Deep-sea habitats cover approximately two-thirds of the planet. Our understanding of deep sea habitats is based on observations or samples from only a very small percentage of these immense environments. Up to 10 million species in the deep-sea remain unknown to science. The limited sampling of deep-sea habitats and increasing societal demands on ocean resources emphasize the need to investigate a number of critical questions concerning the structure, function, and temporal variability of deep sea communities and their role in various biogeochemical transformations. Imaging systems and sensors deployed on a cabled observatory would document the behavior of individuals, the dynamics of populations, and variation in the structure of seep and vent communities.
Concurrent monitoring of fluid chemistry and other environmental factors (e.g., current speed), coupled with measurements of the response of the community to experimental manipulation of fluid chemistry, could help define the roles of intrinsic environmental (e.g., fluid chemistry) and biological factors versus external processes (i.e., effects of ocean currents on larval transport).
In an effort to characterize seafloor habitats and determine potential environmental impacts to the benthos during cable-laying operations, biological data will be obtained at two scales. Epifaunal animals (above right) are those large enough to be seen on video footage obtained on ROV surveys of the proposed route. Infaunal animals (above left) are small organisms that live in soft sediment.
Sediment cores are collected using the ROV, then gently washed through a mesh sieve to recover the animals. Identification of all organisms will be performed to the lowest practical taxonomic level, and the mean organism abundance and number of different taxa will be reported. Specific survey locations were chosen to target representative substrate and habitat types along the proposed route.