Notes and Reflections on Books and Media
by Hannah Leitheiser
The Formation of Vegetable Moulds through the Action of Worms with Observations on their Habits
Listening to one of Darwin's books on worms. I'd been told worms surface to avoid drowning. Apparently worms can absorb oxygen through water -- to them the greater danger is dehydration. So it seems after rain they take their opportunity to move around above ground because they can, not to avoid anything.
The question of about how many calories are in soil is apparently not an easy one for the Internet to answer. Earthworms eat organic matter such as leaves, but they also eat soil, and although an earthworm probably burns few calories, those that have no access to macro organic matter must be getting their fuel from the earth.