• UCSBgauchos twitter avatar
    UCSB Soccer Hosts Eighth Annual AYSO Skills Day on Sunday, Aug. 20 https://t.co/sp5rUScYaO
    4 hours 7 min ago
  • brenucsb twitter avatar
    Balancing dual needs for healthy rivers & low-carbon energy is possible with system-scale thinking https://t.co/4CxFykWghf @WaterSourceMag
    7 hours 23 min ago
  • ucsantabarbara twitter avatar
    A team from #UCSB and @BOEM_DOI are working together to determine effects of oil platform removal scenarios. https://t.co/x3dXN7slCa
    10 hours 2 min ago
  • UCSBgauchos twitter avatar
    WSOC: Chace Schornstein adds another goal off an assist from Shaelan Murison to give @UCSBWomenSoccer a 3-0 lead! #gogauchos
    22 hours 35 min ago
  • UCSBgauchos twitter avatar
    WSOC: Amanda Ball converts a penalty kick, and scores again minutes later to give @UCSBWomenSoccer a 2-0 lead over Idaho! #ucsb
    22 hours 44 min ago
  • UCSBgauchos twitter avatar
    WSOC: At the half, @UCSBWomenSoccer and Idaho are tied 0-0 #gogauchos #ucsb
    23 hours 6 min ago
  • brenucsb twitter avatar
    New Bren Life blog post: MESM 2018 Made Harris shares her summer experiences at @NOAAFisheries in DC. https://t.co/ViBF4vPDni
    1 day 3 hours ago
  • UCSB_GradPost twitter avatar
    Apply for Harvard Academy Postdoc Scholars Program https://t.co/3TH4fwUWwj #UCSB #ucsbgradpost
    1 day 3 hours ago
  • UCSB_GradPost twitter avatar
    Applications now open for Woodrow Wilson International Center for… https://t.co/XnwyHuWAet #UCSB #ucsbgradpost
    1 day 3 hours ago
  • UCSBLibrary twitter avatar
    New England Tours, 1932 Eclipse Edition. From the #UCSB Library's newly acquired David L. Cole Collection.… https://t.co/j7LDYj2l0c
    1 day 4 hours ago

Decoding Ocean Signals

Geographer Tim DeVries and colleagues determine why the ocean has absorbed more carbon over the past decade
Wednesday, February 8, 2017 - 12:00
Santa Barbara, CA

Tim DeVries.jpg

Tim DeVries

Tim DeVries

Photo Credit: 

Sonia Fernandez

With the ocean absorbing more carbon dioxide (CO2) over the past decade, less of the greenhouse gas is reaching the Earth’s atmosphere. That’s decidedly good news, but it comes with a catch: Rising levels of CO2 in the ocean promote acidification, which breaks down the calcium carbonate shells of some marine organisms.

The cause of this recent increase in oceanic CO2 uptake, which has implications for climate change, has been a mystery. But new research from UC Santa Barbara geographer Timothy DeVries and colleagues demonstrates that a slowdown of the ocean’s overturning circulation is the likely catalyst. Their findings appear in the journal Nature.

“Such a slowdown is consistent with the projected effects of anthropogenic climate change, where warming and freshening of the surface ocean from melting ice caps leads to weaker overturning circulation,” DeVries explained. “But over the time periods we studied, it’s not possible to say whether the slowdown is related to natural climate variability or to climate change caused by human activity.”

DeVries and fellow researchers Mark Holzer of the University of New South Wales in Sydney and François Primeau of UC Irvine compiled existing oceanographic tracer data — measurements of temperature, salinity, CFCs (manmade gases that dissolve into the ocean) and carbon-14 — and separated it into three decade-long time periods: the 1980s, the 1990s and the 2000s.

 Subsequent computer analysis of that data enabled the researchers to characterize ocean circulation — the transfer of water from the surface to the deep ocean and back again — for each time period. They then analyzed ocean-atmosphere carbon exchange and ocean carbon cycling within their circulation model.

“As the circulation changed from decade to decade —1980s to 1990s to 2000s — the model predicted a big dip in oceanic CO2 uptake during the 1990s, then a large increase in uptake during the 2000s,” DeVries explained. “Furthermore, these swings were attributed directly to the changes in ocean circulation.”

According to DeVries, this finding may seem counterintuitive. Prevailing scientific wisdom asserts that the deceleration of circulation diminishes the ocean’s ability to absorb anthropogenic CO2 from the atmosphere as surface waters warm and become saturated with CO2.

“While that is true, there is another effect that appears to be more important in the short term,” DeVries said. “The weaker overturning circulation brings less naturally CO2-rich deep waters to the surface, which limits how much of that gas in the deep ocean escapes to the atmosphere. That causes the ocean to absorb more CO2 from the atmosphere.

Contact Info: 

Julie Cohen
(805) 893-7220
julie.cohen@ucsb.edu