@article{fdi:010067700,
  title = {{E}ffect of sporadic destratification, seasonal overturn, and artificial mixing on {CH}4 emissions from a subtropical hydroelectric reservoir},
  author = {{G}u{\'e}rin, {F}r{\'e}d{\'e}ric and {D}eshmukh, {C}. and {L}abat, {D}. and {P}ighini, {S}. and {V}ongkhamsao, {A}. and {G}uedant, {P}. and {R}ode, {W}. and {G}odon, {A}. and {C}hanudet, {V}. and {D}escloux, {S}. and {S}erca, {D}.},
  editor = {},
  language = {{ENG}},
  abstract = {{I}nland waters in general and freshwater reservoirs specifically are recognized as a source of {CH}4 into the atmosphere. {A}lthough the diffusion at the air-water interface is the most studied pathway, its spatial and temporal variations are poorly documented. {W}e measured temperature and {O}-2 and {CH}4 concentrations every 2 weeks for 3.5 years at nine stations in a subtropical monomictic reservoir which was flooded in 2008 ({N}am {T}heun 2 {R}eservoir, {L}ao {PDR}). {B}ased on these results, we quantified {CH}4 storage in the water column and diffusive fluxes from {J}une 2009 to {D}ecember 2012. {W}e compared diffusive emissions with ebullition from {D}eshmukh et al. (2014) and aerobic methane oxidation and downstream emissions from {D}eshmukh et al. (2016). {I}n this monomictic reservoir, the seasonal variations of {CH}4 concentration and storage were highly dependent on the thermal stratification. {H}ypolimnic {CH}4 concentration and {CH}4 storage reached their maximum in the warm dry season ({WD}) when the reservoir was stratified. {C}oncentration and storage decreased during the warm wet ({WW}) season and reached its minimum after the reservoir overturned in the cool dry ({CD}) season. {T}he sharp decreases in {CH}4 storage were concomitant with extreme diffusive fluxes (up to 200 mmol m(-2) d(-1)). {T}hese sporadic emissions occurred mostly in the inflow region in the {WW} season and during overturn in the {CD} season in the area of the reservoir that has the highest {CH}4 storage. {A}lthough they corresponded to less than 10 % of the observations, these extreme {CH}4 emissions (> 5 mmol m(-2) d(-1)) contributed up to 50 % of total annual emissions by diffusion. {D}uring the transition between the {WD} and {WW} seasons, a new emission hotspot was identified upstream of the water intake where diffusive fluxes peaked at 600 mmol m(-2) d(-1) in 2010 down to 200 mmol m(-2) d(-1) in 2012. {T}he hotspot was attributed to the mixing induced by the water intakes (artificial mixing). {E}missions from this area contributed 15-25 % to total annual emissions, although they occur in a surface area representative of less than 1% of the total reservoir surface. {W}e highly recommend measurements of diffusive fluxes around water intakes in order to evaluate whether such results can be generalized.},
  keywords = {{LAOS}},
  booktitle = {},
  journal = {{B}iogeosciences},
  volume = {13},
  numero = {12},
  pages = {3647--3663},
  ISSN = {1726-4170},
  year = {2016},
  DOI = {10.5194/bg-13-3647-2016},
  URL = {https://www.documentation.ird.fr/hor/fdi:010067700},
}