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Highly elevated methane in the eastern tropical North Pacific and associated isotopically enriched fluxes to the atmosphere
Author(s) -
Sansone Francis J.,
Popp Brian N.,
Gasc Anne,
Graham Andrew W.,
Rust Terri M.
Publication year - 2001
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2001gl013460
Subject(s) - upwelling , ocean gyre , oceanography , atmosphere (unit) , subtropics , methane , advection , environmental science , geology , climatology , atmospheric sciences , chemistry , geography , meteorology , biology , physics , organic chemistry , fishery , thermodynamics
During the May ‐ June, 2000 Eastern Pacific Redox Experiment (EPREX) we examined the dynamics of methane (CH 4 ) in the eastern tropical North Pacific (ETNP), a large region of high surface‐ocean productivity fueled by coastal upwelling. We discovered that (1) the ETNP contains by far the largest pool of CH 4 yet discovered in the open ocean; (2) CH 4 production in the upper half of this subsurface pool is associated with the decomposition of locally produced sinking particulate matter; (3) the deeper half of this pool is from a coastal source; (4) advection and oxidation of the upper pool leads to the heavy CH 4 isotopic values seen at midwater in the North Pacific subtropical gyre; and (5) the ETNP is a source of isotopically enriched CH 4 to the atmosphere. Our results suggest that other oceanic areas of upwelling‐induced anoxia may be sites of significant atmospheric input of isotopically heavy CH 4 .