8
$\begingroup$

I read on the cooking.stackexchange site that all natural salt on Earth was created by seas and oceans, starting with primordial oceans four billion years ago. This got me thinking about my fictional terraformed far-future worlds, where people brought organic materials to lifeless planets and engineered new Earth-like planets, starting by seeding the planet with small Earth species chosen to start developing a more and more Earth-like environment, and then working up with later arrivals of larger organisms, perhaps hundreds or even thousands of years later.

My concern is that there may be a need for a lot of salt all over to support an Earth-evolved animal (or even insect?) bio-mass. I understand that animals tend to have a lot of salt in them, and that they need it to do many of their life functions, notably to control the movement of all sorts of things across cell walls via osmosis.

So I'm wondering what would need to be done to get the world salty enough to support abundant animal populations and related ecologies consisting of introduced Earth-evolved animals (perhaps with a little bio-engineering).

The tech level is very far future, but preferably does not include complex nano-machines (i.e. no saying there can be microscopic intelligent self-replicating machines that cooperate and do it), the ability to just zap up anything from anything (i.e. no saying there are machines that can build anything by arranging atoms however wanted), nor genetic modification that isn't something that clearly very possible by today's understanding (i.e. no saying "use GMO" to make animals not need salt or be salt factories, unless that's a real known thing agreed to be eventually possible by today's scientists). Construction of industrial/chemical facilities is an option.

If thousands of years are needed, that's acceptable, but hopefully not many thousands of years.

Improve this question
$\endgroup$
1
  • 2
    $\begingroup$ In defense of nano (and bio) engineering, you don't need nanobots that can build a skyscraper to have nanobots (or GMO microbial life) that catalyze/perform chemical reactions. We can do a fair amount of this with GMO microbes right now, actually. Look up the cautionary tale of Klebsiella planticola. (And, as already mentioned in ventsyv's answer, salt is very readily generated if sodium and chlorine are present.) $\endgroup$
    – SudoSedWinifred
    Commented Dec 19, 2015 at 3:09

3 Answers 3

Reset to default
5
$\begingroup$

Salt is sodium chloride (NaCl) and sodium ions are indeed important nutrients for animal life.

Salt is naturally occurring and not created by seas. Sodium is very reactive and can react with chlorine in air and water to form salt.

Assuming that the planet being terraformed is somewhat similar to Earth, I would expect it to have salt.

Improve this answer
$\endgroup$
2
  • $\begingroup$ Do you mean salt is not created by seas, or just not only by seas? The gasses and liquids of these planets are not starting out entirely Earth-like; we're just picking the closest ones we find and introducing whatever we can (starting with very small Earth species) to get them to become Earth-like. But you're saying it's fairly reasonable to expect there to already (or soon enough) be enough NaCl to support large animal populations? $\endgroup$
    – Dronz
    Commented Dec 17, 2015 at 19:01
  • 1
    $\begingroup$ The two elements, sodium (Na) and chlorine (Cl) will most certainly be present on any Earth like exoplanet that's in the habitable zone of it's star. Since sodium is very reactive, I would expect salt to form, even without any oceans. It's worth mentioning though that Kepler has found a number of planets with vast oceans. All in all I don't expect that you'll need to "import" or "manufacture" salt. $\endgroup$
    – ventsyv
    Commented Dec 17, 2015 at 21:27
2
$\begingroup$

Where is the life in the middle of a large continent on Earth getting its salt from?

The carnivores eat herbivores. The herbivores eat plants. The plants take carbon dioxide from the air, sunlight, and groundwater. That water contains all the other elements. Those elements get there by the weathering of rocks. Weathering includes active attack by plant life as well as inorganic chemistry such as oxidation of surfaces exposed to air.

It takes a fair while for plants to establish a foothold on new volcanic barren rock. It starts with algae, lichen etc: tiny things lodged in tiny crevices. Gradually the rock crumbles and the crumbs become coated with humus: organic matter from dead plants. Then larger plants can establish, starting small and tough. Scrub comes later still, trees last.

You can study this where a volcano or retreating glacier or earthquake fault has exposed virgin rock. Or by filling a pot with crushed sterilised rocks and seeing what can grow given just sun air and rainwater.

Bottom line: plants can establish on barren rock but it takes very many human lifetimes to get to a layer of fertile soil. In river valleys where mechanically pulverised rock (silt) accumulates, the process will be faster but good fertile soil will still take a good while.

BTW local shortages of certain trace minerals can be a problem. Iodine, for animal life, and Boron for plants, are well-known issues. It all depends on the rocks.

Improve this answer
$\endgroup$
5
  • $\begingroup$ Do you think I should be worried about there being enough boron & iodine? $\endgroup$
    – Dronz
    Commented Dec 20, 2015 at 19:10
  • $\begingroup$ Not if your world is Earthlike. Here its a problem in some areas because of the regional geology. $\endgroup$
    – nigel222
    Commented Dec 20, 2015 at 20:38
  • $\begingroup$ Ok but Earth is Earthlike partly because it is what it is and several billion years of evolution took place here, tuning itself to what's here. In my case, we're picking the closest-looking lifeless planets and trying to get them to work for life from Earth, in hundreds or perhaps a few thousand years. So I wonder if boron and iodine are accessible due to astrology & geology so we'd reasonably expect there could be some available on another lifeless planet that was otherwise similar to Earth? I suppose that's another question. $\endgroup$
    – Dronz
    Commented Dec 20, 2015 at 21:54
  • 1
    $\begingroup$ We don't know enough about other solar systems to say whether the geology of Earth is usual or unusual. Earth and the moon formed out of a low speed collision between two smaller planets in almost the same orbit. That probably is unusual. So elsewhere a rocky planet might be less well stirred with a shortage of heavier elements in its crust (esp. Life critical Mo. and I.) Speculation at present, not science. $\endgroup$
    – nigel222
    Commented Dec 20, 2015 at 23:30
  • 1
    $\begingroup$ One other thing is that all elements above Helium are "cooked" by a supernova explosion of a first generation star. So natural abundances of elements in a random solar system will be fairly similar everywhere to the extent that supernovae are similar. Planetary formation and geology will redistribute elements with respect to the averages. $\endgroup$
    – nigel222
    Commented Dec 20, 2015 at 23:41
2
$\begingroup$

The oceans would already be salty on the world, even if life had not formed naturally. It washes out of rocks and weathering, and accumulates over time in the oceans. I think this is what you took to be "created". This would happen even without life.

Improve this answer
$\endgroup$

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .