SG: RUI: Resilience of mountain lakes across a gradient of glacial retreat and vegetation advance

长期以来，世界各地的山脉景观一直被认为是环境变化的哨兵，随着冰川的消退和植被的向上推进，这些景观正在迅速变化。这些景观中的原始湖泊，特别是湖泊，其标志性的美丽导致其被指定为世界遗产，具有强大的旅游吸引力。然而，这种美丽受到了湖水清澈程度的变化的威胁。对这些潜在脆弱生态系统的保护工作将受益于对湖泊对全球气候变化反应的预测性理解。这项研究探索了这些景观水平的变化对湖泊生态系统的影响。这些研究人员不会在很长一段时间内研究一个单一的系统，而是将目前在集水区冰川和植被覆盖程度上不同的湖泊生态系统进行比较。这项研究的主要目的是比较湖泊对雨和雪融化驱动的材料输入的反应，这些材料包括冰川面粉、冰川细碎的岩石和有机物分解的溶解产物。这两种材料对水的清晰度或水的透明度都有很强的影响，进而影响湖泊生态系统功能的许多方面。将使用两种相辅相成的生态复原力测量来检验湖泊的反应：抵抗力，即降雨或融雪事件后系统的变化幅度；以及恢复率，即恢复到以前状况的速度。该项目的发现将加深对变化的地貌对落基山脉湖泊生态系统影响的基本科学理解。本科生将参与研究的所有阶段，包括规划、数据收集、分析和发表。将有针对性地努力吸引来自不同背景和经历的学生。由于山地湖泊的水透明度是一个强大的案例研究，通过它向更广泛的受众传达环境变化对生态系统水平的影响，将制作并发行一部描述这项研究的短片。拟议的研究将检验最重要的假设，即随着湖泊集水区从冰川状态转变为岩石状态，再到植被状态，水透明度的弹性发生系统性的变化。具体地说，水透明度的阻力预计会随着冰川的消失而增加，随着植被的推进而减少。此外，随着透明度调节器从冰川集水区湖泊的悬浮岩粉转向植被覆盖的集水区湖泊中的溶解有机物(DOM)，预计水透明度的恢复率将会增加。为了验证这些假设，将在五个湖泊中部署高频监测浮标，这些浮标配备了测量浊度和DOM荧光成分的传感器，这些湖泊的冰川和植被覆盖程度不同。将使用并行水文数据，以更好地了解材料输入的动态及其与附近气象站记录的气象数据的关系。更广泛地说，这项研究通过测试抵抗力和恢复力是否随着冰川消退和植被的发展而独立变化，来探索韧性的两个组成部分之间的关系。复原力的两个组成部分的潜在变化是研究计划的一个独特和变革性的方面。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Mountain landscapes worldwide, long considered sentinels of environmental change, are changing rapidly as glaciers retreat and vegetation advances upslope. Pristine lakes within those landscapes, especially lakes whose iconic beauty has led to their designation as World Heritage sites, have strong tourist appeal. Yet that beauty is threatened by changes to the clarity of the lake waters. Conservation efforts for these potentially fragile ecosystems would benefit from a predictive understanding of lake responses to global climate change. This research explores the consequences of these landscape-level changes for lake ecosystems. Rather than study a single system over a long time, these researchers will substitute a comparison of lake ecosystems that currently differ in the extent of glacial and vegetation coverage in the catchment. The primary aim of the research is to compare lake responses to rain and snowmelt-driven inputs of materials such as glacial flour, the finely ground rock from glaciers, and dissolved products of organic matter decomposition. Both of these materials have strong effects on the clarity of the water or water transparency, which in turn influences many aspects of lake ecosystem function. Lake responses will be examined using two complementary measurements of ecological resilience: resistance, the magnitude of change in the system following rain or snowmelt events; and recovery, the rate of return to previous conditions. Project findings will deepen the basic scientific understanding of the effects of changing landscapes on lake ecosystems in the Rocky Mountains. Undergraduate students will be engaged in all stages of the research, including planning, data collection, analysis, and publication. Targeted efforts will be made to attract students from diverse backgrounds and experiences. Because water transparency of mountain lakes is a powerful case study through which to communicate ecosystem-level effects of environmental change to a broader audience, a short film describing the research will be produced and distributed.The proposed research will test the overarching hypothesis that changes in the resilience of water transparency occur systematically as lake catchments shift from glaciated to rocky to vegetated states. Specifically, resistance of water transparency is predicted to increase with glacial loss and decrease with vegetation advance. Additionally, recovery rates of water transparency are predicted to increase as the regulator of transparency shifts from suspended rock flour in glacial catchment lakes to dissolved organic matter (DOM) in vegetated catchment lakes. To test these hypotheses, high frequency monitoring buoys equipped with sensors that measure turbidity and the fluorescent component of DOM will be deployed in five lakes that vary across a gradient of glacial and vegetation coverage. Concurrent hydrological data will be used to better understand dynamics of material inputs and their relationships to meteorological data recorded at nearby weather stations. More generally, the research probes the relationship between the two components of resilience by testing whether resistance and recovery change independently as glaciers retreat and vegetation advances. The potential for uncoupled changes in the two components of resilience is a unique and transformative aspect of the research program.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.