By Samuel Georgian, Marine Biogeographer at Marine Conservation Institute

Rodriguez Seamount is a 10–12 million-year-old seamount located approximately 42 miles off the coast of southern California. It towers over a mile above the seafloor, with its tallest summit cone standing over a little over 2,000 feet below the surface. Once upon a time, Rodriguez was an island standing as tall as 230 feet above sea level, with an area of 2.6 square miles. Like the neighboring San Juan Seamount, it has since sunk back beneath the waves largely due to the subsidence of the ocean crust beneath it. Due to the erosional forces it was exposed to as an island, its modern summit largely consists of a large flat dome, qualifying Rodriguez as a guyot – a flat-topped seamount.…