@article{fdi:010083271,
  title = {{I}nfluence of aphotic haloclines and euxinia on organic biomarkers and microbial communities in a thalassohaline and alkaline volcanic crater lake},
  author = {{S}ala, {D}. and {G}rossi, {V}. and {A}gogue, {H}. and {L}eboulanger, {C}hristophe and {J}ezequel, {D}. and {S}arazin, {G}. and {A}ntheaume, {I}. and {B}ernard, {C}. and {A}der, {M}. and {H}ugoni, {M}.},
  editor = {},
  language = {{ENG}},
  abstract = {{S}tudies on microbial communities, and their associated organic biomarkers, that are found thriving in the aphotic euxinic waters in modern stratified ecosystems are scarce compared to those undertaken in euxinic photic zones. {T}he {D}ziani {D}zaha ({M}ayotte, {I}ndian {O}cean) is a tropical, saline, alkaline crater lake that has recently been presented as a modern analog of {P}roterozoic {O}ceans due to its thalassohaline classification (having water of marine origin) and specific biogeochemical characteristics. {C}ontinuous intense photosynthetic production and microbial mineralization keep most of the water column permanently aphotic and anoxic preventing the development of a euxinic (sulfidic and anoxic) photic zone despite a high sulfide/sulfate ratio and the presence of permanent or seasonal haloclines. {I}n this study, the molecular composition of the organic matter in {L}ake {D}ziani {D}zaha was investigated and compared to the microbial diversity evaluated through 16{S} r{RNA} gene amplicon sequencing, over two contrasting seasons (rainy vs. dry) that influence water column stratification. {D}epth profiles of organic biomarker concentrations (chlorophyll-a and lipid biomarkers) and bacterial and archaeal {OTU} abundances appeared to be strongly dependent on the presence of aphotic haloclines and euxinia. {OTU} abundances revealed the importance of specific haloalkaliphilic bacterial and archaeal assemblages in phytoplanktonic biomass recycling and the biogeochemical functioning of the lake, suggesting new haloalkaline non-phototrophic anaerobic microbial precursors for some of the lipid biomarkers. {U}ncultured {F}irmicutes from the family {S}yntrophomonadaceae ({C}lostridiales), and {B}acteroidetes from the {ML}635{J}-40 aquatic group, emerged as abundant chemotrophic bacterial members in the anoxic or euxinic waters and were probably responsible for the production of short-chain n-alkenes, wax esters, diplopterol, and tetrahymanol. {H}alocline-dependent euxinia also had a strong impact on the archaeal community which was dominated by {W}oesearchaeota in the sulfide-free waters. {I}n the euxinic waters, methanogenic {E}uryarchaeota from the {M}ethanomicrobia, {T}hermoplasmata, and {WSA}2 classes dominated and were likely at the origin of common hydrocarbon biomarkers of methanogens (phytane, pentamethyl-eicosenes, and partially hydrogenated squalene).},
  keywords = {bacterial and archaeal diversity ; bacteroidetes {ML}635{J}-40 aquatic group ; haline and aphotic euxinia ; lipid biomarkers ; syntrophomonadaceae ; {WSA}2 ; methanogenic {E}uryarchaeota ; {MAYOTTE} ; {OCEAN} {INDIEN} ; {DZIANI} {DZAHA} {LAC}},
  booktitle = {},
  journal = {{G}eobiology},
  volume = {20},
  numero = {2},
  pages = {292--309},
  ISSN = {1472-4677},
  year = {2022},
  DOI = {10.1111/gbi.12477},
  URL = {https://www.documentation.ird.fr/hor/fdi:010083271},
}