Can Venus host lifeforms?

"An artist’s impression of the proposed VERVE mission to Venus the answer whether tiny bacterial lifeforms really do exist in the planet’s clouds. Credit: Danielle Futselaar" (ScitechDaily, Unexplained Gases on Venus: Could They Be the Sign of Alien Life?)

"Could microbial life be drifting in the clouds of Venus? With unexplained signs of phosphine and ammonia scientists are developing a bold new space mission to find out." ScitechDaily, Unexplained Gases on Venus: Could They Be the Sign of Alien Life?)

Phosphine in Venus' atmosphere still remains. Researchers found phosphine and ammonia in that planet’s atmosphere. That causes the possibility that there can be lifeforms on Venus’ clouds. That planet’s atmosphere is far different from Earth's. It’s mainly carbon dioxide and carbon monoxide. 

That means that the atmosphere is very flat. It turns denser differently from Earth. The density rises lower and faster than Earth's atmosphere. If there are some kind of lifeforms, that means there can be some kind of diatoms or other algae or bacteria that can hover. Using their oxygen bubbles. Carbon dioxide is heavier than nitrogen and oxygen. So, if we fill a bag using air, that bag rises to Venus’s atmosphere. 

In some SciFi novels, astronauts rise to their Venus platforms by filling the bags using air, and that bag raises them to the Venus highlands. That causes an idea that in some planet’s atmosphere could hover medusa-type lifeforms that can create oxygen in their cells. Then those “medusas” can hover in that planet’s atmosphere. Originally, astronomer Carl Sagan introduced the idea of “living balls” that could hide in Jupiter or Saturn’s atmospheres. 

So the high pressure of the Venus surface denies water boiling. And one of the models of lifeforms that can survive in extreme conditions is found near hydrothermal vents deep under the ocean surface. 

Supercritical water that doesn’t boil at extremely high temperatures keeps worms, bacteria, and shrimp alive near hydrothermal vents. Hydrothermal vents, called “black smokers,” maintain ecosystems at the depths of the oceans. 

"Black smoker in the Atlantic Ocean" (Wikipedia, Hydrothermal vent)

The reality is that there are always people who say that lifeforms on planets like Venus are impossible because of their temperature and pressure. Those arguments cause discussions because high pressure increases the water's boiling point. The high pressure causes a situation where there could be lifeforms near black smokers, or officially, hydrothermal vents. Water pressure near those hydrothermal vents that are over 3000 meters below the surface is enormous. That pressure forms supercritical water near those hydrothermal vents.

There are bacteria and some worms near those extremely hot points. Those bacteria, worms, and shrimps can stay alive because of the supercritical water. Because water doesn’t form bubbles, those organisms that require enzyme and protein synthesis in that environment can stay alive. If those same organisms rise to normal air pressure and to that temperature, they will die immediately. 

Because of the boiling water, maybe those things can give hints about the lifeforms that can survive on extreme planets. And then we must consider that those lifeforms are fully adapted to their environment, which can be deadly to us. We and no lifeform that lives on drylands can survive near hydrothermal vents. But those lifeforms cannot survive on Earth either. 

https://scitechdaily.com/unexplained-gases-on-venus-could-they-be-the-sign-of-alien-life/

https://en.wikipedia.org/wiki/Hydrothermal_vent