Publications des scientifiques de l'IRD

Renedo M., Point David, Sonke J. E., Lorrain Anne, Demarcq Hervé, Graco M., Grados D., Gutierrez D., Medieu A., Munaron Jean-Marie, Pietri A., Colas F., Tremblay Yann, Roy Amédée, Bertrand Arnaud, Bertrand S. L. (2021). ENSO climate forcing of the marine mercury cycle in the Peruvian upwelling zone does not affect methylmercury levels of marine avian top predators. Environmental Science and Technology, 55 (23), 15754-15765. ISSN 0013-936X.

Titre du document
ENSO climate forcing of the marine mercury cycle in the Peruvian upwelling zone does not affect methylmercury levels of marine avian top predators
Année de publication
2021
Type de document
Article référencé dans le Web of Science WOS:000758717600021
Auteurs
Renedo M., Point David, Sonke J. E., Lorrain Anne, Demarcq Hervé, Graco M., Grados D., Gutierrez D., Medieu A., Munaron Jean-Marie, Pietri A., Colas F., Tremblay Yann, Roy Amédée, Bertrand Arnaud, Bertrand S. L.
Source
Environmental Science and Technology, 2021, 55 (23), 15754-15765 ISSN 0013-936X
Climate change is expected to affect marine mercury (Hg) biogeochemistry and biomagnification. Recent modeling work suggested that ocean warming increases methylmercury (MeHg) levels in fish. Here, we studied the influence of El Nino Southern Oscillations (ENSO) on Hg concentrations and stable isotopes in time series of seabird blood from the Peruvian upwelling and oxygen minimum zone. Between 2009 and 2016, La Nina (2011) and El Nino conditions (2015-2016) were accompanied by sea surface temperature anomalies up to 3 degrees C, oxycline depth change (20-100 m), and strong primary production gradients. Seabird Hg levels were stable and did not co-vary significantly with oceanographic parameters, nor with anchovy biomass, the primary dietary source to seabirds (90%). In contrast, seabird Delta Hg-199, proxy for marine photochemical MeHg breakdown, and delta N-15 showed strong interannual variability (up to 0.8 and 3%, respectively) and sharply decreased during El Nino. We suggest that lower Delta Hg-199 during El Nino represents reduced MeHg photodegradation due to the deepening of the oxycline. This process was balanced by equally reduced Hg methylation due to reduced productivity, carbon export, and remineralization. The non-dependence of seabird MeHg levels on strong ENSO variability suggests that marine predator MeHg levels may not be as sensitive to climate change as is currently thought.
Plan de classement
Sciences du milieu [021] ; Limnologie physique / Océanographie physique [032] ; Limnologie biologique / Océanographie biologique [034]
Description Géographique
PEROU ; PACIFIQUE
Localisation
Fonds IRD [F B010084335]
Identifiant IRD
fdi:010084335
Contact