生物地球化学案.docVIP

1-2 Origins 1. How is the nitrogen cycle coupled (or linked) to the carbon cycle? In other words, how is the carbon cycle important in driving some components of the nitrogen cycle?氮循环跟碳循环的联系（1-8图） 总体来说碳循环为氮循环提供物质（分子骨架）和能量。植物吸收矿质态氮合成自身物质，在这个过程中需要碳为其提供分子骨架以及氮吸收同化过程中需要碳为其提供能量。另外在土壤中有机氮的矿化、硝化和反硝化过程中微生物都需要碳为其提供能量。因此碳氮循环式紧密联系在一起的 2. What is the average oxidation state of carbon in soil organic matter?土壤有机碳平均氧化态值1.11 3. Where does the energy (or electrons) that drive the process of denitrification come from?反硝化过程所需能量或电子来源1-12二价铁，硫，硫化氢 4. Where does the energy that drives the process of N-fixation by rhizobia bacteria on legume plants come from?豆科植物根瘤菌固氮能量来源（1-15表）光能利用菌能量来源光照，无机营养菌来源无机营养，异养菌来源有机碳 5. Which form of nitrogen contains more energy for metabolic processes, NH4+ orNO3-? How did you make your decision?哪种形式的氮包含代谢更多的能量NH4+ or NO3-？为什么？NH4+ 1.10 因为NH4+是一种电子供体，NO3一般作为一种电子受体，还原性化合物（富含电子的电子供体）比氧化性物质含有较高的能量。另外一方面，NO3在被植物利用的过程中需要首先转换成NH4+在用于有机质的合成，这一过程也需要一部分能量。 6. Rank the following electron acceptors in terms of the energy available to organisms when they are used in the oxidation of soil organic matter. 土壤有机碳氧化态生物可用能量电子受体排序 (#1 = most energy; #6 = least energy)_2_ NO3 __6_CO2 _1_ O2 _4 Fe3+ _3_Mn4+ _5_ SO41-14 7. How does the transfer of energy between different trophic levels of the food web change with each step up the food web (e.g., between primary producers and the herbivores that eat them)? (What percentage of the fixed energy is transferred up the food chain and what percentage is lost as heat due to respiration?)在不同营养级上的食物网的每一步能量的如何转换的, 1.20营养级之间的能量传递遵循10%规则。就是一级消费者（食草动物）以初级生产者为食的时候，初级生产者的能量只有10%传递给了一级消费者，90%以呼吸或者热的形式损失。 改变食物网之间(例如,初级生产者和食草动物之间) 多少百分比的固定能量转移在食物链上,有百分之多少的热量由于呼吸而丧失? 8. If you were specifically interested in determining the degree of heavy metal (e.g., Cu, Cd, Zn) accumulation in rice produced in Zhejiang province, what spatial scaling considerations might you consider in designing your experimental approach. What additional information could be