The submarine will most likely find data that shows the highest pressure data and the lowest temperature data (unless of course it's near a hydrothermal vent). This is because due to the depth there's a lot more water above it putting a lot of pressure on the sub, and very little sunlight to heat up the water.
Explanation:
Microspheres were spherical bodies with metabolic abilities that could successfully sustain their existence. However they did not contain any genetic material. Which means that they could not replicate or pass off their parts to their successive generations.
But they had no way to evolve since they could not pass off any genetic material to their offspring's. This is why RNA came into existence. RNA enabled an Organism to store its genetic material into nucleic acids, that could be passed on to generations to come. This is also how they could evolve into more complex organisms.
There are less trees and plants to absorb CO2 (carbon dioxide) and convert it to oxygen.