Rimicaris exoculata: biology and ecology of a shrimp from deep-sea hydrothermal vents associated with ectosymbiotic bacteria
|Author(s)||Zbinden M1, Cambon-Bonavita Marie-Anne2|
|Affiliation(s)||1 : Sorbonne Université, Univ Paris 06, UMR CNRS MNHN 7208 Biologie des Organismes Aquatiques et Ecosystèmes (BOREA), Equipe Adaptation aux Milieux Extrêmes, 75005 Paris, France
2 : Univ Brest, Ifremer, CNRS, Laboratoire de Microbiologie des Environnements Extrêmes, 29280 Plouzané, France
|Source||Marine Ecology Progress Series (0171-8630) (Inter-Research Science Center), 2020-10 , Vol. 652 , P. 187-222|
|Keyword(s)||Alvinocaridid shrimp, Chemoautotrophic symbiont, Deep-sea, Epibiosis, Holobiont, Hydrothermal vents, Mid-Atlantic Ridge, Rimicaris exoculata|
Rimicaris exoculata, the ‘blind shrimp,’ is the most abundant species living on active hydrothermal edifices at deep-sea vents of the Mid-Atlantic Ridge. Its unusually enlarged branchial chamber houses a dense ectosymbiotic community of chemoautotrophic bacteria. Long debated, shrimp nutrition has been proven to be a kind of osmotrophy, whereby small organic molecules produced by the symbionts pass through the integument of the shrimp directly into the circulatory system, rather than through the digestive system. The broad phylogenetic and metabolic diversity of this epibiotic community suggests a highly flexible and adjustable microbial consortium, adapted to the chemically contrasting environments inhabited by the shrimp. To cope with the highly fluctuating oxygen and temperature conditions of its habitat, R. exoculata possesses hemocyanin with a strong oxygen affinity, and has developed both molecular and behavioral responses to heat stresses. If R. exoculata is able to detect very dim light or chemical compounds emitted by vents, the relatively small visual and olfactory areas in the brain, along with the disproportionately enlarged higher centers, argue for a significant involvement of navigational skills using learning and place memory to orient itself within its aphotic environment. This shrimp undergoes unconventional larval development, with a primary lecithotrophic stage followed by an extended planktotrophic period, allowing a huge potential for dispersion. In light of mining licenses posing a threat for deep-sea environments, this species is a model still to be studied to better understand life in extreme deep-sea ecosystems at the global scale of an ocean.