Environmental gradients and physical barriers drive the basin-wide spatial structuring of Mediterranean Sea and adjacent eastern Atlantic Ocean prokaryotic communities

The Mediterranean Sea is a miniature ocean divided by the Sicily Strait into two basins with a marked west to east trophic gradient, and separated of the nearby Eastern Atlantic Ocean by the Strait of Gibraltar. All these orographic features provide physical and environmental barriers that reduce water mass mixing in the bathypelagic. Here we test the hypothesis of whether these barriers favour the development of specific prokaryotic assemblages both in the vertical and horizontal spatial scales. By looking at the 16S-rRNA based phylogenetic diversity we show that there is a high vertical structuring similar to that found in other areas of the ocean, but also a clear horizontal structuring among the three basins. Publication: https://doi.org/10.1002/lno.11944