Disentangling marine microbial networks across space

Abstract

Although microbial interactions underpin ocean ecosystem functions, they remain barely known. Different studies have analyzed microbial interactions using static association networks based on omics-data. However, microbial associations are dynamic and can change across physicochemical gradients and spatial scales, which needs to be considered to understand the ocean ecosystem better. We explored associations between archaea, bacteria, and picoeukaryotes along the water column from the surface to the deep ocean across the northern subtropical to the southern temperate ocean and the Mediterranean Sea by defining sample-specific subnetworks. Quantifying spatial association recurrence, we found the lowest fraction of global associations in the bathypelagic zone, while associations endemic of certain regions increased with depth. Overall, our results highlight the need to study the dynamic nature of plankton networks and our approach represents a step forward towards a better comprehension of the biogeography of microbial interactions across ocean regions and depth layers.