Cruise Report - RRS James Cook, Cruise No. JC136, 14th May – 23rd June, DEEPLINKS: Influence of population connectivity on depth-dependent diversity of deep-sea marine benthic biota

Cruise JC136 is associated with a NERC joint standard research grant (NE/K011855/1 and NE/K013513/1) entitled “Influence of population connectivity on depth-dependent diversity of deep-sea marine benthic biota”. The aims of this project are to investigate connectivity among deep-sea populations at different depths and spatial scales using: 1) larval dispersal modelling using Lagrangian particle tracking, driven by hydrographic models, 2) population genetics/genomics, and 3) benthic community analysis. The aims of cruise JC136 were then to sample a range of sites and depth bands to:
1. obtain physical samples of 4 model organisms for molecular analysis,
2. gather benthic biological survey data for community level analysis,
3. collect oceanographic data to validate high resolution oceanographic models with which we will model larval dispersal.

We visited 5 sites in the NE Atlantic (Rockall Bank, George Bligh Bank, Anton Dohrn Seamount, Wyville-Thomson Ridge, and Rosemary Bank) undertaking 27 ROV dives, 12 AUV missions, 43 CTD casts, 2 mooring deployments and equipment trials. All cruise aims were broadly met. We obtained 3630 biological samples, including sufficient depth and site coverage for molecular analysis of 3 target species. We obtained video transect data with sufficient replication and depth stratification from 3 sites and near complete sampling from a 4th. We obtained sufficient oceanographic data to validate our models. In addition, we gathered 5811.66 km2 of seafloor multibeam to contribute to ongoing efforts to map the North Atlantic, including the first multibeam from the Geike Slide and Hebridean Slope Nature Conservation Marine Protected Area (NCMPA). Poor visitbility at the seabed prevented a planned resurvey of the Darwin Mounds Marine Protected Area (MPA) (see JC60).