Welcome to OCB

OCB was established in 2006 as one of the major activities of the U.S. Carbon Cycle Science Program, an interagency body that coordinates and facilitates activities relevant to carbon cycle science, climate, and global change issues. The scientific mission of OCB is to study the evolving role of the ocean in the global carbon cycle, in the face of environmental variability and change through studies of marine biogeochemical cycles and associated ecosystems.

Overarching Themes

Improve understanding and prediction of:

  1. oceanic uptake and release of atmospheric CO2 and other greenhouse gases;
  2. environmental sensitivities of biogeochemical cycles, marine ecosystems, and interactions between the two   

Currently Identified Research Priorities

  • Climate- and human-driven changes in ocean chemistry (e.g., acidification, expanding low-oxygen conditions, nutrient loading, etc.) and associated impacts on biogeochemical cycles and marine ecosystems 
  • Ocean carbon uptake and storage
  • Estuarine and coastal carbon fluxes and processes, including exchanges with open ocean, terrestrial, and atmospheric reservoirs
  • Water column and seafloor ecological and biogeochemical processes and associated effects on carbon export and the biological pump
  • Molecular-level responses of marine organisms (primarily lower trophic levels, including plankton, mollusks, etc.) to their changing environment  
  • Impacts of evolutionary changes on plankton community structure, function and biogeochemical cycling in the face of global change

Science Highlights

Submit your science features to the OCB Project Office.

New In Situ Sensor Technology for Simultaneous Spectrophotometric
Measurements of Seawater Total Dissolved Inorganic Carbon and pH

Figure from Wang et al. (2015)

A new, in situ sensing system, Channelized Optical System (CHANOS), was recently developed to make high-resolution, simultaneous measurements of total dissolved inorganic carbon (DIC) and pH in seawater. Measurements made by this single, compact sensor can fully characterize the marine carbonate system. Read the full article by Z. A. Wang et al., 2015: In Situ Sensor Technology for Simultaneous Spectrophotometric Measurements of Seawater Total Dissolved Inorganic Carbon and pH. Environ. Sci. Technol. 49 (7), 4441–4449 DOI: 10.1021/es504893n). Submitted by Z. Aleck Wang (WHOI).

Decreasing calcification in the Southern Ocean may be linked to acidification

 

A scanning electron micrograph of a single coccolithophore cell, Emiliania huxleyi - single-celled marine phytoplankton that produces calcium carbonate scales. Credit: Alison Taylor, Wikimedia CC  

The Southern Ocean absorbs a large fraction of anthropogenic-sourced carbon dioxide from the atmosphere each year, driving decreases in the pH and the carbonate ion concentration.  This acidification occurs in a region with a naturally low carbonate ion concentration, and studies suggest that the surface of the Southern Ocean will become undersaturated with respect to calcium carbonate minerals aragonite and calcite by the end of the century.  Most laboratory studies suggest that higher carbon dioxide concentration leads to decreased calcification in coccolithophores, the tiny phytoplankton that contribute to the base of Southern Ocean food webs. 

Using satellite observations of particulate inorganic carbon (PIC), chlorophyll, and sea surface temperature, a recent study reports a decrease in phytoplankton calcification in the Southern Ocean over the satellite record (1998 to 2014).  Averaged over the whole Southern Ocean, summertime calcification declines by 4%, and large regions in the Pacific and Indian sectors exhibit 9% reductions in calcification and 24% reductions in PIC over the same time period.  The decreases in calcification and PIC occur simultaneously with decreases in the observed carbonate ion concentration, suggesting a possible link between acidification and decreasing calcification in this vulnerable region. 

Read the full article: Freeman, N.M., and N.S. Lovenduski, 2015: Decreased calcification in the Southern Ocean over the satellite record, Geophysical Research Letters, doi:10.1002/2014GL062769.

Submitted by Natalie M. Freeman and Nicole S. Lovenduski (University of Colorado, Boulder).

 

OCB receives support from the National Science Foundation and the National Aeronautics and Space Administration.

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