Deep-Sea Creatures Follow Surface Seasonal Patterns

"Islands" of exotic deep-sea life might not be protected from catastrophes at the Earth's surface, according to research presented this week at the British Association for the Advancement of Science (BA) Festival of Science.

Jon Copley, an ocean and Earth scientist at the University of Southampton in the U.K., discussed how he and fellow researchers have discovered that exotic, deep-sea shrimp and mussels still rely on resources from the sea's surface.

While such adult creatures feed solely on minerals spewing from volcanic vents on the ocean's floor, their offspring hatch away from these regions, the scientists found. To ensure that their young have enough food to grow, adults time their reproductive cycles to breed in late autumn and hatch in the spring. The hatching time coincides with the blooming of microscopic plants at the ocean's surface. When those plants die and sink to deeper regions, they provide food to the deep-sea hatchlings.

The discovery runs contrary to what scientists previously believed about communities of life at the deepest parts of the ocean. Many thought such deep-sea creatures could continue to thrive even if, for example, an asteroid hit the Earth and kicked up enough dust and debris to blot out sunlight and kill off life at the surface.

"I used to think these deep-sea communities would be safe from whatever havoc happens up here," Copley said. "But finding seasonality down there shows that life beneath the waves is far more connected than we realized. Like nineteenth-century naturalists, we are enjoying a golden age of discovery as we visit these previously-unexplored 'islands' in the abyss -- and we are gaining new insights into the patterns of life throughout the oceans as we do so."

While no research has yet found deep-sea regions feeling the effects of climate change, Copley said his findings show it's possible that changes at the ocean's surface could affect life deep below. Over the next two years, he and his team plan to set off on a first-ever exploration of life at undersea volcanic vents around Antarctica, as well as on an expedition to the planet's deepest volcanic ridge.