Climate study predicts declining marine biological productivity

Mar 09, 2018

A national team of Earth system modelers analyzed simulations through the year 2300 and found that increasing global temperatures could drive declines in marine biological productivity, decreasing fishery output by 20% globally and 60% in the North Atlantic.

Using high-performance computing and scenarios developed by the international modeling community, scientists simulated alterations in global environmental systems over the next two centuries. Their analysis — published in Science—examines how changes in climate could lead to the trapping of nutrients in the Southern Ocean.

The simulations showed that as strong westerly winds shift toward the poles and surface waters warm, sea ice disappears and ocean currents around Antarctica change, fostering the growth of phytoplankton in southern waters and limiting the movement of key nutrients such as nitrogen and phosphorous to the northern oceans. With these elements concentrated in the southern latitudes, phytoplankton in northern waters would decline, impacting the entire food chain, including humans who catch and eat fish.

These changes could also cause a significant decline in the movement of carbon into the deep ocean and trigger a shift in pH at the ocean surface, reducing the capacity of the ocean to absorb and remove carbon from the atmosphere, the researchers found.

Similar studies typically examine potential climate changes through 2100. By extending the simulation to 2300, the research team gained new insights into shifts in the biogeochemistry of the ocean that take centuries longer to manifest.

Keith Moore of the University of California, Irvine led the research in collaboration with a national team of scientists, including Oak Ridge National Laboratory’s Forrest Hoffman, who contributed to the development of the simulation and resulting analysis.

Other coauthors on the paper include Weiwei Fu, Francois Primeau, Gregory Britten, and James Randerson of the University of California, Irvine; Keith Lindsay and Matthew Long of the National Center for Atmospheric Research; Scott Doney of the University of Virginia; and Natalie Mahowald of Cornell University.

The research was conducted as part of the Reducing Uncertainties in Biogeochemical Interactions through Synthesis and Computation (RUBISCO) Scientific Focus Area, which is sponsored by the Department of Energy’s Biological and Environmental Research program.

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--by Kim Askey