The current state of the oceans is very different from what it was in the past. Actually, most marine ecosystems are affected by climate change (e.g. ocean warming, acidification, sea level rise) and other multiple human-derived threats (e.g. overfishing, pollution, habitat destruction) which threaten marine global biodiversity and modify oceanic environments to the point of being considered “unnatural oceans” nearly devoid of “pristine” areas. Such pristine areas are minimally affected by major human threats, thus providing a unique opportunity to better understand how marine ecosystems are structured and behave. They are also essential to study the effects of climate change on the Antarctic continental shelf where one can find still relatively undisturbed environments.
Gorgonians (other name for corals) are among the main structural species of many benthic communities (organisms that live on, in, or near the seabed) across all latitudes and depths, from shallow to deep habitats. Hence, the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) has recognized gorgonians as a Vulnerable Marine Ecosystems (VME) indicator taxon. These organisms add three-dimensional complexity to the habitat providing architectural complexity and shelter for several species. During the last decade, knowledge about diversity, distribution, ecology and state of conservation of gorgonian populations on the continental shelf has significantly increased in the Mediterranean Sea, the Pacific Ocean and the Atlantic Ocean but in Antarctica there is still an important lack of knowledge on their ecological characteristic.
Non-destructive sampling techniques like video-equipped towed gear, Remotely Operated Vehicles (ROVs) or manned submersibles are commonly used to study coastal areas, deep reefs of cold-water corals and seamounts. Although the majority of studies on Antarctic benthos have been carried out using destructive techniques like bottom trawls, respectful image methodology has also been commonly used to provide essential information on the distribution of benthic megafauna communities over large spatial scale.
Antarctic deep ecosystems are still pristine areas that hide a huge knowledge on how are virgin ecosystems, and may also provide basic knowledge on how other continental shelf may have thrived in the decades before bottom trawling fishing ensued.
