Converging evidence constrains late pleistocene bering land bridge history

Abstract

The Bering Land Bridge was an important biotic corridor and climatic modifier during the Pleistocene (2.58 million to 11,700 thousand years ago [ka]). Understanding when the land bridge was most recently exposed reveals insights into past climate, the modern distribution of plants and animals, and potential human migration into the Americas. While the timing of the most recent flooding of the land bridge has been constrained to during the last deglaciation, the timing of its most recent exposure before the Last Glacial Maximum (LGM, 26.5–19 ka) is less clear. Here, we combine data from three disciplines— paleoceanography, sea level reconstruction, and terrestrial paleogenomics—to constrain the most recent exposure of the Bering Land Bridge to shortly before the LGM, 30–40 kyr later than previously suggested by comparisons of eustatic sea level reconstructions with the modern Bering Strait Sill depth. These results have implications for understanding the timing and nature of human arrival in the Americas and highlight the importance of interdisciplinary collaboration across paleoclimatology and paleoecology for refining Pleistocene environmental history.