The deep sea is the greatest habitat on Earth, covering up to 70 % of the seabed. However, this environment is still poorly known and underexplored, partially due to its greatness and difficult accessibility. Currently, the deep sea is being threatened by various anthropogenic activities, such as fishing and mineral-resource exploitation, in addition to climate change effects. Understanding deep-sea biodiversity is of prime importance to comprehend how these impacts can be mitigated to preserve this environment. Therefore, our research proposes an interdisciplinary approach to unravel global and regional species distribution patterns, population connectivity, their drivers and species’ trophic niches. We aim to investigate how nematodes, as the most abundant and diverse metazoan taxon in the abyss, are distributed, and how their distribution is related to environmental changes and physical barriers. In addition, we also want to examine why nematodes are successful in the deep sea and how they thrive in this food-poor environment. Our research will combine modelling approaches with molecular techniques. Firstly, we will model regional and global species distribution. Then, we will make use of molecular approaches (population genetics) to examine how regional environmental drivers and physical barriers or routes affect species distribution. Lastly, using next-generation sequencing techniques, we will investigate how specialized nematodes are in terms of feeding strategies.