Aphanizomenon
Aphanizomenon is a genus of cyanobacteria that inhabits freshwater lakes and can cause dense blooms. These cyanobacteria are unicellular organisms that form linear chains known as trichomes. Parallel trichomes can further unite into aggregates called rafts. Cyanobacteria such as Aphanizomenon are known for using photosynthesis to create energy and thus rely on sunlight as their energy source. Aphanizomenon bacteria also play a significant role in the Nitrogen cycle due to their ability to perform nitrogen fixation. Studies on the species Aphanizomenon flos-aquae have shown that it can regulate buoyancy through light-induced changes in turgor pressure. The genus is also capable of gliding motility, although the specific mechanism responsible for this ability remains unknown.
Species
Species and synonymy from AlgaeBase:- Aphanizomenon americanum S → Aphanizomenon flos-aquae
- Aphanizomenon aphanizomenoides S → Sphaerospermopsis aphanizomenoides
- Aphanizomenon balticum U
- Aphanizomenon capricorni S → Cuspidothrix capricorni
- Aphanizomenon chinense C
- "Aphanizomenon cyaneum" S → Aphanizomenon flos-aquae
- Aphanizomenon elenkinii S → Aphanizomenon flos-aquae
- Aphanizomenon favaloroi C
- Aphanizomenon flexuosum C
- Aphanizomenon flos-aquae C - see note
- Aphanizomenon gracile C
- Aphanizomenon holsaticum S → Aphanizomenon flos-aquae
- Aphanizomenon hungaricum C
- Aphanizomenon incurvum C
- Aphanizomenon issatschenkoi → Cuspidothrix issatschenkoi
- Aphanizomenon kaufmannii S → Cylindrospermopsis raciborskii
- Aphanizomenon klebahnii C
- Aphanizomenon manguinii C
- Aphanizomenon morrenii C
- Aphanizomenon ovalisporum S → Umezakia ovalisporum
- Aphanizomenon paraflexuosum C
- Aphanizomenon platense C
- Aphanizomenon schindleri C
- Aphanizomenon skujae C
- Aphanizomenon slovenicum C
- Aphanizomenon sphaericum S → Aphanizomenon aphanizomenoides
- Aphanizomenon strictum U
- Aphanizomenon tropicale S → Cuspidothrix tropicalis
- Aphanizomenon ussaczevii S → Cuspidothrix ussaczevii
- Aphanizomenon volzii S → Macrospermum volzii
- Aphanizomenon yezoense C
Ecology
Overcoming phosphate limitation
Aphanizomenon may become dominant in a water body partially due to their ability to induce phosphate-limitation in other phytoplankton while also increasing phosphate availability to itself through release of cylindrospermopsin. The cylindrospermopsin causes other phytoplankton to increase their alkaline phosphatase activity, increasing inorganic phosphate availability in the water to Aphanizomenon during times when phosphate becomes limiting.Photosynthesis
All species in the cyanobacteria phylum can perform photosynthesis. They use a similar photosynthesis to plants, using two photosystems which is called the Z-scheme. This is different from other photosynthetic bacteria that only use one photosystem and do not have thylakoids. Cyanobacteria species such as Aphanizomenon also use Oxygen as their final electron acceptor in the Electron Transport Chain, which is also different from other photosynthetic bacteria, which perform a type of photosynthesis called anoxygenic photosynthesis.Nitrogen fixation
Aphanizomenon are a special type of cyanobacteria called heterocysts, which are capable of producing biologically useful nitrogen by the process of nitrogen fixation from atmospheric nitrogen.A large proportion of fixed nitrogen may be released into the surrounding water, providing an important source of biologically available nitrogen to the ecosystem. Since Aphanizomenon are one of the few species of bacteria that can perform nitrogen fixation, other bacterial species that use nitrogen ions as a reactant will start to rely on the species as a source of usable nitrogen. This will cause a bacterial bloom to form, which is a condition under which the number of bacterial colonies in an area will suddenly increase.