绿色中国英语说绿色中国英语说 (17).ppt

[Clean Waters and Green Mountains]5.1 The cycling of matterGreen ChinaGreen China ObjectivesLearn about cycles of matter01Be familiar with the concept of LCA02 Cycle of MatterUnlike the one-way flow of energy, matter is recycled within and between ecosystems. Elements that pass through from one organism to the other in closed loops is called biogeochemical cycles. Types of Biogeochemical cyclesBiological 01Geological 02Chemical 03Physical04 Biological Natural biological processes consist of any and all activities performed by living organisms. Geological Geological processes include volcanic eruptions, the formation and breakdown of rocks, and major movements of matter within and below the surface of the Earth. Chemical and Physical Chemical and Physical processes include the formation of clouds and precipitation, the flow of running water, and the action of lightning. Renewable VS NonrenwableSome cycles process elements quickly, on the scale of a human lifetime or less, and result in renewable resources. Nonrenewable resource cycles, however, take much longer, operating on geological timescales. such as millions of years. Exchange Pool A component of a biogeochemical cycle that holds an element for a short period of time.For example, the atmosphere is an exchange pool for water. It usually holds water (in the form of water vapor) for just a week or two. ReservoirA component of a biogeochemical cycle that holds an element for a long period of time.For example, the deep ocean is a reservoir for water. It may hold water for thousands of years. The role of human activitiesHuman activities also play a significant role in biogeochemical cycles. A broader concept of cycles of matter would be the life cycle of human activities such as manufacturing a commercial product or providing commercial services.mining for raw materialsburning of fossil fuelsclearing of land LCA is a modelling tool to assess environmental impacts related to a product during its entire lifespan: f