Limpet Larvae Migrate to Ocean Surface Before Settling at Deep Vents

Researchers at the University of Tokyo documented that larvae of three limpet species endemic to deep-sea hydrothermal vents migrate upward to feed near the ocean surface before returning to colonize new vent habitats. The team published its findings July 15 in Science Advances.

Chemical analysis of millimeter-sized larval shells attached to 39 adult limpets revealed signatures of warmer near-surface waters.

The shells lacked heavy metals such as manganese and barium that are abundant in vent fluids. The specimens came from the 1,845-meter-deep Tu’i Malila site in the Southwest Pacific and a 440-meter-deep field on the Kaikata Seamount in the northwestern Pacific.

All 39 limpets shared the same shallow-water chemical traces, indicating the surface phase forms a regular part of the life cycle rather than an occasional event.

Larvae feed on sun-loving phytoplankton while surface currents carry them across long distances to new vents. Marine biologist Takuya Yahagi said almost all larvae are probably eaten or lost before finding a suitable hydrothermal vent. Vent animals offset the low odds by producing enormous numbers of eggs, he added.

Marine biologist Yasunori Kano of the University of Tokyo said the results suggest hydrothermal vent ecosystems are much more connected to the sunlit ocean than previously thought. Marine ecologist Lisa Levin of the Scripps Institution of Oceanography at UC San Diego called the study convincing documentation of the extreme larval journey.

The same surface-migration strategy has been suggested for other vent animals such as mussels and shrimp.