how big are cyanobacteria
2-100 um
outline some characteristics of cyanobacteria
- blue green algae
- gram negative bacteria
- only photosynthetic prokaryotes to produce o2
how are cyanobacteria important
first organisms to produce oxygen into the atmosphere 2.5 billion years ago
what have we used as ancient evidence to prove the existence of cyanobacteria
presence of stromatolites
what are stromatolites
rock like structures made of cyanobacteria which are used as modern day examples of life in Precambrian times
what are some physical characteristics of the cyanobacteria
- thylakoids
- slime coats
- peptidoglycan layer
- phycobilisome = protein complexes in the membrane
how are cyanobacteria pivotal for the evolution of life
it was hypothesised that they gave rise to the first eukaryotic cell via endosymbiosis
what are the different classifications based on the number of membranes for endosymbiosis
- primary endosymbiosis
- secondary endosymbiosis
- tertiary endosymbiosis
what do phycobilisomes contain
- phycoerythrin
- phycocyanin
allows cyanobacteria to capture a wider spectrum of light increasing photosynthetic efficiency
how are cyanobacteria involved in nitrogen fixation
they are capable of fixing nitrogen converting nitrogen into nitrate or ammonia
how are cyanobacteria involved in marine ecosystems
- grazed on by reef organisms
- provide nitrogen to coral reef ecosystems
- important in calcification and decalcification
- symbiosis in sponges and ascidians
how are cyanobacteria extremophiles
- flexible metabolism and lifestyle
- survive extremely high and low temps
- able to colonise infertile substrates
what are the different types of cyanobacterial cells
- single cells
- colonies
- filaments with specialised cells
name the three different types of cells found in filamentous cyanobacteria
1) akinete = resting stage
2) heterocyst’s = used for nitrogen fixation
3) hormogonia
how are hormogonia used in asexual reproduction
short piece of trichome found is filaments which detaches from the parent and glides away
what are the main morphological groups of cyanobacteria
- unicellular
- filaments lacking specialsed cells
- exospores
- endospores
- filaments with heterocysts and akinetes
- filaments with true branching
what are synechocystis
a unicellular spherical cell which produces asexually and found in freshwater
name some characteristics of synechoccus
unicellular
prokaryotic autotrophic picoplankton
fresh water strains
main source of primary production in marine waters
what are trichodesmium (sea sawdust)
a non-heterocystous cyanbacteria
fixes nitroge without heterocysts
gas vesicles regulate buoyancy
what are spirulina
fresh water species
occurs in tropical/subtropical lakes with high PH
used in commercial production
what are nostacales
colonial filaments
terrestrial and freshwater species
forms loose clumps in the soil
what is BMAA
a neurotoxin produced by some cyanobacteria which can cause neurodegenerative diseases like alzheimers
why are cyanobacteria good to use in biotechnology
- minimal nutrient requirements
- high photosynthetic efficiency
- improve fertility by N fixation
- produce high value compounds
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Marine ecology27
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The properties of water, currents and tides25
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Estuarine and intertidal ecosystems20
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shallow seas30
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tropical coasts28
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the open ocean22
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Polar seas21
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nutrient cycling18
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cyanobacteria23
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Dinoflagellates22
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Haptophytes and Diatoms25
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sea grasses12
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invertebrates in the pelagic zone22
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Benthic invertebrates18
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sharks and rays24
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bony fish14
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marine mammals20
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marine reptiles24
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Humans and the ocean15
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the changing ocean11
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Algal groups- Red, Brown and Green algae23
