ALBERT

Description: A neural network-based method is developed to assess the vertical distribution of (1) chlorophyll a concentration ([Chl]) and (2) phytoplankton community size indices (i.e. microphytoplankton, nanophytoplankton and picophytoplankton) from in situ vertical profiles of chlorophyll fluorescence. This method (FLAVOR for Fluorescence to Algal communities Vertical distribution in the Oceanic Realm) uses as input only the shape of the fluorescence profile associated with its acquisition date and geo-location. The neural network is trained and validated using a large database including 896 concomitant in situ vertical profiles of High-Performance Liquid Chromatography (HPLC) pigments and fluorescence. These profiles were collected during 22 oceanographic cruises representative of the global ocean in terms of trophic and oceanographic conditions, making our method applicable to most oceanic waters. FLAVOR is validated with respect to the retrieval of both [Chl] and phytoplankton size indices using an independent in situ dataset and appears to be relatively robust spatially and temporally. To illustrate the potential of the method, we applied it to in situ measurements of the BATS (Bermuda Atlantic Time-Series Study) site and produce monthly climatologies of [Chl] and associated phytoplankton size indices. The resulting climatologies appear very promising compared to climatologies based on available in situ HPLC data. With the increasing availability of spatially and temporally well-resolved datasets of chlorophyll fluorescence, one possible global-scale application of FLAVOR could be to develop 3D and even 4D climatologies of [Chl] and associated composition of phytoplankton communities. The Matlab and R codes of the proposed algorithm are provided as auxiliary material. This article is protected by copyright. All rights reserved.

Description: Abstract Understanding spatial and temporal dynamics of non‐algal particles (NAP) in open ocean is of the utmost importance to improve estimations of carbon export and sequestration. These particles covary with phytoplankton abundance but also accumulate independently of algal dynamics. The latter likely represents an important fraction of organic carbon but it is largely overlooked. A possible way to study these particles is via their optical backscattering properties (bbp) and relationship with chlorophyll‐a (Chl). To this aim, we estimate the fraction of bbp associated with the NAP portion ( ) that does not covary with Chl by using a global Biogeochemical‐Argo dataset. We quantify the spatial, temporal and vertical variability of . In the northern productive areas, is a small fraction of bbp and shows a clear seasonal cycle. In the Southern Ocean, bkbp is a major fraction of total bbp. In oligotrophic areas, has a smooth annual cycle.

Description: Phytoplankton--the microalgae that populate the upper lit layers of the ocean--fuel the oceanic food web and affect oceanic and atmospheric carbon dioxide levels through photosynthetic carbon fixation. Here, we show that multidecadal changes in global phytoplankton abundances are related to basin-scale oscillations of the physical ocean, specifically the Pacific Decadal Oscillation and the Atlantic Multidecadal Oscillation. This relationship is revealed in approximately 20 years of satellite observations of chlorophyll and sea surface temperature. Interaction between the main pycnocline and the upper ocean seasonal mixed layer is one mechanism behind this correlation. Our findings provide a context for the interpretation of contemporary changes in global phytoplankton and should improve predictions of their future evolution with climate change.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Martinez, Elodie -- Antoine, David -- D'Ortenzio, Fabrizio -- Gentili, Bernard -- New York, N.Y. -- Science. 2009 Nov 27;326(5957):1253-6. doi: 10.1126/science.1177012.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉UPMC University of Paris 06, UMR 7093, Laboratoire d'Oceanographie de Villefranche (LOV), 06230 Villefranche-sur-Mer, France. martinez@obs-vlfr.fr〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19965473" target="_blank"〉PubMed〈/a〉

Description: The present study proposes a novel method that merges satellite ocean-color bio-optical products with Argo temperature-salinity profiles to infer the vertical distribution of the particulate backscattering coefficient (b bp ) . This neural network-based method (SOCA-BBP for Satellite Ocean-Color merged with Argo data to infer the vertical distribution of the Particulate Backscattering coefficient) uses three main input components: (1) satellite-based surface estimates of b bp and chlorophyll a concentration matched-up in space and time with (2) depth-resolved physical properties derived from temperature-salinity profiles measured by Argo profiling floats and (3) the day of the year of the considered satellite-Argo matchup. The neural network is trained and validated using a database including 4725 simultaneous profiles of temperature-salinity and bio-optical properties collected by Bio-Argo floats, with concomitant satellite-derived products. The Bio-Argo profiles are representative of the global open-ocean in terms of oceanographic conditions, making the proposed method applicable to most open-ocean environments. SOCA-BBP is validated using 20% of the entire database (global error of 21%). We present additional validation results based on two other independent datasets acquired (1) by four Bio-Argo floats deployed in major oceanic basins, not represented in the database used to train the method; and (2) during an AMT (Atlantic Meridional Transect) field cruise in 2009. These validation tests based on two fully independent datasets indicate the robustness of the predicted vertical distribution of b bp . To illustrate the potential of the method, we merged monthly climatological Argo profiles with ocean color products to produce a depth-resolved climatology of b bp for the global ocean. This article is protected by copyright. All rights reserved.

Description: Agulhas rings provide the principal route for ocean waters to circulate from the Indo-Pacific to the Atlantic basin. Their influence on global ocean circulation is well known, but their role in plankton transport is largely unexplored. We show that, although the coarse taxonomic structure of plankton communities is continuous across the Agulhas choke point, South Atlantic plankton diversity is altered compared with Indian Ocean source populations. Modeling and in situ sampling of a young Agulhas ring indicate that strong vertical mixing drives complex nitrogen cycling, shaping community metabolism and biogeochemical signatures as the ring and associated plankton transit westward. The peculiar local environment inside Agulhas rings may provide a selective mechanism contributing to the limited dispersal of Indian Ocean plankton populations into the Atlantic.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Villar, Emilie -- Farrant, Gregory K -- Follows, Michael -- Garczarek, Laurence -- Speich, Sabrina -- Audic, Stephane -- Bittner, Lucie -- Blanke, Bruno -- Brum, Jennifer R -- Brunet, Christophe -- Casotti, Raffaella -- Chase, Alison -- Dolan, John R -- d'Ortenzio, Fabrizio -- Gattuso, Jean-Pierre -- Grima, Nicolas -- Guidi, Lionel -- Hill, Christopher N -- Jahn, Oliver -- Jamet, Jean-Louis -- Le Goff, Herve -- Lepoivre, Cyrille -- Malviya, Shruti -- Pelletier, Eric -- Romagnan, Jean-Baptiste -- Roux, Simon -- Santini, Sebastien -- Scalco, Eleonora -- Schwenck, Sarah M -- Tanaka, Atsuko -- Testor, Pierre -- Vannier, Thomas -- Vincent, Flora -- Zingone, Adriana -- Dimier, Celine -- Picheral, Marc -- Searson, Sarah -- Kandels-Lewis, Stefanie -- Tara Oceans Coordinators -- Acinas, Silvia G -- Bork, Peer -- Boss, Emmanuel -- de Vargas, Colomban -- Gorsky, Gabriel -- Ogata, Hiroyuki -- Pesant, Stephane -- Sullivan, Matthew B -- Sunagawa, Shinichi -- Wincker, Patrick -- Karsenti, Eric -- Bowler, Chris -- Not, Fabrice -- Hingamp, Pascal -- Iudicone, Daniele -- New York, N.Y. -- Science. 2015 May 22;348(6237):1261447. doi: 10.1126/science.1261447.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Aix Marseille Universite, CNRS, IGS UMR 7256, 13288 Marseille, France. villar@igs.cnrs-mrs.fr not@sb-roscoff.fr hingamp@igs.cnrs-mrs.fr iudicone@szn.it karsenti@embl.de cbowler@biologie.ens.fr. ; CNRS, UMR 7144, Station Biologique de Roscoff, Place Georges Teissier, 29680 Roscoff, France. Sorbonne Universites, Universite Pierre et Marie Curie UPMC, Universite Paris 06, UMR 7144, Station Biologique de Roscoff, Place Georges Teissier, 29680 Roscoff, France. ; Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA. ; Laboratoire de Physique des Oceans (LPO) UMR 6523 CNRS-Ifremer-IRD-UBO, Plouzane, France. Department of Geosciences, Laboratoire de Meteorologie Dynamique (LMD) UMR 8539, Ecole Normale Superieure, 24 Rue Lhomond, 75231 Paris Cedex 05, France. ; CNRS, UMR 7144, Station Biologique de Roscoff, Place Georges Teissier, 29680 Roscoff, France. Sorbonne Universites, Universite Pierre et Marie Curie UPMC, Universite Paris 06, UMR 7144, Station Biologique de Roscoff, Place Georges Teissier, 29680 Roscoff, France. Ecole Normale Superieure, Institut de Biologie de l'ENS (IBENS), and Inserm U1024, and CNRS UMR 8197, F-75005 Paris, France. ; Laboratoire de Physique des Oceans (LPO) UMR 6523 CNRS-Ifremer-IRD-UBO, Plouzane, France. ; Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85721, USA. ; Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy. ; School of Marine Sciences, University of Maine, Orono, ME, USA. ; Sorbonne Universites, UPMC Universite Paris 06, Observatoire Oceanologique, F-06230 Villefranche-sur-Mer, France. INSU-CNRS, UMR 7093, LOV, Observatoire Oceanologique, F-06230 Villefranche-sur-Mer, France. ; Universite de Toulon, Laboratoire PROTEE-EBMA E.A. 3819, BP 20132, 83957 La Garde Cedex, France. ; CNRS, UMR 7159, Laboratoire d'Oceanographie et du Climat LOCEAN, 4 Place Jussieu, 75005 Paris, France. ; Aix Marseille Universite, CNRS, IGS UMR 7256, 13288 Marseille, France. ; Ecole Normale Superieure, Institut de Biologie de l'ENS (IBENS), and Inserm U1024, and CNRS UMR 8197, F-75005 Paris, France. ; Commissariat a l'Energie Atomique et aux Energies Alternatives (CEA), Institut de Genomique, Genoscope, 2 Rue Gaston Cremieux, 91057 Evry, France. CNRS, UMR 8030, CP5706, Evry, France. Universite d'Evry, UMR 8030, CP5706, Evry, France. ; Structural and Computational Biology, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany. Directors' Research, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany. ; Department of Marine Biology and Oceanography, Institute of Marine Sciences (ICM), CSIC, Passeig Maritim de la Barceloneta, 37-49, Barcelona E08003, Spain. ; Structural and Computational Biology, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany. Max-Delbruck-Centre for Molecular Medicine, 13092 Berlin, Germany. ; PANGAEA, Data Publisher for Earth and Environmental Science, University of Bremen, Bremen, Germany. MARUM, Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany. ; Structural and Computational Biology, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany. ; Ecole Normale Superieure, Institut de Biologie de l'ENS (IBENS), and Inserm U1024, and CNRS UMR 8197, F-75005 Paris, France. Directors' Research, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany. villar@igs.cnrs-mrs.fr not@sb-roscoff.fr hingamp@igs.cnrs-mrs.fr iudicone@szn.it karsenti@embl.de cbowler@biologie.ens.fr. ; Ecole Normale Superieure, Institut de Biologie de l'ENS (IBENS), and Inserm U1024, and CNRS UMR 8197, F-75005 Paris, France. villar@igs.cnrs-mrs.fr not@sb-roscoff.fr hingamp@igs.cnrs-mrs.fr iudicone@szn.it karsenti@embl.de cbowler@biologie.ens.fr. ; CNRS, UMR 7144, Station Biologique de Roscoff, Place Georges Teissier, 29680 Roscoff, France. Sorbonne Universites, Universite Pierre et Marie Curie UPMC, Universite Paris 06, UMR 7144, Station Biologique de Roscoff, Place Georges Teissier, 29680 Roscoff, France. villar@igs.cnrs-mrs.fr not@sb-roscoff.fr hingamp@igs.cnrs-mrs.fr iudicone@szn.it karsenti@embl.de cbowler@biologie.ens.fr. ; Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy. villar@igs.cnrs-mrs.fr not@sb-roscoff.fr hingamp@igs.cnrs-mrs.fr iudicone@szn.it karsenti@embl.de cbowler@biologie.ens.fr.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25999514" target="_blank"〉PubMed〈/a〉

Description: [1]  The winter of 2012 experienced peculiar atmospheric conditions that triggered a massive formation of dense water on the continental shelf and in the deep basin of the Gulf of Lions. Multi-platforms observations enabled a synoptic view of dense water formation and spreading at basin scale. Five months after its formation, the dense water of coastal origin created a distinct bottom layer up to few hundreds of meters thick over the central part of the NW Mediterranean basin, which was overlaid by a layer of newly formed deep water produced by open-sea convection. These new observations highlight the role of intense episodes of both dense shelf water cascading and open-sea convection to the progressive modification of the NW Mediterranean deep waters.

Description: We present here a unique oceanographic and meteorological dataset focus on the deep convection processes. Our results are essentially based on in situ data (mooring, research vessel, glider, and profiling float) collected from a multi-platform and integrated monitoring system (MOOSE: Mediterranean Ocean Observing System on Environment), which monitored continuously the northwestern Mediterranean Sea since 2007, and in particular high-frequency potential temperature, salinity and current measurements from the mooring LION located within the convection region. From 2009 to 2013, the mixed layer depth reaches the seabed, at a depth of 2330m, in February. Then, the violent vertical mixing of the whole water column lasts between 9 and 12 days setting up the characteristics of the newly-formed deep water. Each deep convection winter formed a new warmer and saltier '“vintage” of deep water. These sudden inputs of salt and heat in the deep ocean are responsible for trends in salinity (3.3+/-0.2 *10 −3 /yr) and potential temperature (3.2+/-0.5 *10 −3 °C/yr) observed from 2009 to 2013 for the 600-2300m layer. For the first time, the overlapping of the 3 “phases” of deep convection can be observed with secondary vertical mixing events (2-4 days) after the beginning of the restratification phase, and the restratification/spreading phase still active at the beginning of the following deep convection event. This article is protected by copyright. All rights reserved.