Global warming to drive massive ocean biodiversity shift

Where will fish go as the oceans warm?

Changes will come at unprecedented pace

Staff Report

FRISCO — Ocean biodiversity is set to change at an unprecedented pace, a team of researchers said in a new study after modeling how global warming will affect some 13,000 ocean species.

The findings reinforce a large body of previous research showing that, in general, many fish will move toward toward the poles looking for cooler water. The researchers pointed out that similar redistributions have happened before — but always on a geological timescale spanning millions of years.

But the current rapid increase in global ocean temperatures means there will be massive biodiversity shifts in the next century, with as-yet unknown effects on for people who depend on that biodiversity, for  seafood and economies linked to ocean tourism.

The new study was done by 10 scientists affiliated with UC Santa Barbara’s National Center for Ecological Analysis and Synthesis and published in the journal Nature Climate Change. The findings suggest that the global changes will increase biodiversity in some areas and lead to extinctions in others.

“Climate change is going to reshuffle marine biodiversity, creating novel communities,” said Ben Halpern, a professor at UCSB’s Bren School of Environmental Science & Management and an NCEAS associate.

“We focus on the simple assumption that species track water temperature, and we have data on temperature preferences for most species,” Halpern said.

As some species migrate, they will mingle with other species that can tolerate a wider range of water temperatures may not move right away. That means more biodiversity, at least initially, But eventually, the migration will drive a homogenizing process as once-unique communities come to resemble one another.

Other species that have more restricted ranges — especially those in the so-called Coral Triangle, the center of global marine biodiversity — are more likely to face extinction.

The modeling suggests that there will be a widespread redistribution of existing marine biodiversity with any increase in global temperatures, whether warming is closer to the maximum predicted amount or more moderate.

“We have a chance to minimize the impacts of climate change on marine biodiversity,” Halpern said. “Our simulations show that if we can slow down climate change, changes in biodiversity will be much less than if we leave climate change unchecked.”


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