科学家发现，吹向山地的沙漠尘埃可能改变植物对调控其生命周期的气候信号的响应。山地的尘埃水平自从19世纪以来一直在增加，这在很大程度上是由于人类在沙漠的活动增加。
Heidi Steltzer及其同事模拟了尘埃对科罗拉多州落基山上的实验区域融雪的影响，从而测量尘埃对高山植物的生命周期的影响。在正常条件下，融雪的时机向山地植物发出了开始生长和开花的信号。然而，沙漠尘埃吸收了干净的雪本来能够反射的热量，因此增加了来自太阳光的热效应并导致了雪更早融化。这种提前融雪可能导致植物推迟它们的年度生长周期，直到空气温度变暖。这组作者预测说，尘埃的增加量可能让高山冻原的植物变绿和开花时间同步，而且有可能通过改变传粉者和野生动物可以获取的资源从而改变物种相互作用以及营养循环。这组作者说，他们的结果显示，人类改变沙漠与山地的植物生命周期有联系。（生物谷Bioon.com）
生物谷推荐原始出处：
PNAS June 29, 2009, doi: 10.1073/pnas.0900758106
Biological consequences of earlier snowmelt from desert dust deposition in alpine landscapes
Heidi Steltzera,1, Chris Landryb, Thomas H. Painterc, Justin Andersond and Edward Ayresa
Dust deposition to mountain snow cover, which has increased since the late 19th century, accelerates the rate of snowmelt by increasing the solar radiation absorbed by the snowpack. Snowmelt occurs earlier, but is decoupled from seasonal warming. Climate warming advances the timing of snowmelt and early season phenological events (e.g., the onset of greening and flowering); however, earlier snowmelt without warmer temperatures may have a different effect on phenology. Here, we report the results of a set of snowmelt manipulations in which radiation-absorbing fabric and the addition and removal of dust from the surface of the snowpack advanced or delayed snowmelt in the alpine tundra. These changes in the timing of snowmelt were superimposed on a system where the timing of snowmelt varies with topography and has been affected by increased dust loading. At the community level, phenology exhibited a threshold response to the timing of snowmelt. Greening and flowering were delayed before seasonal warming, after which there was a linear relationship between the date of snowmelt and the timing of phenological events. Consequently, the effects of earlier snowmelt on phenology differed in relation to topography, which resulted in increasing synchronicity in phenology across the alpine landscape with increasingly earlier snowmelt. The consequences of earlier snowmelt from increased dust deposition differ from climate warming and include delayed phenology, leading to synchronized growth and flowering across the landscape and the opportunity for altered species interactions, landscape-scale gene flow via pollination, and nutrient cycling.
