@article{fdi:010079974,
  title = {{A}ccumulation of methylmercury in the high-altitude lake {U}ru {U}ru (3686 m a.s.l, {B}olivia) controlled by sediment efflux and photodegradation},
  author = {{G}u{\'e}dron, {S}t{\'e}phane and {A}cha, {D}. and {B}ouchet, {S}. and {P}oint, {D}avid and {T}essier, {E}. and {H}eredia, {C}. and {R}ocha-{L}upa, {S}. and {F}ernandez-{S}aavedra, {P}. and {F}lores, {M}. and {B}ureau, {S}. and {Q}uino-{L}ima, {I}. and {A}mouroux, {D}.},
  editor = {},
  language = {{ENG}},
  abstract = {{I}n shallow aquatic environments, sediment is a significant source of monomethylmercury ({MMH}g) for surface water ({SW}). {H}igh-altitude aquatic ecosystems are characterized by extreme hydro-climatic constraints (e.g., low oxygen and high {UV} radiation). {W}e studied, during two seasons, the diel cycles of {MMH}g in {SW} and sediment porewaters ({PW}) of {L}ake {U}ru {U}ru (3686 m a.s.l, {B}olivia) contaminated by urban and mining activities. {O}ur results show that diel changes in {SW} {MMH}g concentrations (up to 1.8 ng {L}-1) overwhelm seasonal ones, with higher {MMH}g accumulation during the night-time and the dry season. {T}he calculation of {MMH}g diffusive fluxes demonstrates that the sediment compartment was the primary source of {MMH}g to the {SW}. {M}ost {MMH}g efflux occurred during the dry season (35.7 +/- 17.4 ng m(-2) day(-1)), when the lake was relatively shallow, more eutrophicated, and with the redoxcline located above the sediment-water interface ({SWI}). {C}hanges in {MMH}g accumulation in the {PW}s were attributed to diel redox oscillations around the {SWI} driving both the bacterial sulfate reduction and bio-methylation. {F}inally, we highlight that although {MMH}g loading from the {PW} to the {SW} is large, {MMH}g photodegradation and demethylation by microorganisms control the net {MMH}g accumulation in the water column.},
  keywords = {monomethylmercury ; water sediment interface ; diel and seasonal cycles ; photodegradation ; {BOLIVIE} ; {ALTIPLANO} ; {URU} {URU} {LAC}},
  booktitle = {},
  journal = {{A}pplied {S}ciences},
  volume = {10},
  numero = {21},
  pages = {7936 [14 p.]},
  year = {2020},
  URL = {https://www.documentation.ird.fr/hor/fdi:010079974},
}