Currents are unique drivers of oceanic phylogeography and thus determine the distribution of marine coastal species, along with past glaciations and sea-level changes. Here we reconstruct the worldwide colonization history of eelgrass (Zostera marina L.), the most widely distributed marine flowering plant or seagrass from its origin in the Northwest Pacific, based on nuclear and chloroplast genomes. We identified two divergent Pacific clades with evidence for admixture along the East Pacific coast. Two west-to-east (trans-Pacific) colonization events support the key role of the North Pacific Current. Time-calibrated nuclear and chloroplast phylogenies yielded concordant estimates of the arrival of Z. marina in the Atlantic through the Canadian Arctic, suggesting that eelgrass-based ecosystems, hotspots of biodiversity and carbon sequestration, have only been present there for ~243 ky (thousand years). Mediterranean populations were founded ~44 kya, while extant distributions along western and eastern Atlantic shores were founded at the end of the Last Glacial Maximum (~19 kya), with at least one major refuge being the North Carolina region. The recent colonization and five- to sevenfold lower genomic diversity of the Atlantic compared to the Pacific populations raises concern and opportunity about how Atlantic eelgrass might respond to rapidly warming coastal oceans.
|Title||Ocean current patterns drive the worldwide colonization of eelgrass (Zostera marina)|
|Authors||Lei Yu, Marina Khachaturyan, Michael Matschiner, Adam Healey, Diane Bauer, Brenda Cameron, Mathieu Cusson, J. Emmett Duffy, F. Joel Fodrie, Diana Gill, Jane Grimwood, Masakazu Hori, Kevin Hovel, A. Randall Hughes, Marlene Jahnke, J. Jenkins, K. Keymanesh, C. Kruschel, S. Mamidi, Damian M. Menning, P. Moksnes, M. Nakaoka, C. Pennacchio, K. Reiss, F. Rossi, J. Ruesink, S. Schultz, S. Talbott, R. Unsworth, David H. Ward, T. Dagan, J. Schmutz, J. A. Eisen, J. Stachowicz, Y. Van de Peer, J. L. Olsen, T. B. H. Reusch|
|Publication Subtype||Journal Article|
|Series Title||Nature Plants|
|Record Source||USGS Publications Warehouse|
|USGS Organization||Alaska Science Center Ecosystems|