Programme LEFE/ CYBER AMOP («Activities of research dedicated

Programme LEFE/ CYBER
Intermediate report
AMOP («Activities of research dedicated to the
Minimum of Oxygen in the eastern Pacific»)
X
PI Lab: LEGOS (Toulouse)
Aurélien PAULMIER (PI); Boris DEWITTE, Christophe
MAES, Véronique GARCON (Co-PIs).
Participating Laboratories:
1) Labs involved In France: CNRM/Meteo, ECOSYM,
EME, EPOC, ISTO, LATMOS, LEGOS, LOCEAN, LOMIC,
LOV, LSCE, MIO with the technical support from the
US191-IRD and DT/INSU
2) Foreign labs/firms: Aahrus University/Unisense
(DENMARK),
CICESE/UABC
(MEXICO),
GEOMAR(GERMANY), IMARPE/IGP (PERU), MPI/IOW
(GERMANY), NUI (IRELAND), UCLA (USA) and the
Technical University of Xiamen (CHINA)
Final report
Années 2012 – 2014
□
Contribution to
SOLAS, IMBER, GEOTRACE
Laboratoires Mixtes Internationaux IRD: DISCOH,
PALEOTRACE
Other funding sources: IRD, LEGOS, Observatoire MidiPyrénées (OMP), co-PIs teams, EUR-OCEANS, German
GEOMAR/SFB754
The AMOP project will investigate the mechanisms leading to the OMZ existence off Peru and its variability
from hourly to centennial timescales. The Central Hypothesis of this project is based upon a two-layer conceptual
model of the OMZ: the oxycline and upper OMZ core where physics and biogeochemistry contribute comparably
to the rate of O2 changes, and the lower OMZ core where physical processes dominate the changes in O2.
Conversely to other studies dedicated to different OMZ impacts, AMOP is focusing on the oxygen parameter, with
the objective to carry out a quantitative and comprehensive O2 budget considering physical (advection/diffusion)
and biological (O2 consumption/production through bacteria, phytoplankton and zooplankton) contributions.
The project implies a multidisciplinary approach: biogeochemistry, microbiology, physics, coupling with the
atmosphere, acoustics, ecology, study of benthos, paleoceanography, all aiming towards the understanding of the
O2 fluxes. The approach is based on: i) a 30-day cruise with two ships in simultaneous (L’Atalante from IFREMER
and a Peruvian vessel from IMARPE), associated with glider and Argo float experiments, ii) a mooring (> 3-yr) on
one of the historical IMARPE station coupling water column and sediments (the mooring is deployed since January
5th, 2013), iii) a modeling platform in order to bridge the gap between sampled and non-sampled spatio-temporal
scales, and to assist the interpretation of our full data set (from in vitro to in situ, satellite and proxy data). The
cruise with on board experimentations and use of innovative technologies (e.g. Pump-CTD, HPBs-O2,
IODAs/sediment traps) is focused on 9 fixed stations (3 days) and on 3 transects in the North (7°S), Center (12°S)
and South (14°S), covering 3 distinct topographic conditions of the OMZ system: the continental shelf, the slope,
and the open deep ocean.
AMOP involves 14 research units in France, 7 research units from 2 Institutes in Peru and 10 Institutions in 6 other
countries (China, Denmark, Germany, Ireland, Mexico, USA) acting as an international consortium on the
deoxygenation topic (~90 participants). It is associated with new programs, both in terms of themes and
multidisciplinary approaches, Regional (RTRA/MAISOE, ICE), European (SENSEnet, HYPOX, EURO-ARGO, EUROCEANS, SENSEOcean) and International (SOLAS, IMBER, GEOTRACES). AMOP is viewed as one of the main pilot
projects of an initiative to coordinate, on the OMZ and in partnership with Peruvian Institutions, international
actions (e.g. German SFB754; US Torero) from 2013- 2014: cruises, scientific flights, experiments, long-term
monitoring, and modeling. Presently, the AMOP project is approved and labeled by LEFE-CYBER and GMMC from
INSU, and considered as a priority by the CNFH and programmed by the Glider National Commission, but up to
now it did not receive any National funding (except 5 kEuros for meetings during the preparatory phase:
LEFE/CYBER).
Since 2011, the modelling approach has started (e.g. Flagship of the EUR-OCEANS Consortium and GEOMAR
funding, and recently IRD Spiral funding). Thanks to a French-Peruvian-German collaboration between LEGOS
(Toulouse), IMARPE (Lima) and GEOMAR (Kiel) and thanks to DT/INSU and US IMAGO support in terms of
equipment and engineers time, the AMOP fixed subsurface mooring could be deployed at the beginning of 2013
from the German RV Meteor, and recovery and re-deployment have been performed end of June 2013 from the
Peruvian RV Olaya.
The vertical structure of the OMZ can be defined by three layers (oxycline, suboxic core ([O2] < 20 μM), lower O2
gradient) that exhibit distinct short-term variability associated to the productivity and environmental forcing (i.e.
wind-forced upwelling, mesoscale activity and equatorial Kelvin wave). Both the vertical structure and variability
of the OMZ has been documented at different timescales, which is central for getting insights in the OMZ
dynamics. The recent mooring data acquired in the Peruvian OMZ off Callao (oxycline and core up to the bottom
around 180 m deep) near the continental slope (12°02’S; 77°40’W) are currently being analyzed.. The high
frequency (each 15-30 minutes) data presented are covering a 6 months period from the mooring deployment on
January 5th 2013. In a close future, the mooring data will be described and interpreted in the light of estimates of
the local (wind) and remote (equatorial Kelvin wave) forcing of the Eastern Tropical Pacific. Preliminary
comparisons with a climatological biogeochemical coupled model simulation will also be presented (cf. EurOceans Hot Topics Conference, Ocean deoxygenation session, November 6-8th 2013).
Illustration 1
(cf également: http://www.legos.obs-mip.fr/recherches/projets-encours/amop)
Illustration 2
Illustration 1:
(a) Synthèse du projet d’expérimentation AMOP incluant la campagne à deux navires océanographiques, le mouillage fixe, l’activité des planeurs sousmarins (gliders) et flotteurs-profileurs (Argo-floats); (b) Tracés et stations sur le bateau français (e.g. N/O L’Atalante) durant la campagne AMOP; (c) Stratégie
du deploiement des planeurs sous-marins, illustrée pour l’expérience au large de Callao; (d) Schéma du mouillage fixe AMOP, déployée le 5 Janvier 2013 au
large de Callao (12°02’S; 77°40’W) avec la ligne instrumentée comportant les différents capteurs (température, salinité, oxygène, fluorescence) et pièges à
sédiment (PPS3) et la ligne de fond avec cage pour le profileur acoustique de courant (ADCP) selon les calculs de la cellule de la Division Technique de
l’INSU/CNRS.
Illustration 2:
Photos illustrant la phase de déploiement du mouillage AMOP à bord du Météor allemand le 5 Janvier 2013 (panel d’en haut), et son premier relevé et redéploiement les 24-25 Juin 2013 avec l’Olaya péruvien (panel d’en bas). Equipe mouillage-AMOP: Aurélien PAULMIER, Boris DEWITTE (LEGOS,
Toulouse); Jacques GRELET (US IMAGO/IRD, Brest); Olivier DEPRETZ-DE-GESINCOURT (DT INSU/CNRS, Brest); Edgardo CARRASCO, Jesus
LEDESMA, Federico VELAZCO (IMARPE).
 Paulmier, A., Garçon, V., Graco, M., Maes, C., Gutierrez, D., Dewitte, B., and K. Takahashi. AMOP: Activity of research dedicated to the Minimum of Oxygen in the
Eastern Pacific. SOLAS Letter, 2012, 14 (Summer), 11-12.
 Montes I., B. Dewitte, E. Gutknecht, A. Paulmier, I. Dadou, V. Garçon, 2013: Modeling the Oxygen Minimum Zone of the Eastern Tropical Pacific: Sensitivity to the tropical
oceanic circulation. J. Geophys. Research. (en révision).
 Paulmier, A., Lajaunie, K., Ledesma, J., Montes, I., and V. Garcon. Spatio-temporal O2 structure of the oxygen minimum zone (OMZ) off Peru (en préparation)
 Auto-regulación de la actividad en la zona de mínima de oxigeno: Un estudio por modelo conceptual. Jonathan Valle. Tesis de Licenciatura, Universidad Nacional del
Callao. Tesis de Licenciatura, Universidad Nacional del Callao (UNAC). Jonathan VALLE.
 Caractérisation spatio-temporelle de l’OMZ du Pacifique Sud Est au large du Pérou. Master de Recherche (M2R) « Océan, Atmosphère et Surfaces Continentales »,
Université Paul Sabatier (Toulouse III). Katixa LAJAUNIE.
 Paulmier, A., Garçon, V., Dewitte, B., and C. Maes. Activities of research dedicated to the Minimum of Oxygen in the eastern Pacific (AMOP). SOLAS OSC Conference. 710 May 2012, Cle Elum, WA, USA (2012).