Larvae from deep-sea methane seeps disperse in surface waters

• Published in: Proceedings of the Royal Society. B, Biological sciences Biological sciences, 2014-07, Vol.281 (1786), p.20133276
• Main Authors: Arellano, Shawn M., Van Gaest, Ahna L., Johnson, Shannon B., Vrijenhoek, Robert C., Young, Craig M.
• Format: Article
• Language: English
• Subjects: Animal Distribution; Animal Migration; Animals; Bathynerita naticoidea; Cold Seep; Dispersal; Gulf of Mexico; Larva - growth & development; Larva - physiology; Molecular Sequence Data; Mytilidae - genetics; Mytilidae - growth & development; Mytilidae - physiology; Polymerase Chain Reaction; Seasons; Sequence Analysis, DNA; Snails - genetics; Snails - growth & development; Snails - physiology; Vertical Migration; “Bathymodiolus” childressi
• ISSN: 0962-8452; 1471-2945; 1471-2954
• DOI: 10.1098/rspb.2013.3276

Many species endemic to deep-sea methane seeps have broad geographical distributions, suggesting that they produce larvae with at least episodic long-distance dispersal. Cold-seep communities on both sides of the Atlantic share species or species complexes, yet larval dispersal across the Atlantic is expected to take prohibitively long at adult depths. Here, we provide direct evidence that the long-lived larvae of two cold-seep molluscs migrate hundreds of metres above the ocean floor, allowing them to take advantage of faster surface currents that may facilitate long-distance dispersal. We collected larvae of the ubiquitous seep mussel “Bathymodiolus” childressi and an associated gastropod, Bathynerita naticoidea, using remote-control plankton nets towed in the euphotic zone of the Gulf of Mexico. The timing of collections suggested that the larvae might disperse in the water column for more than a year, where they feed and grow to more than triple their original sizes. Ontogenetic vertical migration during a long larval life suggests teleplanic dispersal, a plausible explanation for the amphi-Atlantic distribution of “B.” mauritanicus and the broad western Atlantic distribution of B. naticoidea. These are the first empirical data to demonstrate a biological mechanism that might explain the genetic similarities between eastern and western Atlantic seep fauna.