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Old 01-25-2015, 01:37 PM   #11
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Default Re: Terraformed Ecosystem Peculiarities

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Originally Posted by Johnny1A.2 View Post
But does that necessarily mean that there would be no calcium carbonate type minerals at all?
No. It will precipitate abiotically, and in deep water it will do so in bulk.
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Old 01-25-2015, 01:40 PM   #12
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You pretty much want wild uncontrolled excess in the prey. Actually, for a long time you probably only want plants, feeders are what you introduce when you want to stop the process.
I don't think that's quite right. You don't want to create a set of biomes dominated by the rapid accumulation of fuel loads and periodic sterilising wildfire. The main action in sequestering carbon and generating oxygen is going on in the top few millimetres of the oceans. On land, the big story is forming soil.
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Old 01-25-2015, 01:49 PM   #13
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Default Re: Terraformed Ecosystem Peculiarities

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What are some ways that an ecoystem designed for a terraforming project might be somewhat unusual compared to natural ecosystems?
This might be slightly off from what you're asking, but in my world there are millions of terraformed planets, more-or-less copied from Earth, but many of them were terraformed hundreds of millions of years ago (while the youngest are no more than a few tens of millions of years ago, too complicated to go into why). It was done by aliens for their own reasons, but the result is that even the long-transformed worlds have their share of peculiarities.

For ex, on the older ones, the fossil record is weird, as you get into older rocks, you come to the Discontinuity, where the former environment was replaced. Younger rocks more-or-less like Earth, older ones often very, very different, and no traces of biological activities below the local Discontinuity. None. Zero. Zip. Sometimes the Discontinuity is really odd, if the former environment was particularly alien.

The biospheres are complicated, too, by the fact that the aliens sometimes introduce new forms from other worlds later, so you find entire families of fossils that seem to appear from nowhere, with intermediate forms within that family but nothing necessarily linking them to other groups of organisms. This goes down to the cellular level.

The aliens did this for experimental reasons, and sometimes introduced new species and groups of species just to see what would happen, including humans when we evolved on Earth. The result is doubly strange when those humans start developing civilizations, and try to make sense of their surroundings.

For ex, there's a world in my universe where humans (actually near-humans) are the only placental mammals on the planet. There is an are immense thriving ecosystem with marsupials in most of the typical 'mammalian' niches, but no placentals anywhere other than Man.

But the same star also has another terraformed world which not only has placental mammal species present, but various apes and monkeys. So imagine the shock of the sapients when they first visited their neighboring world...
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Old 01-25-2015, 01:52 PM   #14
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No. It will precipitate abiotically, and in deep water it will do so in bulk.
That's what I was thinking.

Here's a thought: a terraformed world might be very short of good-quality iron deposits, though. It's widely thought that Earth's iron ore is largely of biotic origin.

Absent life, what might precipitate iron out of the oceans into useful form (assuming there were oceans). Absent oceans, what abiotic processes might produce useful iron ore?
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Old 01-25-2015, 02:13 PM   #15
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That's what I was thinking.
Because of those hills of travertine in Turkey, right?

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Here's a thought: a terraformed world might be very short of good-quality iron deposits, though. It's widely thought that Earth's iron ore is largely of biotic origin.

Absent life, what might precipitate iron out of the oceans into useful form (assuming there were oceans). Absent oceans, what abiotic processes might produce useful iron ore?
Well, I think the thing there is that you have to precipitate that iron out to get a breathable atmosphere. On a pre-biotic "Ocean world" (as GURPS Space denotes them) the iron is in solution as Fe II ions in the +2 oxidation state. On exposure to oxygen it oxidises to insoluble Fe III and precipitates out. This process depletes the ocean water of oxygen and indirectly sucks the oxygen out of the air. Only after the oceans are fully oxidised can significant oxygen start accumulating in the air. (And that is when the first generation of photosynthesising organisms poison themselves with toxic oxygen and have to be replaced with oxygen-tolerating successors.
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Old 01-25-2015, 04:32 PM   #16
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Default Re: Terraformed Ecosystem Peculiarities

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...
If you're taking the long evolutionary view, mother nature will provide the parasites for you over time. It's too effective a niche to go empty for long.
Evolution can only work with what it's given. If you only have mammals, for example, I doubt you'll ever get endo-parasites in under 200 million years.
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Old 01-25-2015, 04:41 PM   #17
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Default Re: Terraformed Ecosystem Peculiarities

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Because of those hills of travertine in Turkey, right?



Well, I think the thing there is that you have to precipitate that iron out to get a breathable atmosphere. On a pre-biotic "Ocean world" (as GURPS Space denotes them) the iron is in solution as Fe II ions in the +2 oxidation state. On exposure to oxygen it oxidises to insoluble Fe III and precipitates out. This process depletes the ocean water of oxygen and indirectly sucks the oxygen out of the air. Only after the oceans are fully oxidised can significant oxygen start accumulating in the air. (And that is when the first generation of photosynthesising organisms poison themselves with toxic oxygen and have to be replaced with oxygen-tolerating successors.
There is a whole lot about that oxygen catastrophe, its endemic life, and likely subsequent "snowball earth" that is unknown.

There is life that can reduce Fe III, so runaway O2 disasters aren't inevitable.

My alien world evolved a branch of photosynthesizing methanogenic lithotrophic oxygen tolerating life that limped along with the more classic aerobic heterotrophs. A few well placed disasters and a low oxygen atmosphere helped them to take over the planet leaving animal-like life amoeboid.
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Old 01-25-2015, 04:52 PM   #18
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If you only have mammals,
Only mammals and neither bacteria nor archaea? Not even as intestinal flora and decay organisms? No mycorrhizal fungi? It doesn't sound like a very plausible starting-point for anything.

Your general point is true enough — evolution has to work with what it has to start with — but I reckon that any set of biomes designed for terraformation is bound to include organisms that are only a short jump away from re-specialising as pathogens and parasites.
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Old 01-25-2015, 04:58 PM   #19
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Only mammals and neither bacteria nor archaea? Not even as intestinal flora and decay organisms? No mycorrhizal fungi? It doesn't sound like a very plausible starting-point for anything.
I tend to think of single celled organisms as more pathogenic than parasitic. Of course critters that can already get inside other organisms have an easy way into parasitism, so to speak.
Good point about fungi. Those dietarily non-discriminating bastards are always finding novel ways to consume the still living.
I think if anything could infect visiting alien life it would be fungi.
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Old 01-25-2015, 05:10 PM   #20
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On land, the big story is forming soil.
Not only is pedogenesis a key goal of terraforming in itself, but also more carbon is stored in soil than in [living] plants.
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