Collaborative Research: RAPID: Identifying the biogeochemical causes of sudden widespread metal loading in streams of the western Brooks Range, Alaska

国家公园和野生动物保护区保护着阿拉斯加布鲁克斯山脉的大片区域，但无法保护其荒野免受气候变化的影响。变暖的速度是地球上其他地方的四倍，更高的温度融化了海冰，融化了永久冻土，甚至增加了冬季降雪量。这也鼓励了驼鹿、云杉、海狸和灌木进入冻土带。在所有气候驱动的变化中，最近溪水水质的恶化可能是最令人担忧的。布鲁克斯山脉长期以来一直以其晶莹剔透的水域而闻名。突然变成橙色浑浊的水域是令人震惊的，可能会威胁到生活在那里的丰富的北极灰鲸、多莉·瓦登鲑鱼和鲑鱼。目前没有人知道溪流为什么会改变，也不知道这对鱼类、野生动物和依赖它们的人来说意味着什么。研究人员是一群在“酸性岩石排水”方面有丰富经验的地质学家，还有一群对布鲁克斯山脉有广泛了解的生态学家。他们计划在2023年夏天访问一个有大量退化溪流的地区，花一个半月的时间在野外收集岩石、土壤和水样进行实验室分析。他们的发现将帮助我们了解现在正在发生的事情以及未来会发生什么。在北极阿拉斯加，数以千计的人依靠清澈和多产的溪流饮用饮用水和捕捞自给自足的鱼类。那里的人们已经对他们所看到的水质恶化感到震惊。为了分享他们的研究成果，研究人员将在科泽布的公开演讲中展示他们的发现，科策布是该地区的枢纽和最大的人口中心。他们将为该地区最大的公共广播电台提供采访，以便周围较小村庄的居民能够了解当地溪流、区域河流的变化，以及这些变化已经如何影响当地生态。他们还将在西北北极区域生存咨询理事会的会议上发言，直接与生存资源的区域经理和关心的公众分享他们的结果。历史上，布鲁克斯山脉南坡以原始的溪流为特征，支持着北极灰熊、多莉·瓦尔登和鲑鱼的旺盛种群，为当地社区提供了宝贵的经济和生存资源。然而，自2019年以来，30多条清流的溪流因铁沉淀物而变得浑浊和橙色。已经在冻土带和高地岩层中发现了渗漏。有限的数据显示，渗漏水的酸碱值非常低(3.0)，坡下植被死亡，受影响源头的幼鱼数量急剧下降。原始溪流迅速蔓延退化的原因尚不清楚。该项目的目标是确定导致最近在整个西部布鲁克斯山脉浑浊的橙色溪流广泛扩散的陆地生物地球化学过程。通过现场采样和实验室分析，研究人员将检验两个假说，以解释受影响流域内金属的流动情况。他们的两个假设都可能被证明是相关的，但对溪流水质和未来溪流退化风险地区的空间范围具有不同的影响。通过确定橙流扩散的原因，研究人员将能够告知土地管理人员和当地村庄的居民饮用水、生存资源的可用性以及现在和未来阿拉斯加西北部日益增长的商业鲑鱼渔业的潜在后果。这项关于西部布鲁克斯山脉溪流退化原因的研究与该地区的阿拉斯加土著村庄高度相关，这些村庄依赖这些溪流提供饮用水和自给自足的鱼类。Kiana和Kivalina的村庄尤其危险，因为附近的乌利克河、松鼠河和科布克河的支流已经退化。研究人员将在Kotzebue发表公开演讲，并安排接受Kotzebue公共广播电台的采访，与周围较小村庄的居民分享他们的发现。他们还计划在西北北极地区生存咨询理事会的会议上分享他们的发现，将他们的结果直接传达给生存资源的区域经理和相关的公众成员。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。

National Parks and Wildlife Refuges protect a vast area of Alaska’s Brooks Range but cannot shield its wilderness from climate change. Warming four times faster than elsewhere on Earth, the higher temperatures melt sea ice, thaw permafrost, and even increase winter snowfall. This also encourages moose, spruce, beavers, and shrubs to move into tundra. Of all the climate-driven changes, the recent degradation of stream water quality may be most alarming. The Brooks Range has long been known for its crystal-clear waters. The abrupt change to orange-colored, murky waters is startling and likely threatens the abundant Arctic grayling, Dolly Varden trout, and chum salmon that live there. No one currently knows why the streams are changing or what it means in the near or long term for fish, wildlife, and the people who depend upon them. The researchers are a group of geologists with extensive experience in “acid-rock drainage” joined by ecologists with extensive Brooks Range knowledge. They plan to visit an area with numerous degraded streams during the summer of 2023, spending a month and a half in the field collecting rock, soil, and water samples for laboratory analysis. What they find will help us understand what is happening now and what to expect in the future. Thousands of people depend on clear and productive streams for drinking water and subsistence fish harvest in Arctic Alaska. People there are already alarmed about the degradation in water quality they can see. To share what they learn, the researchers will present their findings in public presentations in Kotzebue, the regional hub and largest population center. They will provide interviews for the region’s largest public radio station, so that residents of smaller surrounding villages can learn about the changes to their local streams, regional rivers and how those changes are already impacting local ecologies. They will also speak at meetings of the Northwest Arctic Regional Subsistence Advisory Council to share their results directly with regional managers of subsistence resources and concerned members of the public.Historically characterized by pristine streams that support robust populations of Arctic grayling, Dolly Varden, and chum salmon, the southern slopes of the Brooks Range provide valuable economic and subsistence resources for local communities. However, since 2019, more than 30 clear-running streams have turned turbid and orange with iron precipitates. Seeps have been identified in the tundra and in upland rock formations. Limited data show very low pH in seep water (3.0), downslope vegetation mortality, and dramatic declines in juvenile fish abundance in affected headwaters. The causes of this rapidly spreading degradation of pristine streams remain unknown. The goal of this project is to identify the terrestrial biogeochemical processes causing the recent and widespread proliferation of turbid orange streams throughout the western Brooks Range. Through field sampling and laboratory analysis, the researchers will test two hypotheses to explain the mobilization of metals within affected watersheds. Their two hypotheses, which may both prove relevant, have divergent implications for stream water quality and the spatial extent of areas at risk of future stream degradation. By identifying the causes of orange stream proliferation, the researchers will be able to inform land managers and residents of local villages of the potential consequences for drinking water, subsistence resource availability, and the growing commercial salmon fishery in northwest Alaska now and in the future. This research on the causes of stream degradation in the western Brooks Range is highly relevant to Alaska Native villages in the region, which depend on these streams for drinking water and subsistence fish harvest. The villages of Kiana and Kivalina are especially at risk because of nearby degraded tributaries of the Wulik, Squirrel and Kobuk Rivers. The researchers will deliver public presentations in Kotzebue and arrange to be interviewed by Kotzebue Public Radio to share their findings with residents of smaller surrounding villages. They also plan to share their findings during meetings of the Northwest Arctic Regional Subsistence Advisory Council to communicate their results directly to regional managers of subsistence resources and concerned members of the public.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.