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2. Twenty years of satellite and in situ observations of surface chlorophyll-a from the northern Bay of Biscay to the eastern English Channel. Is the water quality improving?

Author

Gohin, Francis, Van der Zande, Dimitry, Tilstone, Gavin, Eleveld, Marieke A., Lefebvre, Alain, Andrieux-Loyer, Françoise, Blauw, Anouk N., Bryère, Philippe, Devreker, David, Garnesson, Philippe, Hernández Fariñas, Tania, Lamaury, Yoann, Lampert, Luis, Lavigne, Héloïse, Menet-Nedelec, Florence, Pardo, Silvia, and Saulquin, Bertrand

Published
2019
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3. WATERHYPERNET: a prototype network of automated in situ measurements of hyperspectral water reflectance for satellite validation and water quality monitoring.

Author

Ruddick, Kevin G., Brando, Vittorio E., Corizzi, Alexandre, Dogliotti, Ana I., Doxaran, David, Goyens, Clémence, Kuusk, Joel, Vanhellemont, Quinten, Vansteenwegen, Dieter, Bialek, Agnieszka, De Vis, Pieter, Lavigne, Héloise, Beck, Matthew, Flight, Kenneth, Gammaru, Anabel, Vilas, Luis González, Laizans, Kaspars, Artenzio, Francesca, Perna, Pablo, and Piegari, Estefania

Subjects
WATER quality monitoring, SPECTRAL imaging, MULTISPECTRAL imaging, REFLECTANCE, REFLECTANCE measurement, SEAWATER, WATER quality
Abstract

This paper describes a prototype network of automated in situ measurements of hyperspectral water reflectance suitable for satellite validation and water quality monitoring. Radiometric validation of satellite-derived water reflectance is essential to ensure that only reliable data, e.g., for estimating water quality parameters such as chlorophyll a concentration, reach end-users. Analysis of the differences between satellite and in situ water reflectance measurements, particularly unmasked outliers, can provide recommendations on where satellite data processing algorithms need to be improved. In a massively multi-mission context, including Newspace constellations, hyperspectral missions and missions with broad spectral bands not designed for "water colour", the advantage of hyperspectral over multispectral in situ measurements is clear. Two hyperspectral measurement systems, PANTHYR (based on the mature TRIOS/ RAMSES radiometer) and HYPSTAR® (a newly designed radiometer), have been integrated here in theWATERHYPERNET network with SI-traceable calibration and characterisation. The systems have common data acquisition protocol, data processing and quality control. The choice of validation site and viewing geometry and installation considerations are described in detail. Three demonstration cases are described: 1. PANTHYR data from two sites are used to validate Sentinel-2/MSI (A- 2. HYPSTAR® data at six sites are used to validate Sentinel-3/OLCI (A- 3. PANTHYR and HYPSTAR® data in Belgian North Sea waters are used to monitor phytoplankton parameters, including Phaeocystis globosa, over two 5 month periods. Conclusion are drawn regarding the quality of Sentinel-2/MSI and Sentinel-3/OLCI data, including indications where improvements could be made. For example, a positive bias (mean difference) is found for ACOLITE_DSF processing of Sentinel-2 in clear waters (Acqua Alta) and clues are provided on how to improve this processing. The utility of these in situ measurements, even without accompanying hyperspectral satellite data, is demonstrated for phytoplankton monitoring. The future evolution of the WATERHYPERNET network is outlined, including geographical expansion, improvements to hardware reliability and to the measurement method (including uncertainty estimation) and plans for daily distribution of near real-time data. [ABSTRACT FROM AUTHOR]

Published
2024
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9. Multi-scale observations of deep convection in the northwestern Mediterranean Sea during winter 2012-2013 using multiple platforms

Author

Testor, Pierre, Bosse, Anthony, Houpert, Loïc, Margirier, Félix, Mortier, Laurent, Legoff, Hervé, Dausse, Denis, Labaste, Matthieu, Karstensen, Johannes, Hayes, Daniel, Olita, Antonio, Ribotti, Alberto, Schroeder, Katrin, Chiggiato, Jacopo, Onken, Reiner, Heslop, Emma, Mourre, Baptiste, D'ortenzio, Fabrizio, Mayot, Nicolas, Lavigne, Héloise, de Fommervault, Orens, Coppola, Laurent, Prieur, Louis, Taillandier, Vincent, Durrieu de Madron, Xavier, Bourrin, Francois, Many, Gael, Damien, Pierre, Estournel, Claude, Marsaleix, Patrick, Taupier-Letage, Isabelle, Raimbault, Patrick, Waldman, Robin, Bouin, Marie Noelle, Giordani, Hervé, Caniaux, Guy, Somot, Samuel, Ducrocq, Véronique, Conan, Pascal, Variabilité de l'Océan et de la Glace de mer (VOG), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU), Bjerknes Centre for Climate Research (BCCR), Department of Biological Sciences [Bergen] (BIO / UiB), University of Bergen (UiB)-University of Bergen (UiB), Scottish Association for Marine Science (SAMS), Développement Instrumental et Techniques Marines (DITM), Leibniz-Institut für Meereswissenschaften (IFM-GEOMAR), Cyprus Oceanography Center, University of Cyprus (UCY), CNR Institute for Coastal Marine Environment (IAMC), Consiglio Nazionale delle Ricerche (CNR), Istituto di Science Marine (ISMAR ), Helmholtz-Zentrum Geesthacht (GKSS), SOCIB Balearic Islands Coastal Ocean Observing and Forecasting System, Laboratoire d'océanographie de Villefranche (LOV), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de la Mer de Villefranche (IMEV), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Centre de Formation et de Recherche sur les Environnements Méditérranéens (CEFREM), Université de Perpignan Via Domitia (UPVD)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'aérologie (LAERO), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Institut méditerranéen d'océanologie (MIO), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Océanographie Microbienne (LOMIC), Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire océanologique de Banyuls (OOB), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Bio-Argo project (CNES-TOSCA), COST Action ES0904 ‘‘EGO’’ (Everyone’s Gliding Observatories), MISTRALS, ANR-12-BS06-0003,ASICS-MED,Couplage Océan-Atmosphère en présence de structures de Submésoéchelle(2012), ANR-10-EQPX-0040,NAOS,Observations de l'océan global pour l'étude et la prévision de l'océan et du climat: préparation de la nouvelle décennie d'Argo(2010), European Project: 284321,EC:FP7:INFRA,FP7-INFRASTRUCTURES-2011-1,GROOM(2011), European Project: 287600,EC:FP7:ENV,FP7-OCEAN-2011,PERSEUS(2012), European Project: 262584,EC:FP7:INFRA,FP7-INFRASTRUCTURES-2010-1,JERICO(2011), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), University of Cyprus [Nicosia] (UCY), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Université de Perpignan Via Domitia (UPVD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Université de Toulouse (UT)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), and Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Observatoire océanologique de Banyuls (OOB)

Subjects
0106 biological sciences, Ocean observations, 010504 meteorology & atmospheric sciences, oceanic deep convection, ocean observation, Oceanography, 01 natural sciences, Symmetric instability, Deep convection, Mediterranean sea, symmetric instability, Geochemistry and Petrology, plumes, Mediterranean Sea, Earth and Planetary Sciences (miscellaneous), 14. Life underwater, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, Argo, 0105 earth and related environmental sciences, energy and buoyancy fluxes, 010604 marine biology & hydrobiology, Plumes, Ocean observation, Mooring, Energy and buoyancy fluxes, Geophysics, Oceanic deep convection, Eddy, 13. Climate action, Space and Planetary Science, Climatology, Thermohaline circulation, eddies, Bloom, Eddies, Geology
Abstract

International audience; During winter 2012–2013, open‐ocean deep convection which is a major driver for the thermohaline circulation and ventilation of the ocean, occurred in the Gulf of Lions (Northwestern Mediterranean Sea) and has been thoroughly documented thanks in particular to the deployment of several gliders, Argo profiling floats, several dedicated ship cruises, and a mooring array during a period of about a year. Thanks to these intense observational efforts, we show that deep convection reached the bottom in winter early in February 2013 in a area of maximum 28 ± 3 109 m2. We present new quantitative results with estimates of heat and salt content at the subbasin scale at different time scales (on the seasonal scale to a 10 days basis) through optimal interpolation techniques, and robust estimates of the deep water formation rate of 2.0 ± 0.2 Sv. We provide an overview of the spatiotemporal coverage that has been reached throughout the seasons this year and we highlight some results based on data analysis and numerical modeling that are presented in this special issue. They concern key circulation features for the deep convection and the subsequent bloom such as Submesoscale Coherent Vortices (SCVs), the plumes, and symmetric instability at the edge of the deep convection area.

Published
2018
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11. Multiscale Observations of Deep Convection in the Northwestern Mediterranean Sea During Winter 2012-2013 Using Multiple Platforms

Author

Testor, Pierre, primary, Bosse, Anthony, additional, Houpert, Loïc, additional, Margirier, Félix, additional, Mortier, Laurent, additional, Legoff, Hervé, additional, Dausse, Denis, additional, Labaste, Matthieu, additional, Karstensen, Johannes, additional, Hayes, Daniel, additional, Olita, Antonio, additional, Ribotti, Alberto, additional, Schroeder, Katrin, additional, Chiggiato, Jacopo, additional, Onken, Reiner, additional, Heslop, Emma, additional, Mourre, Baptiste, additional, D'ortenzio, Fabrizio, additional, Mayot, Nicolas, additional, Lavigne, Héloise, additional, de Fommervault, Orens, additional, Coppola, Laurent, additional, Prieur, Louis, additional, Taillandier, Vincent, additional, Durrieu de Madron, Xavier, additional, Bourrin, Francois, additional, Many, Gael, additional, Damien, Pierre, additional, Estournel, Claude, additional, Marsaleix, Patrick, additional, Taupier-Letage, Isabelle, additional, Raimbault, Patrick, additional, Waldman, Robin, additional, Bouin, Marie-Noelle, additional, Giordani, Hervé, additional, Caniaux, Guy, additional, Somot, Samuel, additional, Ducrocq, Véronique, additional, and Conan, Pascal, additional

Published
2018
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12. Multiscale observations of deep convection in the northwestern mediterranean sea during winter 2012-2013 using multiple platforms

Author

Testor, Pierre, Bosse, Anthony, Houpert, Loïc, Margirier, Félix, Mortier, Laurent, Legoff, Hervé, Dausse, Denis, Labaste, Matthieu, Karstensen, Johannes, Hayes, Daniel, Olita, Antonio, Ribotti, Alberto, Schroeder, Katrin, Chiggiato, Jacopo, Onken, Reiner, Heslop, Emma, Mourre, Baptiste, D'ortenzio, Fabrizio, Mayot, Nicolas, Lavigne, Héloise, de Fommervault, Orens, Coppola, Laurent, Prieur, Louis, Taillandier, Vincent, Durrieu de Madron, Xavier, Bourrin, Francois, Many, Gael, Damien, Pierre, Estournel, Claude, Marsaleix, Patrick, Taupier-Letage, Isabelle, Raimbault, Patrick, Waldman, Robin, Bouin, Marie-Noelle, Giordani, Hervé, Caniaux, Guy, Somot, Samuel, Ducrocq, Véronique, Conan, Pascal, Testor, Pierre, Bosse, Anthony, Houpert, Loïc, Margirier, Félix, Mortier, Laurent, Legoff, Hervé, Dausse, Denis, Labaste, Matthieu, Karstensen, Johannes, Hayes, Daniel, Olita, Antonio, Ribotti, Alberto, Schroeder, Katrin, Chiggiato, Jacopo, Onken, Reiner, Heslop, Emma, Mourre, Baptiste, D'ortenzio, Fabrizio, Mayot, Nicolas, Lavigne, Héloise, de Fommervault, Orens, Coppola, Laurent, Prieur, Louis, Taillandier, Vincent, Durrieu de Madron, Xavier, Bourrin, Francois, Many, Gael, Damien, Pierre, Estournel, Claude, Marsaleix, Patrick, Taupier-Letage, Isabelle, Raimbault, Patrick, Waldman, Robin, Bouin, Marie-Noelle, Giordani, Hervé, Caniaux, Guy, Somot, Samuel, Ducrocq, Véronique, and Conan, Pascal

Abstract

During winter 2012–2013, open‐ocean deep convection which is a major driver for the thermohaline circulation and ventilation of the ocean, occurred in the Gulf of Lions (Northwestern Mediterranean Sea) and has been thoroughly documented thanks in particular to the deployment of several gliders, Argo profiling floats, several dedicated ship cruises, and a mooring array during a period of about a year. Thanks to these intense observational efforts, we show that deep convection reached the bottom in winter early in February 2013 in a area of maximum 28 ± 3 . We present new quantitative results with estimates of heat and salt content at the subbasin scale at different time scales (on the seasonal scale to a 10 days basis) through optimal interpolation techniques, and robust estimates of the deep water formation rate of 2.0 . We provide an overview of the spatiotemporal coverage that has been reached throughout the seasons this year and we highlight some results based on data analysis and numerical modeling that are presented in this special issue. They concern key circulation features for the deep convection and the subsequent bloom such as Submesoscale Coherent Vortices (SCVs), the plumes, and symmetric instability at the edge of the deep convection area.

Published
2018

13. Phytoplankton winter blooms in the offshore south Adriatic waters are regulated by hydroclimatic events in the period 1995-2012

Author

Batistić, Mirna, Viličić, Damir, Kovačević, Vedrana, Jasprica, Nenad, Lavigne, Héloise, Carić, Marina, Garić, Rade, and Car, Ana

Subjects
phytoplankton winter blooms, South Adriatic, hydroclimatic events
Abstract

Data of phytoplankton abundance in winters of 1994 and 1995, and surface chlorophyll satellite- derived data(1997-2012) are the basis for investigation of characteristics and intensity of phytoplankton blooms in the open South Adriatic. Special attention is paid to the relation of different circulation regimes in the Ionian Sea (prevalently anticyclonic or cyclonic direction of Northern Ionian Gyre - NIG) to intensity of phytoplankton blooms. Different circulation regimes in the Ionian Sea cause inflow of water of different physical and biochemical properties into the Adriatic. Relatively high winter production events were evident in the open South Adriatic during both anticyclonic and cyclonic regimes. In the nutrient rich anticyclonic years, shallow vertical mixing is sufficient for enrichment of euphotic layers with the nutrients and development of the bloom, while in nutrient poor cyclonic years deep vertical mixing is necessary. Moreover, intense blooms have occurred in the years of specific hydroclimatic properties (i.e. East Mediterranean Transient – EMT and during extremely cold winters) and reversal years (from anticyclonic to cyclonic circulation of NIG and vice versa). In conclusion, winter season is important for production in the open South Adriatic waters and could not be omitted in the total yearly production estimates. Winter bloom intensity in the open South Adriatic depends on synergistic effects of local meteorological conditions and large time scale climatic variabilities in the Eastern Mediterranean on one hand, and water masses of different properties entering the Adriatic on the other.

Published
2017

17. Impact of decadal reversals of the North Ionian circulation on phytoplankton phenology.

Author

Lavigne, Héloise, Civitarese, Giuseppe, Gacic, Miroslav, and D'Ortenzio, Fabrizio

Subjects
PHYTOPLANKTON, PHENOLOGY, CHLOROPHYLL, MIXING height (Atmospheric chemistry), OCEAN circulation
Abstract

In the North Ionian, water circulation is characterized by a decadal alternation of cyclonic and anticyclonic regime driven by the mechanism called BiOS (Bimodal Oscillating System). The circulation regime affects the vertical dynamics and the nutrient distribution. The North Ionian is then a good study area to investigate how changes in circulation can affect phytoplankton dynamics in oligotrophic regions. From in situ observations, for each circulation regime the averaged distribution of isopycnals is provided, and a depth difference of about 80 m is estimated for the nitracline between cyclonic and anticyclonic regime. Based on phytoplankton phenology metrics extracted from annual time-series of satellite ocean color data for the period 1998-2012, the cyclonic and anticyclonic regimes are compared. Results show that the average chlorophyll in March, the date of bloom initiation and the date of maximum chlorophyll were affected by circulation patterns in the North Ionian. In the center of the gyre, bloom initiation occurred in December and chlorophyll was low in March when circulation was anticyclonic, whereas during the cyclonic circulation regime, a late chlorophyll peak, likely resulting from different phytoplankton dynamics, was commonly observed in March. An additional analysis shows that the winter buoyancy losses, which govern the Mixed Layer Depth (MLD) also contribute to explain the interannual variability in bloom initiation and intensity. Two scenarios involving the relative position of the MLD and nitracline are finally developed, discussed and tested with model data to explain the different phenology patterns observed in the North Ionian. [ABSTRACT FROM AUTHOR]

Published
2017
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18. Winter phytoplankton blooms in the offshore south Adriatic waters (1995-2012) regulated by hydroclimatic events: Special emphasis on the exceptional bloom of 1995.

Author

Batistić, Mirna, Viličić, Damir, Kovačević, Vedrana, Jasprica, Nenad, Lavigne, Héloise, Carić, Marina, Garić, Rade, and Car, Ana

Subjects
ALGAL blooms, CHLOROPHYLL, EUPHOTIC zone, CLIMATOLOGY, ATMOSPHERIC sciences
Abstract

The characteristics and intensity of winter phytoplankton blooms in the open South Adriatic (OSA) were investigated by combining data on abundance and satellite-derived surface chlorophyll (1995-2012). Particular attention was paid to the different circulation regimes in the Ionian Sea, namely the anticyclonic and cyclonic Northern Ionian Gyres (NIG), both of which influence the physical and biochemical properties of the South Adriatic. Relatively high winter production was evident during both. Contrary to nutrient-poor cyclonic years, in nutrient-rich anticyclonic years, shallow vertical mixing is sufficient for enrichment of euphotic layers and bloom development. Moreover, intense blooms have occurred under certain hydroclimatic conditions: the East Mediterranean Transient (EMT), extreme winters, and reversal years that switch between anticyclonic and cyclonic circulation. Winter phytoplankton bloom in February 1995, with microphytoplankton abundance exceeding 105 cells L-1, was related to the phenomenon of EMT which produced dramatic changes in the East Mediterranean basin-wide circulation patterns. Dominance of a microphytoplankton species uncommonly encountered in the OSA may be related to strong inflow of Atlantic Water (AW) into the Adriatic during EMT and anticyclonic circulation in the NIG. [ABSTRACT FROM AUTHOR]

Published
2017
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