''Trichodesmium erythraeum'' is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

cyanobacteria Cyanobacteria (), also known as Cyanophyta, are a phylum of gram-negative bacteria that obtain energy via photosynthesis. The name ''cyanobacteria'' refers to their color (), which similarly forms the basis of cyanobacteria's common name, blu ...

that are unique in being visible to the

naked eye Naked eye, also called bare eye or unaided eye, is the practice of engaging in visual perception unaided by a magnifying, light-collecting optical instrument, such as a telescope or microscope, or eye protection. Vision corrected to normal ...

. This

is also known as " sea sawdust". It was originally discovered in 1770 by Captain Cook off the coast of Australia.

Anatomy

This is a prolific

nitrogen Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at se ...

-fixing and phosphorus reducing

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among ...

that fixes approximately half of the

in the

food chain A food chain is a linear network of links in a food web starting from producer organisms (such as grass or algae which produce their own food via photosynthesis) and ending at an apex predator species (like grizzly bears or killer whales), det ...

of the

ocean The ocean (also the sea or the world ocean) is the body of salt water that covers approximately 70.8% of the surface of Earth and contains 97% of Earth's water. An ocean can also refer to any of the large bodies of water into which the wo ...

and contributes to the turn over of phosphorus. Unlike other

, it can also

photosynthesize Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that, through cellular respiration, can later be released to fuel the organism's activities. Some of this chemical energy is stored in c ...

. This is a

colonial Colonial or The Colonial may refer to: * Colonial, of, relating to, or characteristic of a colony or colony (biology) Architecture * American colonial architecture * French Colonial * Spanish Colonial architecture Automobiles * Colonial (1920 au ...

species that forms long filaments and tends to accumulate with other ''Trichodesmium''. It is gram-negative and motile. Some of the bacteria in the colony fix the

, and others are specialized for photosynthesis. However, the two processes must be done with two of them, because the

oxygen Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as wel ...

byproduct A by-product or byproduct is a secondary product derived from a production process, manufacturing process or chemical reaction; it is not the primary product or service being produced. A by-product can be useful and marketable or it can be consid ...

that results from photosynthesis would interfere with the

-fixing process. This is done either by, having two separate cells share resources with each other or by separating the processes by time in the same cell. If the cells are physically separated, then one cell specializes as a diazotroph and undergoes nitrogen fixation while other cells undergo photosynthesis. Alternatively, ''T. erythraeum'' also has been shown to separate the processes of photosynthesis and nitrogen fixation in the same cell by separating the time at which these processes occur. When this is done ''T. erythraeum'' will stop photosynthesizing at midday or night and begin oxygen scavenging as it begins nitrogen fixation. Additionally, ''T. erythraeum'' have gas vesicles that account for 60–70% of the cell's volume. These vesicles allow ''T. erythraeum'' to move in the water coulomb up to 200 m using its buoyancy based on the concentrations of carbohydrates in order to search out nutrients such as nitrogen, phosphorus and iron.

Genetics

''T. erythraeum'' has one of the largest bacterial

genome In the fields of molecular biology and genetics, a genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding ge ...

s sequenced so far at 7.75 mbp. It has a

GC content In molecular biology and genetics, GC-content (or guanine-cytosine content) is the percentage of nitrogenous bases in a DNA or RNA molecule that are either guanine (G) or cytosine (C). This measure indicates the proportion of G and C bases out o ...

of 34% and contains approximately 40% non-coding DNA. There is evidence to suggest that the genome is in an expanding dynamic state due to the expansion of the genome through

horizontal gene transfer Horizontal gene transfer (HGT) or lateral gene transfer (LGT) is the movement of genetic material between Unicellular organism, unicellular and/or multicellular organisms other than by the ("vertical") transmission of DNA from parent to offsprin ...

. ''T. erythraeum'' shows a 98% homology with ''T. thiebautii'' but only a 75% homology with other cyanobacteria such as ''Oscillatoria''.

Environment

''T. erythraeum'' was isolated off the coast of North Carolina. It resides in tropical and subtropical areas of the ocean typically from the surface to 40m however they can travel as deep as 200 m in search of nutrients. They have a pH optima of 7.8–8.4 and an optimal temperature of 24–30 degrees Celsius in aerobic conditions. ''T. erythraeum'' can, however, survive in lower temperatures and through periods of darkness.

Discoloration of the Red Sea

This

can also literally turn the

Red Sea The Red Sea ( ar, البحر الأحمر - بحر القلزم, translit=Modern: al-Baḥr al-ʾAḥmar, Medieval: Baḥr al-Qulzum; or ; Coptic: ⲫⲓⲟⲙ ⲛ̀ϩⲁϩ ''Phiom Enhah'' or ⲫⲓⲟⲙ ⲛ̀ϣⲁⲣⲓ ''Phiom ǹšari''; T ...

a red color that can be seen from

outer space Outer space, commonly shortened to space, is the expanse that exists beyond Earth and its atmosphere and between celestial bodies. Outer space is not completely empty—it is a near-perfect vacuum containing a low density of particles, pred ...

. The cause of this is unknown, but most scientists believe that a species of bacteria of the ''

Trichodesmium ''Trichodesmium'', also called sea sawdust, is a genus of Filamentation, filamentous cyanobacteria. They are found in nutrient poor tropical and subtropical ocean waters (particularly around Australia and in the Red Sea, where they were first des ...

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

, most likely this species, is the cause.

References

Oscillatoriales {{cyanobacteria-stub