@article{fdi:010075624,
  title = {{A} new definition of the south-east {M}adagascar bloom and analysis of its variability},
  author = {{D}ilmahamod, {A}. {F}. and {P}enven, {P}ierrick and {A}guiar-{G}onzalez, {B}. and {R}eason, {C}. {J}. {C}. and {H}ermes, {J}. {C}.},
  editor = {},
  language = {{ENG}},
  abstract = {{T}he {S}outh-{E}ast {M}adagascar {B}loom occurs in an oligotrophic region of the southwest {I}ndian {O}cean. {P}hase locked to austral summer, this sporadic feature exhibits substantial temporal and spatial variability. {S}everal studies, with different hypotheses, have focused on the initiation mechanism triggering the bloom, but none has been as yet clearly substantiated. {W}ith 19years of ocean color data set available as well as in situ measurements ({A}rgo profiles), the time is ripe to review this feature. {T}he bloom is characterized in a novel manner, and a new bloom index is suggested, yielding 11 bloom years, including 3 major bloom years (1999, 2006, and 2008). {S}patially, the bloom varies from a mean structure (22-32 degrees {S}; 50-70 degrees {E}) both zonally and meridionally. {A} colocation analysis of {A}rgo profiles and chlorophyll-a data revealed a bloom occurrence in a shallow-stratified layer, with low-salinity water in the surface layers. {A}dditionally, a quantitative assessment of the previous hypotheses is performed and bloom occurrence is found to coincide with {L}a {N}ina events and reduced upwelling intensity south of {M}adagascar. {A} stronger {S}outh-{E}ast {M}adagascar {C}urrent during {L}a {N}ina may support a detachment of the current from the coasts, dampening the upwelling south of {M}adagascar, and feeding low-salinity waters into the {M}adagascar {B}asin, hence increasing stratification. {A}long with abundance of light, these provide the right conditions for a nitrogen-fixing cyanobacterial phytoplankton bloom onset. {P}lain {L}anguage {S}ummary {T}he {S}outh-{E}ast {M}adagascar {B}loom is one of the largest bloom in the world. {I}t can play a major role in the fishing industry, as well as capturing carbon dioxide from the atmosphere. {H}ence, it needs to be better understood. {I}n previous studies, several hypotheses have been put forward to explain the bloom but none have as yet been clearly substantiated. {T}his study shows that the bloom occurs in a surface layer of low salinity, which tends to favor a specific type of phytoplankton, namely, cyanobacteria. {T}he climate phenomenon, {L}a {N}ina, also seems to co-occur with the bloom, 10 out of 11 events. {T}he input of nutrient-rich waters to the surface south of {M}adagascar is weakened during the bloom, and this goes against what was previously thought. {T}he present study gives a possible new reasoning as to why the bloom occurs. {T}he current southeast of {M}adagascar detaches from the coast and brings low-salinity and nutrient-rich waters into the bloom region where enhanced photosynthesis occurs, hence causing the bloom.},
  keywords = {{S}outh-{E}ast {M}adagascar {B}loom ; {S}outh-{E}ast {M}adagascar {C}urrent ; {L}a {N}ina ; cyanobacterial bloom ; {OCEAN} {INDIEN} ; {MADAGASCAR} ; {MADAGASCAR} {SUD} {EST} {COURANT}},
  booktitle = {},
  journal = {{J}ournal of {G}eophysical {R}esearch : {O}ceans},
  volume = {124},
  numero = {3},
  pages = {1717--1735},
  ISSN = {2169-9275},
  year = {2019},
  DOI = {10.1029/2018jc014582},
  URL = {https://www.documentation.ird.fr/hor/fdi:010075624},
}