Tiny shells reveal waters off California are acidifying twice as fast as the global ocean

These colorful spots are tiny foraminifera shells taken from the mud of core samples as seen under a microscope. Credit: NOAA

California coastal waters contain some of our nation's more economically valuable fisheries, including salmon, crabs and shellfish. Yet, these fisheries are also some of the most vulnerable to the potential harmful effects of ocean acidification on marine life. That increase in acidity is caused by the ocean absorbing excess carbon dioxide from the atmosphere.

100 years and 2,000 shells later

In the new study published in the journal Nature Geoscience, scientists examined nearly 2,000 shells of microscopic animals called foraminifera by taking core samples from the seafloor off Santa Barbara and measuring how the shells of these animals have changed over a century.

Every day, the shells of dead foraminifera rain down on the ocean floor and are eventually covered by sediment. Layers of sediment containing shells form a vertical record of change. The scientists looked back through time, layer by layer, and measured changes in thickness of the shells.

“By measuring the thickness of the shells, we can provide a very accurate estimate of the ocean's acidity level when the foraminifera were alive,” said lead author Emily Osborne, who used this novel technique to produce the longest record yet created of ocean acidification using directly measured marine species. She measured shells within cores that represented deposits dating back to 1895.

The fossil record also revealed an unexpected cyclical pattern: Though the waters increased their overall acidity over time, the shells revealed decade-long changes in the rise and fall of acidity.

This pattern matched the Pacific Decadal Oscillation, a natural warming and cooling cycle. Human-caused carbon dioxide emissions are driving ocean acidification, but this natural variation also plays an important role in alleviating or amplifying ocean acidification.

“During the cool phases of the Pacific Decadal Oscillation, strengthened winds across the ocean drive carbon dioxide-rich waters upward toward the surface along the West Coast of the U.S.,” said Osborne, a scientist with NOAA's Ocean Acidification Program. “It's like a double whammy, increasing ocean acidification in this region of the world.”

Scientists hope to build on the new research to learn more about how changes in ocean acidification may be affecting other aspects of the marine ecosystem.

Media Contact

Monica Allen
monica.allen@noaa.gov
202-379-6693

 @NOAA

Media Contact

Monica Allen EurekAlert!

Alle Nachrichten aus der Kategorie: Earth Sciences

Earth Sciences (also referred to as Geosciences), which deals with basic issues surrounding our planet, plays a vital role in the area of energy and raw materials supply.

Earth Sciences comprises subjects such as geology, geography, geological informatics, paleontology, mineralogy, petrography, crystallography, geophysics, geodesy, glaciology, cartography, photogrammetry, meteorology and seismology, early-warning systems, earthquake research and polar research.

Zurück zur Startseite

Kommentare (0)

Schreib Kommentar

Neueste Beiträge

Endangered botanic predators

Globally, one fourth of carnivorous plants are threatened An international research team including botanist Andreas Fleischmann from SNSB-BSM has evaluated the Red List threat categories for all 860 known species…

The smallest particle sensor in the world

Styrian technological innovation – made in Graz TU Graz, ams and Silicon Austria Labs has developed a compact and energy-efficient sensor for mobile devices, which informs users in real time…

Nanostructures with a unique property

Nanoscale vortices known as skyrmions can be created in many magnetic materials. For the first time, researchers at PSI have managed to create and identify antiferromagnetic skyrmions with a unique…

By continuing to use the site, you agree to the use of cookies. more information

The cookie settings on this website are set to "allow cookies" to give you the best browsing experience possible. If you continue to use this website without changing your cookie settings or you click "Accept" below then you are consenting to this.

Close