Sea cucumbers and Earthworms play a similar role in their habitats; both of them break down organic waste matter and play a major role in their recycling.
Sea cucumbers which live deep in the oceans feed on tiny algae, marine animals and waste materials. These are broken down into smaller particles which the bacteria in the oceans can consume, thus recycling them into the oceanic ecosystem.
Earthworms on land play a similar role. They burrow into the soil and consume any waste matter that is left behind by other animals. Earthworms also eat small rocks and solid particles. These are broken down into very small particles with the organic matter and released. The matter released by earthworms forms a very nutritious medium for plants to grow in.