FN Archimer Export Format PT J TI Stable mercury concentrations of tropical tuna in the south western Pacific ocean: An 18-year monitoring study BT AF Médieu, Anais Point, David Receveur, Aurore Gauthier, Olivier Allain, Valerie Pethybridge, Heidi Menkes, Christophe E. Gillikin, David P. Revill, Andrew T. Somes, Christopher J. Collin, Jeremy Lorrain, Anne AS 1:1;2:2;3:3;4:1;5:3;6:4;7:5;8:6;9:4;10:7;11:1;12:1; FF 1:;2:;3:;4:;5:;6:;7:;8:;9:;10:;11:;12:; C1 Univ Brest, CNRS, IRD, Ifremer, LEMAR, F-29280, Plouzané, France Observatoire Midi-Pyrénées, GET, UMR CNRS 5563/IRD 234, Université Paul Sabatier Toulouse 3, Toulouse, France Pacific Community, Oceanic Fisheries Programme, Nouméa, France CSIRO Oceans and Atmosphere, Hobart, Tasmania, Australia ENTROPIE (UMR 9220), IRD, Univ. de La Réunion, CNRS, Nouméa, New Caledonia Department of Geology, Union College, 807 Union St., Schenectady, NY, 12308, USA GEOMAR Helmholtz Centre for Ocean Research Kiel, Düsternbrooker Weg 20, 24105 Kiel, Germany C2 UBO, FRANCE OBSERV MIDI PYRENEES, FRANCE PACIFIC COMMUNITY, FRANCE CSIRO OCEANS AND ATMOSPHERE, AUSTRALIA IRD, FRANCE UNION COLL, USA IFM GEOMAR, GERMANY UM LEMAR ENTROPIE IN WOS Cotutelle UMR copubli-france copubli-europe copubli-int-hors-europe IF 8.943 TC 17 UR https://archimer.ifremer.fr/doc/00648/76020/77845.pdf LA English DT Article DE ;Methylmercury;Stable isotope data;Yellowfin tuna;Bigeye tuna;Skipjack tuna;New Caledonia-Fiji region AB Global anthropogenic mercury (Hg) emissions to the atmosphere since industrialization are widely considered to be responsible for a significant increase in surface ocean Hg concentrations. Still unclear is how those inputs are converted into toxic methylmercury (MeHg) then transferred and biomagnified in oceanic food webs. We used a unique long-term and continuous dataset to explore the temporal Hg trend and variability of three tropical tuna species (yellowfin, bigeye, and skipjack) from the southwestern Pacific Ocean between 2001 and 2018 (n = 590). Temporal trends of muscle nitrogen (δ15N) and carbon (δ13C) stable isotope ratios, amino acid (AA) δ15N values and oceanographic variables were also investigated to examine the potential influence of trophic, biogeochemical and physical processes on the temporal variability of tuna Hg concentrations. For the three species, we detected significant inter-annual variability but no significant long-term trend for Hg concentrations. Inter-annual variability was related to the variability in tuna sampled lengths among years and to tuna muscle δ15N and δ13C values. Complementary AA- and model-estimated phytoplankton δ15N values suggested the influence of baseline processes with enhanced tuna Hg concentrations observed when dinitrogen fixers prevail, possibly fuelling baseline Hg methylation and/or MeHg bioavailability at the base of the food web. Our results show that MeHg trends in top predators do not necessary capture the increasing Hg concentrations in surface waters suspected at the global oceanic scale due to the complex and variable processes governing Hg deposition, methylation, bioavailability and biomagnification. This illustrates the need for long-term standardized monitoring programs of marine biota worldwide. PY 2021 PD JAN SO Chemosphere SN 0045-6535 PU Elsevier BV VL 263 UT 000595802200153 DI 10.1016/j.chemosphere.2020.128024 ID 76020 ER EF