The effects of climate change on the world's seas might be felt thousands of years from now and not just in the immediate future.

Scientists from the University of California analyzed thousands of invertebrate fossils to prove that ecosystem recovery from climate change and seawater deoxygenation might take place on a millennial scale. The study involved 5,400 invertebrate fossils within a sediment core from offshore Santa Barbara, California.

Like Us on Facebook

The new study shows how long it has historically taken ecosystems to begin recovery following dramatic shifts in climate. The slice of ocean life (called tube-like sediment core) existed between 3,400 and 16,100 years ago.

It gives scientists an idea of the before-and-after events that happened during the last major deglaciation.

There was a period of abrupt warming and oxygen loss in the oceans during that period. When oxygen levels fell, the result was a rapid loss of biodiversity with fossils nearly disappearing from the record.

The study reveals invertebrate fossils are nearly non-existent during times of lower-than-average oxygen levels.

"These past events show us how sensitive ecosystems are to changes in Earth's climate - it commits us to thousands of years of recovery. It shows us what we're doing now is a long-term shift - there's not a recovery we have to look forward to in my lifetime or my grandchildren's lifetime," said Sarah Moffitt, PhD, from the UC Davis Bodega Marine Laboratory and Coastal and Marine Sciences Institute

Scientists used a 30 foot-long core sample of the Pacific Ocean seafloor. They emphasized the importance of using a large sample from one portion of the seafloor. The team "cut it up like a cake" to analyze the full, unbroken record.

The results also suggest future periods of global climate change might result in similar ecosystem-level effects with millennial-scale recovery periods.

As the planet warms, scientists expect to see much larger areas of low-oxygen "dead zones" in the world's oceans.

The study appeared in the journal PNAS.

TagsMarine Ecosystems Can Recover from Climate Change after Millennia, Ocean, global warming, Marine Ecosystems, marine animals, invertebrate fossils, oxygen levels, sediment core