Export of submicron particulate organic matter to mesopelagic depth in an oligotrophic gyre.
Proc Natl Acad Sci U S A
; 110(31): 12565-70, 2013 Jul 30.
Article
in En
| MEDLINE
| ID: mdl-23858459
ABSTRACT
Sixty percent of the world ocean by area is contained in oligotrophic gyres [Longhurst A (1995) Prog Oceanog 3677-16], the biomass of which is dominated by picophytoplankton, including cyanobacteria and picoeukaryotic algae, as well as picoheterotrophs. Despite their recognized importance in carbon cycling in the surface ocean, the role of small cells and their detrital remains in the transfer of particulate organic matter (POM) to the deep ocean remains disputed. Because oligotrophic marine conditions are projected to expand under current climate trends, a better understanding of the role of small particles in the global carbon cycle is a timely goal. Here we use the lipid profiles, radiocarbon, and stable carbon isotopic signatures of lipids from the North Pacific Subtropical Gyre to show that in the surface ocean, lipids from submicron POM (here called extra-small POM) are distinct from larger classes of suspended POM. Remarkably, this distinct extra-small POM signature dominates the total lipids collected at mesopelagic depth, suggesting that the lipid component of mesopelagic POM primarily contains the exported remains of small particles. Transfer of submicron material to mesopelagic depths in this location is consistent with model results that claim the biological origin of exported carbon should be proportional to the distribution of cell types in the surface community, irrespective of cell size [Richardson TL, Jackson GA (2007) Science 315838-840]. Our data suggest that the submicron component of exported POM is an important contributor to the global biological pump, especially in oligotrophic waters.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Cyanobacteria
/
Geologic Sediments
/
Aquatic Organisms
Language:
En
Journal:
Proc Natl Acad Sci U S A
Year:
2013
Type:
Article
Affiliation country:
United States