Currents and Connections Post #3

Sockeye salmon spawning in a Wood River tributary. Credit: NOAA Fisheries/Wes Larson

Today, we're excited to welcome guest blogger, Elizabeth Djajalie, to Currents and Connections. Elizabeth graduated from Thunder Mountain High School in Juneau, Alaska last spring and is now attending Harvard University. As a high school senior, Elizabeth studied ways to detect, quantify, and conserve Pacific salmon species using a genetic technique called environmental DNA metabarcoding. Read on to learn more about Elizabeth's journey into science and the wonders of environmental DNA biotechnology.

Salmon Environmental DNA Science Project

The iridescent red and green shapes slipped under the bridge as four-year-old me tried to count every sockeye salmon fighting the creek current. Little did little me know that there was a much better way to count fish than Dr. Seuss's one fish, two fish, red fish, blue fish method.

Environmental DNA (eDNA)is DNA living things shed in their environment. Think about the hair your golden retriever leaves on the couch, the fish poop in your aquarium, or the pollen making you sneeze - that's all eDNA! Using a process called metabarcoding, we can use eDNA collected from an area to figure out what species are present and in what abundances. In Alaska, this process is being tested for counting salmon, fish species vital to the state's economy, ecology, and way of life. Existing methods for counting salmon are costly, time-consuming, and need expertise. In contrast, eDNA methods are cheaper, faster, and open to citizen scientists-meaning the general public can also help collect eDNA samples.

The first time I heard the words "environmental DNA" was on a phone call with the head of the NOAA Alaska Fisheries Science Center, Dr. Bob Foy. I had been searching for a way to get involved in environmental science research, and there was no better place to look than NOAA. Everything Dr. Foy said about eDNA fascinated me. The biotechnology's novelty had me hooked like a fish on a line. I learned that eDNA technology was only about two decades old, just slightly older than myself. It was cutting edge. eDNA was also a reservoir of potential with implications not only in species conservation but also disease monitoring, animal diet analysis, and countless other key fields. In the fall of my junior year of high school, Dr. Foy introduced me to Dr. Wes Larson, the manager of the NOAA Alaska Fisheries Science Center Genetics Department. I did not know it then, but Dr. Larson's mentorship would become a keystone of my high school education and development as a young scientist.

Creek or Crime Scene? Investigating Nature's Fingerprints with Environmental DNA

The science project Dr. Larson and I worked on studied eDNA's ability to identify and quantify six species of wild Pacific salmon. We focused the project on metabarcoding, a method of analyzing eDNA that allowed multiple species to be quantified at once. This method uses DNA animals leave behind in their environments to figure out what species are in an area.

Water samples were collected from eight creeks in the Wood River watershed of Southwest Alaska. Credit: NOAA Fisheries. Undergraduate students from the University of Washington collecting eDNA samples in Wood River tributaries. Credit: NOAA Fisheries/Wes Larson.

eDNA metabarcoding and subsequent DNA sequencing produced a read count for each species. These were compared to visual survey counts, a standard counting method that involves walking along a stream and eyeballing how many fish there are; visual counts were taken to be the true counts for the purposes of this study.

Undergraduate students from the University of Washington walking up the floodplain of Ice Creek in the Wood River drainage. Credit: NOAA Fisheries/Wes Larson. An undergraduate student from the University of Washington collects an eDNA sample in a Wood River tributary. Credit: NOAA Fisheries/Wes Larson.

Data analyses showed a positive, linear relationship between visual survey count and eDNA count for sockeye salmon and supported eDNA's potential to detect and, to some level, quantify species. eDNA detections of non-sockeye species generally corresponded to visual survey observations of species presence or absence. The results showed that eDNA abundances generally agreed with those of visual counts. The bottom line was this: eDNA shows huge potential to accurately quantify animal species and eventually be integrated into biodiversity management and conservation strategies.

Why does it matter? Imagine looking out your window and seeing only half of the species there today. The United Nations reports that as many as 50% of today's species may be extinct by 2050. Already, wildlife populations have declined by about 69% since 1970. Due to anthropogenic climate change, we live in a time some scientists call the sixth mass extinction.

eDNA has tremendous potential to help us conserve our planet's species and biodiversity. The research Dr. Larson and I conducted is a step toward unlocking this potential. By investigating eDNA's ability to quantify Pacific salmon, our research brings eDNA's cost- and time-saving methods closer to implementation. On a personal level, having lived in Alaska my whole life, I understand firsthand salmon's importance to our ecology, economy, and culture. Conserving salmon is preserving our Alaskan way of life.

Environmental DNA is sampled in 1-Liter bottles of water, just like the one I'm holding in this picture. Credit: NOAA Fisheries.

Next steps should optimize quantification using eDNA as well as detail real world conditions that could affect eDNA's efficacy. Further research is needed to apply eDNA to more species, regions, and fields. Researchers, students, citizen scientists, and the public all have a role in realizing these goals. Our collective efforts can sharpen this biotechnological tool to conserve the diversity of life we coexist with.

Science Takes You Places

Discoveries need to be shared to make an impact. What if Alexander Fleming had never told anyone about the mold on his petri dish that led to the discovery of penicillin? What if Newton had never shared his thoughts about the apple that fell from his tree?

In the spring of my junior year, I gave the first presentation of the salmon eDNA project at the Alaska Junior Science and Humanities Symposium in Fairbanks, Alaska. The state competition then funded my trip to compete at the National Junior Science and Humanities Symposium in Virginia Beach, Virginia. I will always remember the shock and surprise of winning first place at the national competition.

Left Image: My first place finish at the National Junior Science and Humanities Symposium. Right image: My fourth place category grand award at the 2023 Regeneron International Science and Engineering Fair. Credit: NOAA Fisheries.

That same spring, I also presented the salmon eDNA project at the Alaska Science and Engineering Fair, whose virtual participation option enables anyone anywhere in the state to enter. This competition sent me to Dallas, Texas in May for the Regeneron International Science and Engineering Fair (ISEF). With over 1,600 students from over 70 countries, this event is the annual Olympics of STEM. At ISEF, you are immersed in a sea of brilliance, fun, learning, and experience you will find nowhere else. ISEF opened my eyes to the tremendous innovation that young people were doing all over the globe. There, I met some of my best friends, people I can lean on for a lifetime. Even the moment walking onstage to accept a grand award paled in comparison to the lasting friendships I gained from ISEF.

Through ISEF, I was selected as one of two United States students to represent the U.S. at the 2024 Taiwan International Science Fair in Taipei, Taiwan. The memories of that incredible event are still fresh in my mind. It was a unique experience attending a science fair as one of the international students. I became great friends with my Taiwanese student guides as well as the students from Switzerland, Tunisia, Brazil, Turkey, Guam, and New Zealand. On the last day of the event, I had the honor of claiming for the U.S. the international Young Scientist Award, the top award at the event with over 600 students representing 27 countries.

Discover science projects and fairs for yourself here:

1. Alaska Junior Science and Humanities Symposium

2. Alaska Science and Engineering Fair

3. National STEM Challenge/Festival

Exploration Doesn't End

Almost a year-and-a-half after beginning the salmon eDNA project with Dr. Larson, I presented my project one last time at the first ever National STEM Festival hosted by the U.S. Department of Education and EXPLR in Washington, D.C. There, I met Kari Byron from Myth Busters and learned from the hundreds of other National STEM Champions. Given the tight-knit national and international science fair community, the event was a kind of reunion with friends from across the U.S. and U.S. territories. The culmination of about two years of research will be a paper I look forward to co-authoring with Dr. Larson.

My project poster at the National STEM Festival in Washington, D.C.. Credit: NOAA Fisheries.

This fall, I am continuing my scientific exploration at Harvard University. I have immense gratitude to everyone at NOAA Fisheries Alaska Fisheries Science Center who sent me on this incredible journey. Scientific research has not only opened my eyes to environmental DNA and conservation but also to the groundbreaking work young scientists are doing all over the globe.

Will you be the next young scientist from Alaska?

Previous: Currents and Connections Post #2