Non-conventional stable isotopes have received increasing attention in the past decade to investigate multi-level ecological connections from individuals to ecosystems. More recently, isotopes from trace and non-nutrient elements, potentially toxic (i.e., Hg), have also been recognized of great significance to discriminate sources, transports, and bioaccumulation, as well as trophic transfers. In contrast, lithium (Li) concentrations and its isotope compositions (δ 7 Li) remain poorly documented in aquatic ecosystems, despite its possible accumulation in marine organisms, its increasing industrial production, and its demonstrated hazardous effects on biota. Here, we present the first Li isotope investigation of various soft tissues, organs or whole organisms, from marine plankton, bivalves, cephalopods, crustaceans, and fish of different biogeographical regions [North Mediterranean Sea, North Atlantic Ocean (Bay of Biscay), South East Pacific Ocean (New Caledonia), and Southern Indian Ocean (Kerguelen Islands)]. Independently of the considered organisms, δ 7 Li values range widely, from 4.6‰ (digestive gland of bivalves) to 32.0‰ (zooplankton). Compared to homogeneous seawater (δ 7 Li ∼ 31.2‰ ± .3‰), marine organisms mostly fractionate Li isotopes in favor of the light isotope ( 6 Li). Within the same taxonomic group, significant differences are observed among organs, indicating a key role of physiology on Li concentrations and on the distribution of Li isotopes. Statistically, the trophic position is only slightly related to the average Li isotope composition of soft tissues of marine organisms, but this aspect deserves further investigation at the organ level. Other potential influences are the Li uptake by ingestion or gill ventilation. Overall, this work constitutes the first δ 7 Li extensive baseline in soft tissues of coastal organisms from different large geographic areas mostly preserved from significant anthropogenic Li contamination.

Harmful algal blooms are a source of increasing concern within the health, economic and ecological sectors. In the Mediterranean Sea, severe blooms of the benthic dinoflagellate Ostreopsis cf. ovata have been occurring since the beginning of the century, causing human intoxications by inhalation of bio-aerosols or direct contact with cells. The toxicity of this dinoflagellate is attributed to the presence of palytoxin and several of its analogs called ovatoxins, palytoxin being one of the most potent marine toxins. While mass mortalities of marine invertebrates have already been reported in relation with O. cf. ovata blooms, the toxic effects of this dinoflagellate on benthic organisms is still poorly documented. In the present study, laboratory experiments were performed on a meiobenthic copepod (Sarsamphiascus cf. propinquus), which naturally lives on macrophytes in close contact to O. cf. ovata, in order to assess its potential toxic effects on mortality, fecal pellet production (as a proxy of feeding), as well as fecundity and fertility ratios. Both, O. cf. ovata as well as a non-toxic competitive diatom (Licmophora paradoxa), were used as food in the experiments. Regarding acute toxicity evaluation, this copepod proved to be the most tolerant organism to O. cf. ovata reported to date. Nevertheless, its fecundity and fertility ratios were lower when fed with the toxic dinoflagellate, indicating a possible reprotoxic effect. Moreover, although fecal pellet production decreased significantly when the copepod was fed with a mono-diet of O. cf. ovata, epifluorescence microscopy observations revealed the presence of the toxic cells inside the digestive track, hence suggesting that these primary grazers could be a vector of toxins through the marine food web.

TARA-Mediterranean expedition crossed the entire Mediterranean Sea in 2014 to study the distribution and concentration of floating microplastics and zooplankton. Surface samples were collected with a 330 µm Manta net, plastics were sorted from 124 samples and digitally imaged with the ZoosCan system. Results showed that plastic fragments were present in all samples with an average of 2.6 x 105 items/km2 and values varying from 2 x 103 items/km2 in the Eastern basin, to more than 2 x 106 items/km2 in the Western basin. Coastal zones of Naples, Corsica and Marseille were clearly identified as areas of particularly high plastic concentration.

When dividing the ocean, the aim is generally to summarise a complex system into a representative number of units, each representing a specific environment, a biological community or a socio-economical specificity. Recently, several geographical partitions of the global ocean have been proposed using statistical approaches applied to remote sensing or observations gathered during oceanographic cruises. Such geographical frameworks defined at a macroscale appear hardly applicable to characterise the biogeochemical features of semi-enclosed seas that are driven by smaller-scale chemical and physical processes. Following the Longhurst’s biogeochemical partitioning of the pelagic realm, this study investigates the environmental divisions of the Mediterranean Sea using a large set of environmental parameters. These parameters were informed in the horizontal and the vertical dimensions to provide a 3D spatial framework for environmental management (12 regions found for the epipelagic, 12 for the mesopelagic, 13 for the bathypelagic and 26 for the seafloor). We show that: (1) the contribution of the longitudinal environmental gradient to the biogeochemical partitions decreases with depth; (2) the partition of the surface layer cannot be extrapolated to other vertical layers as the partition is driven by a different set of environmental variables. This new partitioning of the Mediterranean Sea has strong implications for conservation as it highlights that management must account for the differences in zoning with depth at a regional scale.

The present work aims to show that high throughput imaging systems can be useful to estimate mesozooplankton community size and taxonomic descriptors that can be the base for consistent large scale monitoring of plankton communities. Such monitoring is required by the European Marine Strategy Framework Directive (MSFD) in order to ensure the Good Environmental Status (GES) of European coastal and offshore marine ecosystems. Time and cost-effective, automatic, techniques are of high interest in this context. An imaging-based protocol has been applied to a high frequency time series (every second day between April 2003 to April 2004 on average) of zooplankton obtained in a coastal site of the NW Mediterranean Sea, Villefranche Bay. One hundred eighty four mesozooplankton net collected samples were analysed with a Zooscan and an associated semi-automatic classification technique. The constitution of a learning set designed to maximize copepod identification with more than 10,000 objects enabled the automatic sorting of copepods with an accuracy of 91% (true positives) and a contamination of 14% (false positives). Twenty seven samples were then chosen from the total copepod time series for detailed visual sorting of copepods after automatic identification. This method enabled the description of the dynamics of two well-known copepod species, Centropages typicus and Temora stylifera, and 7 other taxonomically broader copepod groups, in terms of size, biovolume and abundance–size distributions (size spectra). Also, total copepod size spectra underwent significant changes during the sampling period. These changes could be partially related to changes in the copepod assemblage taxonomic composition and size distributions. This study shows that the use of high throughput imaging systems is of great interest to extract relevant coarse (i.e. total abundance, size structure) and detailed (i.e. selected species dynamics) descriptors of zooplankton dynamics. Innovative zooplankton analyses are therefore proposed and open the way for further development of zooplankton community indicators of changes

We gathered information on the functional traits of the most representative copepod species in the Mediterranean Sea. Our database includes 191 species described by 7 traits encompassing diverse ecological functions: minimal and maximal body length, trophic group, feeding type, spawning strategy, diel vertical migration and vertical habitat. Cluster analysis in the functional trait space revealed that Mediterranean copepods can be separated into groups with distinct ecological roles.

PERSEUS project aims to identify the most relevant pressures exerted on the ecosystems of the Southern European Seas (SES), highlighting knowledge and data gaps that endanger the achievement of SES Good Environmental Status (GES) as mandated by the Marine Strategy Framework Directive (MSFD). A complementary approach has been adopted, by a meta-analysis of existing literature on pressure/impact/knowledge gaps summarized in tables related to the MSFD descriptors, discriminating open waters from coastal areas. A comparative assessment of the Initial Assessments (IAs) for five SES countries has been also independently performed. The comparison between meta-analysis results and IAs shows similarities for coastal areas only. Major knowledge gaps have been detected for the biodiversity, marine food web, marine litter and underwater noise descriptors. The meta-analysis also allowed the identification of additional research themes targeting research topics that are requested to the achievement of GES.

Lipid class profiles and total fatty acid composition of particulate matter were studied in the northeast Atlantic during the spring bloom and fall. Eddies of known physical and chemical properties were sampled at different depths. HPLC pigment data were used to characterize the phytoplankton communities. In spring, a dominance of prymnesiophytes was recorded at all depths, while in fall prochlorophytes dominated near the surface and prymnesiophytes only at deep chlorophyll maximum. Lipid classes included triglycerides, sterols, glycolipids and phospholipids. A differential relationship between phytoplankton abundance and lipid accumulation was observed: spring lipid concentrations were positively related to phytoplankton biomass, while fall particulate lipid did not show any relationship. The main feature was a northward increase in lipid concentrations unrelated to the mesoscale hydrological structures. Polar lipids dominated over neutral acyl-glycerols with phospholipids dominating over glycolipids in spring, while glycolipids dominated in fall. This resulted from different nutrient availability with a dominance of flagellates associated with mesotrophy in spring and of picophytoplankton associated with oligotrophy in fall. In terms of fatty acids, factorial correspondence analyses illustrate the influence of seasonally changing assemblages: (1) in spring, the main source of variability was the bloom with an opposition between bloom sites characterized by n-3 and n-6 PUFA, and more detrital deep samples characterized by saturated, monoenoic and branched acids; (2) fall fatty acid profiles were similar at all depths and very close to those observed for spring deep samples. Comparison of pigment and fatty acids using redundancy analysis suggested that pelagophytes were linked to saturated and branched acids. It also showed that prymnesiophytes and prochlorophytes were significantly associated with n-6 and n-3 PUFA. The spring period illustrated the complexity of these relationships with dinoflagellates and prymnesiophytes linked with n-3 PUFA, diatoms linked with palmitoleic and myristic acids, and pelagophytes linked with n-6 PUFA and higher-chain-length monoenes.

Lipid classes and the respective fatty acid composition of natural particulate matter were studied on a seasonal basis in the Arctic fjord Kongsfjorden (Svalbard) during the early summer of 2006 and the spring, summer of 2007. Polar lipids were the major lipid class most of the times in 2006 and at all times in 2007. Among neutral lipids triglycerides were dominant. Polar lipids were divided into glycolipids (chloroplast membranes) and phospholipids (live cell membranes). Glycolipids were further divided into monogalactosyldiglycerides (MGDG), the major glycolipid, followed by digalactosyldiglycerides (DGDG) and Sulfoquinovosyldiglycerides (SQDG). In 2007, changes in both polar lipid constituents showed similar increasing trend from May to mid June but subsequently showed opposite trends from July to September. The seasonal pattern of particulate glycolipids was one of the low concentrations of MGDG in June followed by an increase between late June and September. SQDG exhibited a similar trend while DGDG displayed an opposing trend. In 2007, fatty acid composition of phospholipids, glycolipids and neutral lipids was dominated by saturated acids at all times followed by mono unsaturated acids and polyunsaturated acids with docosahexaenoic acid (DHA, 22:6n-3), eicosapentaenoic acid (EPA, 20:5n-3) and 18:5n-3 as major contributors. Glycolipid fatty acid pattern differed from that of phospholipids, showing a more important contribution of 18:5n-3. Neutral lipid composition differed from the other two classes by a larger contribution of 16:1n-5 and percentages of EPA, DHA, 18:5 and 18:4n-3 lower than in the two structural classes. Factorial correspondence analysis (FCA) of the fatty acid composition of all classes illustrated a seasonal transition in species composition and/or physiological states for the phospholipids and the different processes of chloroplast membrane adaptation in relation to taxonomic changes for the glycolipids. Neutral lipid changes were more complex because of the combined influence of growth rates, nutrient limitations and community shifts. The differential response of the different lipid classes is discussed in relation with the complex interactions between community structure, environmental adaptation and metabolic processes. (C) 2013 Published by Elsevier B.V.

The total lipids and fatty acid composition of natural particulate matter and nutritional quality for zooplankton grazers was studied on a seasonal basis in the Arctic fjord Kongsfjorden (Svalbard) during the spring, summer of 2007 and during the early summer of 2006. Both years were abnormally warm, and the study attempted to evaluate the potential impact of the intrusion of North Atlantic waters. Samples were collected in surface layers and at deep chlorophyll maximum (DCM when present). Both years, chlorophyll concentrations were low (< 2 mu g L-1) even during bloom periods. Species determination indicated Phaeocystis spp. as main constituent of the May bloom while ciliates and flagellates dominated the rest of the survey period. Total lipids showed similar changes at both depths with maximum values in mid-summer of 2007, while it showed reverse patterns between surface and DCM in 2006. Total fatty acid composition was dominated by saturates and monoenoic acids at both depths with significant percentages of pentaenoic acids and 22:6n-3 (DHA) recorded at all times. The 2007 fatty acid dynamics identified four main successions in term of particulate assemblage related mainly to the succession of living cells versus detrital material and to a lesser extent to phytoplankton community changes (diatoms versus non-diatoms). Redundancy analysis confirmed that live phytoplankton is one of the main drivers in the fatty acid changes. Temperature and density of the surface water are also influential in relation to water mass dynamics. Concentrations of fatty acids available to consumers showed n-3 PUFA ranging from 2 to 15 mu g L-1 and n-6 PUFA ranging from 0.3 to 2 mu g L-1. Concentration of EPA (20:5) and DHA are potentially limiting, suggesting a negative impact of Phaeocystis pouchetti-type phytoplankton linked to advection of Atlantic waters in relation to global warming of Arctic waters.

The main goal of the multidisciplinary MediOs project was to acquire and analyze pertinent scientific knowledge in fields as diverse as ecology, biology, chemistry, epidemiology or socio-economics concerning the occurrence of species belonging to genus Ostreopsis (toxic benthic dinoflagellates) in the Mediterranean. The economic impact of Ostreopsis was estimated, based on the intensity and frequency of blooms. Results obtained allowed science-based recommendations concerning the management of risk, with suggestions to optimize environmental surveys, to initiate a food risk survey, and to structure actions at the national level.

The fatty acid and alcohol composition of the pelagic amphipod, Themisto libellula, was monitored during the 5 first months of its life cycle (4-20 mm length) in an Arctic fjord, Kongsfjorden, Svalbard. Fatty acids of the three major lipid classes, polar lipids (PL), triacylglycerol (TAG), and wax esters (WE), were analyzed to highlight ontogenic changes in their diet and metabolism. The PL composition of T. libellula did not show any strong variations along their growth except during the first month where an important increase of 20:5(n-3) (EPA) and 22:6(n-3) (DHA) was observed. The TAG composition revealed a clear gradient corresponding to a diet shift from omnivorous juveniles toward carnivorous sub-adults and adults. Indeed, fatty acid trophic markers of diatoms were dominant in the juveniles, whereas 20:1(n-9) and 22:1(n-11), the Calanus sp. trophic markers, overwhelmed in the older stages. The WE composition highlighted the same general trend, however, differences were found with the TAG and are discussed as a result of differences in turnover rates and assimilation pathways between the two lipid classes.

The tropical benthic dinoflagellate Ostreopsis cf. ovata recently occurred in the shallow coastal NW Mediterranean where blooms have caused health problems to humans. As part of the MediOs 2 project within the French research program Liteau III, we investigated the possible effects of this toxic microalga on the meiofauna (i.e. metazoans ranging from 40 mu m to 1 mm in size) inhabiting the very common brown macroalga Halopteris scoparia. The macroalga was sampled in triplicate at 0.5 m depth in six stations along the French and Italian coasts on seven occasions in 2008. Ostreopsis bloomed in summer in three out of the six stations with abundances ranging from 2.5 to 6.6 10(5) cells g(-1) macroalgal wet weight. Mean metazoan meiofauna densities ranged from 1274 to 9774 individuals g(-1) macroalgal spin-wet weight. Statistical analyses revealed that changes in the community structure were associated with high abundances of Ostreopsis. The most affected organisms were the nauplii suggesting a negative impact on harpacticoid copepod reproduction.

The effect of Ostreopsis cf. ovata, a toxic benthic dinoflagellate, on phytal meiofauna from the coastal NW Mediterranean.

Blastodinium are chloroplast-containing dinoflagellates which infect a wide range of copepods. They develop inside the gut of their host, where they produce successive generations of sporocytes that are eventually expelled through the anus of the copepod. Here, we report on copepod infections in the oligotrophic to ultra-oligotrophic waters of the Mediterranean Sea sampled during the BOUM cruise. Based on a DNA-stain screening of gut contents, 16% of copepods were possibly infected in samples from the Eastern Mediterranean infected, with up to 51% of Corycaeidae, 33% of Calanoida, but less than 2% of Oithonidae and Oncaeidae. Parasites were classified into distinct morphotypes, with some tentatively assigned to species B. mangini, B. contortum, and B. cf. spinulosum. Based upon the SSU rDNA gene sequence analyses of 15 individuals, the genus Blastodinium was found to be polyphyletic, containing at least three independent clusters. The first cluster grouped all sequences retrieved from parasites of Corycaeidae and Oncaeidae during this study, and included sequences of Blastodinium mangini (the ``mangini'' cluster). Sequences from cells infecting Calanoida belonged to two different clusters, one including B. contortum (the ``contortum'' cluster), and the other uniting all B. spinulosum-like morphotypes (the ``spinulosum'' cluster). Cluster-specific oligonucleotidic probes were designed and tested by fluorescence in situ hybridization (FISH) in order to assess the distribution of dinospores, the Blastodinium dispersal and infecting stage. Probe-positive cells were all small thecate dinoflagellates, with lengths ranging from 7 to 18 mu m. Maximal abundances of Blastodinium dinospores were detected at the Deep Chlorophyll Maximum (DCM) or slightly below. This was in contrast to distributions of autotrophic pico- and nanoplankton, microplanktonic dinoflagellates, and nauplii which showed maximal concentrations above the DCM. The distinct distribution of dinospores and nauplii argues against infection during the naupliar stage. Dinospores, described as autotrophic in the literature, may escape the severe nutrient limitation of ultra-oligotrophic ecosystems by living inside copepods.

Spatial and temporal variability of zooplankton was studied during five summers (2004-2008) in the Dumont d'Urville Sea, east Antarctica. The species recorded, based on the catch of a 500 μm-mesh Bongo net, were typical of southern continental shelf communities in Antarctica, including Euphausia crystallorophias, polychaetes, pteropods and biomass-dominant copepods. There was a strong degree of temporal variation in abundance, possibly related to the thickness and extent of the sea ice cover during each spring prior to the surveys. Total mean abundance was highly variable between years, with a minimum of 961 ind. 1000 m-3 in 2004 (range 65-3407 ind. 1000 m-3) and a maximum of 15,627 ind. 1000 m-3 in 2005 (range 5109-33,869 ind. 1000 m-3). Spatially, within each year, abundances were also variable, and there were no uniform patterns in abundance from year to year. Water column physical characteristics (temperature and salinity) were relatively constant and did not contribute substantially to variation between the years. It is likely that variation in zooplankton distribution was largely related to a combination of localised features, such as the thickness and extent of sea ice cover, the position and extent of the Mertz Polynya, local wind conditions and bathymetric features.

Copepod, chaetognath, decapod larva, siphonophore and jellyfish monthly abundances, from 1974 to 2003 at Point B (northwestern Mediterranean), were obtained with the ZooScan. Principal component analysis (PCA) was performed on zooplankton, and another PCA on local environment. Almost-decadal periods (1974-1982, 1983-1991, 1992-1999, and 2000-2003) were distinguished in the 1st PC of zooplankton, and that of local environment (1974-1980, 1981-1991, 1992-1998, and 1999-2003). The 1st PC of local environment was correlated with winter North Atlantic Oscillation (NAO) until early 19905. In early 1980s, all groups increased and the majority of the decade abundances were above the long-term average for most groups. In the 1990s, all decreased, and in early 2000s they increased. This synchrony suggests bottom-up control as main mechanism structuring these groups. The 1980s were characterized by low winter temperature and high salinity. We hypothesize that phytoplankton production was favored during that decade due to increased nutrient uprise to surface by strong winter vertical mixing. In the 1990s salinity decreased probably to the detriment of vertical mixing and carrying capacity of the system. These results stress the role of salinity as physical forcing on water-column stability, in the NW Mediterranean, and the importance of winter conditions to determine the state of pelagic ecosystems. (C) 2011 Elsevier B.V. All rights reserved.

An integrated analysis of the pelagic ecosystems of the Ligurian Sea is performed combining time series (1995-2005) of several zooplankton groups (one group for copepods smaller than 0.724mm(3) and nine groups for individuals larger than 0.724mm(3), i.e. large copepods, decapod larvae other crustaceans, chaetognaths, appendicularians, pteropods, thaliaceans, gelatinous predators and other zooplankton), chlorophyll-a, nutrients, salinity, temperature, density, and local weather at Point B coastal station (Northern Ligurian Sea). From 1995 to 2000 winters were wet and mild resulting in lower winter sea surface density. These years showed lower than average nutrients and zooplankton concentrations while chlorophyll-a biomass was high. After 2000, winters were colder and dryer resulting in higher sea surface density. Nutrients and zooplankton showed higher concentrations while chlorophyll-a was lower than average. The ca. 2000 change was observed for most zooplankton groups with a one-year delay for some groups. Inter-annual variability within each period was also observed. The observed patterns suggest that the pelagic ecosystem trophic state at the studied point is mostly set by the winter forcing on the vertical mixing that upwells nutrients to the surface sustaining primary production. Surprisingly, low chlorophyll-a biomass in high nitrate and zooplankton conditions during the well mixed years suggest that phytoplankton biomass is controlled by grazers. The proposed mechanisms of stronger winter vertical mixing hold for most of the time series, but specific years with contradicting patterns suggest also the possible influence of the summer climate. A review of recent literature suggests that changes in the pelagic ecosystem are not limited to the studied site but concern also the central Ligurian Sea.

The French research project MediOs 2 (Mediterranée Ostreopsis): Ecological aspects. International workshop "Blooms and invasions of marine species

The semi-enclosed nature of the Mediterranean Sea, together with its smaller inertia due to the relative short residence time of its water masses, make it highly reactive to external forcings, in particular variations of water, energy and matter fluxes at the interfaces. This region, which has been identified as a “hotspot” for climate change, is therefore expected to experience environmental impacts that are considerably greater than those in many other places around the world. These natural pressures interact with the increasing demographic and economic developments occurring heterogeneously in the coastal zone, making the Mediterranean even more sensitive. This review paper aims to provide a review of the state of current functioning and responses of Mediterranean marine biogeochemical cycles and ecosystems with respect to key natural and anthropogenic drivers and to consider the ecosystems’ responses to likely changes in physical, chemical and socio-economical forcings induced by global change and by growing anthropogenic pressure at the regional scale. The current knowledge on and expected changes due to single forcing (hydrodynamics, solar radiation, temperature and acidification, chemical contaminants) and combined forcing (nutrient sources and stoichiometry, extreme events) affecting the biogeochemical fluxes and ecosystem functioning are explored. Expected changes in biodiversity resulting from the combined action of the different forcings are proposed. Finally, modeling capabilities and necessity for modeling are presented. A synthesis of our current knowledge of expected changes is proposed, highlighting relevant questions for the future of the Mediterranean ecosystems that are current research priorities for the scientific community. Finally, we discuss how these priorities can be approached by national and international multi-disciplinary research, which should be implemented on several levels, including observational studies and modeling at different temporal and spatial scales.

Carnivorous zooplankton is a key element to the energy transfer through the arctic food web, linking lipid rich herbivores to the top predators. We investigated the growth and lipid dynamic of the Arctic pelagic amphipod Themisto libellula in Kongsfjorden (Svalbard, 79 degrees N) from May to October 2007. Additional samplings were performed in spring and summer 2006 and further north in Rijpfjorden (80 degrees N), in September 2006 and 2007. In Kongsfjorden, the first free-swimming stages (3 mm) appeared early May and reached their adult length (25 mm), in October. During their first year, they grew according to a Von Bertalanffy model and most probably constituted a single cohort. Juveniles had the highest growth rate (0.19 mm day(-1)) and revealed relatively low total lipid (TL) content (about 2.5% wet weight (WW)) with phospholipids as the major lipid class. Sub-adults showed a distinct decrease of growth rates which coincided with the increase of neutral lipid storage, reflecting a switch in energy allocation, from somatic growth to lipid storage. Indeed wax esters (WE) increased up to 48.5% TL on average in adults in 2006 while triacylglycerols (TAG) remained almost constant below 25.2% TL. The absence of lipid accumulation (in disproportion of the weight) in 2007 could be explained by a higher metabolism of T. libellula or preys of lower quality. In Rijpfjorden, adults in their second year continued accumulating lipid (up to 10% WW) with high and similar proportions of both lipid classes, WE and TAG. We highlighted that T. libellula exhibited a variable lipid metabolism along its life cycle depending on its physiological needs and environmental conditions.

Development of the benthic toxic dinoflagellate Ostreopsis cf. ovata in the NW Mediterranean sea.

Impact d'un dinoflagellé benthique toxique Ostreopsis cf. ovata sur l'abondance et la composition de la méiofaune des macroalgues en Méditerranée nord-occidentale.

The French research project MediOs 2 (Mediterranée Ostreopsis) and the relations with managers and policy makers.

A long-term time series of plankton records collected by the continuous plankton recorder (CPR) Survey in the northeast Atlantic indicates an increased occurrence of Cnidaria since 2002. In the years 2007 and 2008, outbreaks of the warm-temperate scyphomedusa, Pelagia noctiluca, appeared in CPR samples between 45 degrees N to 58 degrees N and 1 degrees W to 26 degrees W. Knowing the biology of this species and its occurrence in the adjacent Mediterranean Sea, we suggest that P. noctiluca may be exploiting recent hydroclimatic changes in the northeast Atlantic to increase its extent and intensity of outbreaks. In pelagic ecosystems, Cnidaria can affect fish recruitment negatively. Since P. noctiluca is a highly venomous species, outbreaks can also be detrimental to aquaculture and make bathing waters unusable, thus having profound ecological and socio-economic consequences.

ZooScan with ZooProcess and Plankton Identifier (PkID) software is an integrated analysis system for acquisition and classification of digital zooplankton images from preserved zooplankton samples. Zooplankton samples are digitized by the ZooScan and processed by ZooProcess and PkID in order to detect, enumerate, measure and classify the digitized objects. Here we present a semi-automatic approach that entails automated classification of images followed by manual validation, which allows rapid and accurate classification of zooplankton and abiotic objects. We demonstrate this approach with a biweekly zooplankton time series from the Bay of Villefranche-sur-mer, France. The classification approach proposed here provides a practical compromise between a fully automatic method with varying degrees of bias and a manual but accurate classification of zooplankton. We also evaluate the appropriate number of images to include in digital learning sets and compare the accuracy of six classification algorithms. We evaluate the accuracy of the ZooScan for automated measurements of body size and present relationships between machine measures of size and C and N content of selected zooplankton taxa. We demonstrate that the ZooScan system can produce useful measures of zooplankton abundance, biomass and size spectra, for a variety of ecological studies.

We have investigated the relationships between covariations in environmental variables and variations in distributions of marine copepod diversity over an extensive latitudinal range from 86.5 degrees N to 46.5 degrees S. For this purpose, 7 data sets (representing 13,713 samples) of copepod species composition data and 11 environmental data sets were assembled. Principal components analysis was applied to investigate the relationships among the mean and seasonal variations in environmental descriptors (ocean temperature, chlorophyll a [ Chl a], net primary production, and other physical and chemical properties of the ocean) and their relationships with spatial variations in copepod diversity. High copepod diversity corresponded to a combination of high ocean temperature and salinity and low Chl a and nutrient concentrations (nitrate, silicate, phosphate). To a lesser extent, high-diversity regions were also correlated to low seasonal variability in oxygen, ocean temperature, and mixed-layer depth. Regression on principal components provided a robust prediction of global copepod diversity (R-2 = 0.45, p < 0.001) as our subset of environmental data was representative of the full range of environmental variability that occurs globally.

The inter-annual variability of the pelagic ecosystems of the Ligurian Sea is investigated combining original datasets (from 1995 to 2006 collected weekly) of zooplankton abundances, hydrology and local weather conditions obtained in the bay of Villefranche-sur-mer. Two main patterns of zooplankton dynamics were observed with a shift between 1999 and 2000. The first period was characterized by high precipitation and mild air temperature during the winter. This induced lower salinity and higher seawater temperature and low density of surface seawater during the winter. These waters were characterize by low loads of nutrients. During these years, zooplankton total biovolume was also lower as shown by the strong negative anomalies in the time series. Starting in 2000, the climate changed toward drier and colder winters with denser surface water and more intense convections as suggested by higher nutrients concentrations. An increase of the abundances of all zooplankton categories was observed with a doubling of the total zooplankton average annual means and a change in the zooplankton phenology with a spring development happening 2.5 weeks earlier during these years. These results could be explained by a strong bottom-up control on the pelagic ecosystem of the Ligurian Sea at the inter-annual scale. Whereas the summer thermal stratification increase was often suggested to drive long-term dynamic in Ligurian Sea zooplankton, our results highlight the strong influence of the Winter convection properties as the main factor governing inter-annual changes in zooplankton abundance. The effect of global climate cycles will be discussed as being possible factors driving the pelagic ecosystem in the NW Mediterranean Sea.

The lipid storage of the cyclopoid copepod Oithona similis was investigated from spring to late summer 2007 in Kongsfjorden (Svalbard, Norway). The volume of lipid droplets in each individual reflected the amount of stored wax esters. Seasonal changes of lipid storage coupled with informative inter-individual variability were thus obtained. The seasonal pattern showed an increase in lipid store during the spring bloom, starting before the chlorophyll a maximum for both copepodids stage V and females. Those reserves were used during the main reproductive event in June. Individual variability was very high, with a significant proportion of copepods having no droplet, while others were lipid rich. Because of the overlap of generation, females could have different age and feeding history, particularly in September. Consideration of intra-population variability in lipid storage using an optical approach has been shown to be important to understand O. similis's ecology and life cycle.

We examined the mesoscale distribution of zooplankton populations using a continuous recording system: the optical plankton counter (OPC). Data were collected in the mid-latitude northeast Atlantic inter-gyre region in April and September 2001 during the POMME 2 and POMME 3 cruises. This sector of the North Atlantic system is characterized by subduction phenomena and mesoscale eddies. Estimated mean biomass was 2.88 DW g m(-2) in April and 1.64DW g m(-2) in September with populations dominated by small copepods of the genera, Clausocalanus, Paracalanus and Oithona. Day-night changes in vertical distribution appeared to be seasonally variable. During April, absolute concentrations within the upper layer above 50 m were higher at night. During September, vertical profiles of relative biomass were quite similar for day and night. Highest depth-integrated biomasses were located mainly on the periphery of anticyclonic eddies, with maxima related to the increase in depth range of vertical distribution. This pattern suggested that maximum biomass was associated with the most dynamic parts of the frontal features. Other zones of high zooplankton biomass were associated with the centers of cyclonic eddies and high fluorescence values. Using a 3D view, we found that zooplankton distribution showed a more complex pattern than in a 2D view with variable vertical distribution. Hence, proper description of the distribution of zooplankton underlines the need to describe this submesoscale with an order of magnitude around 10 nautical miles. (C) 2009 Elsevier Ltd. All rights reserved.

A continuous high-resolution time-series survey of the hyperbenthic community and local environmental conditions was conducted in the benthic boundary layer (BBL) of the DYFAMED-BENTHOS station (43 degrees 24.61'N, 7 degrees 51.67'E at 2347 in depth in the NW Mediterranean) between January 1996 and April 1998 using bottom-moored sediment traps and a current meter. Sediment traps were set 4 m above the bottom. Hyperbenthos was collected as `swimmers', i.e. those organisms that are alive when they enter the traps but are not part of the particle flux. Identification of these organisms showed that similar to 90%, were meiobenthic, Copepods dominated and comprised on average 75%, of total swimmers. They were followed by nauplii (12%), annelids (7.8%), nematodes and bivalves (1.8%, each), ostracods, isopods, and amphipods (1.2%, altogether). Of the 3930 copepods examined, 4%, were calanoids, 15% were harpdcticoids and 81% were cyclopoids. Among the non-calanoid copepods, 25 species or groups of species were distinguished. Two benthic copepod species outnumbered all others: the cyclopinid genius Barathricola represented 90%, of the cyclopoids, and the tisbid genus Tisbe represented 57%, of the harpacticoids. Temporal variations, both intra- and interannual, in swimmer fluxes were high (26 to 361 ind. m(-2) d(-1)), but not all groups/taxa/species were equally affected. Statistical analyses showed that these variations were the result of variability in both physical (near-bottom current) and trophic (particle flux) environmental factors. Organisms had both immediate and delayed responses, which involved passive (i.e. erosion, suspension) and active (i.e. emergence) reactions, as well as population growth. Most of the dispersal mechanisms previously reported for shallow-water benthic organisms were encountered, denoting the remarkable similarities in the general processes between coastal and deep-sea environments.

Ingestion rates and selectivity of the Arctic pelagic amphipod Themisto libellula were studied experimentally in Kongsfjorden (Svalbard, 78A degrees N) during the summer period. Feeding incubations were conducted on naturally occurring copepod communities at different concentrations ranging from 25 to 250 preys L-1. The ingestion rates increased with food availability from 1.3 to 17.7 preys ind(-1) day(-1), which corresponded to 0.3-11% of body carbon day(-1). Despite the high prey concentration used in the experiments the satiation level was not reached. We suggested that T. libellula is able to take the maximum benefit from dense patches of preys, which represent a good adaptation to the high variability in food supply characteristic of polar environment. Copepodids stage III of Calanus spp. appeared to be the preferred preys of T. libellula. Smaller copepods such as Oithona similis and Pseudocalanus spp., were also selected but only when their relative abundance exceeded 25% of the total prey available. The potential predation impact of T. libellula is discussed in relation to the mesozooplankton small-scale patchiness and predator abundance.

Évolution d'Ostreopsis cf. ovata épiphyte et planctonique en 2008 entre Cassis et Gênes en fonction de la profondeur, de la température et de la concentration en sels nutritifs.

In diversity research, the use of survey data appears to have declined in favour of experimental or modeling approaches because direct relationships are difficult to demonstrate. Here we show that use of field data can yield information concerning the mechanisms governing diversity. First, we establish that tintinnids display a global latitudinal pattern of diversity similar to other pelagic organisms; species numbers appear to peak between 20 degrees and 30 degrees north or south. This common large scale spatial trend has been attributed to the gradient in water column structure across the global ocean. We then examine the generality of a relationship between planktonic diversity and water column structure by considering data from the Mediterranean Sea, in which water column structure changes seasonally. Among populations of foraminifera, tintinnids, and the dinoflagellates of the genus Ceratium, we compare data from trans-Mediterranean sampling conducted at different times and monthly changes in species richness at single sites. We find that water column structure alone appears to be a poor predictor of temporal changes in diversity. Lastly, we present an example of temporal changes in tintinnid diversity based on data from an oceanographic sampling station in the N. W. Mediterranean where resources, as chlorophyll, appear distinctly unrelated to changes in water column structure. We show that short-tem temporal changes in diversity (week to week shifts) can be related to changes in chlorophyll concentration. We conclude that in tintinnids diversity can be directly linked to characteristics of food resources.

A compilation of available data in between 1967 and 2002 on spring zooplankton abundance was made for the brackish and the freshwater zone of the Schelde estuary. The general picture is a significant increase of 1-2 orders of magnitude in abundance for Rotifera, Copepoda and Branchiopoda (mainly Cladocera) in the freshwater zone, while zooplankton abundance in the brackishwater zone remained more constant. Possible natural and management related causes for this increase in zooplankton abundance are briefly discussed.

The accessory pigment alloxanthin is a well-known taxonomic marker for Cryptophyceae in natural seawater. The use of alloxanthin to estimate in situ zooplankton grazing and selectivity on Cryptophyceae was studied using 2 dominant copepods of the southern North Sea, Temora longicornis and Centropages hamatus. High-performance liquid chromatography (HPLC) analyses of water samples and of freshly caught copepods, starvation experiments, and feeding experiments (shipboard bottle-incubations) were carried out. Although alloxanthin was always detected in copepod extracts, (1) no correlation was found with alloxanthin in seawater, and (2) no significant grazing on Cryptophyceae was observed. Results of our gut-evacuation experiments showed that at least 78 % of the initial alloxanthin content of T longicornis and C. hamatus remained after 90 min, whereas fucoxanthin and chloropigments decreased rapidly with time. Alloxanthin and astaxanthin esters were the only pigments remaining in the body of T longicornis after several hours' starvation. It is concluded that most of the detected alloxanthin did not originate from the gut but from the body tissues. Our results suggest that alloxanthin is not suitable as a biomarker for quantitative or qualitative estimates of copepod grazing on Cryptophyceae.

The copepod Eurytemora affinis generally lives under estuarine conditions, where the suspended particulate matter (SPM) is strongly dominated by non-living particles. This article investigates as to how far E. affinis is capable of feeding selectively on phytoplankton under these extreme circumstances. Selectivity for phytoplankton by E. affinis was studied from samples taken from the Westerschelde (Belgium/The Netherlands). Copepod clearance rates exerted on natural phytoplankton quantified from the gut pigment content were significantly higher than those exerted on total particulate matter, calculated from microscopic image analysis of total gut content and total particulate matter concentration in the water. In addition, gut pigment content data on adult E. affinis measured during spring in three European estuaries (the Gironde (France), the Westerschelde and the Elbe (Germany)) were used to study the quantitative response of gut pigment content to varying ratios of phytoplankton to total SPM. A model, expressing maximum gut fluorescence as a function of body weight and gut fluorescence as a product of maximum gut fluorescence with the proportion of phytoplankton to total SPM in the feeding medium, satisfactory fitted the gut fluorescence observations made in the three estuaries. Over the range of phytoplankton-carbon/particulate organic carbon ratios observed in the three estuaries, gut fluorescence decreased with SPM concentration, but maximum gut fluorescence was reached when phytoplankton-carbon was >5% of particulate organic carbon. Limitation of selective feeding apparently only occurred under extremely high SPM loads, such as observed in the Gironde. Maximum gut fluorescence values corresponded exactly to those obtained previously for planktonic copepods in general, affirming the relationship with copepod size. (C) 2003 Elsevier Science B.V. All rights reserved.

The egg production of the copepod Acartia bifilosa was measured and related to environmental variables and food availability in two estuaries located in the same biogeographic region (Bay of Biscay) but showing very strong differences in abiotic and biotic features: the Gironde estuary (France) and the estuary of Mundaka (Spain). The study was conducted during the spring-summer-autumn period of 1994, Food availability was evaluated by analysing the chlorophyll a (Chi a), the particulate organic carbon (POC) and the easily extractable macromolecular compounds such as proteins, carbohydrates and lipids of the seston. The egg production of copepods was estimated from field incubations with natural water, and phytoplankton feeding of adult females was estimated by means of the gut fluorescence method. The nutritional environment of the Gironde was characterised by high amounts of suspended particulate matter (SPM) with low food value, emphasising the mainly detrital origin of the organic matter (OM). In Mundaka, the higher contribution of phytoplankton to the seston led to marked increase, in particulate food value accounting for up to 35% of organic matter. The weight-specific egg production was found to be sharply higher in Mundaka (ranging from 0.2 to 0.63 x 10(-3) day(-1)) than in the Gironde (ranging from 0 to 0.13 x 10(-3) day(-1)), but the seasonal trend of variations was similar, the highest weight-specific egg production rates occurring in early summer and the lowest in autumn in both estuaries. Egg production was not correlated linearly with temperature since maximal egg production occurred at intermediate temperatures. In Mundaka, the egg production showed a significant positive con-elation with the chlorophyll and the Chl/SPM and the POC/SPM ratios. This coupled with higher values of algal food availability (Chi a/SPM: 10 to 1870 mug g(-1)) and gut fluorescence (between 0, 12 and 0,38 ng Chi a Eq ind(-1)) indicate that a herbivorous diet could cover the energy requirements of A. bifilosa and support egg production. In the Gironde, the algal food availability and the gut fluorescence were lower (Chi a/SPM: 10 to 80 mug g(-1) GF: 0.09 and 0.25 ng Chi a Eq ind(-1)), and the egg production showed significant positive correlation with the particulate food value, suggesting that other sources of carbon rather than phytoplankton ere responsible for the observed changes in egg production, Results indicate that the particular seston properties of each system may be responsible for the noticeable differences in A. bifilosa fertility among estuaries. (C) 2002 Elsevier Science B.V All rights reserved.

The compositions of free guanidine and polyamine pools of three marine bivalves, the oyster Crassostrea gigas, the japanese clam Ruditapes philippinarum and the common cockle Cerastoderma edule were investigated. The major arginine-related metabolites were 4-guanidinobutyric acid in the oyster C. gigas and octopine (N-2-(1-D-carboxyethyl)-L-arginine) in the clam R. philippinarum. The diamine and polyamine pattern of the cockle C. edule showed the presence of unusual polyamines, norspermidine and norspermine. In the three bivalves studied, spermine appears to be the major polyamine and spermidine the second. The occurrence of the guanidine octopine and the presence of spermine as the major polyamines in bivalves is discussed in relation to the ecology of these organisms. (C) 2000 Elsevier Science Ltd. All rights reserved.