Marine ecosystems can take millennia to recover from climate-related upheavals

A new study has revealed that ocean ecosystems can take millennia to recover from the climate-related disturbances.

The first massive study helped explore the historical ocean response to abrupt climate change with the help of a 30-foot-long core sample of Pacific Ocean seafloor.

The study's authors, including Peter Roopnarine, PhD, of the California Academy of Sciences, analyzed thousands of invertebrate fossils to show that ecosystem recovery from climate change and seawater deoxygenation might take place on a millennial scale.

The scientific collaborative, led by Sarah Moffitt, PhD, from the UC Davis Bodega Marine Laboratory and Coastal and Marine Sciences Institute, analyzed more than 5,400 invertebrate fossils, from sea urchins to clams, within a sediment core from offshore Santa Barbara, California.

The tube-like sediment core was a slice of ocean life as it existed between 3,400 and 16,100 years ago, and provides a before-and-after snapshot of what happened during the last major deglaciation, a time of abrupt climate warming, melting polar ice caps, and expansion of low oxygen zones in the ocean.

The new study documented how long it has historically taken for ecosystems to begin recovery following dramatic shifts in climate.

The results suggested that future periods of global climate change may 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 is published today in the journal PNAS.