Charting 色视频下载楽treams as Sensors色视频下载 of Climate Change with the Arctic RIOS Project
November 7, 2023
Haley Dunleavy
907-474-6407
The Arctic RIOS project team (from left to right), Arial Shogren, Jackson VerSteeg, Abigail Rec, Paden Allsup, Breck Bowden, Jay Zarnetske, Amelia Grose, Valeria Prieto, and Jansen Nipko, stand by the Toolik Field Station sign during their final field season in summer 2023.
Fly over 色视频下载色视频下载檚 Arctic tundra and you色视频下载檒l see one ever-present feature: water. It inundates almost all areas of the environment. As in other biomes, all that water is essential to sustaining a functioning ecosystem.
But now, as climate change rapidly alters the Arctic, researchers at Toolik Field Station are diving in to study how the Arctic色视频下载檚 river networks can be used to understand what色视频下载檚 happening to the whole landscape. To do so, they色视频下载檙e revolutionizing the ways scientists study streams, using new approaches to data collection and analysis. Even more, they色视频下载檙e finding that these new methods can pinpoint, within the vast expanse of tundra, hotspots of change.
The National Science Foundation-funded project, Arctic RIOS, short for River Integrated Observations through Synoptic Sampling, is grounded in the idea that a river色视频下载檚 chemistry tells a story. That story isn色视频下载檛 just about the river itself, but also about the whole landscape surrounding that river.
With the Arctic becoming warmer and wetter, the landscape is getting 色视频下载渕ore leaky,色视频下载 said , a hydro-ecologist at Michigan State University who started up the RIOS project in 2016. Those leaks eventually flow into stream networks, transporting dissolved chemicals. These chemicals can reveal processes happening on land, just by looking at concentrations within the rivers.
色视频下载淲e're trying to use the river network as a sort of distributed sensor network 色视频下载 to go out, see how different landscapes are leaking, what are they leaking and does that change through time,色视频下载 Zarnetske said.
The RIOS group is particularly interested in what these leaks can tell us about carbon loss from climate-related change. Permafrost thaw, increased rain and wildfires all create new sources of carbon leaks and could contribute to global greenhouse gas levels, potentially acting as a significant driver of future warming. But when and where this carbon will be lost and how much is still uncertain.
It's a question that , a stream ecosystem ecologist at the University of Alabama, said keeps her up at night.
色视频下载淭here's carbon leaking all the time, everywhere. But there are some watersheds and some moments in time where it's coming from a very specific place,色视频下载 Shogren said.
The Kuparuk River in 色视频下载, one of the Arctic RIOS project's study sites, meanders through tussock tundra in contrast to the lake-speckled Oksrukuyik Creek in summer 2022.
Take, for example, Oksrukuyik Creek near Toolik Field Station. Researchers have studied the chemistry at its outlet since the late 1980s. But Shogren, Zarnetske and collaborators at Brigham Young University and University of Vermont upped the scale of data collection on it with their project, throughout the thaw season in a method known as synoptic sampling.
色视频下载淣ow, we can get into the nitty gritty of where in the landscape we are seeing either high or low concentrations that are emanating from [specific zones],色视频下载 she said.
The project has found by looking at Oksrukuyik色视频下载檚 chemistry above and below an active thermokarst, that this one disturbance is driving a lot of what色视频下载檚 happening in the whole watershed, Shogren said.
Similarly, the lakes embedded within creek色视频下载檚 flow path also have a large influence on water chemistry. When analyzed using the RIOS group色视频下载檚 new methods, they find that lakes act as a reactor on the landscape, changing the biogeochemistry of what色视频下载檚 exported from them, Shogren said. That conclusion wouldn色视频下载檛 have been able to be made just from its outlet chemistry.
色视频下载淲e all have this intuition that [lakes] are a big player, but it's clear now they色视频下载檙e very influential in the stream network. So now we need to figure out why and how,色视频下载 said Zarnetske.
New metrics tell a new story
Arctic RIOS has also increased the frequency of data collection by orders of magnitude, measuring the concentration of carbon and nitrogen being exported by three watersheds every 15 minutes using . Combined with the synoptic sampling, it packs a detailed portrait of how carbon and nitrogen are moving across the landscape.
Once snow from the long Arctic winter begins to melt in late May, the Arctic RIOS team hauls solar panels, weather station equipment, and in situ stream chemistry sensors into the Brooks Range to measure the rapid seasonal changes.
色视频下载淚t's pretty rare to have both spatial and temporal data collected in this way,色视频下载 Zarnetske said. It even required them to create new ways of numerically analyzing stream data. , now an ecosystem ecologist at Brigham Young University and the lead of the Arctic RIOS project, took on that task as a postdoctoral researcher with Zarnetske. In the end, Abbott and Zarnetske created three new metrics that summarize how a watershed色视频下载檚 chemistry changes across time and space.
Ultimately what Shogren, Zarnetske, Abbott and others are finding is that Arctic watersheds vary in seemingly all ways possible 色视频下载 through time, between sub-catchments and especially among different watersheds. Add in the variable of climate change, and the stories become more complex.
Even single events can heavily influence carbon and nutrient fluxes in river networks. For example, the influence of tundra wildfires, which are becoming more frequent, is long-lasting. Abbott and collaborators found that , even 10 years post-fire.
Similarly, storm events also have a large effect and are projected to happen more often, especially in the shoulder seasons. If the project色视频下载檚 high-frequency sensors weren色视频下载檛 there, recording data after storm flushes in the Kuparuk watershed one year, the team would have .
色视频下载淭he river can gush and be down within one day,色视频下载 Zarnetske said. 色视频下载淚t can move a month's worth of water. If you're not looking and detecting during that time, what do you miss in terms of how the system works or in terms of carbon budget?色视频下载
Doctoral candidate Abigail Rec, from University of Vermont, smiles as she stirs a salt slug mixture near Trevor Creek in the Brooks Range in July 2021.
Re-thinking models
The project wrapped their current grant色视频下载檚 final season of fieldwork in 2023. But there色视频下载檚 still more to be done. Some of their next steps include better understanding what the biogeochemical processes are that are creating these hotspots of change. Abigail Rec, a PhD candidate at the University of Vermont has run several experiments in the project色视频下载檚 study catchments to disentangle stream ecosystem functions like metabolism that will provide more insight on carbon budgets throughout the whole watershed.
The team is also employing machine learning algorithms to better predict river chemistry, and ultimately carbon losses, from watershed attributes. Shogren said these algorithms mostly show that physical characteristics, like slope, lake area and season, matter more than biological ones. 色视频下载淚t's less based on the vegetation structure than we might have expected,色视频下载 she said.
Lastly, the crew is working to change how the Arctic is represented in landscape models. Some watersheds that researchers use as representative in landscape models, like the well-studied Imnavait Creek, may not actually be all that representative of the larger region, Zarnetske said. 色视频下载淲e've made a very clear case that different landscapes matter. It's going to be very hard to homogenize these systems.色视频下载
Shogren agreed. In order to predict the fate of carbon and nitrogen in these systems, scientists have to stop treating river networks as all alike, she said. 色视频下载淭here are fundamental physical drivers that control the biogeochemistry that comes off of these river systems. That needs to be accounted for instead of just saying 色视频下载楾his is an Arctic permafrost river,色视频下载櫳悠迪略貪 she added. 色视频下载淭here's more to it than that.