Global Ocean Currents Facilitate the Global Expansion of Eelgrass (Zostera marina)

Researchers have reconstructed the colonization history of eelgrass, a critical seagrass species, using complete nuclear and chloroplast genomes. The study reveals that eelgrass first crossed the Pacific from west to east in multiple colonization events, and then dispersed to the Atlantic through the Canadian Arctic about 243 thousand years ago. The findings suggest that eelgrass-based ecosystems in the Atlantic are relatively recent, with less time for animal-plant co-evolution. The study also highlights the significant difference in genomic diversity between Pacific and Atlantic populations, raising concerns about the Atlantic eelgrass's ability to adapt to climate change. Restoring genetic diversity from Pacific eelgrass may be a potential solution for fortifying Atlantic populations.