Thread: Silly Venus Idea

just a question, I dunno if it's in the right section

but I was wondering, what would happen if you introduced stromatolites into a carbon dioxide rich environment, such as a planet like Venus.

Would this kick start any sort of process to creating a breathable atmosphere like that of Earth

tbh, the way things stand now you'd have to find a way to cool the planet down to a level where liquid water can exist in appreciable amounts
i doubt that any process of life would be possible without that prerequisite
maybe once we've figured how to absorb CO2 emissions on earth can we attempt to reduce it on Venus at a vastly larger scale

If there is any life with chemistry similar to life on earth, it can only exist in the upper atmosphere.

I agree with others the big problem is the share amount of solar radiation that planet receives and atmosphere density. You'd have to block in the incoming radiation with dust in orbit or another way as a starting point. After centuries (and continuous maintenance of the solar blocking) perhaps you get the rain out to plant Stromatolites into the small oceans from the relatively dry atmosphere. They in turn would take a long time to change the atmospheric chemistry.

You'd find it much easier on Mars - the temperature won't kill the shit out them outright; though it is mightily cold...

So here's a scenario for Terraforming: #1 get large mirror arrays in orbit around Mars, focusing sunlight to drive the temperature above freezing at least at the equator year-round. When you've done that (should be pretty quick) #2 start transplanting either water alone, or better yet, water with the algae and even lifeforms you need.

Hell if we could invent a 'Star Trek' transporter, then you've got it made - transport alot of Earth Ocean Water and you already get established life - assuming the rock on Mars doesn't poison them...in any event you're bound to have alot of die-off at first, and then the surviving species will make use of the extra biomass.

Small scale experiments will need to be done first to verify problems with pressure differentials - but I'd be surprised if Algae couldn't adapt pretty fast. By that time, we could probably bioengineer lower-pressure animals, let alone plants.

Venus is trouble. Needs alot more work I would say; and it seems that would need to be mechanicals to handle it rather than stroms.

now if you could find an easy way to transport some of Venus' excess CO2 to beef up Mars' atmosphere you'd be on a winner ...

The atmospheric pressure (9 times that of earth) is also a bit of an issue on Venus. Try life in the stratosphere instead of ground-based.

does anyone have any idea whether the earth also would have the same CO2 density if most of it wasn't locked up in carbonate rocks ?

Partial pressure of CO2 on Earth is approx. 387/1000000 x 14.7 psia, or 0.006 psia.

Partial pressure of CO2 on Mars is 0.95 x 0.13 (ref. Wikipedia) or 0.124 psia.

So why isn't Mars hot?

Certainly distance from sun contributes.

Originally Posted by free radical

Certainly distance from sun contributes.

Well, there is that...

Originally Posted by Bunbury

So why isn't Mars hot?

surely the overall density of the atmosphere must count for something - on earth CO2 is only a small portion of the atmosphere, whilst on Mars it's practically all of the atmosphere

Originally Posted by marnixR

Originally Posted by Bunbury

So why isn't Mars hot?

surely the overall density of the atmosphere must count for something - on earth CO2 is only a small portion of the atmosphere, whilst on Mars it's practically all of the atmosphere

Also, I would imagine that the lack of oceans makes quite a difference.

Don't know why those didn't occur to me as they all seem like excellent reasons. Brain in hibernate mode or something.

Distance from sun
No water vapor
Not much mass of atmosphere to retain heat

Sounds like a prescription for a cold planet.

Thanks

Originally Posted by Bunbury

Don't know why those didn't occur to me as they all seem like excellent reasons. Brain in hibernate mode or something.

Distance from sun
No water vapor
Not much mass of atmosphere to retain heat

Sounds like a prescription for a cold planet.

Thanks

Just as distance of Venus being closer to the sun makes it unbearable for any life as we know it.

Mars gets about 43% the solar radiation that the earth gets. Venus gets about 91% more solar radiation than the earth gets.

Originally Posted by free radical

The atmospheric pressure (9 times that of earth) is also a bit of an issue on Venus. Try life in the stratosphere instead of ground-based.

I think you'll find it's closer to 90 times (ie, ~90 atm at surface) ...

Stratospheric life? hmmm ... much less impossible than surface life -
microbial, acidophilic, thermophilic ...

From memory (which can be vague and unreliable on occasions), similar discussions among planetary scientists in the 1990s concluded that, whether for Venus or Mars, orbital distance is less of an issue than atmospheric density and chemistry when considering the planet's surface heat budget.

In other words, if Venus had the atmospheric density of Mars, its nightside would be extremely cold, despite being closer to the sun; likewise, if Mars could retain ~90 atm of atmospheric pressure at surface, it would be uncomfortably warm - the amount of incoming solar radiation (insolation) is only one part of the equation; the critical factor is how much OLR (outgoing longwave radiation - infrared or heat) is retained or lost by the atmosphere that determines the surface temperatures ...

Originally Posted by marnixR

does anyone have any idea whether the earth also would have the same CO2 density if most of it wasn't locked up in carbonate rocks ?

not directly, but indirectly the estimates are substantially less than for Venus -
estimates for how much oxygen is tied up in older (Precambrian) carbonates range from ~10x to ~20x PAL (Present Atmospheric Level); ie, ~2.3 -4.6 bars of oxygen partial pressure - a rather small fraction of the ~90 bars on Venus ...

Probably because of the thread title, and its mention as example in the OP, we've only really addressed one part of the question -
that extreme heat and lack of liquid water (probably coupled with a very long retrograde rotation, and little or no evidence of nitrogen) would make Venus a non-starter for such a project.

Originally Posted by petemcr

... but I was wondering, what would happen if you introduced stromatolites into a carbon dioxide rich environment [?] ...
Would this kick start any sort of process to creating a breathable atmosphere like that of Earth [?]

The mainstream answer to this part of the question is "yes" - because the geological evidence tells us that this has happened at least once.

stromatolites are colonial cyanobacteria (sometimes called blue-green algae) which form as filamentous mats that trap sediments in shallow water surface environments.

C_Sensei mentioned Mars, and I believe the use of cyanobacteria has been proposed and/or considered for this purpose.

from - https://www.researchgate.net/publica..._cyanobacteria
Journal of the British Interplanetary Society. 01/02/1993
Terraforming Mars: dissolution of carbonate rocks by cyanobacteria
E I Friedmann, M Hua, R Ocampo-Friedmann

... As Mars lacks plate tectonics as well as active volcanism, an Earth-like carbon cycle cannot be reproduced there. We suggest that Matteia sp., a lime-boring cyanobacterium isolated from Negev desert rocks, be used to dissolve carbonate rocks both for initial release of CO2 and in design of a Martian carbon cycle.

There has also been some study into cyanobacteria in CO2-rich atmospheric conditions ... acidity (pH) of the water becomes a factor as CO2 concentrations increase ...

from - http://www.ncbi.nlm.nih.gov/pubmed/15711170
Astrobiology. 2005 Feb;5(1):66-74.
Common freshwater cyanobacteria grow in 100% CO2
Thomas DJ, Sullivan SL, Price AL, Zimmerman SM.
Science Division, Lyon College, Batesville, Arkansas 27501, USA. dthomas@lyon.edu

... We investigated the tolerance of several cyanobacteria to very high (>20 kPa) concentrations of atmospheric CO2...
Synechococcus and Anabaena survived 101 kPa** (100%) pCO2 when pressure was gradually increased by 15 kPa per day, and Plectonema actively grew under these conditions...
Strains that were sensitive to high CO2 were also sensitive to low initial pH (pH 5-6). However, low pH in itself was not sufficient to prevent growth. Although mechanisms of damage and survival are still under investigation, we have shown that modern cyanobacteria can survive under Earth's primordial conditions and that cyanobacteria-like organisms could have flourished under conditions on early Mars, which probably had an atmosphere similar to early Earth's.

**Note - 101 kPa is ~1 atm - ie, the modern average atmospheric pressure at sea level, or ~1/90th the surface barometric pressure of Venus. The assumption that the Earth's atmospheric pressure has remained constant throughout geological time is widely accepted, though not well evidenced.