Browsing by Author "Coppola, Laurent"
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Item Open Access A global ocean oxygen database and atlas for assessing and predicting deoxygenation and ocean health in the open and coastal ocean(Frontiers Media, 2021-12-21) Grégoire, Marilaure; Garçon, Véronique; Garcia, Hernan; Breitburg, Denise; Isensee, Kirsten; Oschlies, Andreas; Telszewski, Maciej; Barth, Alexander; Bittig, Henry C.; Carstensen, Jacob; Carval, Thierry; Chai, Fei; Chavez, Francisco; Conley, Daniel; Coppola, Laurent; Crowe, Sean; Currie, Kim; Dai, Minhan; Deflandre, Bruno; Dewitte, Boris; Diaz, Robert; Garcia-Robledo, Emilio; Gilbert, Denis; Giorgetti, Alessandra; Glud, Ronnie; Gutierrez, Dimitri; Hosoda, Shigeki; Ishii, Masao; Jacinto, Gil; Langdon, Chris; Lauvset, Siv K.; Levin, Lisa A.; Limburg, Karin E.; Mehrtens, Hela; Montes Torres, Ivonne; Naqvi, Wajih; Paulmier, Aurélien; Pfeil, Benjamin; Pitcher, Grant; Pouliquen, Sylvie; Rabalais, Nancy; Rabouille, Christophe; Recape, Virginie; Roman, Michaël; Rose, Kenneth; Rudnick, Daniel; Rummer, Jodie; Schmechtig, Catherine; Schmidtko, Sunke; Seibel, Brad; Slomp, Caroline; Sumalia, U. Rashid; Tanhua, Toste; Thierry, Virginie; Uchida, Hiroshi; Wanninkhof, Rik; Yasuhara, MoriakiIn this paper, we outline the need for a coordinated international effort toward the building of an open-access Global Ocean Oxygen Database and ATlas (GO₂DAT) complying with the FAIR principles (Findable, Accessible, Interoperable, and Reusable). GO₂DAT will combine data from the coastal and open ocean, as measured by the chemical Winkler titration method or by sensors (e.g., optodes, electrodes) from Eulerian and Lagrangian platforms (e.g., ships, moorings, profiling floats, gliders, ships of opportunities, marine mammals, cabled observatories). GO₂DAT will further adopt a community-agreed, fully documented metadata format and a consistent quality control (QC) procedure and quality flagging (QF) system. GO₂DAT will serve to support the development of advanced data analysis and biogeochemical models for improving our mapping, understanding and forecasting capabilities for ocean O₂ changes and deoxygenation trends. It will offer the opportunity to develop quality-controlled data synthesis products with unprecedented spatial (vertical and horizontal) and temporal (sub-seasonal to multi-decadal) resolution. These products will support model assessment, improvement and evaluation as well as the development of climate and ocean health indicators. They will further support the decision-making processes associated with the emerging blue economy, the conservation of marine resources and their associated ecosystem services and the development of management tools required by a diverse community of users (e.g., environmental agencies, aquaculture, and fishing sectors). A better knowledge base of the spatial and temporal variations of marine O₂ will improve our understanding of the ocean O₂ budget, and allow better quantification of the Earth’s carbon and heat budgets. With the ever-increasing need to protect and sustainably manage ocean services, GO₂DAT will allow scientists to fully harness the increasing volumes of O₂ data already delivered by the expanding global ocean observing system and enable smooth incorporation of much higher quantities of data from autonomous platforms in the open ocean and coastal areas into comprehensive data products in the years to come. This paper aims at engaging the community (e.g., scientists, data managers, policy makers, service users) toward the development of GO₂DAT within the framework of the UN Global Ocean Oxygen Decade (GOOD) program recently endorsed by IOC-UNESCO. A roadmap toward GO₂DAT is proposed highlighting the efforts needed (e.g., in terms of human resources).Item Open Access Modulation of the vertical particle transfer efficiency in the oxygen minimum zone off Peru(European Geosciences Union (EGU), 2018) Bretagnon, Marine; Paulmier, Aurélien; Garçon, Véronique; Dewitte, Boris; Illig, Seréna; Leblond, Nathalie; Coppola, Laurent; Campos, Fernando; Velazco, Federico; Panagiotopoulos, Christos; Oschlies, Andreas; Hernandez-Ayon, J. Martin; Maske, Helmut; Vergara, Oscar; Montes Torres, Ivonne; Martinez, Philippe; Carrasco, Edgardo; Grelet, Jacques; Desprez-De-Gesincourt, Olivier; Maes, Christophe; Scouarnec, LionelThe fate of the organic matter (OM) produced by marine life controls the major biogeochemical cycles of the Earth's system. The OM produced through photosynthesis is either preserved, exported towards sediments or degraded through remineralisation in the water column. The productive eastern boundary upwelling systems (EBUSs) associated with oxygen minimum zones (OMZs) would be expected to foster OM preservation due to low O₂ conditions. But their intense and diverse microbial activity should enhance OM degradation. To investigate this contradiction, sediment traps were deployed near the oxycline and in the OMZ core on an instrumented moored line off Peru. Data provided high-temporal-resolution O₂ series characterising two seasonal steady states at the upper trap: suboxic ([O₂] < 25µmolkg−1) and hypoxic–oxic (15 < [O₂] < 160µmolkg−1) in austral summer and winter–spring, respectively. The OMZ vertical transfer efficiency of particulate organic carbon (POC) between traps (Teff) can be classified into three main ranges (high, intermediate, low). These different Teff ranges suggest that both predominant preservation (high Teff > 50%) and remineralisation (intermediate Teff 20 < 50% or low Teff < 6%) configurations can occur. An efficient OMZ vertical transfer (Teff > 50%) has been reported in summer and winter associated with extreme limitation in O₂ concentrations or OM quantity for OM degradation. However, higher levels of O₂ or OM, or less refractory OM, at the oxycline, even in a co-limitation context, can decrease the OMZ transfer efficiency to below 50%. This is especially true in summer during intraseasonal wind-driven oxygenation events. In late winter and early spring, high oxygenation conditions together with high fluxes of sinking particles trigger a shutdown of the OMZ transfer (Teff < 6%). Transfer efficiency of chemical elements composing the majority of the flux (nitrogen, phosphorus, silica, calcium carbonate) follows the same trend as for carbon, with the lowest transfer level being in late winter and early spring. Regarding particulate isotopes, vertical transfer of δ15N suggests a complex pattern of 15N impoverishment or enrichment according to Teff modulation. This sensitivity of OM to O₂ fluctuations and particle concentration calls for further investigation into OM and O₂-driven remineralisation processes. This should include consideration of the intermittent behaviour of OMZ towards OM demonstrated in past studies and climate projections.