Why not bring life to Venus along with the next exploring mission?

Question

Why not bring cyanobacteria and fertilizer to the atmosphere of Venus to improve conditions for life there by producing oxygen ?

Planetary protection could be a reason. According to Wikipedia:

Planetary protection is a guiding principle in the design of an interplanetary mission, aiming to prevent biological contamination of both the target celestial body and the Earth in the case of a sample return mission.

The missions are categorized into 5 groups and Venus is classified into Category II, implying no requirements for bioburden reduction or sterilization of equipment, supposing that there is only a remote chance that contamination by terrestrial microorganisms could jeopardize future explorations.

Only a few scientists have speculated that thermoacidophilic extremophile microorganims might exist in the lower-temperature, acidic upper layers of the Venusian atmosphere. It has been speculated that the clouds there could contain chemicals that can initiate forms of biological activity, like sulfur allotropes, but it is very unlikely that there will be Venusian microorganisms that use water and carbon dioxide for their existence.

So the biosignatures for instance that the Venus Atmospheric Maneuverable Platform will look for will be very different from those from the introduced cyanobacteria and consequently they will not jeopardize the explorations of the existence of Venusian life in the cloud region.

Cyanobacteria are a group of photosynthetic bacteria who use the energy of light to synthesize organic compounds from carbon dioxide, producing oxygen this way.

Nostoc commune is a colonial species of cyanobacterium which forms a gelatinous mass with other colonies growing nearby and in some cells nitrogen-fixing occurs. It is able to survive in extreme conditions in polar regions and arid areas. The cells also contain pigments that absorb ultraviolet radiation, which enables it to survive high levels of it. A dessicated colony is resistant to heat and to repeated patterns of freezing and thawing.

Nostoc commune can also withstand acidic exposure

So it seems that Nostoc commune could be a good candidate for surviving the harsh conditions within the cloud layers if it could be supplied with the necessary trace elements. The sticky biofilms that it produces could be supported by a mattress-like shape made of silica aerogel to keep it buoyant and to supply it with those elements.

The fertilizer could be delivered mainly in the form of hydroxides like KOH, Ca(OH)2 and Mg(OH)2 that would react with the suluric acid in the clouds to form the required water and sulfates.

The big question would be if the biofilms could float themselves outside the supporting mattress, feeding on the droplets of water with fertilizer.

Summarized, the water used by the cyanobacteria will be recycled eventually and the produced oxygen will accumulate and CO$_2$ removed !

Could not one trip for cyanobacteria to the atmosphere of Venus be a giant leap for life ?

Answer 1

Question: Why not bring cyanobacteria and fertilizer to the atmosphere of Venus to improve conditions for life there by producing oxygen ?

... Only a few scientists have speculated that thermoacidophilic extremophile microorganims might exist in the lower-temperature, acidic upper layers of the Venusian atmosphere. It has been speculated that the clouds there could contain chemicals that can initiate forms of biological activity, like sulfur allotropes, but it is very unlikely that there will be Venusian microorganisms that use water and carbon dioxide for their existence. ...

Comments: @notstoreboughtdirt No, it would be producing oxygen which would be useful to later life. – called2voyage♦ May 16 at 18:55

There is a carbon chauvinism (or if you prefer Star Trek: "The Devil in the Dark") aspect to this, that we would alter the conditions of Venus to our liking, at the expense of any existing life, and damage the existing conditions (life, or no) calling future exploration and measurements into doubt.

So there is the 'be nice' aspect.

Probably more important is the cost and usefulness of such actions. Let's simply say that the cost would be significant and that the money could go elsewhere, let's skip to the usefulness ...

Venus is exiting the habitable zone and Mars is within it. Terraforming of Venus is a lost cause, terraforming of Mars has a future purpose. It will take a long time to perform either action (terraform Venus or Mars) slowly (at a lower cost) so it makes sense to choose the location on the way in than to choose the location that has left the building.

As for alternative uses for funding destined for such purposes, it could be used to search for existing life on other bodies within habitable zones (plural).

NASA has a project "Mars Ecopoiesis Test Bed" where phase one (Last Updated: Aug. 6, 2017) is completed. There's a .PDF report on that webpage that lists this rationale:

"Rationale

Ecopoiesis will require water. That means maximizing the chances of liquid-phase water being transiently present in the test bed with the most likely sites being found at Mars’ lowest altitudes and latitudes [Kuznetz, 2006]. A preliminary identification of these “landing” sites, already considered for certain past and future robots, is given briefly in Table 1. The tidal pressure swings of +0.5 mbar need to be considered. These sites are also thought to contain evaporites, possibly including nitrates (all of which are water soluble) to provide nitrogen and magnesium salts [Tosca, 2006]. Recent results from the Curiosity Rover in Gale Crater are encouraging with regard to the availability of minerals to support autotrophic life [Navarro-González, 2013]. The big question of course has to do with the thermodynamics and transport processes of water in real and simulated Martian environments. Even at 11 mbar, the vapor pressure of water is well below the 6.1-mbar triple point, where, at increased temperature ice will normally sublime. However, speculative calculations modeling the diffusion of water vapor from ice surfaces during sublimation indicate a local (within a few mm of ice) increase in water vapor concentration to some 60%, or the required 6.1 mbar in the 11 mbar environment [Levin and Weatherwax, 2004]. Therefore, early proposed research will use the Techshot simulator [N. Thomas, 2006] to test such hypotheses.".

They also have a webpage titled: "Planting an Ecosystem on Mars" (May 6, 2015). I can't find NASA's 'Terraforming Venus' webpage but the idea is unpopular on Quora: "Does NASA have any plans to terraform Venus?". On the other side of the coin Universe Today has an article favoring the idea: "How do we terraform Venus?".

Answer 2

To date, while there are discussions and plans being formed with respect to terraforming, there has not been any serious plans to do so. And that isn't likely until we are able to start really exploring the Solar System with manned missions.

I suspect that this sounds like a good plan to start terraforming Venus, but it will take time to actually make it work. But for now, terraforming is for the far distant science or science fiction.