The deep chlorophyll maximum (DCM) is a seasonal phenomenon in the Mediterranean Sea, and a very dynamic feature that mayhave associated a broad spectrum of microbial niches. To study so, we performed a vertical high-resolution vertical sampling of theDCM to explore the structure of the microbial community in the northwest Mediterranean Sea during fall. We analyzed the Chloro-phyll- a concentration, nutrients (nitrate, nitrite, silicate, ammonium and phosphate), the abundance of bacteria and eukaryotes, andtheir diversity through Illumina amplicon sequencing (16S and 18S rRNA gene) in the pico and nanoplankton size fraction, and bac-terial heterotrophic production across the DCM. We studied the changes of microbial groups across the DCM and also focused onthe vertical connectivity of the different communities. Our results show that the DCM is much more heterogeneous than hitherto as-sumed

1st Iberian Ecological Society Meeting (2019); XIV Congreso Nacional de la Asociación Española de Ecología Terrestre (AEET), Ecology: an integrative science in the Anthropocene, 4-7 February 2019, Barcelona, Spain

Peer Reviewed