RAPID: Effects of wildfires on lake productivity and oxygen deficits in the western U.S.

在北美西部和世界其他地区，极端野火现在越来越频繁地发生。这些野火产生大量的烟雾和火山灰，可以传播数千英里，并在大气中持续数周或更长时间。这些“烟雾风暴”阻挡了阳光，并在表面沉积了火山灰。湖泊和池塘受到野火造成的光线和火山灰输入减少的影响，但关于这些潜在影响的许多情况尚不清楚。光和营养物质都是调节水生生态系统中植物和藻类生长的重要因素。植物和藻类的初级生产量反过来决定了其他生物(如鱼类)可以获得多少食物，并可能影响水质的许多方面。因此，了解水生初级生产力如何以及为什么对野火作出反应是一个关键的研究目标。该项目将有助于建立对水生生态系统如何应对野火的预测性理解，为29个国家森林、14个国家公园以及加利福尼亚州和俄勒冈州管理的众多土地提供服务。该项目将为本科生、研究生和博士后学者提供科学、技术、工程和数学(STEM)培训。研究结果将通过塔霍环境研究中心主办的专业会议和公开讲座系列，以及通过其他州和联邦机构向科学家、管理人员和普通公众介绍。该项目将阐明太阳辐射减少、烟雾存在增加以及大气中颗粒和火山灰沉积增加对小湖泊生态系统新陈代谢和溶解氧动力学的交互影响。该项目将利用加利福尼亚州和俄勒冈州沿生态相关坡度的湖泊网络。将汇编卫星遥感数据，结合地面空气质量监测数据，量化烟雾和颗粒物沉积动力学。在2020年野火季节之前，已经测量了几个生态系统响应变量，该项目将增加关于火灾影响的重要短期知识，从几天到几个月。将在23个水生生态系统正在进行的测量基础上增加新的测量和仪器。通过研究不同大小、水体透明度和生产力的湖泊中的基本生态系统功能，该项目将确定野火产生的烟雾和灰烬的影响。最终，来自该项目的数据将有助于描述大型地区性野火产生的烟雾和火山灰沉积的空间联系。湖泊的功能将通过测量总初级生产量、生态系统呼吸和生态系统氧气动态，包括秋季和冬季之间的跨季节联系来确定。这将导致对景观尺度上受野火影响的生态系统功能驱动因素之间的相互作用如何影响单个水生生态系统的响应的机械性理解。该奖项反映了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。

Extreme wildfires now occur with increasing regularity in western North America and other parts of the world. These wildfires generate large plumes of smoke and ash that can travel thousands of miles and persist for weeks or longer in the atmosphere. These “smoke storms” block sunlight and deposit ash on surfaces. Lakes and ponds are affected by the reduced light and ash inputs from wildfires, but much about these potential impacts is unknown. Light and nutrients are both important factors that regulate the growth of plants and algae in aquatic ecosystems. Rates of primary production from plants and algae in turn determine how much food becomes available for other organisms, such as fish, and can affect many aspects of water quality. Thus, understanding how and why aquatic primary production is responding to wildfires is a critical research objective. This project will help develop a predictive understanding of how aquatic ecosystems respond to wildfire, serving the 29 National Forests, 14 National Parks, and numerous lands managed by the states of California and Oregon. The project will provide Science, Technology, Engineering, and Mathematics (STEM) training to undergraduate, graduate students, and post-doctoral scholars. Presentations of the results will be given to scientists, managers, and the general public through professional conferences and public lecture series hosted by the Tahoe Environmental Research Center, and through other state and federal agencies. This project will disentangle the interactive effects of reduced solar radiation, elevated presence of smoke and increased atmospheric deposition of particulates and ash on the ecosystem metabolism and dissolved oxygen dynamics of small lakes. The project will make use of a network of lakes in California and Oregon along ecologically relevant gradients. Satellite remote sensing data will be compiled, in combination with ground-based air quality monitoring data to quantify smoke and particulate deposition dynamics. Several ecosystem response variables have been measured prior to the 2020 wildfire season and this project will add important short-term knowledge about fire impacts from days to months. New measurements and instrumentation will be added to ongoing measurements from 23 aquatic ecosystems. By studying basic ecosystem functioning in lakes of varying size, water clarity, and productivity, the project will ascertain the effects of smoke and ash from wildfires. Ultimately, data from this project will help characterize the spatial linkages of smoke and ash deposition from large regional wildfires. The functioning of lakes will be determined through measurements of gross primary production, ecosystem respiration, and ecosystem oxygen dynamics, including cross-seasonal linkages between autumn and winter. This will lead to a mechanistic understanding of how interactions among drivers of ecosystem function affected by wildfires at landscape scales affect responses in individual aquatic ecosystems.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.