Biodiversity Taxonomy Animalia Annelida Grant Agreement No 679849 Horizon 2020 Polychaeta SponGES Deep-sea Sponge Grounds Ecosystems of the North Atlantic: an integrated approach towards their preservation and sustainable exploitation European Union (EU) Porifera Cirratulidae Cirratulus Lopadorrhynchidae Pelagobia Phyllodocida Population genetics Terebellida microbiome 16S rRNA amplicon Amplicon sequencing Antarctica Blastomeres Bottleneck Cirratulus balaenophilus Collagens Cytoplasm Deep-sea Sponge Grounds Ecosystems of the North Atlantic: an Integrated approach towards their preservation and sustainable exploitation Dispersal Embryos European Union Genetic differentiation Glycogens Hardy-Weinberg equilibrium Inbreeding Lagrangian modelling Lipids Migration Ocean sensing Oocytes Opheliidae Ophelina Single-nucleotide polymorphisms (SNPs) chemosynthesis cold seep host‐specificity nutrition sponges