Scientific Criteria and Guidance for Identifying EBSAs and Designing Representative Networks of Marine Protected Areas in Open Ocean Waters and Deep Sea Habitats

Knowing less about the deep sea habitats than the surface of the moon Most scientifi c studies have focused on easily accessible coastal waters and surface ocean. Only a small percentage of the deep seafl oor has been subject to biological investigation. Revealing the natural beauty and ecological value of deep sea habitats With the technological advances of the past few decades, much has been added to our knowledge of deep sea habitats, and people have begun to realize the value and importance of this large and remote habitat to life on Earth. Deep seabed habitats, long perceived to be a biological desert, host a wealth of species. Current estimates for species diversity in the deep sea range between 500,000 and 10 million species. Recent scientifi c results highlighted that higher biodiversity can enhance the functioning and effi ciency of deep sea ecosystems. Without deep sea life, life on Earth would be compromised because of the fundamental role of the deep sea in global biogeochemical cycles including nutrient regeneration and oxygen itself. As such, the sustainability of our biosphere signifi cantly relies on the goods and services provided by deep sea ecosystems.

HYDROTHERMAL VENTS were the fi rst ecosystem on Earth found to be basically independent from the sun as an original source of energy, relying instead on chemosynthesis. Deep sea hydrothermal vent organisms tolerate great extremes in water temperature and survive toxic concentrations of heavy metals. They are therefore of particular interest because of their adaptation to a high pressure, high temperature, high acidity and high toxicity environment. Despite these extreme conditions, the biomass of organisms around vents is very high, and made up of endemic species.

SEAMOUNTS and the water column above them serve as important habitats, feeding grounds, and reproduction sites for many open ocean and deep sea species of fi sh, sharks, sea turtles, marine mammals, seabirds, and benthic organisms. Seamounts thus form biological hotspots with a distinct, abundant and diverse fauna, and sometimes reveal many species new to science.

COLD-WATER CORAL REEFS may be many hundred to thousands of years old. Because of their age and slow growth rates, reefs contain high-resolution records of long-term climate change and may also serve as important speciation centres in the deep sea. Recent research in paleo-climatology has discovered the enormous potential of climate records in the skeletons of cold-water corals, since they are found in all oceans and at all bathymetries, from sea level to at least 4 km below the surface.