Quote:We know enough about terran biology to have a pretty good idea what it can adapt to. The claims I'm making are on a par with saying fast swimming fish will be streamlined, dictated by principles beyond dispute.
Carbohydrate/protein based alien life isn't going to chemically any stranger than what we've already encountered on this world.
That is utter Earth system only centric speculation. You have no actual system to compare it to and are making broad generalizations with no proof.
Not all life on earth uses the standard proteins and sugars, so we do know what happens when terran biochemistries encounter non-standard biochemestries, since we can study it in the lab.
In the more extreme cases, such as using the opposite chirality, you'd pretty much need to redesign every single enzyme in the human body, which requires a level of genetic engineering beyond that otherwise suggested for these precursors. Maybe they were just that good, but it's better to keep their abilities limited. That way, you get more interesting plots, such as the bioengineering failing.
In less extreme cases, it is sufficient to add a few enzymes to cope with the novel amino acids, sugars, etc, and to syntheise any that don't occur in the local biochemistry. Many of the needed enzymes already exist in our liver, and the rest can be copied from other earthly life. This approach amounts to multiple point mutations, which is not the kind of thing that causes a reproductive barrier.
Quote:Which confirms my point. Humans have no trouble adapting to ecosystems where such things are commonplace, even without genetic engineering. In fact, we use potent neurotoxins as spices and drugs. It helps that we often cook our food - boiling water breaks down many toxins, for reasons of basic chemistry.
Kimono dragons have a bite that is so riddled with rot and bacteria that it will kill pretty much anything else in one bite. Several caterpillars have toxic, foul tasting blood from the plants they eat.
Nor is it necessary to be able to eat absolutely everything in the ecosystem - 99% of pseudomushrooms maybe poisonous, but we can just eat the 1% that aren't. With common sense, and some mild genetic engineering we can reasonably expect humans to be able to cope with moderately alien ecosystems.
And, of course, none of the alien toxins will be fine tuned to affect terran biochemistry, putting severe limits on their likely effectiveness.
Quote:There would probably be some life on the ocean bed, which could swim to the surface to mate - kraken rising from the deep. Maybe the larva lives in the coral, while the adults dwell far below.
All surface life must be around these central cores ecosystems cling to around these floating island.
This is another way of getting nutrients back to the surface, though probably not enough to untether the coral from the volcanic vents.