Fossil evidence for serpentinization fluids fueling chemosynthetic assemblages

Among the deep-sea hydrothermal vent sites discovered in the past 30 years, Lost City on the Mid-Atlantic Ridge (MAR) is remarkable both for its alkaline fluids derived from mantle rock serpentinization and the spectacular seafloor carbonate chimneys precipitated from these fluids. Despite high concentrations of reduced chemicals in the fluids, this unique example of a serpentinite-hosted hydrothermal system currently lacks chemosynthetic assemblages dominated by large animals typical of high-temperature vent sites. Here we report abundant specimens of chemosymbiotic mussels, associated with gastropods and chemosymbiotic clams, in approximately 100 kyr old Lost City-like carbonates from the MAR close to the Rainbow site (36 degrees N). Our finding shows that serpentinization-related fluids, unaffected by high-temperature hydrothermal circulation, can occur on-axis and are able to sustain high-biomass communities. The widespread occurrence of seafloor ultramafic rocks linked to likely long-range dispersion of vent species therefore offers considerably more ecospace for chemosynthetic fauna in the oceans than previously supposed.

Keyword(s)

Bathymodiolus, Ghost City, ultramafic-hosted, mid-ocean ridge, ecogeochemistry

Full Text

FilePagesSizeAccess
Publisher's official version
6343 Ko
Author's final draft
30951 Ko
How to cite
Lartaud Franck, Little Crispin T. S., de Rafelis Marc, Bayon Germain, Dyment Jerome, Ildefonse Benoit, Gressier Vincent, Fouquet Yves, Gaill Francoise, Le Bris Nadine (2011). Fossil evidence for serpentinization fluids fueling chemosynthetic assemblages. Proceedings Of The National Academy Of Sciences Of The United States Of America. 108 (19). 7698-7703. https://doi.org/10.1073/pnas.1009383108, https://archimer.ifremer.fr/doc/00036/14748/

Copy this text