@article{fdi:010071283,
  title = {{T}he {OMZ} and nutrient features as a signature of interannual and low-frequency variability in the {P}eruvian upwelling system},
  author = {{G}raco, {M}. {I}. and {P}urca, {S}. and {D}ewitte, {B}oris and {C}astro, {C}. {G}. and {M}oron, {O}. and {L}edesma, {J}. and {F}lores, {G}. and {G}utierrez, {D}.},
  editor = {},
  language = {{ENG}},
  abstract = {{O}ver the last decades, the {H}umboldt {C}urrent upwelling ecosystem, particularly the northern component off the coast of {P}eru, has drawn the interest of the scientific community because of its unique characteristics: it is the upwelling system with the biggest catch productivity despite the fact it is embedded in a shallow and intense oxygen minimum zone ({OMZ}). {I}t is also an area of intense nitrogen loss and anammox activity and experiences large interannual variability associated with the equatorial remote forcing. {I}n this context, we examined the oceanographic and biogeochemical variability associated with the {OMZ} off central {P}eru from a monthly time series (1996-2011) recorded off the coast of {C}allao (12 degrees 02'{S}, 77 degrees 29'{W}). {T}he data reveal a rich spectrum of variability in the {OMZ} that includes frequencies ranging from seasonal to interannual scales. {D}ue to the efficient oceanic teleconnection off {P}eru, the observed variability is interpreted in the light of an estimate of the equatorial {K}elvin wave contribution to sea level anomalies considering the peculiarities of its vertical structure (i.e., the first two baroclinic modes). {T}he span of the data set allows us to contrast two {OMZ} regimes. {T}he "strong" regime is associated with the strong 1997-1998 equatorial {P}acific {E}l {N}ino, during which the {OMZ} adjusted to {K}elvin-wave-induced downwelling conditions that switched off the upwelling and drastically reduced nutrient availability. {T}he "weak" regime corresponds to the post-2000 period associated with the occurrence of moderate central {P}acific {E}l {N}ino events and enhanced equatorial {K}elvin wave activity, in which mean upwelling conditions are maintained. {I}t is shown that the characteristics of the coupling between physics and biogeochemistry is distinct between the two regimes with the weak regime being associated with a larger explained variance in biogeochemical properties not linearly related to the {ENSO} oceanic teleconnection. {T}he data also reveal a long-term trend from 1999 corresponding to a deepening of the oxygen-deficient waters and warming. {T}he implications of our results for understanding the {OMZ} dynamics off {P}eru are discussed.},
  keywords = {{PEROU} ; {PACIFIQUE} ; {HUMBOLDT} {COURANT} ; {ZONE} {EQUATORIALE} ; {ZONE} {TROPICALE}},
  booktitle = {},
  journal = {{B}iogeosciences},
  volume = {14},
  numero = {20},
  pages = {4601--4617},
  ISSN = {1726-4170},
  year = {2017},
  DOI = {10.5194/bg-14-4601-2017},
  URL = {https://www.documentation.ird.fr/hor/fdi:010071283},
}