Histological changes of the digestive epithelium in Calanus finmarchicus: An index for diapause?

• Published in: Marine Biology
• Main Authors: Bonnet, D., Harris, R.P., Hay, S., Ingvarsdottir, A., Simon, O.
• Other Authors: Plymouth Marine Laboratory (PML), Plymouth Marine Laboratory, Ecologie des systèmes marins côtiers (Ecosym), Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National de la Recherche Scientifique (CNRS), FRS Marine Laboratory, Laboratoire de Radioécologie et d'Ecotoxicologie (DEI/SECRE/LRE), Institut de Radioprotection et de Sûreté Nucléaire (IRSN)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2007
• Subjects: crustacean; diapause; digestive system; life cycle; overwintering; physiological response; vertical distribution; Atlantic Ocean; Irminger Sea; Calanus finmarchicus; [SDV]Life Sciences [q-bio]; Greenland; Irminger Basin; East Greenland; east greenland current
• Online Access: https://hal.archives-ouvertes.fr/hal-03008519; https://doi.org/10.1007/s00227-006-0481-3

Samples collected in the Irminger Basin during the Marine Productivity Programme (2001-2004) were used to study Calanus finmarchicus vertical distribution and histological changes of its mid-gut epithelium in relation to overwintering strategy. Previous studies have shown that cell composition of the glandular part of the mid-gut, size and abundance of B cells responsible for digestive enzyme secretion and thickness of the epithelium could be good indicators of individual physiological state. We used C. finmarchicus abundance, vertical distribution, lipid sac volume and mid-gut epithelium histological composition of individuals collected in contrasting hydrographic areas of the Irminger Basin and sampled at different seasons to understand C. finmarchicus life cycle in the Irminger Basin. Lipid sac volumes were significantly different between the seasons but neither between the hydographic areas nor the various depths of the water column. B cells concentrations and thickness of the epithelium have allowed us to distinguish a non-diapausing surface population (350 m) in the East Greenland Current while individuals at depth (1,250 m) were overwintering. This result is correlated by a bimodal vertical distribution of the CV in this biozone. In the other hydrographic areas, all CV were dormant, although surface individuals were not analysed in the Southern Irminger Current. © 2006 Springer-Verlag.