@article{fdi:010091476,
  title = {{N}et heterotrophy in the {A}mazon continental shelf changes rapidly to a sink of {CO}2 in the outer {A}mazon plume},
  author = {{L}ef{\`e}vre, {N}athalie and {F}lores {M}ontes, {M}. and {G}aspar, {F}.{L}. and {R}ocha, {C}. and {J}iang, {S}. and {D}e {A}raújo, {M}.{C}. and {I}bánhez,  {J}.{S}.{P}.},
  editor = {},
  language = {{ENG}},
  abstract = {{T}he {A}mazon continental shelf and adjacent oceanic area were sampled for inorganic and organic carbon parameters in order to improve data coverage and understanding of carbon cycling dynamics within this important region. {S}easonal coverage of the {A}mazon plume on the {F}rench {G}uiana continental shelf further north, was provided by {CO}2 monitoring using a merchant ship sailing from {F}rance to {F}rench {G}uiana (2006-2016). {S}alinity ranged from 1 to 36 (transects in {A}pril 2013, and {M}ay 2014). {A}t salinity below 10, strong outgassing was observed with fugacity of {CO}2 (f{CO}2) over 2,000 {M}u atm. {T}his region displayed net heterotrophy, fueled by organic matter with terrestrial origin, as shown by delta 13{C} and delta 15{N} values of suspended particles. {A} delta 13{C} cross shelf average of -31% was measured during {M}ay 2014, contrasting with oceanic values in excess of -20%. {T}he reactivity of this terrestrial material resulted in the local production of dissolved inorganic and organic carbon as well as fluorescent humic compounds. {F}urther offshore, the dilution of freshwater by ocean waters created a sink for {CO}2, enhanced by biological activity. {T}he strongest {CO}2 drawdowns, associated with high chlorophyll a concentrations, were observed on the {F}rench {G}uiana continental shelf in the outer {A}mazon plume, with f{CO}2 values below 150 {M}u atm. {H}ere, a {CO}2 sink was present almost throughout the year, with a seasonal maximum of ?9.2 mmol {CO}2 m-2d-1 observed in {J}une 2015. {H}owever, both the {CO}2 and salinity distributions could vary significantly within a few days, confirming the presence of many eddies in this region. {T}he {A}mazon continental shelf hence behaved as a transition zone between an inshore source of {CO}2 to the atmosphere and an offshore sink. {S}ome marine phytoplankton production was detected but occurred mainly close to the {F}rench {G}uiana shelf. {A} mean net {CO}2 outgassing of 44 ± 43.6 mmol m-2d-1 was estimated for the area. {Q}uantifying the {CO}2 flux for the entire {A}mazon shelf area led to a revised annual estimate of the net ocean carbon export of 2.86 1012 mol {C} from the region.},
  keywords = {{GUYANE} {FRANCAISE} ; {ATLANTIQUE} ; {ZONE} {TROPICALE} ; {AMAZONIE} {BASSIN}},
  booktitle = {},
  journal = {{F}rontiers in {M}arine {S}cience},
  volume = {4},
  numero = {},
  pages = {278 [16 ]},
  ISSN = {2296-7745},
  year = {2017},
  DOI = {10.3389/fmars.2017.00278},
  URL = {https://www.documentation.ird.fr/hor/fdi:010091476},
}