Bicose 3 campaign: 47 days at sea to explore the hidden biodiversity of the deep sea

Bicose 3 News
TAG site

Here are a few images taken during the campaign currently underway in the middle of the North Atlantic on the ridge, currently at the TAG site at 26°Nn 15 dives planned in this area.

A few videos
A scientist reacts to images of these deep-sea shrimp ! - interview of Marie-Anne Cambon Head of Bicose 3 Mission © Alwin Courcy
What is a second captain ? - interview of Solen Grozel © Alwin Courcy
The vessel never sleeps - © Alwin Courcy
A surprise guest on board - © Alwin Courcy
Nautile submarine diving with Olivier Rouxel - © Alwin Courcy
What it means to be a mechanic on the nautilus - interview of Romain Mathieu
What's a deckhand on a research vessel? - interview of Jeronimo Scalabrin

Diving on the active site of Puy des Folles

Slide show of a dive by Valérie Cueff-Gauchard of the LMEE lab on the Puy des Folles active site, discovered as non-active by the French in 1996 but visited by a ROV by NOAA in April 2023. This exceptionally active site is home to numerous aggregations of Rimicaris exoculata shrimp (the numerous white ones), as well as Alvinocaris markensis shrimp (the rusty ones). The fish are Zoarcidae, and the crabs Segonzacia mesatlantica. Anemones can also be seen. The Nautile's first dive on this exceptional site at an average depth of 1900 m.

Bicose 3 aims

On October 20, 2023, more than 30 scientists boarded the Pourquoi pas? vessel, part of the French Oceanographic Fleet operated by Ifremer, to study 5 hydrothermal fields spread over more than 800 km along the Mid-Atlantic Ridge, down to depths of more than 3,700 meters.

Mapping biodiversity along 800 km of ridge to understand links between hydrothermal sites

Hydrothermal fields are areas of just a few square kilometers in size, the larger ones far apart from one another. Over the years, the same sedentary species have been observed there: shrimps, mussels, snails, tubeworms, bacteria, etc. For over 40 years, scientists have been investigating how these species migrate from one site to another. This is the case, for example, between the TAG hydrothermal field, some 125,000 years old, and the young, volcanic Snake Pit site: the same species are found in both areas, despite being separated by more than 300 km of cold water (around 2.6°C) and lacking the chemical elements on which these species depend.

The study of recently discovered hydrothermal sites, in partnership with American teams from NOAA (National Oceanic and Atmospheric Administration), could provide valuable answers about the connectivity between these zones. Scientists believe that these sites could serve as relays for the colonization of new hydrothermal springs. With 30 dives with the Nautile submarine, the Bicose 3 campaign aims to establish a precise map of hydrothermal fields, from the most active to fossil sites, and of associated species communities on an 800 km-long segment of the ridge, in order to gain a global understanding of how these environments function.

Unravelling the mysteries of young deep-sea shrimp and their symbiosis with bacteria

The Rimicaris shrimp is one of the emblematic species of deep-sea hydrothermal vents. If these crustaceans are able to proliferate in such harsh environments, it's thanks to their cooperation
with friendly bacteria housed in their heads. Yet it remains a mystery how this symbiosis between shrimp and bacteria comes about in the early stages of crustacean life.
To find out, scientists will have to answer a preliminary question: where are the Rimicaris larvae located?