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JEDIs on the YK Delta

Updated: Sep 15

The force is strong with the Polaris Project, whose "JEDI" mission for Justice, Equity, Diversity, and Inclusion in Arctic research lead me to Alaska's Yukon-Kuskokwim Delta this summer. I spent two weeks with this brilliant, enthusiastic research team of students and faculty from diverse backgrounds, populations that have historically been underrepresented in Arctic sciences, studying climate change processes and the tundra ecosystem. This was a total tundra emersion experience, stationed in tents in the middle of the aviation chart's "area of numerous small lakes," on a vast river delta formed by glacial, river, and coastal processes. As a Polaris mentor, I helped students create personalized projects driven by curiosity and grounded by observational scientific method. In two short weeks, students explored the tundra, made inquiries, created hypotheses, developed conceptual models, and collected and analyzed data. Student projects, ranging from spider diversity and abundance to land-water carbon exchange, were as unique as the individuals who devised them. Although we are still analyzing data, student projects will be ready to present this December at the American Geophysical Union (AGU) conference's poster session.

Fig. 1: Polaris camp situated on the YK-Delta on one of numerous small lakes dotting the region.

Fig. 2: Where in the world is this? My Gaia GPS app showing our location on the YK-Delta (left) and a map of Alaska indicating the region bounded by the Yukon and Kuskokwim Rivers known as the YK-Delta (right).

The Yukon-Kuskokwim Delta in southwestern Alaska was created over thousands of years by complex geological and environmental interactions, including glacial, riverine, and coastal processes. Thawing permafrost, that underlies this vast, dynamic landscape, alters storage and release rates of important climate warming greenhouse gases, including carbon dioxide and methane. Understanding shifts in rates of carbon cycling and the influence of climate change on tundra ecosystems helps scientists better predict the earth's atmospheric carbon budget and the implications this might have on ecosystems and humans across the globe.

Fig. 3: Departure from Bethel, AK by float plane.

The Drs Golden (Fig. 3, left), Dr Nigel Golden, JEDI master and expedition lead of the Polaris Project, and Dr Heidi Golden (me), helped shuttle students and gear from the University of Alaska's Bethel dorms, where we stayed overnight, to Papa Bear Adventures' float plane departure site. Weather delayed arrival of our float plane but spirits were high as Polaris students and I waited out rain and fog (Fig. 3, upper right). With a break in the weather, an old Army plane appeared out of the clouds and landed on the lake, where we loaded our gear and prepared shuttle flights in shifts of four to Polaris camp on the YK-Delta (Fig. 3, lower right).

Figure 4. Dr Sue Natali leading a tundra hike near Polaris camp (left), where Mandala Pham observed variation in mushroom species (right).

By necessity, most of the student research sites were walking distance from camp. On our first day at camp, project lead Dr Sue Natali (Fig. 4, left), pointed out observable differences between tundra burned by wild fire and unburned tundra. Incidence of fire on tundra has increased in recent years with climate change, altering ecosystem processes, including permafrost thaw, greenhouse gas storage and release (i.e., carbon dioxide and methane), and changes in plant community composition. During this hike, the distribution, abundance, and diversity of mushrooms on burned and unburned tundra sparked Polaris student, Mandala Pham's research project (Fig. 3, right).

Fig. 5: Examples of some different sampling methods used for collecting student project data.

Simple metrics, such as measuring distance, counting occurrence, recording diversity, and weighing biomass, often provide important observational indicators of differences in ecosystem function. For example, quadrat sampling using a square frame with a string grid allowed Aaron MacDonald to investigate plant composition around animal burrows (Fig. 5, left). Esme Torres Martinez used a transect tape measure to place water sampling wells from upland habitat down-slope to watery fens to measure soil water and chemistry along this gradient (Fig. 5, center). Counting cloudberry (Rubus chamaemorus) flowers allowed Max Grensted to investigate differences in reproductive timing between burned and unburned tundra sites (Fig 5., right).

Fig. 6: Dr Logan Berner and Dr Seeta Sistla find evidence of beaver near camp (left) which further inspired Loreto Paulino to research beaver influences with mentor Gabriel Duran (right).

Some other projects included JK Goongoon and Ambra Jacobson's joint project comparing carbon fluxes on tundra plateaus in burned and unburned sites; Jordan McDavid's drop-trap project examining terrestrial invertebrate diversity and abundance among tundra habitats, and Loreto Paulino's investigation of beaver-influenced aquatic habitats (Fig. 6).

Fig. 7: MaryBridget and I sampling fish (left and right) and setting methane bubble traps (center) in unburned tundra lakes near camp. One species found in these lakes (right) was Alaskan blackfish (Dallia pectoralis).

Bubble traps deployed in lakes (Fig. 7, center) helped MaryBridget Horvath quantify rates of carbon dioxide and methane exchange between aquatic and atmospheric systems. Methane bubbling (aka ebullition) recalled a conversation I had with a colleague at Toolik Field Station regarding observations of Alaska blackfish (Dallia pectoralis) in lakes with high ebullition rates, so MaryBridget included fish sampling via minnow traps in her experimental design, as well (Fig. 7, left and right).

Fig. 8: Sampling the YK-Delta's colorful lakes. A color palette of soil horizons from a sediment core sample displayed on a secchi disk (left). MaryBridget and Annemarie sampling lake water chemistry (center). A lake sediment core from a "brown" lake (right).

The colorful mosaic of YK-Delta lakes as seen in satellite imagery inspired Annemarie Timling's ambitious project to correlate lake color with quantifiable physical and biological data. Sampling these lakes required advanced planning, flexibility, and lots of luck because it depended on the limited availability of an R44 helicopter and, simultaneously, good weather for flying (Fig. 8). We developed a SWAT team-like style of dropping down fully loaded with sampling equipment, each with a job to do and ready to jump to the aid of the other as needed to efficiently sample each lake.

Fig. 9: Invertebrates captured using an aquarium dipnet along the shores of one of the YK-Delta's colorful green lakes. Tadpole shrimp, likely from the Lepidurus genus (left) and so many snails (right).

Limited time on the ground meant limited time and ability to capture biotic information from the YK-Delta's colorful lakes. We resorted to quick swipes of the shoreline using an aquarium dipnet to investigate species presence. Some interesting finds included tadpole shrimp (Fig. 9, left), millions of tiny snails (Fig. 9, right), wee larval pond smelt fish (not shown) and a few little ninespine stickleback fish (not shown). We also collected environmental DNA (eDNA), genetic material suspended in water that can be used to determine species presence. These samples were sent to a laboratory for analysis. I'm looking forward to receiving the data!

Fig. 10: Almost everyone from the 2023 Polaris team. Back row from left to right: Nigel Golden, Logan Berner, Christina Minions, Aaron MacDonald, Tiffany Windholz, Adam Pissaris, Annemarie Timling, Mandala Pham, Savannah (pilot), Jacqie Hung, MaryBridget Horvath, Ambra Jacobson, Mitch Korolev, Max Grensted, Lauren Chastang, (name not known). Front row from left to right: Loreto Paulino, Heidi Golden, Cameron Gaspard, Aqua Sanders, Gavin Stewart, JK Goongoon, Jordan McDavid, Gabriel Duran, and Esme Torres Martinez. Missing from this photo are Sue Natali, Seeta Sistla, and Arnell Garrett. Working in the confines of a remote field setting can be challenging under the best conditions, but this group of passionate, creative individuals showed respect and empathy for each other, helped each other troubleshoot problems, and assisted each other with field sampling, lab procedures, and data entry, as well. The Polaris Project exemplified collaborative, team research at it's best and provided testament to the synergy that arises when diversity joins force for common humanitarian good. The data collected this year will help forward our understanding of climate change on global ecosystems. But, equally important, I know these young researchers will pay forward their experience on the YK-Delta by continuing to break down society's divisive barriers.

Go forth young JEDIs!

And, may the forces of justice, equity, diversity, and inclusion be with you.

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