We returned to Utqiagvik, the northernmost town in the U.S., for fieldwork for our project “clarifying linkages between canopy SIF and physiological function for high latitude vegetation.” We want to learn how to use the information from the light emitted by tundra plants as solar induced fluorescence (SIF) to describe the functioning of the tundra ecosystem. In the process of photosynthesis, plants not only absorb light, but they also emit light called chlorophyll fluorescence. The fluoresced light provides information about the rate of photosynthesis and about plants responses to stress. Although not much light is emitted by fluorescence, we can detect it with sensitive instruments, and even from space with instruments on satellites. We are making measurements on the ground so that we can understand how the diverse tundra vegetation is responding to environmental conditions, and how to make the best use of satellite images of this region.
This project is part of the NASA Terrestrial Ecology program’s Arctic-Boreal Vulnerability Experiment (ABoVE), a large-scale field study in Alaska and western Canada, whose overall goals are to make use of NASA technology to gain a better understanding of ecosystems at high latitudes, their responses to environmental change, and the effects of those changes.
Our field team …
In June, which is early spring for the tundra, we set up automated instruments at two existing tundra sites. Our instruments include the FLoX (Fluorescence Box), which measures the reflected light and solar induced chlorophyll fluorescence of patches of the tundra, and the monitoring PAM (MoniPAM), whose probes illuminate small patches of leaves or moss with controlled pulses of light to measure fluorescence and photosynthetic processes at the leaf level. These instruments automatically measured the fluorescence throughout the day to observe effects of varying light levels and temperatures and through the course of the growing season as the tundra plants grow. The FLoX gives us measurements of patches of ground that are like the data we can get from satellites, although measuring a very much smaller area than the satellite sees.
We returned in August to measure the tundra during its peak of summer growth.
It is a bit of a stroll out to our sites. The path has boardwalks and plastic matting laid down to protect the tundra from serious erosion from people’s feet.
Along the way there were flowers, birds, and animals to see. There were a lot of lemmings this year. When we startled these small gerbil-like animals, they would quickly run along their trails through the tundra and disappear into holes in the ground. The lemmings need to be quick because we also saw several snowy owls and a couple of arctic foxes. The owls and foxes eat the lemmings, and these predators’ populations were high because of the number of lemmings. There were also Lapland longspurs and snow buntings, sparrow sized birds that breed in the Arctic, popping around our sites.
We visited our automated sensors at the Department of Energy Next Generation Ecosystem Experiment (NGEE) Arctic flux tower site.
This image shows the three main instruments on the NGEE flux tower. On the left is an infrared gas analyzer, which measures the concentration of CO2 and water vapor in the air. On the right is an instrument to measure the methane concentration. In the center is a sonic anemometer. The sonic anemometer very accurately and rapidly measures the upward and downward wind speed. The vertical wind speed information combined with the measurements of CO2, water vapor, and methane concentrations from the other sensors can be used to calculate their transport into and out of the ecosystem. For example, CO2 taken up by the ecosystem is a measure of the rate of photosynthesis.
We visited our sites to check on our automated sensors to make sure they are running and collecting and storing data.
While at the sites, we also make additional measurements to add to the data from the automated sensors.
Our second site was at the National Science Foundation’s National Ecological Observatory Network (NEON) flux tower.
We also measured a number of plots with different types of vegetation cover within this area of high-centered polygon tundra near the lab building.
When the weather turned bad (rainy and in the 30s Fahrenheit) we worked in the lab measuring photosynthesis, fluorescence spectra, and chlorophyll content for plant samples from our study plots.
As a side project we located the transect I worked on 20 years ago and remeasured it. Even after all of these years I was surprised that I didn’t have any problem finding the start of the transect, and there was still a wooden stake there. But we couldn’t locate a marker for the far end, so we had to use GPS to locate it. It pleased me to see that the path we had worn by walking on the tundra 20 years ago had healed and I couldn’t see any sign of it now.
Another day we visited the International Tundra Experiment (ITEX) site. The site was established back in the 1990s for the long-term monitoring of plant growth.
Regular measurements of reflectance, soil moisture, water table height, and the depth of permafrost thaw (using the high-tech method of pushing a rod into the ground until it hits the frozen layer) are made throughout the growing season.
At the end of our field campaign, we removed all of our equipment from the field.
We live and work outside of Utqiagvik on the grounds of the former Naval Arctic Research Lab (NARL). NARL was founded 75 years ago, during the height of the Cold War. NARL was part of a tradition of research in Utqiagvik. The facility is now managed by the Ukpeaġvik Iñupiat Corporation (UIC), the native-owned corporation that manages the Barrow Arctic Research Center (BASC). Some of the buildings left behind by NARL are now used by BASC and Ilisagvik College, the only tribally controlled college in Alaska and the northernmost accredited community college in the U.S.
There are no roads to Utqiagvik. Almost everything has to come in by air.
Heavy or bulky stuff that is not shipped by air freight comes up once a year on a barge.
The annual barge arrived while we were up there. There’s no dock to unload on (the sea ice would probably destroy one) so they use a landing craft to bring the stuff ashore.
The most exciting animal sighting was on my last day when we saw several Beluga whales swimming near shore near the place where they had been bringing the cargo from the barge ashore.
In a lot of ways Utqiagvik is like any other town.
There’s a modern supermarket, the Stuaqpak (which means “big store” in Iñupiaq), a hardware store, pizza places, Chinese restaurant, and gas station. But then there are twists. All the streets are gravel, except for the one street that runs in front of the airport. The auto parts store also sells whaling equipment. Gas comes up on the barge once a year, so the price of gas stays the same until they start tapping the new shipment. When the restaurant is open, you can look out on the Arctic Ocean while you have a slice at Arctic Pizza.
Also in town is the Iñupiat Heritage Center, which has exhibits on the people and their culture.
In front of the building is a bowhead whale skull about the size of a VW Beetle. There is a picture of a field sewing kit and sinew used for thread (upper-right). One thing I learned at the center is the critical importance of sewing for survival in the Arctic. The quality and maintenance of clothes is a matter of life and death in this harsh climate (middle-left picture). The ability to sew is also important for making the coverings for skin boats, which are used to hunt whales and other sea life. The middle right picture is a sled made out of the baleen from the whales. In the lobby is a life-sized model of a young bowhead whale (lower pictures). You can get a sense of its size compared to Brenda.
July 14th, 2022 by Fred Huemmrich and Petya Campbell / University of Maryland Baltimore County
We learned in school that plants take in CO2 and water and use light to drive photosynthesis to grow. But what you may not know is that as part of the process of photosynthesis plants also emit light, called chlorophyll fluorescence. The fluoresced light provides information about the rate of photosynthesis and plant responses to stress. Although the fluoresced light is very dim, we can use sensitive instruments to measure that fluorescence, and this can be done even with satellite instruments in space.
Arctic tundra is the coldest ecological community. It circles the high latitudes of the northern hemisphere which is experiencing strong climate changes that affects the growth of tundra plants. Much of the tundra regions are remote and very hard to reach, so it is difficult for us to know just how tundra is responding to climate change. Satellites flying overhead can provide information about the tundra across the entire region, even in all of those difficult to reach places. In our project, “clarifying linkages between canopy SIF and physiological function for high latitude vegetation,” we want to learn how to use the fluorescence signal to describe the functioning of the tundra ecosystem so that we can understand how the diverse tundra vegetation is responding to climate change and make the best use of satellite images of this region. Our project is part of the NASA Terrestrial Ecology program’s Arctic-Boreal Vulnerability Experiment (ABoVE), a large-scale field study in Alaska and western Canada, whose overall goals are to make use of NASA technology to gain a better understanding of ecosystems at high latitudes, their responses to environmental change, and the effects of those changes.
This took our team—from the University of Maryland Baltimore County, NASA’s Goddard Space Flight Center, and the University of Texas El Paso—north to Utqiaġvik (formerly Barrow) Alaska on the shores of the Arctic Ocean. Utqiaġvik, the northernmost city in the United States, is on the lands of the Iñupiat people. There are no roads to Utqiaġvik, so all of our equipment had to be shipped by air up there.
The goal of our June campaign was to install automated sensors to capture the springtime green-up of the tundra. Even though it is June and after the official first day of summer, spring is just starting in Utqiaġvik. There is ice in the ocean (Figure 1), the snow is just melting off the land, and the tundra is brown. Our instruments include the FLoX (Fluorescence Box) that measures the reflected light and solar induced chlorophyll fluorescence of patches of the tundra (Figures 2, 3 and 4) and the monitoring PAM (MoniPAM) whose probes illuminate small patches of leaves or moss with controlled pulses of light to measure fluorescence and photosynthetic processes at the leaf level (Figure 5). These instruments automatically measure the fluorescence throughout the day to observe the effects of varying light levels and temperatures and through the course of the growing season as the tundra plants grow. The FLoX gives us measurements that are similar to the kinds of data we can get from satellite. Making these measurements on the ground lets us know exactly what we are looking at, which helps better understand what the data mean.
Our instruments are deployed at existing flux tower sites. Flux towers measure water, heat, and carbon dioxide exchange between the ground and the atmosphere as well as provide weather data. The flux towers were about a mile from the nearest road, so all of our equipment had to be backpacked into the sites (Figures 6 and 7). It is a soggy hike in because this time of year the tundra is very wet, since the snow has just melted and the soil is still frozen keeping the water from seeping into the ground (Figure 8).
The trip wasn’t all work, Petya Campbell and students were able to attend a Nalukataq, the Iñupiat whaling festival, and see the traditional blanket toss that throws the blanket dancer high into the air (Figure 9).
We will return in August at the time of peak growth of the tundra to collect further measurements of fluorescence and productivity to add to the seasonal descriptions of fluorescence from these automated sensors.
October 5th, 2021 by Logan Berner and Patrick Burns (Northern Arizona University), and Roman Dial (Alaska Pacific University)
Following caribou and brown bear trails when possible, a small NASA-supported research team trekked 800 miles across Alaska’s Brooks Range last summer. With additional support from NSF, the Alaska Space Grant Program, and the Explorers Club/Discover, the research team is collecting extensive ecological field data that will be linked with satellite observations to better understand long-term changes in vegetation, including impacts of climate warming. The Arctic is warming nearly twice as rapidly as the rest of the planet and the impacts are becoming increasingly evident as glaciers melt, permafrost thaws, and tundra greens.
Arctic greening and browning
Earth-observing satellites have detected widespread increases in tundra greenness in the Arctic over the last four decades. The phenomena is caused, in part, by increases in vegetation growth as summers have become warmer and longer, and has been termed “Arctic greening.” On the other hand, satellite observations have also detected localized declines in tundra greenness attributed to surface flooding, extreme weather, and other disturbances. This has been termed “Arctic browning.” Satellite observations of greening and browning show that extensive changes are occurring in the Arctic, but much remains unclear about why specific regions have greened or browned in recent decades.
To better understand recent greening and browning in northern Alaska, Professor Roman Dial’s team from Alaska Pacific University (APU) has been collecting extensive ecological observations while trekking throughout Alaska’s Brooks Range. For nearly forty years, Dial has studied and traversed the Alaskan wilderness, including nearly 2,000 miles by foot and packraft throughout the Brooks Range during the last three field seasons. For 11 days last summer, Dial’s team was joined by Dr. Logan Berner and Patrick Burns who are research ecologists from Northern Arizona University (NAU) and members of NASA’s Arctic-Boreal Vulnerability Experiment (ABoVE). While Dial is an expert in field ecology and wilderness travel, Berner and Burns are experts in satellite remote sensing and ecological informatics. By combining their expertise, these researchers hope to shed light on the extent, nature, and causes of vegetation changes during recent decades in the Brooks Range.
Trekking through the Brooks Range
The Brooks Range forms a natural barrier that separates the boreal forest of Alaska’s interior from the arctic tundra of Alaska’s North Slope. This mountain range includes the largest complex of protected wilderness in the United States, including 21,000,000 acres among the Arctic National Wildlife Refuge, Noatak National Preserve, and Gates of the Arctic National Park. Berner and Burns joined Dial’s research team as they trekked from the northern edge of boreal forest into the Noatak Wilderness where trees give way to thickets of shrubs, wetlands, and barren rocky ridges. During the course of 11 rain-soaked days, the team followed caribou and brown bear trails through verdant valley bottoms and over cloud-choked mountain passes as they traversed about 80 miles from the Ambler River to the Cutler River. While trekking, the researchers collected ecological field data to be linked with measurements of vegetation greenness from NASA Earth-observing satellites.
Ecological research often involves establishing field plots and then meticulously characterizing the composition and other attributes of the plant community in each field plot. Plot sampling provides valuable information, but the time consuming nature of the approach limits the spatial extent over which measurements can be made. Dial recognized that to better understand recent greening and browning, there is a need for more spatially extensive information on plant community composition than can be provided by field plots alone. He thus has pioneered an alternative approach that involves continuously documenting plant community composition and other attributes while trekking across the landscape. Termed “pixel-walking”, this approach harnesses the multifunctionality of smartphones to record and geolocate visual observations of vegetation composition and density for the overstory, midstory, and understory. While pixel-walking, researchers record a new observation every time they visually detect a change in vegetation composition or density at about a 30 meter spatial scale, corresponding to one pixel from the Landsat satellites. These spatially extensive field observations are thus collected with the explicit goal of being linked to decades of Landsat satellite observations.
During summer 2021, Dial’s research team pixel-walked over 800 miles from east to west through the Brooks Range, collecting data on vegetation composition for about 100,000 Landsat pixels. Over the coming year, Dial’s team will work with Berner, Burns, and Professor Scott Goetz (ABoVE Science Team Lead) at NAU to link these extensive field data with several decades of Landsat satellite observations provided by NASA. This collaboration will help unravel the mysteries of Arctic greening and browning by shedding light on where, how, and why plant communities changed in recent decades. NASA’s Earth-observing satellites provide long-term observations that are crucial for monitoring and understanding ongoing environmental changes in the rapidly-warming Arctic, especially when complemented by field data collected across large regions.
If only I could collect my thoughts about how I feel here in the tiny village of Batamay, idyllically located at the confluence of the Lena and Aldan rivers, after four weeks of campaigning in the burned larch forests of Northeast Siberia. But this process started much earlier. In December of last year we started analyzing satellite images to find suitable burn scars for carbon combustion sampling. Many people told me the idea of collecting data in Northeast Siberia is nice, theoretically, but logistically not feasible. These logistic challenges are likely part of the reason why so little data has been collected here. Yet, a data shortage in the large swaths of larch forests in Northeast Siberia is also a prime reason why we wanted to come here.
Are the logistical challenges in Siberia greater than in for example Alaska and Canada? From my experience, yes. This is mostly a matter of the difficult to travel ‘last mile’. It was surprisingly easy to reach the tiny villages of Ert and Batamay (of approximately 500 and 200 people), the small villages near our burn scars of interest. Reaching Batamay even included a scenic boat ride across the Lena river. From the villages it was about 5 km to the burn scar and 10 to 20 km to our camping sites. And this is where the adventure began. Did we get stuck in the mud? Yes, multiple times, but we made it out every time. Was it difficult to reach our sites? Yes, if often required scrambling over boggy grassland and woody debris, and through dense bush, but we always made it, and more importantly, we made it safely back to the camp. Were the stretches of camping and sampling physically challenging? Yes, we definitely felt weathered and sometimes charred, but rain or shine, we kept true to our goal of sampling more plots. And I feel proud about what we accomplished as a team! In total we measured 42 burned plots and 12 unburned plots. These plots cover gradients of forest types (larch and pine forests), fire severity and landscape position. In the fires, we collected data that will estimate carbon emissions. We also assessed how larch forests recover after fire and how the active layer, the seasonally thawed top layer of soils in permafrost regions, thickens after fire (at least before our active layer probe broke half way the campaign).
We are eager to analyze samples in the lab, and later interpret the data in our offices. We are hopeful the data we collected will improve our understanding of the role of fire in the Northeastern Siberian larch forests. We will graph our results, and write a manuscript. People will read our work, and may cite it and use our data. But we will be the only ones that know how this campaign really evolved; how we crossed rivers, woody debris and endless bush to get to these locations; how we shared our simple lunches of bread, salami, cheese, cucumber and tomatoes at some burned spot; how we were happy to finally take a serious wash in the banja, Russian sauna, when we came back in the village after days of camping. I am extremely thankful to my team for what we have accomplished. We realize that it is privilege to visit these remote places, yet this does not make the long days, difficult hikes and sometimes monotonous tasks any easier. We came from the Netherlands, USA and Russia to do this together. A big thanks to Clement, Rebecca, Dave, Tatiana, Brendan, Roman and Brian. I am also very grateful to our local collaborator Dr. Trofim Maximov from the Institute of Biological Problems of the Cryolithozone of the Siberian Branch of the Russian Academy of Sciences. Without Trofim and his team, none of this would have been possible. I was also touched by the welcoming and warm-hearted locals from our host villages. They were very curious to our endeavors, and even though language barriers inhibited our conversations, they also helped making our campaign a success.
We sampled burn scars from 2017 and 2018. This year’s fire season in Siberia is extremely vigorous. Many days we experienced smoky skies partly veiling sunlight; a direct consequence of fires burning nearby. This year’s events also demonstrate the urgency of why we need to better understand the interaction between climate change and fires in Siberia. As our field campaign developed this year, we started talking more and more about next year’s campaign. We are intrigued by the current fires within the Arctic Circle in Northeast Siberia. We want to understand their climatic drivers and consequences. We will be back next year for Fire Expedition Siberia 2020.
This field campaign is part of the ‘Fires pushing trees North’ project funded by the Netherlands Organisation for Scientific Research (NWO) and affiliated with NASA ABoVE. This blog post was written by Sander Veraverbeke, assistant professor in remote sensing at Vrije Universiteit Amsterdam, and project lead of ‘Fires pushing trees North.’
DBH (diameter at breast height)… 3.7 cm, killed by fire, severity 2, … adventitious roots at 7 cm (adventitious roots are small additional roots that larch trees have that help determine the depth of burning in the organic soil layer). Those are the words that would repeatedly disturb the forests’ eternal silence, besides the occasional call of a black woodpecker. This routine is part of making an inventory of the many trees (varying from roughly 50 to more than 300) that cover the 30 meter by 2 meter transect that is laid out in the field plot of interest. Such a transect is selected based on homogeneity in fire effects and assumed to represent a larger area of 30 by 30 meters, the size of a Landsat satellite pixel. This enables the direct comparison of ground s and satellite observations, which is in turn essential for upscaling to regional or continental scale estimates of available biomass and combustion.
Our science team is in Batamay now, a small village about 170 km North of the capital of Yakutia and the coldest city on Earth, Yakutsk. Compared to our previous location, Ert, this is farther away from the main cluster of large fires that plague Siberia right now. However, fires are also active here, as I witnessed during my flight from Amsterdam to Yakutsk.
In order to get to Batamay, we had to drive for multiple hours and cross the Lena river by boat. The boat trip was not exactly like the luxury Lena river cruise that can be booked to visit the well-known ‘Lena pillars’, but it brought us to our study destination. After reaching Batamay, we continued our travels using one of these typical sturdy Russian vans to the designated camp site for a week of camping inside the burn scar that we wanted to measure. This burn scar is the result of a particularly high severity fire from 2017. The current science indicates that fires in Siberia are mostly low severity surface fires compared to the high severity crown fires in boreal North America. The high severity core of the Batamay burn scar may be out of the ordinary and attracted our interest. Could Siberian fires locally be more severe than thought and do we underestimate their emissions? Furthermore, what does this potential of high severity fire in Siberia mean for the future fire regime in a changing climate?
On the way from Yakutsk to the burn scar we have had some fine demonstrations of the Yakutian approach to problem solving. Little time is spent on overthinking possible issues beforehand, and instead problems are solved on the spot. Surprisingly, this method has been successful in every occasion we experienced an obstacle. For example, when a stretch of water is too shallow for a boat to float or a road too muddy for a car to cross, the consequences are faced instead of avoided, but always solved afterwards. This radiates a certain simplicity and relaxed approach to life that is almost fully opposed to the scientific approach and might be hard to relate to as westerners. What do the locals actually think of our complicated scientific instruments and methodologies? Sadly this is hard to say, because of the locals’ Yakutian language which is closer to Turkish than Russian (as if Russian wasn’t hard enough already) and introduces multiple new letters to the Cyrillic alphabet. And also because the locals are not men of many words anyway. However, like everyone else, these people also notice the effects of climate change, such as warmer winters and more heavy rain spells, such as the recent floods near Irkutsk
At the camp site, we were accompanied by five locals from Batamay: a guard, a driver, two cooks, and a guard dog. It was comforting to have this company and it is safe to say that this made all of us sleep better at night. In a matter of minutes a patch of tall grass was transformed into a cosy camp site including a fire place, picnic table and food warehouse, all made from the branches and logs available in the forest, and some old containers used previously by road constructors. Another great example of what you can construct from logs: a trailer able to withstand all bumps we faced on the road.
During our camping stay in the Batamay burn scar we have collected data from 24 field plots with varying degrees of fire severity. The coming week we will stay in a house in village and we will venture out in the fire scar again. Now we will focus more on unburned ‘control’ plots. This allows the comparison of the situation before and after the fire, which gives invaluable insight in quantifying the greenhouse gas emissions from the fire.
This field campaign is part of the ‘Fires pushing trees North’ project funded by the Netherlands Organisation for Scientific Research (NWO) and affiliated with NASA ABoVE. This blog post was written by Dave van Wees, PhD student at Vrije Universiteit Amsterdam, studying global fire emissions using satellite data and biogeochemical modeling.