Mechanical Engineering and Engineering Science, University of North Carolina at Charlotte, North Carolina 28223, USA.
Chaos. 2011 Sep;21(3):033122. doi: 10.1063/1.3624930.
Many microorganisms are advected in the lower atmosphere from one habitat to another with scales of motion being hundreds to thousands of kilometers. The concentration of these microbes in the lower atmosphere at a single geographic location can show rapid temporal changes. We used autonomous unmanned aerial vehicles equipped with microbe-sampling devices to collect fungi in the genus Fusarium 100 m above ground level at a single sampling location in Blacksburg, Virginia, USA. Some Fusarium species are important plant and animal pathogens, others saprophytes, and still others are producers of dangerous toxins. We correlated punctuated changes in the concentration of Fusarium to the movement of atmospheric transport barriers identified as finite-time Lyapunov exponent-based Lagrangian coherent structures (LCSs). An analysis of the finite-time Lyapunov exponent field for periods surrounding 73 individual flight collections of Fusarium showed a relationship between punctuated changes in concentrations of Fusarium and the passage times of LCSs, particularly repelling LCSs. This work has implications for understanding the atmospheric transport of invasive microbial species into previously unexposed regions and may contribute to information systems for pest management and disease control in the future.
许多微生物在低大气层中通过运动被从一个栖息地输送到另一个栖息地，运动的范围可达数百到数千公里。这些微生物在单个地理位置的低大气层中的浓度会迅速发生时间变化。我们使用配备有微生物采样设备的自主无人机在美国弗吉尼亚州布莱克斯堡的一个单一采样地点从地面以上 100 米处采集被孢霉属真菌。一些被孢霉是重要的动植物病原体，其他的是腐生菌，还有一些是危险毒素的生产者。我们将被孢霉浓度的间断变化与被确定为基于有限时间李雅普诺夫指数的拉格朗日相干结构 (LCS) 的大气输送屏障的运动联系起来。对围绕 73 次单独的被孢霉飞行采集的有限时间李雅普诺夫指数场的分析表明，被孢霉浓度的间断变化与 LCS 的通过时间之间存在关系，特别是排斥 LCS。这项工作对于理解入侵微生物物种向以前未暴露地区的大气输送具有重要意义，并可能有助于未来害虫管理和疾病控制的信息系统。
