By Research Assistant Sarah Ludwig.
In early August, four days after returning to Woods Hole from our research expedition in Siberia, I was on another plane flying back to Alaska. At 2 AM I wandered around the Fairbanks airport looking for Christina, the undergraduate student researcher joining our team for the month. I found her curled up fast asleep under a bench. We checked into the University of Alaska apartment housing that would be our home base for the next week and a half while we embarked on the first field season of a NASA-funded project (one of the ABoVE [Arctic-Boreal Vulnerability Experiment] projects), measuring wintertime soil respiration across Alaska. Our collaborators in Dave Risk’s lab at St. Francis Xavier University (Canada) had built a system of sensors for measuring carbon dioxide fluxes from soil, along with some supporting variables such as soil temperature and moisture, continuously over the winter.
Automated soil respiration systems are not novel, but ones that function continuously and well over an Alaskan winter are. In general, Alaska is a difficult place to do field research; there just aren’t many roads or cheap, fast ways to access field sites. In winter it’s even harder to get around. Add to that extremely cold temperatures of -20 to -40 degrees Fahrenheit and only a couple hours of daylight, and most instrumentation just won’t work or remain powered. The systems that Dave designed and Christina built can run on low power, have hardly any moving parts, and automatically adjust sampling frequency as the daylight diminishes to maintain a continuous record. The parts for 12 of these stations were due to arrive in Alaska just before Christina and me. She and I were planning to assemble them over the next couple days, then John Schade and Sue Natali would join us and we would start installing them throughout the state.
Our first morning in Fairbanks we discovered that the “brains” of the stations had been held up in customs in Tennessee (don’t ask me why shipping from Canada to Alaska has to go through Tennessee). So we spent the first two days doing what prep work we could, which consisted of shopping for tools to put together the stations, supplies for the rest of our sampling work, every single AA lithium battery in Fairbanks (I literally bought $400 worth of batteries), food, and camping supplies for the team. Conveniently for us, all of these things were to be found at the same store in Fairbanks, the local Fred Meyer. I must have gone there 10 times that first week and got to know the checkout clerks, who stopped questioning the strange combination of things I was buying. When John and Sue joined, us the brains were still tied up in customs, but we went out in the field anyway, with the car batteries and solar panels and metal skeletons for the framework. We collected vegetation and took soil cores. We measured organic layer depths, thaw depths, and tree biomass.
Five of the stations partially set up in this manner were within a few hours of Fairbanks. Our efforts were assisted by a group of high school students from the Cape and their teacher who had come to learn about science in Alaska and document our work. We put them to work, a couple of them assisting each of us. They asked questions and recorded our work with video cameras. Finally, the brains of our stations arrived. The livingroom of our apartment was covered in data loggers and wires. We had stacks of crates containing forced-diffusion chambers. We built them as fast as we could, but we couldn’t change the fact that we were five days behind schedule. Sue was due in Anchorage to fly into the Yukon-Kuskokwim Delta the next day. I was flying home to Minnesota for a wedding. Christina was taking a few days to hike around Denali National Park. John was staying in Anchorage. The next morning we set up a station in Healy (just outside Denali), and then we all parted ways. Christina stayed around Fairbanks long enough to get another station running.
After a quick two-day trip home, I flew back to Alaska to meet Sue in the Yukon-Kuskokwim Delta and traded places with her. I spent the next three days camping in the subarctic tundra with another group of collaborators. Their work consisted of dragging across the tundra a box that contained a ground penetrating radar (GPR). Their plan was to correlate thaw depth measurements to GPR, and GPR to remote sensing data, and thus to scale up thaw depth for the entire region. Sue and I were the biologists on the team, characterizing vegetation and organic layers. It was fun to get strapped into the harness like an ox and pull the thing across the ground. We finished each day with enough time for me to assemble a couple more of our winter soil respiration stations.
After three days in the delta, I flew to Prudhoe Bay on the north coast of the state to meet the rest of the gang. While I was in the delta, John had picked up Sue and driven back through Healy to pick up Christina, and return to Fairbanks. From there they drove north (setting up stations as they went) to Toolik Lake field station. Two more stations went up in the tundra near Toolik, and they left again for Prudhoe Bay. Our field site at Prudhoe Bay turned out to be a patch of ground surrounded by cement right next to the town and oil fields. Not exactly undisturbed, representative tundra. Without going through the lengthy process of getting permission from the oil companies, we couldn’t explore around to find a more suitable location. John and Sue ended their field season and flew out of Alaska from Prudhoe Bay the next day. Christina and I turned the truck around and drove back to Toolik.
Back at Toolik, we downloaded the data from our stations to make sure they were working properly – a crucial step we had to go through at each station once the instrumentation was running for a couple days. Despite the nifty and streamlined design of our stations, there are still infinite ways things can go wrong and interrupt data collection. Of course, we ended up replacing some dataloggers with the parts we didn’t install in Prudhoe Bay. We spent a day drilling frozen soil cores from the historic long-term nutrient fertilization experiment that the Arctic Long Term Ecological Research station has been maintaining. On the road back to Fairbanks we downloaded data from more of our stations and discovered that some of our buried sensors were flooding with water. This was a larger problem than just losing CO2 data from those sensors, because instead of pumping gas, it was pumping dirty water into the gas probe and into the whole datalogger assembly. Fortunately, everything still worked after drying out.
We found similar problems in some of the other stations near Fairbanks, so over the next couple days, we hit the road and returned to all of our field sites (including driving back up to Toolik) to redo the plumbing inside our instruments and avoid water damage. About this time our station in Healy blew over. The solar panels are basically sails and Healy is a pretty windy place. So we did another circuit to set up guy lines on stations in windy places. At last, we believed all the stations were running properly and we could leave them alone for the winter. Christina had extended her trip in Alaska by a week just to see things through to the end. Walking away from these stations the last time felt like dropping a child off of at summer camp for the first time, if summer camp were cold and dark and in the middle of nowhere.
All told, during August I’d driven about 3,000 miles around Alaska. Those 3,000 miles were spread out between four different pick up trucks, my favorite of which was Big Bertha – a beet red Ford F350 with a diesel engine. We drove her up and down the Haul Road and got her to 99,880 miles before she broke down on us. Trucks just don’t last that long driving on such bad roads, and 100,000 miles would have been an exciting landmark. Too bad we hit some bad rocks and somehow tore the transfer case in half and ripped the driveline. I don’t know much about trucks, and those terms, explained by the tow-truck driver, were all new to me. All I knew was that the awful banging noises + streaming oil + smoke meant I should probably call for help on the satellite phone.
Field seasons in the Arctic are always chaotic with long hours and few, if any, days off. Logistics are always a nightmare, days are so long you forget to stop going, but the summer is so short you have to cram in all the sampling time you can get. This summer was no exception, and by the end of August I was getting tired. What I needed was some low-key, fun fieldwork to help transition back into normal life. Which is why it was great that I had about a week to work on a project for Alessandro Baccini, ground-truthing satellite measurements of tree biomass in Alaska. I recruited a couple of local Fairbanks guys and we hit the road in another pickup truck. We drove until we could find places where satellite images were only a couple miles from the road, then bushwhacked in to measure all the trees in a plot around that point. It was a great way to see a lot of different kinds of forest around the state. We camped out in the woods a few times to cut down on driving time. I brought my puppy with me. She dutifully followed us into the trees and often had an easier time navigating the dense forests than we did. My dog would circle the plot checking in on us every once in a while and chewing on the endless supply of sticks, then dig herself a little den and curl up until we finished our work. My field assistants were the type of guys who always carry a spare axe and cast iron frying pan in their backpacks, and prefer to sleep under a tarp in the pouring rain than bother with a tent. It was a blast. We had only a few hang-ups, where we would drive and hike all day to get out to a point, then discover that there actually weren’t any trees there. Or, that someone had homesteaded the area and the exact location of our imagery was now a cabin.
I left Alaska when temperatures were reaching below freezing and the trees were turning color. While I started working at the Woods Hole Research Center last June, I hadn’t actually moved there yet. So when my work ended in Alaska, I packed up my car and drove from Fairbanks to Massachusetts. I’m happy to be settled, and now I get to tackle the mountain of samples we collected over the summer. One of my first tasks is to organize the walk-in freezer (which currently is stacked from floor to ceiling with coolers of samples). Next time I’m back in the field will likely be to download the stations that have (hopefully) been measuring soil respiration all winter long.