Why the boundaries of the biosphere do not coincide with the boundaries of the outer shells of the Earth?

The outer shells of the earth include: the atmosphere (gas shell, divided into troposphere, stratosphere and ionosphere), hydrosphere (water shell) and lithosphere (rock shell). The atmosphere extends 1000 km from the Earth’s surface, and the lithosphere extends deep into up to 100 km.

The biosphere is the living shell of the earth, which includes flora and fauna. As far as scientists know at the moment, living organisms live in the range from the lower layers of the troposphere to the seabed. Therefore, the boundaries of the outer shells of the Earth and the boundaries of the biosphere do not coincide.