Living Deep: A Synopsis of Hadal Trench Ecology

Abstract

The ocean’s deepest environments are fraught with extreme conditions, including the highest hydrostatic pressures found on earth. The hadal zone, which encompasses oceanic depths from 6,000 to almost 11,000 m, is located almost exclusively within deep-sea trenches. Fauna inhabiting these hadal trenches represent intriguing yet possibly the least understood communities in our ocean. We present a brief historical account of hadal exploration and a synopsis of the fascinating biogeographical trends that have emerged from 60 years of sporadic hadal sampling. Biodiversity and chemosynthesis, two important concepts in deep-sea ecology, are also discussed in relation to hadal trenches.