Continental margins are active regions ecologically, geologically, chemically, and hydrodynamically. These processes create unique ecosystems and increase the benthic biodiversity in this part of the ocean. Biodiversity on continental slopes is thought to exceed that of shelf and deep-sea zones with a maximum in species diversity occurring at mid-slope depths. However, in any area sampled many of the species are unknown. Part of the apparently high regional diversity relates to the complexity of the ocean margin and its many different, fragmented habitats. It is also related to the continual turnover in species with increasing depth, owing to environmental (e.g. food input, currents) and physiological (e.g. temperature, pressure) factors.
The objective of COMARGE was to untangle these many processes interacting at multiple spatial scales to determine local community structure and to shape large-scale biodiversity patterns. Two central themes were developed:
Continental margins are under increasing pressure from human activities. These include in particular the development of oil and gas exploitation, hard mineral mining, deep-sea fisheries, chemical contamination from large cities and climate change. Although the deep ocean might have been perceived as globally resilient due to its vastness, buffering environmental changes, the deep continental margins, where most human activities concentrate, are a tiny ribbon representing about 10% of the ocean seafloor. Key socio economic and governance issues related to the conservation, management and sustainable use of the deep-sea floor are pending knowledge on distribution and diversity patterns along and across margins.