Anabaena Cyanobacteria produces oxygen in water for fish and plants to grow. This is apart of the CELSS system. The CELSS system is a hermetically sealed biological system that only requires light and temperature cooling to sustain itself. The contents of the system never interconnected to the outside. When building a system like this, it is very important to take pictures as you go along. Link to an introduction to the CELSS project, click here
Below is a link describing a number of nitrogen fixing biological systems.
Link to a number of Nitrogen Fixing Bio-Systems
The scope of the project requires the understanding and balancing of four gas cycles for plants to self-sustain themselves. (There are many cycles) They are CO2-O2; NH4-NO3; O3-CH4 and H2SO4-H2S. Ironically, these cycles/balances are not pure carbon, nitrogen or etc… They are mixed because of plant/bacteria biology and the atomic forces of electrons transferring from one atom to another. These forces really dictate the cycles.
People know this cycles as the carbon dioxide and oxygen cycle. We breathe out CO2 and plants take in CO2 to produce O2. Then we breathe in O2 to complete the cycle.
This is known as the nitrogen fixing cycle. Bacteria, plants and a whole load of processes produce fixed nitrogen. It starts out from Ammonium (‘dissolved in water’ version of Ammonia) and passes through a set of bacteria, micro-organisms and etc., producing fixed nitrogen that is directly absorbable by plants. Link to a number of Nitrogen Fixing Bio-Systems
This is the VOC cycle where methane (CH4, BTY, it does not have a smell) is produced by bacteria or a number of anaerobic (without oxygen present) processes, it escapes into the air, combines with OH (hydroxide; this is produced by Ozone (O3) combining with water moisture in the upper atmosphere) and produces CH3 and water. CH3 is absorbed in our soils as bacteria food.
A competing cycle is the NOx cycle. When NOx (NOx is a shorthand for NO2 + NO) is released into the air, it combines with OH (hydroxides) and result in
HO2 + NO → OH + NO2
NO2 + hν → NO + O(3P)
In other words, smog. NOx is produced through exhaust emissions from cars. Nature produces NOx, but not in the same quantities. The VOC molecules are known to stay in the atmosphere for around 7 to 9 years.
The sulpher cycle. Oxidation of hydrogen sulfide produces elemental sulfur. This reaction is done by the photosynthetic green and purple sulfur bacteria and some chemolithotrophs. Below is the sulpher cycle.

Further oxidation of elemental sulfur produces sulfate.
Green and purple sulfur bacteria (photosynthetic). Must live in the light. Cannot exist deep in the deep oceans. Environment must contain a source of hydrogen sulfide, usually arising from desulfuration of decaying organic material or from sulfate reduction. These organisms are often found in waters “one level” above decaying organics or sulfate reducers where they acquire hydrogen sulfide bubbling up from below and are simultaneously illuminated by the sunlight.
Below is a link where the described pictures are taken. The Anabaena Cyanobacteria took about 8 weeks to start growing once the system is setup. It is seeded from an outdoor organic Aquaponics system.
Link for current photographed Anabaena Cyanbacteria
Below is a link for describing where the orgninating water is cultivated.
Description of the outdoors Aquaponics system, click here
I had help identifying the pictures below. I would to thank my friend Brad for helping me determine what things are growing my CELSS tank. Some of his remarks are posted below. The majority of comments are from visual observations. To get an exact species or identification, the micro-organisms would have its DNA sequenced.
I took all of the pictures using a 400X microscope. All slides are prepared by placing some of the specimen on the microscope slide with water and placing a glass cover. Glass is used because it does not scratch. Plastic cover slides do not make a sharp, clear pictures. It comes out milky. The microscope is a filament under lit stage.
Brad: The big cyanobacterium is either Anabaena (probably) or Nostoc. The small one will likely not be identifiable morphologically, but is probably a Phormidium. Anabaena and Nostoc are nitrogen fixers, the larger cells in the trichomes are heterocysts, special cells within which nitrogen fixation takes place. They have thick walls to protect against oxygen, and do not evolve oxygen through photosynthesis (they lack Photosystem II).

Brad: You can see structure within the heterocysts, specifically, the two “polar bodies” where the heterocyst joins the vegetative cells of the filament. The fact that you have these nitrogen fixers in there is a good indication that your ammonium levels are very low.
In fact after measuring the ammonium levels, they are very low.

Brad: The green chards are either diatoms (if they are brownish) or desmids (if they are green). The lumpy filament in the middle may be a sulfur oxidizing bacterium
There is a hint hydrogen sulfide in the tank air. There are white mats forming on the top surface of the algae. Bubbles are protruding through the algae and slime. The DO of the water is around 10 mg/L of O2.
