Marine life is on the brink of experiencing its sixth mass extinction, a disruption that is expected to occur very rapidly once the gears are set in motion (cataclysmic chain events). Now, a new study suggests that it might take a full millennium for marine life to recover from a potential climate change-driven die off, not hundreds as previously suggested.

Image: Wikimedia Commons

When ice melts from the base of an ice shelf, for instance, the oxygen contained within the air bubbles trapped in the ice goes into solution (ocean). However, the dissolved oxygen levels that result from this process are significantly lower than those obtained by equilibration with the atmosphere. To find out how this affects marine life, researchers at  University of California, Davis wanted to see how ancient life reacted to sudden melting periods like those following an ice age. To this end, they carved fossilized marine fauna samples from from the ocean floor off Santa Barbara, California. They recovered some 5,400 invertebrate fossils, including those of spanning a period between 3,400 and 16,100 years ago. During this time the climate abruptly warmed, akin to what we’re currently experiencing because of greenhouse gas emissions. According to the researchers, the fauna “nearly disappeared from the record during those times of low oxygen,” according to the study.

The damage was made in only a couple of decades, however it took thousands of years for marine life to rebound back to previous levels.

“There’s not a recovery we have to look forward to in my lifetime or my grandchildren’s lifetime,” said lead author Sarah Moffitt, a scientist from the Bodega Marine Laboratory and Coastal and Marine Sciences Institute at the University of California, Davis.

“It’s a gritty reality we need to face as scientists and people who care about the natural world and who make decisions about the natural world.”