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