SEVERE PRESSURE TRENCHES. “Terrestrial habitats with pressures of one atmosphere or lower account for <1% of the total volume of the biosphere. The oceans, which cover ~70% of Earth’s surface, have an average depth of 3,800 m and an average pressure 380 times that present at Earth’s surface." And have temperatures of -2'C to 380'C (at hydrothermal vents), with no light for photosynthesis, and little organic food.
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