• ArtsandLectures twitter avatar
    Watch pianist #MurrayPerahia's breathtaking and imaginative performance, tonight at 7PM at UCSB Campbell Hall!… https://t.co/M83EeA6Y53
    2 hours 35 min ago
  • UCSBgauchos twitter avatar
    Softball: Hawai'i Tops UCSB 5-1 in Gauchos' Final Road Series Opener https://t.co/ejf0MWM1g0
    9 hours 56 min ago
  • UCSBgauchos twitter avatar
    Gauchos Sweep Past UCI 4-0 https://t.co/WFwbxDV8eA
    12 hours 33 min ago
  • ucsantabarbara twitter avatar
    We're happy to see you back, alumni! Don't miss the great events we have this weekend. #AllGauchoReunion… https://t.co/Sbz4iirr7i
    16 hours 10 min ago
  • UCSBgauchos twitter avatar
    Women's Tennis: Cal Poly 0, UC Santa Barb. 4 (Final) No.2 UCSB blanks No.7 Cal Poly in Big West Quarterfinal 4-0 https://t.co/m4kdACQFo5
    16 hours 13 min ago
  • UCSBgauchos twitter avatar
    .@UCSB_Baseball vs. UC Riverside on @ESPN3 is live now! Watch here >>> https://t.co/QJMvNLa0mQ
    16 hours 32 min ago
  • UCSBgauchos twitter avatar
    WWP: Defending Big West Champs Defeated by No. 12 LBSU in Another Overtime Match https://t.co/XIO3RJdo9p
    16 hours 50 min ago
  • UCSBgauchos twitter avatar
    Top-Seeded UCSB Set to Host Big West Golf Championship at Sandpiper GC https://t.co/SyXPKB2Ur5
    18 hours 25 min ago
  • UCSBLibrary twitter avatar
    RT @ForestSways: CEMA poster preservation for primary source research. #Chicanohertiage @Marikhasmanyan @UCSBLibrary #sca17 https://t.co/M…
    20 hours 26 min ago
  • UCSBLibrary twitter avatar
    @AmldavisAnn We're glad you're interested in using, please contact (805) 893-3062 or @library.ucsb.edu">special@library.ucsb.edu for m… https://t.co/fwAVOMoWyB
    20 hours 27 min ago
  • UCSB_GradPost twitter avatar
    CPT F-1 Visa workshop for international students on May 11 https://t.co/l6xZEndRVl #UCSB #ucsbgradpost
    20 hours 42 min ago
  • UCSB_GradPost twitter avatar
    Two open postdoc positions on Verification of Quantum Cryptography https://t.co/ZRA2iro7Ym #UCSB #ucsbgradpost
    20 hours 42 min ago
  • UCSB_GradPost twitter avatar
    Professor Micaela J. Díaz-Sánchez to speak about bomba on May 2 https://t.co/D4g84xVXkD #UCSB #ucsbgradpost
    20 hours 43 min ago
  • ArtsandLectures twitter avatar
    #DavidSedaris talks to the @SBIndpndnt about his new book Theft By Finding: "You might say he’s stolen our hearts."… https://t.co/fR3WFw02CL
    21 hours 37 min ago
  • brenucsb twitter avatar
    Is it possible to have negative GHG emissions? #UK launches national initiative to find negative emissions tech https://t.co/gHHHQHJLf1
    21 hours 39 min ago

The Carbon Dioxide Loop

Marine biologists quantify the carbon consumption of bacterioplankton to better understand the ocean carbon cycle
Thursday, March 16, 2017 - 09:45
Santa Barbara, CA

flagellate 2 2.jpg

microbial food web

Bacterioplankton (dots) surrounded by a nanoflagellate (white), which preys on the bacteria.

Photo Credit: 

Rachel Parsons

Passow James and Carlson.jpg

Passow, James and Carlson

Uta Passow, Anna James and Craig Carlson.

Photo Credit: 

Sonia Fernandez

The oceans are great at absorbing carbon dioxide (CO2) from the air, but when their deep waters are brought to the surface, the oceans themselves can be a source of this prevalent greenhouse gas.

Wind patterns together with the Earth’s rotation drive deep ocean water — and the CO2 it sequesters — upward, replacing surface water moving offshore. A process known as upwelling, it occurs on the west coasts of continents. And it’s part of a never-ending loop in which CO2 levels in the surface ocean rise and fall in a natural rhythm.

But when CO2 levels rise, ocean pH falls, causing ocean acidification. Seeking to explore how short-term periods of elevated CO2 from upwelling impact the bacteria in the water, UC Santa Barbara researchers found that the additional CO2 — and corresponding drop in pH — increased the respiration of these organisms. This means more resources are recycled rather than retained in the food web. The results appear in the journal PLOS ONE.

“Despite their microscopic size, these bacteria drive the major cycling of carbon in the ocean’s surface,” said lead author Anna K. James, a graduate student in UCSB’s Interdepartmental Graduate Program in Marine Science. “I wanted to see how much dissolved organic carbon the bacteria were eating and what proportion they dedicated to biomass.”      

In addition to measuring the organisms’ biomass, James calculated bacterial respiration. When these microbes respire, the organic carbon they consume is converted back to CO2, which — as a gas — has the potential to go back into the atmosphere or to once again dissolve in the surface ocean.

“The elevated bacterial respiration could limit the oceans’ ability to store organic carbon by converting it back to CO2,” James explained. 

To measure the flow of carbon through bacteria, James conducted remineralization experiments — seawater culture incubations that use filtered surface seawater. She collected natural bacterial communities from the surface ocean, added them to the filtered seawater and measured how much carbon the bacteria consumed. From that, James was able too calculate their biomass, abundance and respiration.

“It important to know what bacterial respiration is because it has a number of implications for the ocean carbon cycle,” James said. “The first is the movement of organic carbon from the surface into the deep ocean either via physical mixing or sinking. The other is, if the organic carbon is contained in bacterial biomass, it can be consumed by other organisms that eat bacteria.”

The upshot: Factors that affect the recycling rate of microbes alter the fate of organic matter in the ocean’s water column. “It is really surprising to realize that tiny bacteria respond to the concentration of CO2 available and in turn influence the amount of carbon the ocean takes up,” said co-author Uta Passow, a research oceanographer at UCSB’s Marine Science Institute.

“Anna’s work demonstrates an unexpected but important finding that shows marine bacteria can directly respond to rapid decreases in ocean pH,” said co-author Craig Carlson, a professor in UCSB’s Department of Ecology, Evolution and Marine Biology. “By increasing their recycling rate, bacteria convert some of the organic matter back to CO2, which has implications in food web and ocean biogeochemical processes.” 

Contact Info: 

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

Topics: