Benthic Assemblages and Biodiversity Patterns of the Shelf-Break Front

Although the shelf-break frontal region covers a distance of around 2000 kilometers, past studies of the benthic organisms mostly included information based on qualitative surveys with a narrow geographic scope. The body of knowledge has been expanding over the past few decades, leading to current attempts towards an all-encompassing ecosystemic approach. In this chapter, we provide a summary of the benthic assemblages and diversity trends along the frontal ecosystem, from 36 °S to 50 °S. In particular, we describe the megabenthic assemblages using data from surveys of the Patagonian scallop Zygochlamys patagonica, the Argentine hake Merluccius hubbsi, and the Argentine squid Illex argentinus fisheries. With the use of this information, the shelf-break front’s most characteristic species―a total of about 150 taxa―are presented. Some diversity trends with latitude and depth are also shown. Information on deep habitats, including submarine canyons, is also compiled. Therein, a huge number of new species were recently described. The importance of biodiversity boosters, such as sclerobionts, is highlighted. Several Vulnerable Marine Ecosystems (VMEs) were recorded beyond 200 m deep, where coral gardens, coral reefs, rocky environments, submarine canyons, and sponge beds may act as hotspots of biodiversity. Due to the challenges of sampling in deep environments, studying these kinds of ecosystems remains a challenging task. In conclusion, the biological patterns discussed in this chapter call attention to the need for conservation efforts in order to preserve typical regions of the system’s entire benthic diversity.