Atlas Deliverable 1.1 Lagrangian Connectivity Of North Atlantic Ecosystems

One of the overarching goals of ATLAS is to investigate the sensitivity of North Atlantic Ocean ecosystems to the temporal variability of basin-scale physical processes. The export pathways of North Atlantic waters, embedded within temporally-varying, large-scale circulation features such as the Subpolar Gyre Index (SPGI) and the Atlantic Meridional Overturning Circulation (AMOC), set the connectivity between ocean regions. This connectivity has impacts on the dispersal of larvae from benthic communities. While the time-mean pathways are generally well understood, the short observational record and strong mesoscale to interannual variability in the North Atlantic means that the temporal variability of pathways is still an open question. Here, we use output from a high-resolution ocean model to estimate the envelope of variability of the Lagrangian pathways between ATLAS Case Study regions over a 50-year timescale and to identify end-member, extreme pathways/connectivity cases. A secondary goal is to highlight the importance of potential biological assumptions. We begin by investigating how the results may be sensitive to launching particles immediately at the bed or slightly higher in the water column. In future, ATLAS Deliverable 1.5 will build on this work by adding further biological effects.