The Nematodes
They may be tiny and too small for our naked eyes to see, but microscopic worms live all around us. The threadlike worms are called nematodes.
From the tallest mountains to deserts and the deepest oceans, nematodes are present in our soil and water body sediment.
They live at all levels of the food chain and feed off bacteria and fungi, helping them decompose organic matter that keeps soils healthy and resilient to change. They can also live as parasites of both animals and plants.
Nematodes are invertebrates with about 1,000 cells in their entire body. Scientists believe as many as 500,000 to 100 million different nematode species live on Earth.
“They are the most abundant multicellular animals on the planet. They play all kinds of roles in food webs and interactions with other organisms. I don’t know what a world without nematodes would look like. They are a vital component in just about any habitat."
- Dr. Thomas O. Powers (known as TOP), Professor in the Department of Plant Pathology at the University of Nebraska-Lincoln (UNL).
Nematodes are bioindicators of our surrounding environments. Since they are so abundant and diverse, nematologists study how the tiny worms evolve and adapt to survive in ecosystems that change over time.
“Nematodes have short life cycles. So, they can detect if something is going on in an environment,” explained Dr. Dorota Porazinska, Associate Professor in the Entomology and Nematology Department at the University of Florida (UF).
“They can respond in abundance, or their diversity can decrease to be indicative of some disturbance such as pollution. We can look at these changes in a community to have a good understanding of what’s going on in the system.”
The Pursuit and Place
TOP, Porazinska, colleagues, students, and stakeholders have come together to find out more about a collection of nematodes that have adapted to a wide range of habitats, including the Nebraska Sandhills.
The team has received three years of funding (2024-2027) from the National Science Foundation’s Poorly Sampled and Unknown Taxa (NSF PurSUiT) program (AWD# 2327478).
The funding supports scientists’ discovery of biodiversity and description of poorly known species around the world. Currently, it’s estimated that scientists have described less than 30,000 nematode species on the planet.
The team initially focused on Tobrilidae (pronounced Toh-BRILL-ih-dee), a family of aquatic nematodes.
Specifically, the scientists are tracking and studying aquatic worms confined to aquatic sediments, some existing in lakes with extreme chemistries. They may feed on bacteria, algae, or microinvertebrates. The Tobrilidae are believed to have evolutionary roots at the base of the nematode tree, providing insight into the evolution of all nematodes.
These species feed on a variety of foods sources, including bacteria, algae, fungi, and small invertebrates and hence are considered omnivores and predators. They are key to understanding the evolution of all nematodes.
From their previous surveys, the scientists found these nematodes can live in extreme environments, including highly alkaline lakes in the western Nebraska Sandhills.
The Sandhills ecosystem features sand dunes and includes one of the largest continuous grasslands remaining on Earth (Sholtz & Twidwell, 2021). Grasslands provide vital ecosystem services such as carbon sequestration and wildlife habitat.
The Sandhills also have Alkaline Lakes that sit on top of the Ogallala Aquifer, which is one of the world’s largest underground freshwater resources. Groundwater from rain and snow melt seeps through the soil, feeds the lakes, and the aquifer absorbs the water like a sponge.
The lakes are alkaline because they are driven by high concentrations of sodium, potassium, and chloride. These unique lakes have a pH ranging from 7 to 10 or greater.
“Is there such a thing as a healthy alkaline lake system? We don’t know, and we might provide some insight into that,” said TOP.
“Our questions are driven by curiosity. We need to know the science behind the physiology of how these nematodes deal with the unique water chemistry.”
The lakes have also recently been under the stress of drought, which can cause pH levels to rise even higher. Of the invertebrate community, the team has discovered nematodes that appear to thrive in conditions that are lethal to other organisms.
The Process
The team is collecting and analyzing aquatic nematodes throughout water systems in Nebraska to determine their appearance, genetics, and connection to their surrounding environments (ecology). Together, these different pieces of information could provide insights about nematode roles in these lakes.
Collecting nematodes requires travel, fieldwork, and common tools.
Team members pull on their stylish waders to protect their skin, clothing, and equipment from the alkaline water and cold. Then, they either walk through shallow water or kayak into deeper water to collect up to four samples at each lake.
They take sediment samples from the lake bottom using a dredge the size of a toaster, pour the muck into buckets, and then into plastic bags.
TOP calls the bags of sludge “DNA gold.” The labeled samples then go back to TOP’s lab at UNL and Porazinska’s lab at UF to study with their graduate students.
TOP’s lab focuses on recording the nematodes’ characteristics such as size and shape. He then places them into groups based on their appearance.
Under a microscope lit from the bottom, scientists can see the nematode’s organs and other features. Porazinska’s lab extracts DNA to examine their genetics and ecology. She uses metabarcoding, a molecular technique, to identify a species’ unique DNA sequences.
Ultimately, the scientists combine the appearance (morphology) results with the DNA sequence (ecology) results to get a big picture of the Tobrillidae family and how the nematodes relate to alkaline environments.
Results of the research could provide an updated family tree of nematodes and a richer understanding of how the changes in the Sandhills ecosystem are changing the microscopic worms. Scientists predict (hypothesize) the Tobrillidae in the Alkaline Lakes are a complex of what is called a cryptic species – organisms that visually look alike, but are genetically different due to evolutionary pressure to adapt to different environmental conditions.
The Partnerships
It takes time and teamwork to research microscopic worms. Scientists, graduate students, ranchers, and science communicators have come together to discover and document the nematodes.
The core research team initially started collaborating around eight years ago through two inter-campus seed grants from the University of Nebraska. They call their efforts the Sandhills Alkaline Lakes Cooperative Initiative (SALCI), and each iteration of the scientists working together is numbered and named. For example, the current NSF PurSUiT collaboration is called SALCI Expedition 3.0.
“This is a group that’s fluid and flexible. We’re not carved in stone. We enjoy working together. We also partner with what is called Cooperative Extension. Thanks to extension agents in our counties and the Platte Basin Timelapse project, we can reach out to national wildlife refuges and ranchers.”
- Dr. David Dunigan, SALCI co-founder and Research Professor in the UNL Department of Plant Pathology.
The NSF PurSuiT funding has allowed for the initial SALCI project and team to grow to include more members and access to additional sampling sites.
Lab manager and Nematology Assistant Kris Powers in the UNL Department of Plant Pathology is the behind-the-scenes SALCI coordinator. She arranges the expedition logistics such as research permits, refuge and ranch visits, data labeling and recording, and much more.
Powers makes it possible for scientists, ranchers, and science communicators to establish and maintain their partnerships.
The Ranchers
Nematodes are collected not only from public areas but also from private lands. Some ranchers in the Sandhills have agreed to allow the nematologists to sample their alkaline waters to learn more about their local ecosystem. As part of the SALCI Expedition 3.0 in fall 2024, the crew visited two ranches.
The Wilson Flying Diamond Ranch was founded in 1888. Fifth-generation rancher Jaclyn Wilson manages Flying Diamond with her father Blaine, a fourth-generation rancher. They raise Red Angus and Red Angus - Simmental cattle.
“I think a lot of times people always want to blame ranchers for a lot of the problems with the environment, but ranchers were the original conservationists,” Jaclyn Wilson noted.
“We've been sustainable for 100 plus years, and we have to work with the ecosystem, we work together, and we're constantly trying to improve it."
“Partnerships like this one are great opportunities for people from other areas to come and see this beautiful area of Nebraska. It gives us the opportunity to tell our story and show some of the great things that we're doing,” she added.
Wilson Flying Diamond Ranch is known for its sustainable practices such as using pasture management strategies and tools to rotate cattle in ways that improve the landscape. The family was the first in Nebraska to receive the Leopold Conservation Award in 2006.
Also located in the western Sandhills, the Benjamin Ranch began in 1987. Melody Benjamin and her son Rob manage the cow-calf operation. She calls the Sandhills a “ranching paradise” and hopes the partnership with university scientists will help provide an understanding of the local wildlife.
“An important outcome of these partnerships is to let people know that we’re doing a pretty darn good job on the landscape here, and that’s always one of the things I want people to take away,” Melody Benjamin said.
“We love every square inch of this land, and we love this wildlife, and we’re doing the best we can to manage it for everyone.”
Research results from this NSF PurSUiT project may help ranchers to have a richer understanding of the Sandhills’ biodiversity, the role of nematodes, and best management practices for conservation to balance cattle, wildlife, and the land.
The Scientists
The scientists on the project are from around the world and have various backgrounds.
TOP is a Principal Investigator for the NSF PurSUiT grant. He grew up in Washington, D.C. and was always curious about the insects around him. He studied entomology as an undergraduate student, completed a master’s degree focused on marine nematodes, and completed a doctoral degree from the University of California - Riverside.
Porazinska is also a lead investigator on the grant. She is originally from Poland. Porazinska has a master’s degree in biology, another master’s in conservation ecology and sustainable development, and a doctoral degree in soil ecology from the University of Florida.
“My heart is really in soil biodiversity,” she noted. “I believe that soil biodiversity plays a very important role in sustaining current and future life. It forms the foundation for all ecosystems and for people to live on this planet.”
TOP and Porazinska have included graduate and undergraduate students from their labs on the project. UF doctoral student Ricky Critchfield and undergraduate Natalia Madrid, and UNL doctoral student David Sirengo help with data collection.
The fieldwork includes kayaking the waterways to sample for nematodes and data analysis back in the labs. The students describe their experiences on the project as engaging, challenging, and rewarding.
“It’s kind of fun because you are out in a kayak and paddling out to find your place to stop and drop anchor,” said Critchfield.
They use a dredger to collect sediment by throwing it overboard and pulling up the muck.
“If it’s really windy and choppy, it can be frustrating to stay still and then, to get back to shore in the wind,” Critchfield explained.
“But the fun is seeing the layers of muck because you can see the amount of vegetation there is and texture. That is encouraging because chances are, we will see a lot of nematodes in that sample.”
Madrid also helped with navigating the Alkaline Lakes and described the fieldwork as a great opportunity to learn beyond the classroom.
“I think that as a Hispanic person in science it's important that I do my part in serving as a role model for anyone who comes after me and making a space for other cultural backgrounds to be in this science,” Madrid said.
“It's not necessarily something that a lot of them have the opportunity to do or necessarily see themselves as someone who fits the model person to do that job, but I think it's really important that everybody gets the chance to be outside like this.”
Sirengo is from Kenya, completed his master’s degree in Belgium, and is studying with TOP at UNL. He wants to learn more about applying advanced biological methods to study organisms such as nematodes.
“We need to educate people that nematodes exist from a human, plant, and soil health perspectives. For this project specifically, these nematodes are very interesting because they survive on very extreme Alkaline Lakes, and we don’t know how the effects of climate change might impact this group of nematodes’ survival,” said Sirengo.
The Science Communicators
When the scientists drafted their proposal for the NSF PurSUiT funding, they intentionally included science communicators from their universities as project team members to develop multimedia outreach and research for nematode engagement.
The UF Department of Agricultural Education and Communication team includes Dr. Jamie Loizzo (Associate Professor), Dr. Shane White (Instructional Assistant Professor), and Maggie Murphy (master’s student).
The Platte Basin Timelapse team from UNL includes Ethan Freese (Producer and Photographer) and Dakota Altman (Producer, Photographer, and Instructor).
Platte Basin Timelapse (PBT) is a project that began in 2011 to document Nebraska’s watersheds through timelapse photography. It has grown to include a team of professionals who develop conservation stories to share with audiences.
These seasoned communicators from both universities are working closely with the nematologists to develop a mini-documentary, materials for UF students to utilize in project-based learning science communication courses, and to conduct social science research about the impacts of the outreach on students’ nematode content knowledge and science communication learning.
“I hope projects like this engage the public with science in a way that everyone can understand so that they want to share with their communities and especially, to learn more about nematology and nematodes because this can be a very complex issue to understand.”
- Maggie Murphy, UF Agricultural and Natural Resources communication master’s student.
The communication products and outreach will be shared on The Streaming Science Project, an online student-driven agricultural and natural resources communication platform founded by Loizzo in 2016.
The Call for Conservation
The tiny threadlike-microscopic Tobrillidae nematode family in the Nebraska Sandhills is making a big impact to tell us what is happening to the delicate and dynamic world around us.
The SALCI team hopes sharing their journey, science, and communication with others attracts more partners in a variety of ecosystems to conserve and preserve agricultural and natural resources for future generations.
“I think what’s exciting is that for the first time, we really are working in collaboration not only with the scientists, but we are working in collaboration with the real people who depend on the diversity of this land, diversity of soils, and diversity the ranchers need to pass this land to their future generations,” said Porazinska.
“Ranchers have a tremendous role in trying to preserve this area, and it’s not an easy job,” TOP added. “Anything that we can do to promote the welfare of the entire ecosystem, I’m willing to help.”
“The biggest goal that we always have, and live by day-to-day, is to always leave it better than we found it. I think that's the most important,” Jaclyn Wilson said. “Hopefully, this ranch will be around for another 130 years.”
An Ongoing Pursuit
To learn more about the team’s past nematode research, the partnering ranches, and to follow the project’s science communication efforts, please review the below links and social media.
Please continue to follow The Pursuit of Microscopic Marvels the next two years as more data are collected and for research results!
Related Research Publications
- Mullin, P. G., Harris, T., Higgins, R., Dutta, E., Porazinska, D. L., Powers, K., & Powers, T. (2024). Taxonomy of Tobrilidae species from the alkaline lakes of the western Nebraska Sandhills. Journal of Nematology, 56(1), 20240025. https://doi.org/10.2478/jofnem-2024-0025
- Gattoni, K., Gendron, E. M. S., McQueen, J. P., Powers, K., Powers, T. O., Harner, M., Corman, J., & Porazinska, D. L. (2024). The nature of microbial diversity and assembly in the Nebraska Sandhills depends on organismal identity and habitat type. Community Ecology, 1-14. https://doi.org/10.1007/s42974-024-00206-5
- Gattoni, K., Gendron, E. M. S., McQueen, J. P., Powers, K., Powers, T. O., Harner, M., Corman, J., & Porazinska, D. L. (2024). Climate change driven temporal shifts in nematode community diversity and composition. Frontiers in Ecology and Evolution, 12. https://doi.org/10.3389/fevo.2024.1305930
- Gattoni, K., Borgmeier, A., Gendron, E., McQueen, J. P., Mullin, P., Powers, K., Powers, T. O., & Porazinska, D. L. (2022). Context-dependent role of abiotic and biotic factors structuring nematode communities along two environmental gradients. Molecular Ecology, 31(13), 3903-3916. https://doi.org/10.1111/mec.16541
For More Information
The Scientists
The Ranchers
Science Communication
The Authors and Photographers
Written and edited by: Dr. Jamie Loizzo
Photos credits:
Special thanks to University of Nebraska's Cedar Point Biological Station. The team stayed at the station during the fall 2024 Sandhills data collection trip.
Funded by the National Science Foundation Poorly Sampled and Unknown Taxa (NSF PurSUiT) Award #2327478.