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Respiration of new and old carbon in the surface ocean: Implications for estimates of global oceanic gross primary productivity
Author(s) -
Carvalho Matheus C.,
Schulz Kai G.,
Eyre Bradley D.
Publication year - 2017
Publication title -
global biogeochemical cycles
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.512
H-Index - 187
eISSN - 1944-9224
pISSN - 0886-6236
DOI - 10.1002/2016gb005583
Subject(s) - primary production , productivity , autotroph , respiration , heterotroph , carbon fibers , environmental science , nutrient , carbon cycle , primary productivity , photic zone , irradiance , oceanography , environmental chemistry , ecology , chemistry , botany , ecosystem , biology , phytoplankton , bacteria , geology , mathematics , genetics , physics , algorithm , quantum mechanics , composite number , economics , macroeconomics
New respiration ( R new , of freshly fixated carbon) and old respiration ( R old , of storage carbon) were estimated for different regions of the global surface ocean using published data on simultaneous measurements of the following: (1) primary productivity using 14 C ( 14 PP); (2) gross primary productivity (GPP) based on 18 O or O 2 ; and (3) net community productivity (NCP) using O 2 . The ratio R new /GPP in 24 h incubations was typically between 0.1 and 0.3 regardless of depth and geographical area, demonstrating that values were almost constant regardless of large variations in temperature (0 to 27°C), irradiance (surface to ~100 m deep), nutrients (nutrient‐rich and nutrient‐poor waters), and community composition (diatoms, flagellates, etc,). As such, between 10 and 30% of primary production in the surface ocean is respired in less than 24 h, and most respiration (between 55 and 75%) was of older carbon. R new was most likely associated with autotrophs, with minor contribution from heterotrophic bacteria. Patterns were less clear for R old . Short 14 C incubations are less affected by respiratory losses. Global oceanic GPP is estimated to be between 70 and 145 Gt C yr −1 .