Nitrogen stable isotopic composition of leaves and soil: Tropical versus temperate forests
Nitrogen stable isotopic composition of leaves and soil: Tropical versus temperate forests
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DOI：
10.1023/a:1006100128782
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发表时间：
1999-07-01
期刊：
影响因子：
4
通讯作者：
Treseder, K
中科院分区：
文献类型：
--
作者：
Martinelli, LA;Piccolo, MC;Treseder, K
一些证据表明，氮在大多数热带森林中比在大多数温带森林中相对更容易获得，甚至在许多热带森林中它可能作为过量的营养物质。如果这是正确的，热带森林应该有更多的开放N循环比温带森林，与输入和输出的N大相对于N循环系统内。在N损失的幅度和途径上的一致性差异意味着热带森林一般应比大多数温带森林更富含N-15。为了验证这一假设，我们比较了来自各种热带和温带森林的树叶和土壤的氮稳定同位素组成。热带森林的叶片三角洲（15）N值平均比温带森林高6.5 ‰。在热带地区，生态系统与相对较低的N可用性（山地森林，森林桑迪土壤）显着更耗尽N-15比其他热带森林。热带森林土壤的平均δ（15）N值，无论是表层还是深层样品，几乎比温带森林土壤高出千分之八。这些结果提供了另一条证据，N是相对丰富的许多热带森林生态系统。
Several lines of evidence suggest that nitrogen in most tropical forests is relatively more available than N in most temperate forests, and even that it may function as an excess nutrient in many tropical forests. If this is correct, tropical forests should have more open N cycles than temperate forests, with both inputs and outputs of N large relative to N cycling within systems. Consequent differences in both the magnitude and the pathways of N loss imply that tropical forests should in general be more N-15 enriched than are most temperate forests. In order to test this hypothesis, we compared the nitrogen stable isotopic composition of tree leaves and soils from a variety of tropical and temperate forests. Foliar delta(15)N values from tropical forests averaged 6.5 parts per thousand higher than from temperate forests. Within the tropics, ecosystems with relatively low N availability (montane forests, forests on sandy soils) were significantly more depleted in N-15 than other tropical forests. The average delta(15)N values for tropical forest soils, either for surface or for depth samples, were almost 8 parts per thousand higher than temperate forest soils. These results provide another line of evidence that N is relatively abundant in many tropical forest ecosystems.