Brooding strategy of the Arctic cold seep polychaete Oligobrachia haakonmosbiensis

• Published in: Marine Biology
• Main Authors: Marta, Mammone, Courcot, Lucie, Hilário, Ana, Gaudron, Sylvie
• Other Authors: Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 (LOG), Centre National de la Recherche Scientifique (CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Institut national des sciences de l'Univers (INSU - CNRS), Centre for Environmental and Marine Studies Aveiro (CESAM), Universidade de Aveiro
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2020
• Subjects: Larvae; deep sea; dispersal; gametogenesis; Annelida; Siboglinidae; life cycle; [SDV.BA.ZI]Life Sciences [q-bio]/Animal biology/Invertebrate Zoology; [SDV.BDD]Life Sciences [q-bio]/Development Biology; [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography; Arctic; Norwegian Sea
• Online Access: https://hal.sorbonne-universite.fr/hal-02873989; https://hal.sorbonne-universite.fr/hal-02873989/document; https://hal.sorbonne-universite.fr/hal-02873989/file/MABI-D-19-00417_R4.pdf; https://doi.org/10.1007/s00227-020-3656-4

International audience The Arctic polychaete, Oligobrachia haakonmosbiensis (Family Siboglinidae) is the most abundant symbiotic species inhabiting the Haakon Mosby Mud Volcano (Norwegian Sea, depth 1250 m). Different aspects of gametogenesis, fecundity, embryogenesis and larval development were studied using biometric measurements, classical histology and scanning electron microscopy on specimens (n = 15) collected in July 2009 at two sites (72°00.28'N, 14°43.36'E; 72°00.33'N, 14°43.22'E). Several cohorts of oocytes, from oogonia to mature oocytes were observed in brooding females. Embryos with 16-64 cell divisions, trochophore and metatrochophore larvae, were found, in sequence, in female tubes, from just above the tentacles to the anterior end of the tube. Trochophores had both a prototroch and a telotroch; metatrochophores had an additional ciliary band, the neurotroch, but lacked a downstream feeding system. All of female reproductive stages, oocytes, embryos and larvae, were recovered in a single specimen suggesting the release of different batches of oocytes at least on the date of collection, which coincided with the boreal summer. Only one brooding female contained exclusively germ cells in the gonad suggesting a pause in reproduction. Fecundity was low: a maximum of 60 mature oocytes per female was counted, and if all the different stages of oocytes, embryos and larvae were combined, a total fecundity of ~250-300 propagules was found in each female. This study advances knowledge of the reproductive biology of O. haakonmosbiensis and has particular significance for understanding the distribution of this ecologically important deep-sea chemosymbiotic species in the Arctic region. The new data on life-history traits are critical for modeling, and predicting dispersal potential and connectivity among cold seeps in the Arctic, which is an essential component of marine spatial management.