Distribution of pelagic prokaryotes from the surface to 1000m. The epipelagic and mesopelagic layers have been explored, with special interest in the deep scattering layer

Marine ecosystems located at tropical latitudes are typically less variable seasonally than temperate or polar waters. Although they do change temporally this source of variability remains poorly explored in the Red Sea.

Dissolved organic matter DOM represents the ocean’s largest reservoir of reduced carbon. Despite significant progress we still lack a mechanistic understanding of the microbial processes contributing to DOM sources and sinks.

One specific aspect of the interactions between DOM and heterotrophic prokaryotes that we are currently investigating is focused in the Red Sea mesopelagic layer, particularly warmer 22°C that elsewhere.

Cyanobacteria belonging to the genera Prochlorococcusand Synechococcusare the most abundant photosynthetic organisms in the world, responsible for a major share of oceanic primary production, particularly at low latitudes.

Human pathogenic bacteria can reach coastal waters and travel long distances in the ocean.

Heterotrophic bacterioplankton and archaea constitute the largest living biomass in the oceans.