While little is known about these processes, new research described in the journal Molecular Ecology helps elucidate the historical patterns of deep-sea coral migration and gene flow, coincident with oceanic circulation patterns and events. The investigators propose a scenario that could explain the observed evolutionary and present-day patterns in certain coral species. The findings can help scientists determine how climate change and other global processes have affected ocean habitats in the past and how they might do so in the future.

"The information generated in this study provides critical baseline data with which the potential effects of disturbances, such as global warming and ocean acidification, on populations inhabiting earth's largest biome can be assessed," says first author Santiago Herrera, a PhD candidate at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution (WHOI). The research will also provide new opportunities to examine ancient migration patterns of other marine organisms.

Herrera and his colleagues have been investigating ancient deep-water coral migration patterns from various seamounts-geological features that rise at 1,000 meters or more from the seafloor and often form long chains-and other hard-bottom habitats such as canyons, fjords, and continental slopes. The investigators' analyses involve the utilization of museum specimens, some of which date back to the mid 19th century.

This latest study focused on one species of coral: Paragorgia arborea, also known as bubblegum coral. This coral has been found at polar, subpolar, and subtropical regions of all of the world's oceans. Few studies have evaluated the overall genetic diversity of widespread deep-sea species, and researchers have wondered whetherParagorgia arborea is in fact a single species on a global scale or whether it has evolved into a set of 'cryptic' species, in which they exist as a set of genetically distinct species that are morphologically indistinguishable.