Crash Course Ecology Season 1 Episode 8 The Hydrologic and Carbon Cycles: Always Recycle! ( Air Date 2012-12-24 ) Genre Documentary category. Overview "Hank introduces us to biogeochemical cycles by describing his two favorites: carbon and water. The hydrologic cycle describes how water moves on, above, and below the surface of the Earth, driven by energy supplied by the sun and wind. The carbon cycle does the same...".