AUTHOR=Markovski Marsej , Najdek Mirjana , Herndl Gerhard J. , Korlević Marino 

TITLE=Compositional stability of sediment microbial communities during a seagrass meadow decline

JOURNAL=Frontiers in Marine Science

VOLUME=9

YEAR=2022

URL=https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2022.966070

DOI=10.3389/fmars.2022.966070

ISSN=2296-7745

ABSTRACT=<p>The presence of seagrass shapes surface sediments and forms a specific environment for diverse and abundant microbial communities. A severe decline of <italic>Cymodocea nodosa</italic>, a widespread seagrass species in the Mediterranean Sea, has been documented. To characterise and assess the changes in microbial community composition during the decline of a <italic>Cymodocea nodosa</italic> meadow, Illumina MiSeq sequencing of the V4 region of the 16S rRNA gene was performed. Samples of surface sediments from two sites, one without any vegetation and one with a declining <italic>Cymodocea nodosa</italic> meadow, were collected at monthly intervals from July 2017 to October 2018. Microbial communities were stratified by sediment depth and differed between the vegetated and the nonvegetated site. Although the <italic>Cymodocea nodosa</italic> meadow declined to a point where almost no leaves were present, no clear temporal succession in the community was observed. Taxonomic analysis revealed a dominance of bacterial over archaeal sequences, with most archaeal reads classified as <italic>Nanoarchaeota</italic>, <italic>Thermoplasmatota</italic>, <italic>Crenarchaeota</italic>, and <italic>Asgardarchaeota</italic>. The bacterial community was mainly composed of <italic>Desulfobacterota</italic>, <italic>Gammaproteobacteria</italic>, <italic>Bacteroidota</italic>, <italic>Chloroflexi</italic>, <italic>Planctomycetota</italic>, and <italic>Campylobacterota</italic>. Our results show that sediment microbial communities are remarkably stable and may resist major disturbances such as seagrass meadow decline.</p>