AUTHOR=Busch Kathrin , Wurz Erik , Rapp Hans Tore , Bayer Kristina , Franke Andre , Hentschel Ute 

TITLE=Chloroflexi Dominate the Deep-Sea Golf Ball Sponges Craniella zetlandica and Craniella infrequens Throughout Different Life Stages

JOURNAL=Frontiers in Marine Science

VOLUME=7

YEAR=2020

URL=https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2020.00674

DOI=10.3389/fmars.2020.00674

ISSN=2296-7745

ABSTRACT=<p>Deep-sea sponge grounds are underexplored ecosystems that provide numerous goods and services to the functioning of the deep-sea. This study assessed the prokaryotic diversity in embryos, recruits, and adults of <italic>Craniella zetlandica</italic> and <italic>Craniella infrequens</italic>, common and abundant representatives of deep-sea sponge grounds in the North Atlantic. Our results reveal that symbiont transmission in the two <italic>Craniella</italic> sponge species likely occurs vertically, as highly similar microbial consortia have been identified in adults, embryos, and recruits. Moreover, transmission electron microscopy revealed high abundances of sponge-associated microorganisms, among which <italic>Chloroflexi</italic> (<italic>SAR202</italic>) were identified as common representatives by amplicon sequencing and fluorescence <italic>in situ</italic> hybridization (FISH). Equal diversity metrices, a similar overall prokaryotic community composition and a distinct dominance of the phylum <italic>Chloroflexi</italic> within all life stages are the key findings of our analyses. Information such as presented here provide understanding on the recruitment of deep-sea sponge holobionts which is needed to develop integrated management tools of such vulnerable marine ecosystems.</p>