The importance of continental margins in the global carbon cycle
Abstract
Approximately half of the world's net annual photosynthesis occurs in the oceans (~48 Pg C y-1). Areas bordering continents (bottom <2000 m) support 10-15% of this production. We used satellite data to compute annual global net primary production (1998-2001), and derived the global particulate organic carbon (POC) flux settling below the permanent thermocline and to the seafloor using an empirical model of POC remineralization. Approximately 0.68 Pg C y-1 sink below the thermocline on continental margins, compared to 1.01 Pg C y-1 in the deep ocean. Over 0.62 Pg C y-1 settles to the seafloor on margins, compared to 0.31 Pg C y-1 to deep ocean sediments. At least 0.06 Pg C y-1 may be buried in sediments on margins. Therefore, margins may be responsible for >40% of the carbon sequestration in the ocean. These regions must be accounted for in realistic models of the global carbon cycle and its linkages to climate change.
- Publication:
-
Geophysical Research Letters
- Pub Date:
- January 2005
- DOI:
- 10.1029/2004GL021346
- Bibcode:
- 2005GeoRL..32.1602M
- Keywords:
-
- Global Change: Biogeochemical cycles;
- processes;
- and modeling (0412;
- 0414;
- 0793;
- 4805;
- 4912);
- Global Change: Remote sensing (1855);
- Oceanography: General: Continental shelf and slope processes (3002);
- Oceanography: Biological and Chemical: Nutrients and nutrient cycling (0470;
- 1050);
- Geochemistry: Marine geochemistry (4835;
- 4845;
- 4850)