Yes, Worms Live in Yellowstone — From Hot Springs to Forest Soils

Yellowstone's extreme environments host a surprising diversity of worms — **annelids, nematodes, flatworms** — adapted to conditions from boiling acid springs to alpine meadows.

Worm Groups in Yellowstone

• Oligochaetes (segmented worms): Earthworms (introduced), aquatic *Tubificidae* (sludge worms) in thermal outflow streams
• Polychaetes (marine-type): *Nais* spp. in hot spring runoff (up to 40°C) — rare freshwater polychaetes
• Nematodes (roundworms): Ubiquitous in soils, sediments, thermal soils — >100 species estimated
• Flatworms (Platyhelminthes): *Dugesia* (planarians) in cool streams; thermal *Rhynchomesostoma* in warm springs
• Rotifers: Microscopic — in thermal pools, moss, soil water films

Extreme Habitats

Ecological Roles

• Decomposition: Nutrient cycling in thermal and non-thermal soils
• Food web: Prey for beetles, birds, amphibians, fish
• Bioindicators: Nematode community structure reveals soil health, pollution
• Extremophile research: NASA studies thermal worms for astrobiology analogs

Notable Species

• Limnodrilus sulphurensis — sulfide-tolerant oligochaete, Yellowstone endemic
• Rhynchomesostoma rostratum — thermal flatworm, 30–40°C
• Various *Eisenia*, *Lumbricus* — introduced earthworms altering forest floors

Yellowstone's worms prove life doesn't just endure extremes — it **specializes** in them. The park's geothermal gradient is a worm evolution laboratory.