人們可能以為,，氣候變化（如對(duì)很多旱地所預(yù)測(cè)的干旱程度的增加）在21世紀(jì)可能會(huì)打亂碳,、氮和磷的生物地球化學(xué)循環(huán),。這些元素是陸地生態(tài)系統(tǒng)中生物質(zhì)生產(chǎn)的必要營(yíng)養(yǎng)成分,。
這項(xiàng)研究發(fā)現(xiàn),，干旱對(duì)全球旱地土壤有機(jī)碳和氮的濃度有一個(gè)負(fù)面影響,，但對(duì)無(wú)機(jī)磷的濃度卻有一個(gè)正面影響,。這說(shuō)明不同養(yǎng)分循環(huán)因干旱程度的增加會(huì)發(fā)生“去耦合”,，后者可能會(huì)對(duì)控制初級(jí)生產(chǎn)力等關(guān)鍵生態(tài)系統(tǒng)功能的生物地球化學(xué)反應(yīng)產(chǎn)生一個(gè)負(fù)面影響。（生物谷Bioon.com）
生物谷推薦的英文摘要
Nature doi:10.1038/nature12670
Decoupling of soil nutrient cycles as a function of aridity in global drylands
Manuel Delgado-Baquerizo,，F(xiàn)ernando T. Maestre,，Antonio Gallardo，Matthew A. Bowker,，Matthew D. Wallenstein,，Jose Luis Quero，Victoria Ochoa,，Beatriz Gozalo,，Miguel Garcia-Gomez，Santiago Soliveres,，Pablo Garcia-Palacios,，Miguel Berdugo，Enrique Valencia,，Cristina Escolar,，Tulio Arredondo，Claudia Barraza-Zepeda,，Donaldo Bran,，JoseAntonio Carreira，Mohamed Chaieb,，Abel A. Conceicao,，Mchich Derak，David J. Eldridge,，Adrian Escudero,，Carlos I. Espinosa，Juan Gaitanet al.
The biogeochemical cycles of carbon (C),， nitrogen (N) and phosphorus (P) are interlinked by primary production,， respiration and decomposition in terrestrial ecosystems1. It has been suggested that the C， N and P cycles could become uncoupled under rapid climate change because of the different degrees of control exerted on the supply of these elements by biological and geochemical processes. Climatic controls on biogeochemical cycles are particularly relevant in arid,， semi-arid and dry sub-humid ecosystems (drylands) because their biological activity is mainly driven by water availability. The increase in aridity predicted for the twenty-first century in many drylands worldwide. may therefore threaten the balance between these cycles,， differentially affecting the availability of essential nutrients. Here we evaluate how aridity affects the balance between C， N and P in soils collected from 224 dryland sites from all continents except Antarctica. We find a negative effect of aridity on the concentration of soil organic C and total N,， but a positive effect on the concentration of inorganic P. Aridity is negatively related to plant cover,， which may favour the dominance of physical processes such as rock weathering， a major source of P to ecosystems,， over biological processes that provide more C and N,， such as litter decomposition. Our findings suggest that any predicted increase in aridity with climate change will probably reduce the concentrations of N and C in global drylands， but increase that of P. These changes would uncouple the C， N and P cycles in drylands and could negatively affect the provision of key services provided by these ecosystems.
