Naturally occurring climate change lowered oxygen levels in the deep ocean, decimating a broad spectrum of seafloor life that took some 1,000 years to recover, according to a study that offers a potential window into the effects of modern warming.
Earth’s recovery from the last glacial period, in fact, was slower and more brutal than previously thought, according to the study, published online Monday (30 March 2015) in the journal Proceedings of the National Academy of Sciences.
Researchers deciphered that plotline from a 30-foot core of sea sediments drilled from the Santa Barbara Basin containing more than 5,000 fossils spanning nearly 13,000 years, The Los Angeles Times reported on Wednesday (1 April 2015).
“The recovery does not happen on a century scale; it’s a commitment to a millennial-scale recovery,” said Sarah Moffitt, a marine ecologist at UC Davis’ Bodega Marine Laboratory and lead author of the study. “If we see dramatic oxygen loss in the deep sea in my lifetime, we will not see a recovery of that for many hundreds of years, if not thousands or more.”
Studies already have chronicled declines in dissolved oxygen in some areas of Earth’s oceans. Such hypoxic conditions can expand when ocean temperatures rise and cycles that carry oxygen to deeper areas are interrupted, Moffitt added.