3.4
carbon cycle
Cyclic movement of carbon in different chemical forms from the environment to organisms and then back to the environment.
nitrogen cycle
Cyclic movement of nitrogen in different chemical forms from the environment to organisms and then back to the environment.
hydrologic cycle
collects, purifies, and distributes the earth's fixed supply of water
nutrient cycle
continual movement of the elements and compounds that make up nutrients through air, water, soil, rock, and living organisms within ecosystems.
phosphorus cycle
cyclic movement of phosphorus through water, earths crust, and living organisms.
surface runoff
flows over land surfaces into streams, rivers, lakes, wetlands, and the ocean, where it can evaporate and repeat the cycle
aquifers
underground layers of sand, gravel, and water bearing rock.
groundwater
water that seeps deeper through soil