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了阿拉斯加布鲁克斯山脉的大片地区，但无法保护其荒野免受气候变化的影响。变暖速度比地球其他地方快四倍，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。这也鼓励驼鹿、云杉、海狸和灌木进入苔原。在所有气候驱动的变化中，最近溪流水质的恶化可能是最令人担忧的。布鲁克斯山脉长期以来以其清澈的海水而闻名。海水突然变成橙色、浑浊，令人震惊，很可能威胁到生活在那里的大量北极河鳟、多利瓦尔登鳟鱼和鲑鱼。目前没有人知道溪流为何发生变化，或者这对鱼类、野生动物以及依赖它们的人们在短期或长期意味着什么。研究人员由一群在“酸性岩石排水”方面拥有丰富经验的地质学家和拥有丰富布鲁克斯山脉知识的生态学家组成。他们计划在 2023 年夏季访问一个拥有大量退化溪流的地区，花费一个半月的时间在现场收集岩石、土壤和水样本以供实验室分析。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的预期。阿拉斯加北极地区成千上万的人依靠清澈且多产的溪流获取饮用水和维持生计的鱼类捕捞。那里的人们已经对他们所看到的水质恶化感到震惊。为了分享他们所学到的知识，研究人员将在区域中心和最大的人口中心科策布的公开演讲中展示他们的发现。他们将为该地区最大的公共广播电台提供采访，以便周边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如何影响当地生态。他们还将在西北北极地区生存咨询委员会的会议上发言，直接与生存资源的区域管理者和相关公众分享他们的成果。布鲁克斯山脉南坡历史上以原始溪流为北极河鳟、多利瓦尔登和大鲑鱼提供了大量的栖息地，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，已有30多条清澈的溪流因铁沉淀物而变得浑浊和橙色。已在苔原和高地岩层中发现渗漏现象。有限的数据显示，渗水 pH 值极低 (3.0)、下坡植被死亡以及受影响源头的幼鱼丰度急剧下降。原始河流迅速退化的原因仍然未知。该项目的目标是确定导致整个布鲁克斯山脉西部浑浊橙色溪流最近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，研究人员将测试两个假设，以解释受影响流域内金属的流动。他们的两个假设都可能被证明是相关的，但对河流水质和未来河流退化风险区域的空间范围具有不同的影响。通过确定橙色溪流扩散的原因，研究人员将能够向土地管理者和当地村庄的居民通报其对阿拉斯加西北部现在和未来的饮用水、生存资源可用性以及不断增长的商业鲑鱼渔业的潜在影响。这项关于布鲁克斯山脉西部溪流退化原因的研究与该地区的阿拉斯加原住民村庄高度相关，这些村庄依赖这些溪流获取饮用水和维持生计的鱼类捕捞。 Kiana 和 Kivalina 村庄尤其面临风险，因为附近的 Wulik 河、Squirrel 河和 Kobuk 河支流已退化。研究人员将在科策布进行公开演讲，并安排接受科策布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委员会会议期间分享他们的发现，以便将他们的结果直接传达给地区生存资源管理者和相关公众。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值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.