Collaborative Research: RAPID: lake ecosystem responses to fire along gradients of burn characteristics and hydrologic connectivity

高质量的水是维持地球上所有生命所必需的。然而，不同类型的污染会降低水质，危害植物、动物和依赖水生存的人。具体来说，最近美国各地的野火可能会在几个方面降低水质。例如，野火产生的灰烬最终会进入湖泊和河流，潜在地危害水生生物和饮用水供应。在这个项目中，一组研究人员将研究2021年格林伍德大火后明尼苏达州北部湖泊的水质。2021年秋天，这场野火烧毁了苏必利尔州国家森林的大部分地区，包括28个湖泊附近的地区。研究人员预计，在春季融雪或降雨之后，灰烬和大片烧焦的植物将被冲进这些湖泊，降低水质。他们将从2022年春季到夏末五次访问湖泊，记录格林伍德大火后的水质变化。这项研究的结果将帮助明尼苏达州和其他地方的水资源管理者预测未来野火后湖泊和水库的水质将如何变化。该项目还将帮助居住在湖泊附近的人们了解他们所关心的水上活动，如钓鱼和划船，可能会受到未来野火的影响。尽管美国各地的野火活动正在增加，人们越来越担心火灾对水资源的影响，但很少有研究记录了火灾对湖泊生态系统的影响。2021年苏必利尔国家森林的格林伍德火灾面积为10844公顷，是明尼苏达州10年来最大的闪电引起的野火，到2021年10月覆盖了28个湖泊流域的全部或部分地区。该项目汇集了水生生态系统、景观和火灾生态学家，研究明尼苏达州北部湖泊对格林伍德火灾的物理、化学和生物反应。研究人员假设：(1)湖泊响应将与流域燃烧的百分比成比例变化，并在排水与孤立湖泊之间变化；(2)火灾后的时间轨迹将根据主要水文事件（如融雪、降水）而变化。这两种假设正在使用贝叶斯方法（即，信息理论建模和模型选择程序）进行测试。在春季融雪之后开始的(1)燃烧和(2)未燃烧的控制流域，以及整个2022年夏季，分别对大约15个湖泊进行采样。春季融雪是将营养物质和物质从燃烧的景观输送到湖泊的关键时期。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

High-quality water is needed for sustaining all life on Earth. Different types of pollution, however, can reduce water quality and harm the plants, animals, and people that depend on water to live. Specifically, recent wildfires across the U.S. may reduce water quality in several ways. For example, ash from wildfires can end up in lakes and rivers, potentially harming aquatic organisms and drinking water supplies. In this project, a group of researchers will study water quality of northern Minnesota lakes after the 2021 Greenwood Fire. This wildfire burned a large part of Superior National Forest in fall 2021, including areas near 28 lakes. The researchers expect that after spring snowmelt or rain, ash and large pieces of burned plants will wash into these lakes and reduce water quality. They will visit lakes five times from spring to late summer of 2022 to document any water quality changes following the Greenwood Fire. Results of this study will help water managers in Minnesota and elsewhere predict how water quality in lakes and reservoirs may change after future wildfires. This project will also help people who live near lakes understand how the water activities they care about, such as fishing and boating, may be affected by future wildfires.Although wildfire activity is increasing across the U.S. and concern is mounting over fire effects on water resources, few studies have documented fire effects on lake ecosystems. At 10844 ha in size, the 2021 Greenwood Fire in Superior National Forest was the largest lightning-caused Minnesota wildfire in 10 years and covered all or parts of 28 lake watersheds through October 2021. This project assembled an integrative group of aquatic ecosystem, landscape, and fire ecologists to study the physical, chemical, and biological responses of northern Minnesota lakes to the Greenwood Fire. The researchers hypothesized that (1) lake responses will vary proportionally to the percent watershed burned and between drainage vs. isolated lakes and (2) post-fire temporal trajectories will vary according to major hydrologic events (e.g., snowmelt, precipitation). Both hypotheses are being tested using Bayesian approaches (i.e., information theoretic modeling and model choice procedures). Approximately 15 lakes are being sampled each in (1) burned and (2) unburned control watersheds beginning after spring snowmelt, a critical time for the delivery of nutrients and materials from the burned landscape to lakes, and throughout summer 2022.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.