Quote:It would, though not by enough to compensate for the scarcity. The reactions are less than twice as energetic, and chlorine is less than half as common as oxygen. Also, this only helps the animals.
I've had a thought - chlorine is scarcer than oxygen, but if its interactions require more energy, might they not also yield more, ie, support the same size of organism on a lower partial pressure?
The real problem is with the plants. Water is much easier to work with than Cl-, and much more common on unaltered worlds. Since they also need less light Terran-style plants should easily outcompete chlorine plants, unless steps are taken to eliminate all the water.
Do that, and you can then replace oxygen with nitrogen throughout biochemistry - e.g, amines instead of alcohols, hydrogen cyanide instead of carbon dioxide. Water would be mildly corrosive to these creatures.
Quote:The problem here is nutrient loss. Anything that falls to the seabed isn't coming back, which is why most of our oceans are pretty empty.
The fourth moon's notable characteristic is how much water it has - enough that the shallowest part of its world-girdling ocean is still more than a kilometer and a half deep.
Either absolutely everything floats - no bones, or solid excreta - or the floating coral is limited to regions where water is welling up from the depths, carrying fresh nutrients with it. Since the ocean is heated from above, and there are no continents to force the water upwards, the best bet is probably at points above active volcanoes