A Review on the Coupled Carbon and Water Cycles in the Ter r estr ial Ecosystems
陆地生态系统碳- 水耦合机制初探

Carbon and water cycles absorbed much attention in the global change researches. There were many observations indicating that they were robustly coupled in the terrestrial ecosystems. Here we reviewed the correlations between carbon and water cycles from leaf to canopy and to larger scales. Moreover, we discussed the general mechanisms of the coupling relationships between carbon and water cycles. The chain between carbon and water cycles was analyzed into four links: soil-plant link, plant-atmosphere link (stomata link), soil-atmosphere link and biochemical link. The causes for the strong correlations between carbon and water could be generalized as three fundamental functions: 1) the chemosynthesis between carbon and water; 2) the stomatal controls on gas exchange and its optimal function; and 3) the common driving forces and similar controls for carbon and water cycles in the terrestrial ecosystems. Water use efficiency defined as the ratio of carbon assimilation to water use also was discussed as a suitable term indicating the quantity relationship between carbon and water.