第13章：生态系统的物质流与污染 Chapter 13 Nutrient cycle of ecosystem and pollution I.Teaching Objective: Nutrient cycling in ecosystem Relation between Nutrient cycling and pollution L.Focal Points and Difficulties in the Chapter(教学重点和难点) 1.Focus Nutrient ycling of carbon.nitrogen.phosphus and water in cosystem 2.Difficulties Nutrient cycling of carbon and water:Pool,flow and sink General model of ecosystems Linked compartments (boxes)(pools)(air;organisms;soil/rock:water) Rate of movement between compartments(arrows)(fluxes) Sinks:boxes with input/output increasing Soures:boxes with input/ouput decreasing Residence time I.Methodology Powerpoint presentation will be the main method.Blackboard will be an assistance.Case studies will be provided. IV Presentation(课堂讲解，学时分配为2学时左右) Water cycle Physical,not chemical Balance of fluxes Carbon cycle Tied to energy flux:solar-powered Processes Assimilation:dissimilation:redox reactions Photosynthesis,respiration,methanogenesis Exchange of CO:between air and oceans