@article{PAR00025171,
  title = {{R}ecent expansion and intensification of hypoxia in the {A}rabian {G}ulf and its drivers},
  author = {{L}achkar, {Z}. and {M}ehari, {M}. and {L}evy, {M}arina and {P}aparella, {F}. and {B}urt, {J}. {A}.},
  editor = {},
  language = {{ENG}},
  abstract = {{T}he {A}rabian {G}ulf (also known as {P}ersian {G}ulf, hereafter {G}ulf) is a shallow semi-enclosed subtropical sea known for its extreme physical environment. {R}ecent observations suggest a decline in oxygen concentrations in the {G}ulf over the past few decades accompanied by an expansion of seasonal near-bottom hypoxia. {H}ere, we reconstruct the evolution of dissolved oxygen in the {G}ulf from 1982 through 2010 and explore its controlling factors. {T}o this end, we use an eddy-resolving hindcast simulation forced with winds and heat and freshwater fluxes from an atmospheric reanalysis. {W}e show that seasonal near-bottom hypoxia ({O}-2< 60 mmol m(-3)) emerges in the deeper part of the {G}ulf over summer and peaks in autumn in response to enhanced vertical stratification inhibiting mixing and {O}-2 replenishment at depth. {W}e also find a significant deoxygenation in the {G}ulf over the study period, with the {G}ulf {O}-2 content dropping by nearly 1% per decade and near-bottom {O}-2 decreasing by between 10 and 30 mmol m(-3) in the deeper part of the {G}ulf between the early 1980s and the late 2000s. {T}hese changes result in the horizontal expansion of seasonal bottom hypoxia with the hypoxia-prone seafloor area increasing from less than 20,000 km(2) in the 1980s to around 30,000 km(2) in the 2000s. {T}he expansion of hypoxia is also accompanied by a lengthening of the hypoxic season with hypoxia emerging locally 1 to 2 months earlier in the late 2000s relative to the early 1980s. {F}urthermore, declining near-bottom {O}-2 levels result in the expansion of suboxic conditions ({O}-2< 4 mmol m(-3)) and the emergence and amplification of denitrification there. {A}n analysis of the {G}ulf oxygen budget demonstrates that deoxygenation is essentially caused by reduced oxygen solubility near the surface and enhanced respiration near the bottom. {W}hile reduced solubility results from the warming of the {G}ulf waters, enhanced respiration is mostly driven by an increased supply of nutrients imported from the {A}rabian {S}ea due to the weakening of winter {S}hamal winds over the study period. {O}ur findings suggest that recent changes in local climate are not only altering the {G}ulf physical environment but are also having a strong impact on the {G}ulf biogeochemistry with profound potential implications for the ecosystems and the fisheries of the region.},
  keywords = {ocean deoxygenation ; {A}rabian ({P}ersian) {G}ulf ; marine hypoxia ; climate change ; marine biogeochemical ecosystem model ; ocean warming ; semi-enclosed seas ; {OCEAN} {INDIEN} ; {PERSIQUE} {GOLFE}},
  booktitle = {},
  journal = {{F}rontiers in {M}arine {S}cience},
  volume = {9},
  numero = {},
  pages = {891378 [22 p.]},
  year = {2022},
  DOI = {10.3389/fmars.2022.891378},
  URL = {https://www.documentation.ird.fr/hor/{PAR}00025171},
}