Resource cycles in ecosystems

Cycles Essential nutrients for living things flow

through the ecosystem. The reservoirs can be in the air, land, or

oceans. Important resources cycle through the

living and nonliving parts of ecosystems

Biogeochemical Biogeochemical CycleCycle

Energy flows Energy flows throughthrough an an ecosystem.ecosystem.

Water and minerals Water and minerals recyclerecycle in the ecosystem. in the ecosystem. Water NitrogenWater Nitrogen Minerals CalciumMinerals Calcium Carbon PhosphorusCarbon Phosphorus

Think: Why the Earth needs a constant influx of energy from the sun, but does not need water from an outside source.

Water cycle

•Availability of water Availability of water determines determines productivityproductivity

•Water moves from the sky to land as precipitation then back via evaporation

•Transpiration: 90% of 90% of water that evaporates water that evaporates in ecosystem passes in ecosystem passes through plants.through plants.

Carbon cycle

Carbon cycles from atmospheric CO2 into living things through photosynthesis

CO2 returns to atmosphere from respiration & burning Oceans, soils & plants act as a carbon reservoirs

Think: What 2 things do humans burn that put CO2 into

the atmosphere.

Nitrogen cycle

•All living organisms need All living organisms need nitrogennitrogen (N (N22))

•78% of the atmosphere is 78% of the atmosphere is composed of Ncomposed of N22. which is only . which is only usable to a few organisms.usable to a few organisms.

•Nitrogen fixing bacteria Nitrogen fixing bacteria take gaseous Ntake gaseous N22 & turn it & turn it into a liquid or solid form into a liquid or solid form that plants can usethat plants can use..

•Breakdown of organic material Breakdown of organic material results in ammonia.results in ammonia.

•Nitrogen is returned to Nitrogen is returned to the the atmosphere when animals atmosphere when animals and their waste and their waste decomposes.decomposes.

Human impact of natural cycles

Human activity such as burning fossil fuels & deforestation has greatly impacted natural nutrient cycles. Causing air, water, and soil pollution.

Summary Review

Diagram the following cycles: water carbon, and nitrogen then answer the question “ How have humans

impacted these cycles?”