Vitousek Peter M, Kennedy Martin J, Derry Louis A, Chadwick Oliver A
Department of Biological Sciences, Stanford University, Stanford, CA 94305, USA e-mail:
Earth Systems Science, University of California, Los Angeles, CA 90095, USA, , , , , , US.
Oecologia. 1999 Nov;121(2):255-259. doi: 10.1007/s004420050927.
We used isotopes of Sr to quantify weathering versus atmospheric sources of foliar Sr in 34 Hawaiian forests on young volcanic soils. The forests varied widely in climate, and in lava flow age and texture. Weathering supplied most of the Sr in most of the sites, but atmospheric deposition contributed 30-50% of foliar Sr in the wettest rainforests. A stepwise multiple regression using annual precipitation, distance from the ocean, and texture of the underlying lava explained 76% of the variation in Sr isotope ratios across the sites. Substrate age did not contribute significantly to variation in Sr isotope ratios in the range of ages evaluated here (11-3000 years), although atmospheric sources eventually dominate pools of biologically available Sr in Hawaiian rainforests in older substrates (≥150,000 years).
我们利用锶的同位素来量化34片位于年轻火山土壤上的夏威夷森林中叶片锶的风化来源与大气来源。这些森林在气候、熔岩流年龄和质地方面差异很大。在大多数地点，风化作用提供了大部分的锶，但在最湿润的雨林中，大气沉降贡献了叶片锶的30%-50%。使用年降水量、与海洋的距离以及下层熔岩的质地进行的逐步多元回归解释了各地点锶同位素比率变化的76%。在本文评估的年龄范围内（11-3000年），底物年龄对锶同位素比率的变化没有显著贡献，尽管在较老的底物（≥150,000年）中，大气来源最终在夏威夷雨林中生物可利用锶的库中占主导地位。
