1. CYANOBACTERIA (CHLOROXYBACTERIA)
BLUE GREEN ALGAE OR BLUE GREEN BACTERIA
Classified both under International Code of Botanical Nomenclature (ICBN) and under Bacterial Code of Nomenclature
Traditionally:
Order Chroococcales
Order Oscillatoriales
Order Nostocales
Order Stigonematales
Text book
1. Unicellular and colonial CB lacking
specialized cells or reproductive processes
2. Filamentous CB, lacking spores, heterocytes
or akinets
3. Exospore producing CB
4. Endospore producing CB
5. Heterocyte and akinete producing CB
6. True branching CB

2. Cyanobacteria: distribution and numbers
Include ca. 200 genera and 2000 species
All kinds of environments i.e. “ubiquitous”, mostly
aquatic (rarely at pH< 4-5),terrestrial on rocks and soils,
deserts, polar regions, other extreme habitats as thermal
pools (ca. 70 °C),hypersaline waters etc.
In symbioses, ca 8 % of lichens with cyanobacteria
as fycobiont + some with cephalodes (N2-fixation)
In blooms (vannblomst) = mass occurrence with surface scum and often toxin producing species

3. Why treat cyanobacteria together with the algae?
1. Oxygenic photosynthesis and pigments (chlorophyll a) as in algae and plants
light
CO2 +2H2O
(CH2O) + O2 +H2O
chlorophyll a
All other photosynthetic bacteria (e.g. green sulfurbacteria)
have bacterial chlorophyll and anoxic photosynthesis
light
CO2 +2H2S
(CH2O) + 2S + H2O
Bacterial chlorophyll

4. Why treat cyanobacteria together with the algae?
2. Cyanobacteria (blue greens) occur with algae in similar habitats, mainly aquatic environments.
Similar ecological function (as primary producers). Together with the algae they stand for ca. 40 % of global primary production

5. Why treat cyanobacteria together with the algae?
3. Algal (and plant) chloroplasts originated from primary endosymbiosis between heterotrophic eukaryote and a free living cyanobacterium
nucleus
chloroplast
Cyanobacterium taken up
by phagotrophic eukaryote
and eventually transformed
into a chloroplast
cyanobacterium

6. Cyanobacteria: evolutionary history
Oldest photosynthetic organisms, oldest fossil records ca million years
Dominant form of life on Earth million years before present (BP) (e.g stromatolites)
Photosynthesis resulted in a gradual increase of O2 in the atmosphere
Primary endosymbiosis lead to algal chloroplasts
ca million years ago

7. Cyanobacteria: general characteristics
As all Prokaryotes absence of organelles:
- Nucleus
- Chloroplasts
Mitochondria
- Golgi bodies (dictyosomes)
- Endoplasmatic reticulum (ER)

8. Cyanobacteria: general characteristics
Pigments:
chlorophyll a
(three genera with chlorophyll a + b)
phycoerythrin
phycocyanin
phycobilins
allophycocyanin
carotenoids
A variety, some are
specific, others as in
algae and plants
scytonemin - extra cellular, UV-shielding pigment

9. Cyanobacteria: general characteristics
Storage products:
- Cyanophycean-starch (-1,4 glucan)
- Cyanophycin-grains: N-reserve, a
co-polymer of two amino acids (asparagine and arginine)
- Volutin grains - polyphosphate granules
- Lipids

10. Cyanobacteria: general characteristics
Ultra structure:
Thylakoids with phycobilisomes
fykobilisomer

11. Cyanobacteria: general characteristics
Cell wall: as Gram-negative
bacteria
central layer: murein
(peptidoglykan)
cellevegg
Outside the cell wall a ± thick layer of
polysaccharides and polypeptides may form a sheath in some filamentous forms. The sheath may be brownish in color, due to scytonemin (UV absorbing protecting pigment)
The cell row itself is called trichome
mucilaginous
sheath
trichome
filament = trichome + sheath

12. Cyanobacteria: systematic characters
Morphology
Unicellular
as colonies
single cells
free living
attached
(cells polar)
(Order Chroococcales)

13. Cyanobacteria: systematic characters
Morphology
Multicellular (filamentous)
uniseriate trichome
multiseriate trichome

14. Cyanobacteria: systematic characters
False branching

15. Cyanobacteria: systematic characters
True branching
only in some representatives of the order Stigonematales

16. Orden Stigonematales
(no marine representatives
Stigonema

17. Cyanobacteria: systematic characters
Vegetative reproduction:
by binary division and fragmentation
Chroococcus
Merismopedia

18. Cyanobacteria: systematic characters
Vegetative reproduction:
by hormogonia, only in some filamentous forms
hormogonium
Oscillatoria
“separation discs”
(necridia)
Lyngbya

19. Cyanobacteria: systematic characters
Vegetative reproduction:
Akinetes: resting cells with thick cell walls
and enriched with storage products
Anabaena
Akinetes may survive for years in darkness and under dry conditions

20. Cyanobacteria: systematic characters
Asexual reproduction:
Formation of spores, only in some
unicellular forms
exospores
endospores
(= baeocytes)
Dermocarpa
Chamaesiphon

21. Cyanobacteria: systematic characters
Sexual reproduction by gametes:
completely absent
Viral transduction may happen

22. Cyanobacteria: systematic characters
Heterocytes (heterocysts) are cells with nitrogen fixation as a special function.Heterocytes only present in some filamentous forms (Nostocales, Stigonematales), though N-fixation may occur also in some non- heterocysteous forms
NH4+ N2
nitrogenase
intercalary heterocyst
akinete
terminal heterocyst

23. Cyanobacterial nitrogen fixation of great ecological and
commercial importance
Rice agriculture:
Azolla-Anabaena system kg N per hectar per year. Free-living cyanobacteria e.g. Tolypella or Anabaena ca 40 kg
See: Vaishampayan et al. (2001) Cyanobacterial Biofertilizers in Rice Agriculture - Bot.Rev. 67 (4):
cephalodia in som lichens in addition to algal fykobiont
Marine plankton:
Richela intracellularis
N2 fixation endophytic in the diatom
Rhizosolenia sp.
Trichodesmium erythraeum - in tropical marine plankton, Oscillatoria-like trichoms as free floating bundles. May fix up to 30 mg nitrogen m-2 day-1
Nodularia spumigena -
Baltic Sea- Kattegat

24. Cyanobacteria: Traditional taxonomic classification in orders
Unicells, as individual cells or
colonies. Spores may occur,
never akinetes or heterocysts
Order Chroococcales
Uniseriate trichomes, never akinetes or heterocysts
unbranched or false-braching
2. Order Oscillatoriales
Uniseriate trichomes, with
akinetes and heterocysts.
Unbranched or false-braching
3. Order Nostocales
Uni- or multiseriate trichomes,
with akinetes and heterocysts.
True branching
4. Order Stigonematales

25. Phylogeny based on multiple sources

26. Microcystis aeruginosa
Toxin producing
cyanobacterium in
eutrophic fresh waters.
Toxin (microcystin) a
cyclic polypeptide that
cause liver damage
(hepatotoxin).
Other species produce alkaloids that are neurotoxins (anatoxin), Anabaena and others
Skin irritants (e.g. Lyngbya majuscula)
Other secondary metabolites may cause smell and odors to drinking water (geosmin)

27. “Vannblomst” = bloom of Microcystis aeruginosa
forming surface scum (Frøylandsvatnet, Jæren).

28. Marine, benthic habitats
Mud flat (Sandspollen, Oslofjord) “microbial mats” Microcoleus chtonoplastes - Lyngya aestuarii association

29. Film of cyanobacteria on shallow,
muddy bottom(Inner Oslofjord,Frognerkilen)

30. Species composition in the Microcoleus - Lyngbya association
Frequency of the 6 on top species based on 13 localities from Swedish west coast
and Oslofjord (based on data from Lindstedt,1943 and Wiik, 1981)
Microcoleus
Microcoleus chtonoplastes 100
Lyngbya aestuarii 85
Spirulina subsalsa 85
Chroococcus turgidus 50
Anabaena variabilis 50
Merismopedia glauca 40
Lyngbya
Spirulina
Chroococcus
Anabaena
Merismopedia

31. Microcoleus chtonoplastes + Lyngbya aestuarii

32. Lyngbya aestuarii
ALGAS BENTÓNICAS MARINAS DE GALICIA: Iconografías Facultad de Ciencias, Universidad de A Coruña, I. Bárbara 2006

34. Black supralittoral zone consisting of Calothrix scopulorum and other cyanobacteria plus the crustose black lichen Verrucaria maura.

35. Calothrix scopulorum Cosmopolitan in distribution. hormogonium
attenuated trichomes
terminal heterocysts

36. Species composition in the Calothrix scopulorum associasjonen
Frequency of the 6 on top species based on 18 localities from Swedish west coast
and Norwegian coast to Tromsø (based on Lindstedt, 1943 and Wiik, 1983)
Calothrix scopulorum 100
Phormidium fragile 100
(Leptolyngbya fragilis)
Plectonema battersii 95
(Pseudophormidium battersii)
Gloeocapsa crepidinum 80
Plectonema norvegicum
Microcystis minuta
diam 20 m
diam m
diam m

37. Other marine habitats and species.
Epiphytically, on various macroalgae: Calothrix confervicola, Dermocarpa sp.
Endophytically, Calothrix parasitica (in Nemalion)
In shells, Hyella caespitosa, Plectonema terebrans, Mastigocoleus testarum
Epilithic, Rivularia atra
Marine plankton, Synechocystis, shaerical cells, 2-6 m
Synechococcus, cylindrical cells, m
Prochlorococcus, as Synechococcus, lacks phycoblins, has chl. a+b Nodularia spumigena (Baltic Sea, brackish water)
Trichodesmium thiebautii, Oscillatoria like trochomes in bundles
Trichodesmium erythraeum, mainly tropical waters