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Cyanobacteria. THE FIRST ALGAE!!!!!. Evolution. Old 3.5 billion years Dominated as biogenic reefs During Proterozoic – Age of Bacteria (2.5 bya – 750 mya) they were wide spread Then multicellularity took over Cyanobacteria were first algae!. Cyanobacteria terminology.

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cyanobacteria

Cyanobacteria

THE FIRST ALGAE!!!!!

evolution
Evolution
  • Old 3.5 billion years
  • Dominated as biogenic reefs
  • During Proterozoic – Age of Bacteria (2.5 bya – 750 mya) they were wide spread
  • Then multicellularity took over
  • Cyanobacteria were first algae!
cyanobacteria terminology

Cyanobacteria terminology

- Division Cyanophyta

- Cyanobacteria ‘formerly known as’ BlueGreen Algae

- Cyano = blue

- Bacteria – acknowledges that they are more closely related to prokaryotic bacteria than eukaryotic algae

slide4
Green Plants

Red Algae

Bacteria

Animalia

Archeae

Fungi

Other Eukaryotes

Prokaryotes

Eukaryotes

slide5
Cyanobacteria

Green Plants

Brown Algae

Red Algae

Diatoms

Archeae

Fungi

BOTANY

cyanobacteria1

Cyanobacteria

Microscopic organisms

Found in marine sediments and pelagic zone, freshwater lakes, soils,

Live in extreme environments – chemically and temperature.

importance
!!!Importance

1) First organisms to have 2 photosystems and to produce organic material and give off O2 as a bi-product.

Very important to the evolution of the earths’ oxidizing atmosphere .

importance1
Importance

2) Many – fix or convert atmospheric nitrogen into usable forms through Nitrogen Fixation when other forms are unavailable.

IMPORTANT because atmospheric N2 is unavailable to most living organisms because breaking the triple bond is difficult

N

N

cyanobacteria characteristics

Cyanobacteria Characteristics

- Pigments – chl a, phycobiliproteins

- phycoerythrin

- phycocyanin * BlueGreen Color

- allophycocyanin

- Storage – glycogen

- Cell Walls – amino acids, sugars

forms
Forms
  • Unicell – with mucilaginous envelope
  • Colonies –
  • Filaments – uniserate in a single row

- OR - multiserate – not TRUE branching when trichomes are > 1 in rows

features

Features

} Filament

Trichome – row of cells

Mucilaginous sheath –

layer of mucilage outside of the cell wall.

features1

Features

Mucilaginous Sheath –

Function – protects cells from drying and involved in gliding.

Sheath is often colored:

Red = acidic

Blue = basic

Yellow/Brown = high salt

features2

Features

Heterocyst – thick walled cell, hollow looking. Larger than vegetative cells.

FUNCTION – provides the anerobic environment for N fixation.

H- heterocyst

slide14
Heterocyst

Vegetative cells

Anabaena

habit success due to ability tolerate a wide range of conditions
Habit – success due to ability tolerate a wide range of conditions
  • Marine – littoral and pelagic
  • Fresh Water
  • Hot Springs
  • Terrestrial – soil flora
heterocyst
Heterocyst
  • Larger than vegetative cells
  • Hollow looking
  • Thick walled – doesn’t allow atmospheric gas to enter.
  • Photosynthetically inactive
  • No CO2 fixation or O2 evolution
  • Formation of heterocysts triggered by [molybdenum] and and low [nitrogen]
nitrogen
Nitrogen
  • Nitrogen is a limiting nutrient necessary for the production of amino acids = building blocks of life.
nitrogen fixation
Nitrogen Fixation
  • ONLY cyanobacteria and prokaryotic bacteria can FIX nitrogen.
  • Of these two only CYANOBACTERIA evolve OXYGEN during photosynthesis
  • Important because nitrogenase (enzyme involved in fixing nitrogen) is INACTIVATED by O2.
mechanisms to separate nitrogenase from oxygen
Mechanisms to Separate Nitrogenase from Oxygen
  • Heterocyst (spatial)

OR

  • Fix Nitrogen in the DARK but not LIGHT – found in non-heterocystic cyanobacteria (temporal)
aerobic
AEROBIC

LIGHT

CO2 + H2O ----------- CH2O (sugar) +O2

Electrons for PS1 come from PS2 which evolves oxygen (splitting of water)

anaerobic in the presence of sulfer
ANAEROBIC in the presence of sulfer

2H2S + CO2 -------- CH2O +2S + H2O

H2S is the electron donor – so the reaction does not produce oxygen.

advantage for cyanobacteria
Advantage for Cyanobacteria
  • Can live in fluctuating environments of aerobic and anaerobic with light present.
cyanotoxins in cyanobacteria
Cyanotoxins in Cyanobacteria
  • Neurotoxins – block neuron transmission in muscles (Anabaena, Oscillatoria)
  • Hepatotoxins – inhibit protein phosphatase, cause liver bleeding. Found in drinking water. (Anabaena, Oscillatoria, Nostoc)

Eg. swimmers itch - Lygnbia

movement
Movement
  • No flagellae or structures to enhance movement
  • Excrete mucilage – jet propulsion, gliding
  • Helix – fibers send waves of contraction

Spirulina

slide25
Spirulina
  • filamentous
  • common in lakes with high pH
  • major food for flamingo populations
  • commercial food source
slide26
Anabaena with a heterocyst
  • common bloom forming species with nutrient loads
slide27
Lyngbia martensiana

Releases chemicals causing dermatitis

asexual reproduction
Asexual Reproduction

- Hormogonia formation -

- Endospore / Akinete formation -

  • Fragmentation –
  • Exospore
asexual reproduction1
Asexual Reproduction

Hormogonia – short piece of trichome found in filaments. It detaches from parent filament and glides away

Hormogonia

slide30
Oscillatoria with hormogonia
  • short pieces of a trichome that become detached from the parent filament and glide away to form new filament.
asexual reproduction2
A - akinete

H

Asexual Reproduction

Akinete – thick walled resting spore

asexual reproduction3
A - akinete

H

Asexual Reproduction

Akinete – thick walled resting spore

Function – resistant to unfavorable environmental conditions.

Appear as larger cells in the chain and different than heterocyst. Generally lose buoyancy

asexual reproduction4
Asexual Reproduction

Fragmentation - fragmentation

oldest fossils
Oldest Fossils
  • 3.5by old carbonaceous microfossils S.Africa
  • 3.4by old filaments and microbial fossils – W. Australia
  • 3.4 by old stromatolites – S.Africa, Australia
slide37
Cyanobacteria and Understanding the Past

Stromatolites – Shark Bay, W. Australia

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