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See detailConsolidation de l’indice de composition phytoplanctonique ICPP Médit pour les eaux côtières méditerranéennes
Goffart, Anne ULiege

Report (2019)

Lors d’un premier travail, nous avions élaboré l’indice de composition phytoplanctonique IC Médit 2014 à partir des données pigmentaires du phytoplancton des eaux côtières corses sur un jeu de données ... [more ▼]

Lors d’un premier travail, nous avions élaboré l’indice de composition phytoplanctonique IC Médit 2014 à partir des données pigmentaires du phytoplancton des eaux côtières corses sur un jeu de données restreint. Dans cette étude, nous avons fait évoluer l’indice IC Médit 2014 en complétant le premier jeu de données par des données acquises dans des sites côtiers méditerranéens soumis à des forces de pression d’intensité croissante. Le nouvel indice, ICPP Médit, est un indice multimétrique qui répond aux pressions et apporte des informations sur la saisonnalité des perturbations. Le protocole de calcul a été défini et la grille d’évaluation proposée. ICPP Médit a été conçu pour être robuste scientifiquement mais facile à mettre en œuvre par des acteurs ne disposant pas d’expertise spécifique en biodiversité et en écologie du phytoplancton. L’évaluation des incertitudes sur le classement des masses d’eau et/ou des sites échantillonnés et l’éventuel ajustement de la grille nécessitent l’acquisition de données complémentaires, idéalement sur un plan de gestion. Cependant, l’application croisée de l’ICPP Médit et de l’ICBC sur le jeu de données de Méditerranée montre une bonne cohérence des classements issus de l’application des deux méthodologies, ce qui conforte les choix posés dans l’élaboration de l’indice ICCP Médit. [less ▲]

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See detailElaboration d’une méthode de surveillance de la composition phytoplanctonique à grande échelle
Goffart, Anne ULiege

Report (2019)

Au cours de la dernière décennie, les mesures spectrales effectuées par les capteurs spatiaux de couleur de l’océan ont été corrélées à la présence des grands groupes phytoplanctoniques identifiés par ... [more ▼]

Au cours de la dernière décennie, les mesures spectrales effectuées par les capteurs spatiaux de couleur de l’océan ont été corrélées à la présence des grands groupes phytoplanctoniques identifiés par leur composition pigmentaire. La méthodologie, appelée PHYSAT, permet de détecter les grands groupes phytoplanctoniques depuis l’espace et d’élaborer des cartes de distribution à grande échelle (Alvain et al. 2008). Récemment, l’algorithme PHYSAT a été adapté à la Méditerranée dans son ensemble (PHYSAT-MED; Navarro et al. 2014, Navarro et al. 2017). La mise en commun des expertises de Sylvain Coudray (IFREMER, traitement des signaux satellitaire) et d’Anne Goffart (Université de Liège, dynamique du phytoplancton méditerranéen, données pigmentaires, chémotaxonomie) a permis d’adapter l’outil PHYSAT-MED à une échelle locale (downscaling), utile au suivi et à la caractérisation du phytoplancton des eaux côtières de la Méditerranée française. L’adaptation de l’outil PHYSAT-MED a conduit au développement du prototype OC5-PHYSAT. OC5-PHYSAT a été testé et validé sur un premier jeu de données pigmentaires acquis au cours d’une année de référence (2015) en milieu oligotrophe (Baie de Calvi, Corse). L’algorithme a permis de reproduire de manière très satisfaisante les variations hebdomadaires de la biomasse phytoplanctonique totale (Tchl a) et des groupes phytoplanctoniques dominants (prymnesiophycées, cyanobactéries, diatomées et autres eucaryotes), identifiés par leur signature pigmentaire. Au terme de cette étude, il est nécessaire de compléter le travail engagé en validant OC5-PHYSAT sur des jeux de données pluriannuels et dans des masses d’eau côtières caractérisées par des propriétés optiques contrastées (turbidité, matière en suspension non algale, …). Des cartes synthétiques de distribution des groupes phytoplanctoniques dominants pourront alors être fournies pour les masses d’eau DCE et les zones DCSMM. [less ▲]

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See detailRelationships between environmental conditions and phytoplankton in the Mellah lagoon (South Western Mediterranean, Algeria), with an emphasis on HABs species
Draredja, Mohamed Anis; Frihi, Hocine; Boualleg, Chahinez et al

Poster (2018, October)

For the first time, a bi-monthly monitoring of environmental parameters (temperature, salinity, nutrients) and phytoplankton assemblages was conducted in the well-preserved Mellah lagoon ecosystem (South ... [more ▼]

For the first time, a bi-monthly monitoring of environmental parameters (temperature, salinity, nutrients) and phytoplankton assemblages was conducted in the well-preserved Mellah lagoon ecosystem (South Western Mediterranean, Algeria). Sampling was performed at 3 stations in 2016. The objective was to study the evolution of the microphytoplankton community with a focus on HABs species in relation with the environmental characteristics. In total, 227 microphytoplankton species belonging mainly to Diatomophyceae (160 species) and Dinophyceae (53 species), were inventoried in the Mellah lagoon. There was a clear dominance of diatoms (63%), compared to dinoflagellates (37%). Proliferations of some potentially toxic species such as Prorocentrum micans (7 200 cells.l-1) and Gymnodinium sanguineum (6 000 cells.l-1), were observed in summer and autumn respectively. Other HABs species as Alexandrium tamarense/catenella (1 350 cells.l-1) and Alexandrium minutum (1 420 cells.l-1), were present in winter and spring respectively. Temporal differences in the qualitative composition and quantitative phytoplankton communities in the three stations are discussed in relation with environmental variables. Microphytoplankton populations in the Mellah show diversity and equitability indices of 3.04 bits.cell-1 and 0.94 respectively, showing a structured community during winter and spring. The rest of the year is characterized by unstable phytoplankton populations, where only opportunistic species develop. [less ▲]

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See detailInteraction between climate forcing and plankton communities in a pristine NW Mediterranean site, the Bay of Calvi (Corsica) : a long term study
Goffart, Anne ULiege; Hecq, Jean-Henri ULiege; Baldi et al

Conference (2018, May)

In the Mediterranean coastal areas, most of the long-term studies of plankton dynamics concern highly urbanized areas, where long-term variability reflects the combined effects of climate and ... [more ▼]

In the Mediterranean coastal areas, most of the long-term studies of plankton dynamics concern highly urbanized areas, where long-term variability reflects the combined effects of climate and anthropogenic forcing. Here we use a unique long-term time series (1979-) performed in a NW Mediterranean coastal area unbiased by local anthropogenic pressure (Bay of Calvi, Corsica) to understand how climate variation drives changes in plankton communities. From high-frequency field data, we describe a mechanism that links winter physics, nutrient replenishment of the surface layer and plankton biomass and composition under the different combinations of meteorological conditions that occurred during the 4 decades of observations. Focusing on phytoplankton, we point out how climate variation affected (i) the timing, duration and magnitude of the winter-spring phytoplankton blooms, (ii) the mean yearly biomasses, (iii) the abundance of phytoplankton functional groups. We identify threshold values of physical variables below and above which they strongly impact nutrient availability, phytoplankton bloom characteristics and seasonal succession of functional groups. We show that food webs are resource controlled. Striking similarities between our observations and events elsewhere in the NW Mediterranean Sea are presented. We explore ecological consequences of changes occurring at the base of the food webs on services provided by plankton in the Mediterranean coastal waters. [less ▲]

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See detailThresholds of plankton community change in a Mediterranean coastal area : results from a long-term (1979-2014) time series
Goffart, Anne ULiege; Collignon, Amandine; Lejeune, Pierre et al

Poster (2017, September)

In the Mediterranean Sea, which has been identified as a hotspot for climate change, there is evidence for impacts of climate change on marine organisms. However, the lack of information on environmental ... [more ▼]

In the Mediterranean Sea, which has been identified as a hotspot for climate change, there is evidence for impacts of climate change on marine organisms. However, the lack of information on environmental drivers and associated thresholds limits our ability to forecast possible changes in biodiversity and ecological interactions. In this presentation, we use a unique long-term (1979-2014) time series performed in a Mediterranean coastal area unbiased by local anthropogenic pressure (Bay of Calvi, Corsica) to understand how climate variation controls phyto- and zooplankton dynamics and possibly affect artisanal and small-scale fisheries exploiting areas near the coast. From high-frequency field data, we describe a mechanism that links winter physics, nutrient replenishment of the surface layer and plankton dynamics under the different combinations of meteorological conditions that occurred during the 36 years of observations. We identify threshold values of physical variables below and above which they strongly impact nutrient availability, phyto- and zooplankton bloom characteristics and seasonality succession of plankton functional groups. We provide identification of environmental thresholds beyond which diatoms, which are crucial for sustaining fish populations, collapse. We discuss links between climate-related changes in plankton availability, fish recruitment and the success of small-scale fisheries. We show that the mechanism we identified from the 1979 to 2014 period of observation in the Bay of Calvi is pertinent to other Northwestern Mediterranean areas, stressing the importance of winter conditions in determining the state of Mediterranean pelagic ecosystems. We highlight that the thresholds obtained from our long-term time series provide key information for improving model scenarios of the impact of climate change on Mediterranean ecosystems. [less ▲]

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See detailNorth Atlantic Ocean
Bode, A.; Bange, H.W.; Boersma, M. et al

in O'Brien, T.D.; Lorenzoni, L.; Isensee, K. (Eds.) et al What are Marine Ecological Time Series telling us about the ocean? A status report (2017)

Executive Summary (with an focus on the North Atlantic. For the whole summary, see the report). Sustained ocean observations, including ships, autonomous platforms, and satellites, are critical for ... [more ▼]

Executive Summary (with an focus on the North Atlantic. For the whole summary, see the report). Sustained ocean observations, including ships, autonomous platforms, and satellites, are critical for monitoring the health of our marine ecosystems and developing effective management strategies to ensure longterm provision of the marine ecosystem services upon which human societies depend. Ocean observations are also essential in the development and validation of ocean and climate models used to predict future conditions. Ship‐ based biogeochemical time series provide the high‐ quality biological, physical and chemical measurements that are needed to detect climate change‐ driven trends in the ocean, assess associated impacts on marine food webs, and to ultimately improve our understanding of changes in marine biodiversity and ecosystems. While the spatial ‘footprint’ of a single time series may be limited, coupling observations from multiple time series with synoptic satellite data can improve our understanding of critical processes such as ocean productivity, ecosystem variability, and carbon fluxes on a larger spatial scale. The International Group for Marine Ecological Time Series (IGMETS) analyzed over 340 open ocean and coastal datasets, ranging in duration from five years to greater than 50 years. Their locations are displayed in a world map (Discover Ocean Time Series, http://igmets.net/discover) and in the IGMETS information database (http://igmets.net/metabase). These cross‐ time‐ series analyses yielded important insights on climate trends occurring both on a global and regional scale. At a global level, a generalized warming trend is observed over the past thirty years, consistent with what has been published by the IPCC (2013) report as well as other research. There are regional differences in temperature trends, depending on the time window considered, which are driven by regional and temporal expressions of large‐ scale climatic forcing and atmospheric teleconnections. This warming is accompanied by shifts in the biology and biogeochemical cycling (i.e. oxygen, nutrient, carbon), which impact marine food webs and ecosystem services. …/… The first comprehensive analysis of in situ time series provided for the North Atlantic Ocean revealed that, despite being the most studied region of the global ocean, there are large areas in this region still lacking multidisciplinary in situ observations. However, over the 25‐ and 30‐ year analysis periods, > 95% of the North Atlantic Ocean significantly warmed and the chlorophyll concentrations decreased (p < 0.05). At the same time, negative trends in salinity, oxygen and nutrients , as exemplified by nitrate, were noted. The analysis of existing time series showed that even in adjacent areas that appear to be relatively homogenous, there is large variability in ecosystem behaviour over time, as observed in the continental shelves at both sides of the North Atlantic Ocean. In general, over the 5‐year period prior to 2012, ~70% of the area of the South Atlantic showed cooling and 66% decreasing chlorophyll concentrations. However, over the past 30 years, > 85% of the South Atlantic increased in temperature. The paucity of in situ time series in this region, and the striking changes that have been reported in South Atlantic ecosystems over the past two decades, highlight the need to have a better observing system in place. …/… The IGMETS effort highlights the value of biogeochemical time series as essential tools for assessing, and predicting, global and regional climate change and its impacts on ecosystem services. The capacity to identify and differentiate anthropogenic and natural climate variations and trends depends largely on the length of the time‐ series, as well as on the location. Most of the ship based ecological time series are concentrated in the coastal ocean. While coastal zones in North America and Europe are being monitored, there is a conspicuous lack of biogeochemical time‐ series in other coastal regions around the world, and an almost complete absence of such observational platforms in the open ocean, which limits the capacity of analyses such as this. A more globally distributed network of time‐ series observations over multiple decades will be needed to differentiate between natural and anthropogenic variability. [less ▲]

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See detailContrôle de la variabilité interannuelle de la composition du phytoplancton de la Baie de Calvi (Corse) par les facteurs environnementaux
Goffart, Anne ULiege; Andral, Bruno; Baldi, Yoann et al

Conference (2016, November)

Le but de la présentation est de synthétiser les connaissances sur le contrôle de la dynamique du phytoplancton par les contraintes environnementales dans un site de référence méditerranéen. L’étude est ... [more ▼]

Le but de la présentation est de synthétiser les connaissances sur le contrôle de la dynamique du phytoplancton par les contraintes environnementales dans un site de référence méditerranéen. L’étude est réalisée en Baie de Calvi (Corse) à la station PHYTOCLY (42°34.85'N, 08°43.71'E) où des séries temporelles haute fréquence de données physiques, chimiques et biologiques sont réalisées depuis 1979. Depuis 2006, l’acquisition des données de subsurface et le traitement des échantillons, qui inclut des analyses HPLC de contenu pigmentaire du phytoplancton et des comptages de flore totale, sont réalisés grâce au soutien de la DCE. En Baie de Calvi, l’intensité de la rigueur hivernale, identifiée par deux proxys, la température de l’eau et le nombre de jours de vent fort, contrôle le réapprovisionnement en sels nutritifs des couches de surface et le développement du bloom phytoplanctonique (détails dans Goffart et al., 2015, Progress in Oceanography). Lors des années caractérisées par un hiver rigoureux (e.g. 2010), le bloom phytoplanctonique hivernal se développe pendant la période d’eau froide (eau de subsurface ≤13.5°C). Il est dominé par les diatomées et les cryptophycées, deux groupes qui montrent une préférence marquée pour les eaux froides et riches en sels nutritifs. Lorsque l’hiver est très doux (e.g. 2007), la disponibilité en sels nutritifs est réduite et le bloom ne se développe pas. Les diatomées et les cryptophycées sont absentes, et les communautés phytoplanctoniques sont dominées par les prymnesiophycées pico- et nanoplanctoniques et les cyanobactéries. Les résultats de l’étude permettent aussi : • de fixer les limites de la variabilité naturelle du phytoplancton dans un site de référence méditerranéen, • d’expliquer les variations interannuelles de biomasse et de composition phytoplanctonique, • de définir les préférences écologiques des différents groupes phytoplanctoniques, • d’établir des courbes d’évolution saisonnière des principaux groupes phytoplanctoniques qui intègrent la variabilité interannuelle liée aux variations climatiques. La connaissance acquise au cours de cette étude permet de contribuer au développement d’indices de qualité intégrant la composition du phytoplancton (e.g. indice de composition I C MEDIT) et de tester des méthodes de surveillance à grande échelle (e.g. croisement des suivis pigmentaires réalisés à haute fréquence et de l’imagerie satellitaire), contribuant ainsi à la mise en œuvre des politiques publiques (DCE, DCSMM). [less ▲]

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See detailDéveloppement d’un indice de composition phytoplanctonique adapté aux eaux côtières méditerranéennes
Goffart, Anne ULiege

Scientific conference (2015, December)

L'indice de composition phytoplanctonique ICMedit : bilan et perspectives.

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See detailSTAtion of Reference and rEsearch on Change of local and global Anthropogenic Pressures on Mediterranean Ecosystems Drifts: The STARECAPMED project
Richir, Jonathan ULiege; Abadie, Arnaud ULiege; Binard, Marc ULiege et al

Conference (2015, November 08)

The Marine and Oceanographic Research Station STARESO in the Calvi Bay, Corsica (France), is a unique tool in a preserved natural site that includes all the characteristic ecosystems of the Mediterranean ... [more ▼]

The Marine and Oceanographic Research Station STARESO in the Calvi Bay, Corsica (France), is a unique tool in a preserved natural site that includes all the characteristic ecosystems of the Mediterranean littoral. The station, established in 1970, has archived environmental data for decades. The STARECAPMED project, multidisciplinary, articulates itself around these two main features. Its objective is to understand how human activities can interact with the fundamental processes that govern the functioning of the different coastal ecosystems of a Mediterranean bay. The understanding of these interactions involves: (i) the identification of the anthropogenic pressures; (ii) the quantification of their impacts on the ecosystems; (iii) the prioritization of these impacts. STARECAPMED also aims to confirm the relevance of the use of the Calvi Bay as a reference in the study of local and global pressures and the changes they may cause on the structure and the functioning of Mediterranean coastal ecosytems. [less ▲]

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See detailPlankton ecosystem response to the decadal variation of winter intensity in the Mediterranean Sea : a long-term study (1979-2014)
Goffart, Anne ULiege; Collignon, Amandine ULiege; Hecq, Jean-Henri ULiege et al

Poster (2015, October)

In the Mediterranean Sea, several studies with distinct data sets indicate that the pelagic ecosystem underwent periods of change in the late 1980s and in the early 2000s. Here we used a unique long-term ... [more ▼]

In the Mediterranean Sea, several studies with distinct data sets indicate that the pelagic ecosystem underwent periods of change in the late 1980s and in the early 2000s. Here we used a unique long-term time series of data collected in the well-preserved Bay of Calvi (Corsica island, Ligurian Sea, NW Mediterranean) from 1979 and 2014 to explore the synchrony between changes in environmental conditions and phyto- and zooplankton dynamics. We identified an almost decadal, long-term variability in winter intensity, with three distinct periods: the 1980s (1979-1988), the 1990s (1989-1998) and the 2000s (1999-2014), which were characterized by moderate, mild and highly variable winters, respectively. We pointed out how the decadal changes in winter intensity affected (i) the duration and intensity of phyto- and zooplankton blooms, (ii) the mean yearly biomasses, and (iii) the nature of the assemblages. High phyto- and zooplankton biomasses were observed in years characterized by moderate and severe winters, and low phyto- and zooplankton abundances were recorded in years with mild winters. Moderate/severe and mild winters were favorable for diatoms and gelatinous zooplankton, respectively. Focusing on meroplanktonic species, we explored ecological consequences of decadal variations observed in the Bay of Calvi for resource management. We highlighted parallelisms with other European seas. [less ▲]

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See detailPlankton ecosystem response to the decadal variation of winter intensity in the Mediterranean Sea : a long-term study (1979-2014)
Goffart, Anne ULiege; Collignon, Amandine ULiege; Hecq, Jean-Henri ULiege et al

Conference (2015, October)

In the Mediterranean Sea, several studies with distinct data sets indicate that the pelagic ecosystem underwent periods of change in the late 1980s and in the early 2000s. Here we used a unique long-term ... [more ▼]

In the Mediterranean Sea, several studies with distinct data sets indicate that the pelagic ecosystem underwent periods of change in the late 1980s and in the early 2000s. Here we used a unique long-term time series of data collected in the well-preserved Bay of Calvi (Corsica island, Ligurian Sea, NW Mediterranean) from 1979 and 2014 to explore the synchrony between changes in environmental conditions and phyto- and zooplankton dynamics. We identified an almost decadal, long-term variability in winter intensity, with three distinct periods: the 1980s (1979-1988), the 1990s (1989-1998) and the 2000s (1999-2014), which were characterized by moderate, mild and highly variable winters, respectively. We pointed out how the decadal changes in winter intensity affected (i) the duration and intensity of phyto- and zooplankton blooms, (ii) the mean yearly biomasses, and (iii) the nature of the assemblages. High phyto- and zooplankton biomasses were observed in years characterized by moderate and severe winters, and low phyto- and zooplankton abundances were recorded in years with mild winters. Moderate/severe and mild winters were favorable for diatoms and gelatinous zooplankton, respectively. Focusing on meroplanktonic species, we explored ecological consequences of decadal variations observed in the Bay of Calvi for resource management. We highlighted parallelisms with other European seas. [less ▲]

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See detailSTARECAPMED (STAtion of Reference and rEsearch on Change of local and global Anthropogenic Pressures on Mediterranean Ecosystems Drifts) - Année 2014. Rapport de recherches.
Richir, Jonathan ULiege; Abadie, Arnaud ULiege; Binard, Marc ULiege et al

Report (2015)

La prise de conscience, par le grand public, de l'impact grandissant de l'homme sur l'océan est récente. Elle se traduit par une volonté politique sincère de correction par des mesures de protection, de ... [more ▼]

La prise de conscience, par le grand public, de l'impact grandissant de l'homme sur l'océan est récente. Elle se traduit par une volonté politique sincère de correction par des mesures de protection, de gestion et de développement durable. Ces politiques, et leurs conséquences économiques et sociétales lourdes, ne peuvent être acceptées que si les décisions se fondent sur des connaissances scientifiques incontestables et montrent des résultats scientifiquement prouvés. Par ailleurs, ces décisions doivent prendre en compte des impacts qui s'opèrent à des échelles de temps et d’espace très variables, de quelques heures à plusieurs dizaines d’années et de quelques mètres à plusieurs milliers de km. En termes politiques, l'information scientifique nécessaire à la prise de décision doit pouvoir couvrir les différentes échelles depuis le niveau local et régional, jusqu'à l'échelle nationale, européenne voire globale, et cela sur le plus long terme possible. Enfin, pour être complète, l'information scientifique sur les écosystèmes marins doit pouvoir répondre à trois questions objectives : (i) quel est l'état? (ii) quelle est l'évolution? (iii) quels sont les mécanismes et processus mis en jeux? et à une question plus prospective : (vi) que peux-t-on prévoir et comment agir? Le présent rapport ne peut pas, à lui seul, refléter toute la richesse du programme STARECAPMED. En 3 ans, STARECAPMED a généré plusieurs centaines de milliers de données nouvelles, ré-exploité plusieurs centaines de publications, rapports et autres enregistrements passés et présents. Le programme a aussi généré de nombreux documents, rapports et mémoires. Enfin, des publications internationales et des thèses de doctorat sont en cours de réalisation ou abouties. Afin de rester lisible, nous avons donc choisi de présenter ce rapport 2014 sous la forme de 12 exemples parmi les travaux en cours. Ces exemples sont traités selon un schéma identique en 4 points simples : (i) La présentation du cas d’étude dans le projet global ; (ii),Les approches innovatrices développées ; (iii),La présentation de résultats marquants ; (iv),Les délivrables de STARECAPMED pour les politiques publiques. [less ▲]

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See detailLe plastique dans les océans, la Méditerranée est-elle menacée?
Collignon, Amandine ULiege; Hecq, Jean-Henri ULiege; Goffart, Anne ULiege

Scientific conference (2015, March 05)

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See detailControl of plankton phenology by climate variation in a Mediterranean coastal area : results from a long-term study (1979-2011)
Goffart, Anne ULiege; Collignon, Amandine ULiege; Hecq, Jean-Henri ULiege

Conference (2015, March)

Physical processes are known to play major roles in marine plankton succession. However, few studies have addressed the mechanisms that regulate phyto- and zooplankton phenology in a context of changing ... [more ▼]

Physical processes are known to play major roles in marine plankton succession. However, few studies have addressed the mechanisms that regulate phyto- and zooplankton phenology in a context of changing climate. Here we used a unique long-term (1979-2011) time series performed in a Mediterranean coastal area unbiased by local anthropogenic pressure (PHYTOCLY station, Bay of Calvi, Corsica) to understand how environmental forcing affects the timing, duration and magnitude of the winter-spring phyto- and zooplankton blooms. We showed that phyto- and zooplankton blooms were bottom-up controlled by the establishment of favourable abiotic conditions, i.e. nutrient replenishment by vertical mixing under specific water temperature and wind conditions, for which thresholds were defined. According to the intensity of winter characteristics, there were strong differences in both the abundance and composition of phyto- and zooplankton during the winter-spring period. Our study is consistent with the recent reports that, when occurring, diatoms peaks were added to the initial phytoplankton groups instead of replacing them. In contrast, zooplankton groups followed a replacement sequence. Based on the results provided by our time series, we show that plankton phenology in the Bay of Calvi is highly controlled by climate variation and exhibits contrasted patterns in response to different scenarios of environmental forcing. [less ▲]

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See detailBiodiversity and seasonal variations of zooneuston in the northwestern Mediterranean Sea
Collard, France ULiege; Collignon, Amandine ULiege; Hecq, Jean-Henri ULiege et al

in Belgian Journal of Zoology (2015), 145(1), 40-48

Neuston includes animals and plants inhabiting the surface layer of the water column. The neustonic area is an accumulation zone for bacteria, organic molecules but also terrestrial debris. The surface ... [more ▼]

Neuston includes animals and plants inhabiting the surface layer of the water column. The neustonic area is an accumulation zone for bacteria, organic molecules but also terrestrial debris. The surface layer is also the air/water exchange region. Therefore, neustonic organisms are directly exposed to several constraints such as wind stress and turbulence. The present study aims to characterize the zooneuston in terms of abundance and biodiversity and to evaluate the impacts of wind stress on neustonic abundance. Zooneustonic and zooplanktonic (depth of 5 meters) samples were collected twice a month between 30th August 2011 and 10th July 2012 in Calvi Bay, Corsica. Zooneustonic biodiversity was high and, notably, twenty-eight copepod genera were identified. Among these copepods, several organisms, belonging to the Pontellidae family, were much more frequent in neuston than in underlying plankton and their abundance depended on wind direction. Taxon-specific trends in seasonal abundance variation were present. For example, individuals of the Acantharia Lithoptera spp. were found in summer whereas the Pontellidae Anomalocera patersoni appeared in winter. Overall, our data provide a first step towards a better knowledge of neuston community structure in the Mediterranean Sea. [less ▲]

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See detailDrivers of the winter–spring phytoplankton bloom in a pristine NW Mediterranean site, the Bay of Calvi (Corsica): A long-term study (1979–2011)
Goffart, Anne ULiege; Hecq, Jean-Henri ULiege; Legendre, Louis

in Progress in Oceanography (2015), 137

This work is based on a long time series of data collected in the well-preserved Bay of Calvi (Corsica island, Ligurian Sea, NW Mediterranean) between 1979 and 2011, which include physical characteristics ... [more ▼]

This work is based on a long time series of data collected in the well-preserved Bay of Calvi (Corsica island, Ligurian Sea, NW Mediterranean) between 1979 and 2011, which include physical characteristics (31 years), chlorophyll a (chl a, 15 years), and inorganic nutrients (13 years). Because samples were collected at relatively high frequencies, which ranged from daily to biweekly during the winter-spring period, it was possible to (1) evidence the key role of two interacting physical variables, i.e. water temperature and wind intensity, on nutrient replenishment and phytoplankton dynamics during the winter-spring period, (2) determine critical values of physical factors that explained interannual variability in the replenishment of surface nutrients and the winter-spring phytoplankton bloom, and (3) identify previously unrecognized characteristics of the planktonic ecosystem. Over the >30 year observation period, the main driver of nutrient replenishment and phytoplankton (chl a) development was the number of wind events (mean daily wind speed >5 m s-1) during the cold-water period (subsurface water ≤13.5°C). According to winter intensity, there were strong differences in both the duration and intensity of nutrient fertilization and phytoplankton blooms (chl a). The trophic character of the Bay of Calvi changed according to years, and ranged from very oligotrophic (i.e. subtropical regime, characterized by low seasonal variability) to mesotrophic (i.e. temperate regime, with a well-marked increase in nutrient concentrations and chl a during the winter-spring period) during mild and moderate winters, respectively. A third regime occurred during severe winters characterized by specific wind conditions (i.e. high frequency of northeasterly winds), when Mediterranean “high nutrient - low chlorophyll” conditions occurred as a result of enhanced cross-shore exchanges and associated offshore export of the nutrient-rich water. There was no long-term trend (e.g. climatic) in either nutrient replenishment or the winter-spring phytoplankton bloom between 1979 and 2011, but both nutrients and chl a reflected interannual and decadal changes in winter intensity. [less ▲]

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See detailComparative biogeochemistry-ecosystem-human interactions on dynamic continental margins
Levin, Lisa A.; Liu, Kon-Kee; Kay-Christian, Emeis et al

in Journal of Marine Systems (2015), 141

The ocean’s continental margins face strong and rapid change, forced by a combination of direct human activity, anthropogenic CO2-induced climate change, and natural variability. Stimulated by discussions ... [more ▼]

The ocean’s continental margins face strong and rapid change, forced by a combination of direct human activity, anthropogenic CO2-induced climate change, and natural variability. Stimulated by discussions in Goa, India at the IMBER IMBIZO III, we (1) provide an overview of the drivers of biogeochemical variation and change on margins, (2) compare temporal trends in hydrographic and biogeochemical data across different margins (3) review ecosystem responses to these changes, (4) highlight the importance of margin time series for detecting and attributing change and (5) examine societal responses to changing margin biogeochemistry and ecosystems. We synthesize information over a wide range of margin settings in order to identify the commonalities and distinctions among continental margin ecosystems. Key drivers of biogeochemical variation include long-term climate cycles, CO2-induced warming, acidification, and deoxygenation, as well as sea level rise, eutrophication, hydrologic and water cycle alteration, changing land use, fishing, and species invasion. Ecosystem responses are complex and impact major margin services including primary production, fisheries production, nutrient cycling, shoreline protection, chemical buffering, and biodiversity. Despite regional differences, the societal consequences of these changes are unarguably large and mandate coherent actions to reduce, mitigate and adapt to multiple stressors on continental margins. [less ▲]

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See detailValidation de l’indice composition IC Medit dans des masses d’eau côtières méditerranéennes caractérisées par un gradient croissant d’eutrophisation
Goffart, Anne ULiege; Andral, Bruno

Report (2014)

The aim of this study is to show the current status of the development and use of the new IC Medit phytoplankton composition index as a sub-metric within the phytoplankton quality element in assessing ... [more ▼]

The aim of this study is to show the current status of the development and use of the new IC Medit phytoplankton composition index as a sub-metric within the phytoplankton quality element in assessing phytoplankton quality in Mediterranean coastal waters. IC Medit uses pigment concentrations determined by HPLC for assessing phytoplankton composition. Focusing on coastal waters of Corsica, we (i) described the seasonal succession of the main phytoplankton groups in reference conditions, (ii) studied responses of phytoplankton groups to well identified drivers, (iii) assessed the shift of the seasonal succession of phytoplankton groups from the reference conditions in impacted areas, (iv) revealed pressure / impact relationships between nutrients and pigments, and (v) established guidelines for sampling and IC MEDIT implementation. IC Medit is an indicator that improves the information provided by chl a in relation to anthropogenic pressures. It provides useful information on water quality, and could be used for management purposes. Nevertheless, due to the lack of information about the relationship between phytoplankton composition and pressures in highly impacted areas, boundary conditions are still to be defined. This should be done in collaboration with statisticians. [less ▲]

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See detailAbundance and variability of jellyfishes in the Bay of Calvi, Corsica
Collignon, Amandine ULiege; Hecq, Jean-Henri ULiege; Goffart, Anne ULiege

Scientific conference (2014, May 29)

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See detailAnnual variation in neustonic micro- and meso-plastic particles and zooplankton in the Bay of Calvi (Mediterranean–Corsica)
Collignon, Amandine ULiege; Hecq, Jean-Henri ULiege; Galgani, François et al

in Marine Pollution Bulletin (2014), 79(1-2), 293-298

The annual variation in neustonic plastic particles and zooplankton was studied in the Bay of Calvi 23 (Corsica) between 30 August 2011 and 7 August 2012. Plastic particles were classified into three size ... [more ▼]

The annual variation in neustonic plastic particles and zooplankton was studied in the Bay of Calvi 23 (Corsica) between 30 August 2011 and 7 August 2012. Plastic particles were classified into three size classes, small microplastics (0.2–2 mm), large microplastics (2–5 mm) and mesoplastics (5–10 mm). 74% of the 38 samples contained plastic particles of varying composition: e.g. filaments, polystyrene, thin plastic films. An average concentration of 6.2 particles/100 m2 was observed. The highest abundance values (69 particles/100 m2) observed occurred during periods of low offshore wind conditions. These values rose in the same order of magnitude as in previous studies in the North Western Mediterranean. The relationships between the abundance values of the size classes between zooplankton and plastic particles were then examined. The ratio for the intermediate size class (2–5 mm) reached 2.73. This would suggest a potential confusion for predators regarding planktonic prey of this size class. [less ▲]

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