#hi im a bio student dropout with a special interest in evolutionary biology. i completely forgot that the main point of this post

[belfrygargoyles]

subnautica spoilers

my thoughts amount to:

Creepvine can be refined into silicone rubber and naturally incorporates silicone into its seed pod capsules, which the PDA states are eaten by some animals and digested

The silicone layer is biodegradable and will deteriorate on its own once detached from the main plant. I don’t know enough about chemistry to infer anything more about the nature of how the silicone is formed and what its structure would look like from this fact. I can only assume it is somehow made of “weaker” bonds that degrade more readily than synthetically produced silicone, or it’s “impure” silicone or something. Don’t laugh at me.

There are two details I get from this:

Other animals on 4546B must be able to metabolize or otherwise process ingested silicone particles

If one large plant species naturally produces its own silicone, there is a nonzero chance that other life on 4546B does as well

The PDA makes note of specialized digestive enzymes unique to large life forms on 4546B a few times, most notably in regards to the Sea Emperor, the Reefbacks, and an alien data download regarding Enzyme 42 stating that it bears “superficial resemblance to the stomach enzymes of other large predators.”

The assumptions I make based off of this:

Enzyme 42 is an enzyme used specifically for breaking down silicone matter at a very small scale

Other creatures’ digestive enzymes resemble it because large predators will be consuming animals whose main food source is silicone-producing plant life, but the resemblance is only superficial because by the time the silicone particles enter the predator’s digestive system, they have already been partially broken down or undergone some state change

Large animals who consume large amounts of microorganisms or direct producers of natural silicone have evolved a specialized portion of the digestive system in which the silicone buildup is expelled along with the digestive enzymes responsible for breaking the particles down

Two creatures are known to have a special digestive enzyme which is expelled in small amounts into the water around them: Reefbacks, and Sea Emperors. We don’t know if the enzyme expelled by Reefbacks is used by other creatures, but we know that Peepers have coevolved alongside Sea Emperors to have a sense of smell specialized for detecting Enzyme 42 in the water. We also know that Peepers have the ability to directly empty their stomach contents on demand, and that they will consume large amounts of waterborne Enzyme 42 which will be dispersed into the environment. Peepers also have beaks much like Sea Emperors.

What I infer from that is that peepers have a similar diet/feeding type as Sea Emperors, albeit on a smaller scale, in which they ingest large amounts of silicone/environmental silicates which build up in the body. Unlike Sea Emperors, peepers don’t produce a digestive enzyme to deal with it, and instead rely on following families of Sea Emperors to ingest the expelled enzymes they release to break down the silicone in their digestive systems and subsequently flush it out via the waste tube.

ALL OF THIS TO SAY I think Kharaa might be so hardy because it is silicone based, somehow, and can’t be attacked or broken down by the immune systems of most creatures. It’s an alien superbacterium idk dude. N E ways. Enzyme 42 just so happens to be complex and strong enough to break down the silicone cell membrane or whatever. No fucking clue how it’s supposed to also fix your broken DNA or your definitely broken immune system, though. If you survive Kharaa infection you’ll probably have lifelong autoimmune issues and be at high risk for cancers (especially skin cancer and lymphoma). It also fails to completely flush the bacterium from your body and leaves dormant bacterial cells in your bloodstream, which I think might mean there’s a nonzero chance you’ll get sepsis just whenever if your body registers the dormant bacteria as a threat.