They Came from the Pacific! Ecological Connectivity between the Pacific and Atlantic Oceans via a Changing Arctic

In 1999, the Pacific diatom Neodenticula Seminae was found in a continuous plankton recorder survey in the North Atlantic – the wrong ocean. A trans-Arctic migration was hypothesized to be responsible for its appearance in the Atlantic, enabled by changing advective pathways in a warming Arctic Ocean. This has fuelled suggestions that a tipping point may have been crossed, leading to increased ecological connectivity between the Pacific and Atlantic Oceans. If N. Seminae could have traversed a previously closed Arctic pathway, could other species do so as well?

Using a Lagrangian particle-tracking technique in conjunction with a high resolution (1/12°) ocean model, we investigate how connectivity pathways between the Bering Strait and North Atlantic Ocean have changed between 1970 and 2013. We define distinct connectivity pathways, investigate how their associated advective timescales vary both seasonally and interannually, and present evidence for a sporadically available pathway with an anomalously short connectivity timescale. We then discuss these results in the context of their implications for ecological connectivity between the two oceans.