Winter winds may blow and the snow may fall, but work at NEON’s northern field sites continues through the winter months.
While terrestrial organismal sampling and soil sampling are put on hold during winter due to decreased activity, Battelle field ecologists working on the NEON project continue with aquatic sampling even when lakes and waterways are frozen. There is also biweekly maintenance work to do on the flux towers to keep sensors clear of frost or snow build up and make sure there is no damage to the equipment.
Working in the frozen north does present challenges for the field teams. At sites in Alaska, Colorado and North Dakota, aquatic sampling in the winter often requires first drilling through several inches (or feet) of ice. Field ecologists also must take steps to keep water from freezing in collection equipment or sampling bottles before it is sent off to the lab. The crews work quickly to collect liquid water samples from under the ice before the tubes freeze up and then store samples in heavy-duty coolers—used in this case to keep the samples warm rather than cool. Teams continue with observational sampling and tower maintenance as long as weather conditions are not unsafe.
Water chemistry analysis is conducted on water collected at aquatic sites year-round, including dissolved gases, stable isotopes, microbes, nutrients and major cations and anions. Andrea Anteau, the Domain Manager for D09 Northern Plains explains, “There is still a lot of biological activity happening under the ice in winter. Conducting chemical analysis through the winter months helps us understand the dynamics of this activity and how it changes with the seasons.”
In North Dakota, field ecologists maintain three terrestrial field sites (Dakota Coteau Field School - DCFS, Northern Great Plains Research Laboratory - NOGP, Woodworth - WOOD). They also collect aquatic samples from two lake sites, Prairie Lake at Dakota Coteau Field School (PRLA) and Prairie Pothole (PRPO). Before the first freeze, they must pull out buoys from the lake sites that are outfitted with a meteorological station and aquatic sensors to measure surface water quality, temperature, radiation, nitrogen, dissolved organic matter and other metrics. Water samples are taken from both lakes once per month. In the depths of winter, researchers may have to use an auger to drill through three or four feet of ice before they hit liquid water. Conducting tower maintenance may require trekking a mile or more on snowshoes. Temperatures at the North Dakota sites can reach -40°F or below during January and February.
In Colorado, the NEON project maintains three aquatic sites and four terrestrial field sites. Here, researchers contend not just with snow and cold but also with elevation. The Niwot Ridge terrestrial flux tower is located at 11,000 feet. Como Creek is a close second at 10,000 feet and West St. Louis Creek is located at 9,000 feet. Reaching these sites in winter often requires the use of a UTV with snow tracks to get up the mountain roads and then may have to trek an additional 2.5 miles on snowshoes with backpacks full of equipment to reach the aquatic sites for maintenance—sometimes encountering curious cross-country skiers on their way. Once they get there, they may have to clear several feet of snow before chipping away at the ice underneath.
Sites in Wisconsin, Massachusetts, Alaska and other northern climes share these challenges. In Alaska, snowmobiles are used to reach remote field sites in the winter. But no matter the weather, field ecologists are committed to keeping NEON data collection on track throughout the year. Chau Tran, a Colorado-based Assistant Domain Manager, says, “We are able to see how these ecosystems respond to seasonal changes and how different our measurements can be across the year. That’s why it’s important to maintain this work all year round.”