The refuge is located at the northern extent of dense leatherback nesting in Florida, but the species nest in far fewer numbers, laying just 23 nests in 2017 within the portion of the refuge monitored by UCF. (sciencedaily.com)
The Canadian Prairies are at the northern extent so you can add periods of intense cold. (drtimball.com)
The Polar Front marks the northern extent of very cold fresh (low salinity), Antarctic surface water [5]. (journals.plos.org)