Just off the mainstem Yukon River, the banks and river ice are uniform white with snow, other than peeks of brown where cut banks crumble into the water in warmer times.
Research scientist John Magyar stands by a large metal bollard where barges tie up in the summer.
“Over there where the satellite dish is is the old tribal hall,” Magyar said, pointing to the north. “And this riverbank is really rapidly eroding. We estimate that the part over here that's eroding the fastest is going at, like, 20 feet a year.”
Magyar is a research scientist in geology, geochemistry, and geobiology at the California Institute of Technology in Pasadena, California.
“It's a real problem for the community, that so much of this important infrastructure is being eaten away by the river,” Magyar said. “It's a natural process, but it has real impacts on the community, and so we've been working with these local communities to try to understand better how erosion happens in these landscapes, and how we might be able to predict it better in the future.”
Magyar is part of a project mapping erosion in areas with patches of permanently frozen ground – called “discontinuous permafrost.”
“That [discontinuous permafrost] has a big impact on how the river is able to move and erosion rates. And as climate warms and permafrost melts, you get changes in that behavior that we're trying to understand,” Magyar explained.
The project has focuses in Alakanuk, up the Yukon River in Beaver, and on the Koyukuk in Huslia.
“The other part of this is that as permafrost melts, it releases large amounts of organic material into the river, both solids and also gasses like methane and carbon dioxide (CO2),” Magyar said. “And so we're trying to study that as well, and making direct measurements of methane and CO2 from the river in different seasons. We're out here in the winter doing this because the gasses get trapped in the river under the ice. And so there are higher concentrations than we see other times of year.”
It’s one of a number of projects in the region in recent years that are looking at how permafrost thaw affects erosion in riverine communities, and in turn how that erosion affects what’s released into the waterways of those communities. The project is a collaborative effort between scientists from downstates, the Yukon River Inter-Tribal Watershed Council, and social scientists at the University of Alaska Anchorage.
Magyar carries a grey, hardshell case on his back like a turtle. It hums lightly as we walk down the bank to the river ice.
“The instrument on my back is a trace gas analyzer,” Magyar explains. “It pumps air in, and there's a laser system inside that measures concentrations of methane and carbon dioxide, and then it's attached to this flux chamber –”
Magyar holds up a growler-size bottle with the bottom cut off, partly covered in silver duct tape and attached to a variety of tubing and wires.
“The [flux chamber] in my hands is homemade, made from a plastic bottle, and there's two pipes inside, an inlet and an outlet,” he said. “It circulates the gas from the flux chamber into the instrument and back out again. And when we put this down on the ice, we can measure what the flux is out of the environment.”
By flux, Magyar means how those greenhouse gases are escaping into the atmosphere.
Magyar sets the backpack down on a tarp, attaches a thermometer to the flux chamber, then presses it through the snow about 3 inches until it hits hard ice. As we wait for a reading, Magyar explains why it’s so important to measure carbon dioxide and methane on this major world river.
“There are a lot of scientists working now on developing better global climate models, but there's not a lot of data available for this part of the world,” Magyar said. “There's not a lot of studies that have been done up in Alaska, in the Yukon Delta, in the far north, generally.”
The data Magyar collects with the backpack and flux chamber help inform a clearer picture of how gases cycle into and out of the environment. But Magyar said that while these gas readings are important for developing global climate models, it’s not what directly helps the people in Alakanuk. What’s needed are measurements of erosion.
“When we come out in other seasons and measure the height of the banks, and collect soil samples, and look at the hydraulic properties and so forth, those parameters can go into models that help us to make better predictions for the community,” he said.
He points to the sky.
“Going across the river here, I can see the power line from Emmonak coming to Alakanuk, and the power poles are right on the banks that are rapidly eroding. And so these are the kinds of things that they will have to think about as time goes on,” he said.
Still whirring lightly, the machine sitting in the snow on the river ice returns a reading.
“All right,” Magyar said, looking at a screen. “It is showing… it's showing a lot of nothing, which is kind of expected. This may seem like an uninteresting result, because it seems like nothing is happening, but it's actually a really important result.”
Magyar said that’s because he knows there’s methane in the river water that flows below the ice. He went out the previous day, sampled through a hole, and found a lot of it.
“What that's telling me is that the methane is staying in the river and it's not coming out to the atmosphere,” Magyar said.
In the winter, a lot of organic material from thawing permafrost comes downriver from the Yukon Flats area. “But it is trapped in the river during the winter time, staying under the ice, heading out into the Bering Sea, which is also covered in ice. And then as it gets out into the ocean, it has a long time to interact with microorganisms and to be oxidized, to be eaten, basically, by the microbes and decomposed. And so it becomes less of a climate threat because it is trapped under the ice and can get out to the ocean,” Magyar said.
“Whereas, if the rivers are covered with ice less of the year, or if the Bering Sea is covered with ice less or less of the year, [...] that's going to have impacts for how much of this gas from thawing permafrost gets into the atmosphere,” Magyar explained.
Magyar said that he hopes predictive modeling fed by data from Alakanuk, Beaver, and Huslia can eventually help communities decide how to cope with local erosion and climate problems.
“As a community, this is a really pressing issue. Erosion is happening now. This bank is eroding at 20 feet per year. Out on the main Yukon, the big bend up towards Emmo[nak] is eroding at 40 feet per year,” Magyar said. “So these are very short-term issues that communities have to deal with. Sometimes it's frustrating to communities how slow the pace of our scientific work is.”
Magyar said that’s a tension that exists both within the project itself – between erosion monitoring and the longer-term look at carbon dioxide and methane in the environment – but also with the pace of science and what communities really need.
“I think it's important for us as scientists to remember that communities need answers now, not at some point in the distant future,” Magyar said. If scientists can continue to work with communities to explain what’s happening in their local environment, that’s just as valuable as the longer-term work, he said, even when it may take years to fully understand the why.
