Deep-Sea Fauna

After 150 years of exploration, we now know the deep sea represents the largest complex of cosystems on our planet which embrace the greatest number of animal species and biomass of the living world. However, there is still a great deal more information that is needed to improve our knowledge of deep‐sea faunal dynamics which demands more and better targeted sampling. In this chapter we outline the main biological characteristics of deep‐sea organisms, describing aspects of animal life forms, behaviours and adaptations to the deep sea that could affect sampling techniques and survey design. Aspects of spatial and temporal distribution patterns of diversity and abundance are also described for both benthic and pelagic fauna, and examples given of various related sampling issues. The deep sea hosts a huge variety of animal types and faunal communities, with highly variable characteristics. Consideration of these characteristics provides a useful biological context for the sampling techniques that are covered in subsequent chapters of this book.