New research reveals surprising link in ocean carbon cycle: swimming sea cucumbers

by the Monterey Bay Aquarium Research Institute
October 8, 2026

New MBARI research has revealed that the sea cucumber Pelagothuria natatrix plays an important, and unexpected, role in the ocean’s carbon cycle. In a new publication in the scientific journal Ecology, Senior Scientist Bruce Robison reports this unique swimming sea cucumber is a prominent member of the midwater community in the Galápagos Islands, intercepting carbon sinking to the deep seafloor.

Of more than 1,700 species of sea cucumbers, Pelagothuria natatrix is the only one known to live in the water column instead of in close association with the seafloor. Specialized tube feet have evolved into a webbed veil that aids in feeding and swimming. The evolution of a pelagic lifestyle affords access to nutrient-dense marine snow in the water column. Pelagothuria are typically oriented with their veil open like a funnel toward the surface to collect sinking bits of organic material.

Marine life plays an important role in cycling carbon. Tiny plankton at the ocean’s surface convert carbon dioxide into organic material. This carbon enters ocean food webs, transformed by animals in the midwater and eventually locked away by scavengers and microbes on the deep seafloor. 

Keep reading: https://www.mbari.org/news/new-research-reveals-surprising-link-in-ocean-carbon-cycle-swimming-sea-cucumbers/

Read the Ecology paper: https://esajournals.onlinelibrary.wiley.com/doi/10.1002/ecy.70536