美國(guó)康奈爾大學(xué)的研究人員在新一期《科學(xué)》雜志上發(fā)表報(bào)告說,，隨著氣候變暖，沙漠地區(qū)土壤中的氮會(huì)以氣體的形式大量流失,，從而導(dǎo)致生長(zhǎng)在沙漠里的植物越來越少,。
研究人員在美國(guó)莫哈韋沙漠地區(qū)選了幾處試驗(yàn)點(diǎn)，通過精密測(cè)量?jī)x器了解土壤中的氮是如何隨著周圍氣溫升降而變化的,。研究發(fā)現(xiàn),，不管有沒有光照，當(dāng)溫度達(dá)到40攝氏度至50攝氏度時(shí),，土壤中的氮會(huì)以氣體形式從土壤中迅速釋放出來,。溫度越高，釋放的速度越快,。研究人員由此推測(cè),，在世界任何高溫干旱的地方都可能出現(xiàn)類似的情況，因此應(yīng)該引起關(guān)注,。
氮是植物生長(zhǎng)過程中除水之外的第二大必需營(yíng)養(yǎng)元素,。研究人員指出，目前生長(zhǎng)在沙漠地區(qū)的植物本來就很少,，根據(jù)這一新發(fā)現(xiàn),，隨著全球氣候變暖加劇，沙漠土壤里的氮會(huì)大量流失,，那么生長(zhǎng)在沙漠里的植物就會(huì)越來越少,，這將給沙漠地區(qū)的生態(tài)環(huán)境構(gòu)成嚴(yán)重威脅。（生物谷Bioon.com）
生物谷推薦原始出處：
Science 6 November 2009:DOI: 10.1126/science.1178984
Abiotic Gas Formation Drives Nitrogen Loss from a Desert Ecosystem
Carmody K. McCalley* and Jed P. Sparks
In arid environments such as deserts, nitrogen is often the most limiting nutrient for biological activity. The majority of the ecosystem nitrogen flux is typically thought to be driven by production and loss of reactive nitrogen species by microorganisms in the soil. We found that high soil-surface temperatures (greater than 50°C), driven by solar radiation, are the primary cause of nitrogen loss in Mojave Desert soils. This abiotic pathway not only enables the balancing of arid ecosystem nitrogen budgets, but also changes our view of global nitrogen cycling and the predicted impact of climate change and increased temperatures on nitrogen bioavailability.
Department of Ecology and Evolutionary Biology, Corson Hall Room E149, Cornell University, Ithaca, NY 14853, USA.
