Mesoscale ocean eddies determine dispersal and connectivity of corals at the RMS Titanic wreck site

The sinking of the RMS Titanic on 15 April 1912 remains one of most iconic maritime disasters in history. Today, the wreck site lies in waters 3800 m deep approximately 690 km south southeast of Newfoundland, Atlantic Canada. The wreck and debris field have been colonized by many marine organisms including the octocoral Chrysogorgia agassizii. Because of the rapid deterioration of the Titanic and the vulnerability of natural deep-sea coral populations to environmental changes, it is vital to understand the role the Titanic as well as other such structures could play in connecting ecosystems along the North American slope. Based on Lagrangian experiments with more than one million virtual particles and different scenarios for larval behavior, given the uncertainties around the biology of chrysogorgiids, the dispersal of larvae spawned at the Titanic wreck is studied in a high-resolution numerical ocean model. While the large-scale bathymetry shields the Titanic from a strong mean flow, mesoscale ocean eddies can considerably affect the deep circulation and cause a significant speed up, or also a reversal, of the circulation. As a consequence, the position of upper and mid-ocean eddies in the model largely controls the direction and distance of larval dispersal, with the impact of eddies outweighing the importance of active larval swimming in our experiments. Although dependent on larval buoyancy and longevity, we find that the Titanic could be reached by larvae spawned on the upper slope east of the Grand Banks. Therefore, the Titanic could act as a stepping stone connecting the upper to the deep continental slope off Newfoundland. From the Titanic, larvae then spread into deep Canadian waters and areas beyond national jurisdiction.