Afterlife
Our soils are filled with abundant life and activity, but they are also host to bygone decomposing critters. Mythically and literally speaking, soil is both a groundspring and a grave.
Small carrot plants in dry garden soil. Fall 2024.
I was able to fully understand this double-perspective onto soil when I took a peek at our samples underneath the microscope. After collecting samples from the Kinney Center in Fall 2024, I was unable to look at them until early Spring 2025. Therefore, the samples received substantial time to dry out and potentially lose microorganism activity. When it was time to look under the scope, I came across several nematodes which appeared shriveled and stiff within the sample. Considering the normally-active, quick nature of nematodes, I was struck by the utter lack of activity from some of the specimens. What happened to the squirming, moving, kinetic life of my friendly nematodes?
I began to ask: what happens when nematodes lose their wily energy and no longer work with the plants? What do they leave us within the soil? What causes nematode populations to die off? How are nematodes impacted by changing soils as a result of climate change?
Bacterial (free-living) nematode
Upon talking with Emeritus Professor of Plant Pathology & Nematology, Robert Wick, he explained that some of the nematodes could have died as a result of the dryness of the sample. Nematodes can often survive desiccation but may be killed from experiencing excessive heat. The nematodes can also die from natural causes. An example of this might include fungi, which kill living nematodes and also scavenge for dead nematodes. Specifically, nematophagous fungi are able to capture the nematodes and reduce the population size of plant-parasitic nematodes. They are sometimes referred to as “nematode-trapping” or “nematode-destroying” fungi (Zhang et al.). Other than for hungry fungi, nematodes do not provide a very good food source within the soil. Nematodes do provide protein as a result of their thick cuticle (see below). Although nematodes may not leave us with reliable food sources post-death, their roles as decomposers are essential to a viable, healthy ecosystem.
In the case of my trial, our nematodes’ inactivity was likely a result of sustained dryness. Nevertheless, it is important to consider how growing environmental changes are influencing microorganism populations, including nematodes. Due to the versatility of nematodes, changing climatic conditions may simultaneously positively and negatively impact soils. Current research suggests that higher soil temperatures can cause reduced nematode reproduction. Yet, crop losses are likely to increase because the higher temperatures increase the virulence of plant-parasitic nematodes (Khanal & Land, 2023).
Global warming, elevated CO2, heat waves, droughts, floods, wildfires, and storms can all influence the risk potential and habits of plant parasitic nematodes. As a result of our climatic instability, it is important for agriculturalists to consider regenerative techniques that regulate nematode populations and ecological cycling. For instance, regenerative approaches such as crop rotation and cover cropping can provide safer alternatives to improve food production, pest prevention, and overall environmental protection (Dutta & Phani, 2023). Through ethical land management, the small but mighty nematode is able to thrive and improve the life and vitality of our soils. While we may not directly see them at work, our trusty nematodes are consistently working to balance soils and produce the plants we know and love and to sustain the cycles of life and death that feed us all.
References:
Dutta, Tushar K., and Victor Phani. “The Pervasive Impact of Global Climate Change on Plant-Nematode Interaction Continuum.” Frontiers, Frontiers, 24 Mar. 2023, www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2023.1143889/full.
Khanal, Churamani, and Julian Land. “Study on Two Nematode Species Suggests Climate Change Will Inflict Greater Crop Damage.” Nature News, Nature Publishing Group, 30 Aug. 2023, www.nature.com/articles/s41598-023-41466-x.
Zhang, Ying, et al. “Fungi-Nematode Interactions: Diversity, Ecology, and Biocontrol Prospects in Agriculture.” Journal of Fungi (Basel, Switzerland), U.S. National Library of Medicine, 4 Oct. 2020, pmc.ncbi.nlm.nih.gov/articles/PMC7711821/#:~:text=In%20contrast%2C%20a%20number%20of,as%20nematophagous%20fungi%20%5B8%5D.