I think I know how laythe exists

[Rutabaga22]

What if the water is heated by volcanic activity, and there is oxygen from plankton feeding on that bacteria, maybe Laythe has actively moving tectonic plates, and that is why there are a lot of islands.  This and other factors like impacts from asteroids flung in from Tylo, Tidal heating (Maybe),  and other things I don't know about could cause laythe to be a "Kerbin like" body.

 

[Superluminal Gremlin]

Yep probably.

I do agree with the tidal heating. Jool And tylo probably exert enough force to heat the water. But Laythe is cold According to the wiki, Laythe is around - 25 most of the time. So your tectonic activity could probably provide the heat required. Also because laythe is so close to Jool, radiation could be a problem for organisms, unless they have adapted to the intense radiation, or just relicate really fast.

But very good points, and your probably almost right.

[Rutabaga22]

27 minutes ago, TKMK said:

radiation could be a problem for organisms, unless they have adapted to the intense radiation

I would imagine that the plankton would be extremophiles like the thing that live in the arctic and antarctic.

 

[Superluminal Gremlin]

They would be extremeophiles. But what would they "eat". Would they use photosynthesis, or something else. 

[Manul]

On 5/23/2022 at 2:37 AM, TKMK said:

But Laythe is cold According to the wiki, Laythe is around - 25 most of the time.

In-game measurements say that it's not cold: 27C at the equatorial region and -25 at the poles

Wiki says this:

Quote

Air temperatures vary with latitude and time of day. At the equator, sea level temperatures vary between a nighttime low of 9 °C and a daytime high of 15 °C. Mid-latitudes are only slightly cooler than the equatorial zone — at latitudes below 63°, the sea level temperature never drops below 0 °C. At the poles, the temperature varies between -26 °C and -24 °C. The globally averaged sea level temperature is approximately 9 °C. Since Laythe has no axial tilt, there are no seasonal temperature variations.

 

[jimmymcgoochie]

As a former molecular biologist, Laythe having photosynthetic life just doesn’t add up for me, let alone complex plants. There are just too many problems to overcome, the most obvious being light, or lack thereof?

Laythe (and all of Jool system by extension) has a maximum insolation of just 4% of Kerbin, meaning that any given area perpendicular to the sun receives only 4% of the solar energy at Jool compared to Kerbin. Assuming that Kerbin is the same as Earth in this respect (and I believe it is), average illumination is around 1360 watts per square metre; the atmosphere absorbs the majority of this though, so the ground only receives about 340 watts.

Assuming Laythe’s atmosphere behaves the same, average illumination on Laythe’s surface would be about 15-20 watts per square metre- far too dim for all but the most heavily optimised low-light plants to survive, let alone grow.

This is just once facet of plant survival though- while light is vital for photosynthesis, it’s not the only problem a hypothetical plant (or photosynthetic algae) would face:

Temperatures on Laythe range from relatively cool to well below freezing, with significant ice caps at each pole. Lower temperatures lead to slower biological processes, plus the risk of an aquatic organism getting swept up to the poles by ocean currents where it would freeze and die. The Laythean organisms would therefore need to be very cold-adapted and able to survive freezing conditions for potentially long periods.

Volcanic activity generates a lot of sulphur and carbon dioxides, leading to ocean acidification. A moon as volcanic as Laythe with many geysers and subsurface hydrothermal vents would be pretty inhospitable to marine organisms, with acid rain posing a serious problem for land-based ones. It would also make the air pretty noxious and could explain how Laythe manages to hold enough heat to keep its oceans liquid- a runaway greenhouse effect caused by volcanic CO2 trapping what little heat comes in from the sun. This Laythean organism needs to be highly acid-tolerant and capable of dealing with very high levels of carbon and sulphur oxides, which are toxic in high doses.

Volcanoes also tend to emit lots of heavy metals which can be harmful to life, so the Laythean life form needs to be very good at either not absorbing them at all, or getting rid of them. Plants on Earth have a variety of ways of doing this, mostly involving dumping the metals into specialised storage areas in their leaves or roots, but such organisms are relatively rare and highly specialised to grow in these contaminated soils.

Being so close to Jool also presents an even bigger hazard- radiation. Deep inside Jool’s magnetic fields, Laythe would be constantly bombarded by ionising radiation that can destroy DNA and while its atmosphere could block some of that out, the surface is still going to be far more radioactive than almost anywhere on Earth or Kerbin. Again, organisms exist that can cope with high radiation levels using a variety of systems to protect and repair their DNA, but again they’re specialised to do so.

Laythe’s atmosphere is relatively oxygen-poor too (at least, according to the numbers I’ve seen) and despite producing oxygen via photosynthesis plants and algae still need some oxygen to live off of while the sun isn’t shining. Regular eclipses on the Joolward side just add to the oxygen stress by reducing the time they have to generate oxygen. Perhaps a method of storing oxygen for later use would be necessary, or else some very efficient gas exchange systems to extract as much oxygen as possible from the air along with low-oxygen adaptations.

Here’s the problem though: each specialisation requires precious resources to be put into it, reducing the growth rate. A single organism that can survive low temperatures, low light intensity, high radiation, high metal concentrations, high levels of CO2 and sulphur oxides, low levels of oxygen and high acidity is just too far-fetched for me.

Life on hydrothermal vents, on the other hand, makes a lot of sense- almost immune to radiation deep under the water, using the minerals and heat from the vents to survive, unconcerned by oxygen due to anaerobic metabolism and using the metals for cell walls or shells, thriving communities could well exist deep within Layrhe’s oceans.

[Manul]

2 hours ago, jimmymcgoochie said:

Assuming Laythe’s atmosphere behaves the same, average illumination on Laythe’s surface would be about 15-20 watts per square metre- far too dim for all but the most heavily optimised low-light plants to survive, let alone grow.

Laythe's atmosphere is half as thick as on Earth and less dense so it should absorb less light (yesss, less radiation too). Lack of seasons is also good because if the area is illuminated it stays illuminated for the whole year (not as the place where I live).  And the temperature never dropping below 0 (except polar regions) eliminates the need for winter survival mechanisms.

[Rutabaga22]

On 5/22/2022 at 9:52 PM, TKMK said:

They would be extremeophiles. But what would they "eat". Would they use photosynthesis, or something else. 

The only species would be bacteria and plankton that feed on the bacteria.