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

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

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

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

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

Cyanobacteria: evolutionary history Oldest photosynthetic organisms, oldest fossil records ca. 3500 million years Dominant form of life on Earth 1500 - 600 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. 1600 million years ago

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

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

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

Cyanobacteria: general characteristics Ultra structure: Thylakoids with phycobilisomes fykobilisomer

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

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

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

Cyanobacteria: systematic characters False branching

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

Orden Stigonematales (no marine representatives Stigonema

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

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

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

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

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

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

Cyanobacterial nitrogen fixation of great ecological and commercial importance Rice agriculture: Azolla-Anabaena system 120-310 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): 453-516 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

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

Phylogeny based on multiple sources

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)

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

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

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

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

Microcoleus chtonoplastes + Lyngbya aestuarii

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

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

Calothrix scopulorum Cosmopolitan in distribution. hormogonium attenuated trichomes terminal heterocysts

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 75 Microcystis minuta 60 diam 20 m diam 1.2 - 2.5 m diam 2 - 3.5 m

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, 1.5 - 5 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