• Parietal (like a tapestry, middle of cell is
  vacuole)
• Axial (in the middle of cell)

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freshwater benthic algae

• Check next
• Brown algae Diatoms
• Identification of living diatoms only grossly,
  must be prepared (see separate information)

raphe (slit in cell wall)
no raphe
centric
pennate
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freshwater benthic algae

• Check next
• Brown algae
• Chrysophytes and real brown algaeVery few in
  freshwater, very different
• Hydrurus (golden)
• Ophiocytium (green)
• Tribonema (golden)
• Vaucheria (green)
• Pleurocladia (brown)
• Hildenbrandia (brown)

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freshwater benthic algae

• Check next
• Red algae
• Very few in freshwater
• Heribaudiella
• Chroodactylon
• Audouinella
• Batrachospermum

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freshwater benthic algae

• Some algal terms
• Cell organelles cell content with a membrane
  inside the cell
• Siliceous cell wall cell wall outside cell in
  diatoms, made from glass
• Heterocysts special cells in bluegreens
  fixating N2
• Thallus body of alga
• Coccoid ball formed thallus
• Filamentous hair formed thallus
• Coenobia- cell cannot divide mitotically, after
  meiosis, the mother cells dies and relieves a
  certain number of identically shaped daughter
  cells, a finished colony