The mission BIG hold at board of oceanographic vessel L'Atalante from 30th May to 9th July 2010, in the Guaymas basin, located in the Gulf of California.
The Guaymas basin is characterized by the presence of hydrothermal vent activity in a margin area and the presence at a short distance of both hydrothermal and cold seep sites.
Hydrothermal deposits are scattered at the bottom of the basin. This hydrothermal deposits occurs as hydrothermal mounds, with hydrothermal chimneys and also by the presence of rich organic matter sediments percolated by the hydrothermal fluid. Cold seep activity was evidenced along a transforming fault of the Sonora Margin.
According to the presence in a sedimentary environment of both hydrothermal vents and cold seep the Guaymas basin is a perfect area for a comparative study, in the absence of biogeographic barrier, of these two chemosynthetic ecosystems.
This study focused on the characterization of the physicochemical gradients in the two ecosystems, using external sediment as reference, and the characterization of both microbial and animal communities along the physicochemical gradients (horizontal and vertical) in order to evaluate both taxonomical and functional similarities within the two habitats.