Structuring processes of microbial communities and ecological networks in latitudinal gradients of the global ocean

Abstract

Biogeographical patterns have been widely studied for over two centuries. However, investigating such patterns as well as testing ecological theories for microbial communities was methodologically impossible until very recently. These questions only became accountable when modern molecular and bioinformatic tools were developed, thereby allowing the characterization of microbiomes directly from environmental samples. Recent studies have shown that the marine microbiome present latitudinal patterns of distribution, with the highest species richness found in intermediate latitudes as well as different species composition between the North and South poles. Nevertheless, simply investigating the microbial species richness distribution provides a limited understanding of the mechanisms underlying the biogeographical patterns observed in the oceans. In this PhD project, we will apply a community-ecology framework to investigating the main ecological processes driving marine microbial communities and their ecological networks in different latitudinal regions (Polar, Westerlies e Trades) of the global ocean. To accomplish this goal, a dataset consisted of spatial (Tara Oceans Project) and time-series data (marine microbial observatories) will be used. Firstly, we will determine the relative importance of deterministic and stochastic factors structuring microbial communities for each latitudinal region. Next, we will conduct the beta diversity partitioning of these communities and construct networks of their ecological interactions. Finally, we will investigate the effect of oceanic islands on the structuring of prokaryotic and eukaryotic communities and their interactions in the oceans. (AU)