First recording of the non-native species Beroe ovata Mayer 1912 in the Aegean Sea

A new alien species Beroe ovata Mayer 1912 was recorded in the Aegean Sea. It is most likely that this species spread on the currents from the Black Sea. Beroe ovata is also alien to the Black Sea, where it was introduced in ballast waters from the Atlantic coastal area of the northern America. The species is established in the Black Sea and has decreased the population of another invaderMnemiopsis leidyi, which has favoured the recovery of the Black Sea ecosystem.We compare a new 1 species with the native species fam. Beroidae from the Mediterranean and predict its role in the ecosystem of the Aegean Sea using the Black Sea experience

Response of the Calanoid Copepod Clausocalanus furcatus, to Atmospheric Deposition Events: Outcomes from a Mesocosm Study

Atmospheric deposition is assumed to stimulate heterotrophic processes in highly oligotrophic marine systems, controlling the dynamics and trophic efficiency of planktonic food webs, and is expected to be influenced by climate change. In the course of an 8-day mesocosm experiment, we examined the channeling, of the Saharan dust (SD) and mixed aerosols (A) effects on microplankton up to the copepod trophic level, in the highly oligotrophic Eastern Mediterranean Sea. Based on mesocosms with SD and A treatments, we evaluated the feeding response of the dominant copepod Clausocalanus furcatus every other day. We hypothesized that increased food availability under atmospheric deposition would result in increased copepod ingestion rates, selectivity and production. Overall, no robust pattern of food selection was documented, and daily rations on the prey assemblage of all mesocosms were very low indicating severe food limitation of C. furcatus. Although increased food availability was not true, after few days ingestion of ciliates was maximized, followed by egg production, in both the SD and A treatments, indicating their importance in the diet of this copepod as well as a response of C. furcatus feeding performance. Our results help in understanding the trophic efficiency of marine food webs in ultra-oligotrophic environments under atmospheric deposition. We suggest that future mesocosm research in oligotrophic waters should consider more than one copepod speciesVersión del edito

Trying to resolve the taxonomic confusion of Paracalanus parvus species complex (Copepoda, Calanoida) in the Mediterranean and Black Seas through a combined analysis of morphology, molecular taxonomy and DNA metabarcoding

Paracalanus parvus is reported as the most abundant representative of the genus and one of the main components of the coastal zooplankton in the Mediterranean and Black Seas. However, the subtle taxonomic differences between P. parvus and the congeneric species P. indicus and P. quasimodo, in combination with the ample morphological variation found in Mediterranean specimens, render problematic the correct identification. A recent molecular study by Cornils and Held (2014) provided evidence of cryptic speciation in the P. parvus complex and indicated that P. parvus s.s. does not have global distribution, but may be restricted to the northeastern Atlantic. In order to clarify the taxonomic status and distribution of this species complex in the Mediterranean and Black Seas, a study was conducted on Paracalanus specimens collected from different locations across the aforementioned marine basins and sequenced for portion of the COI mitochondrial gene. An accurate taxonomic analysis was also carried out to correlate morphological characteristics with the molecular species' assignation. The phylogenetic analysis of the specimens together with the publicly available sequences of P. parvus complex revealed the presence of four molecular operational taxonomic units (MOTUs) in the Mediterranean, which differed in abundance and geographic distribution. The combination of morphological and molecular data revealed great inconsistencies between morphospecies and MOTUs. Moreover, several bulk zooplankton samples were analyzed through DNA metabarcoding in the frame of the “MetaCopepod” project to provide more extensive information on the spatiotemporal distribution and abundance of the target specie

The “MetaCopepod” project: Designing an integrated DNA metabarcoding and image analysis approach to study and monitor the diversity of zooplanktonic copepods and cladocerans in the Mediterranean Sea

The timely and accurate analysis of marine zooplankton diversity is a challenge in ecological and monitoring studies. Morphology-based identification of taxa, which requires taxonomy experts, is time consuming and cannot provide accurate resolution at species level in several cases (e.g. immature stages, cryptic species, broken specimens). The “MetaCopepod” project is aimed at overcoming these limitations by developing a high-throughput and cost effective methodology that integrates DNA metabarcoding and image analysis. Utilizing the accuracy of DNA metabarcoding in species recognition and the quantitative results of image analysis, zooplankton diversity (mainly of copepods and cladocerans) is assessed both qualitatively (species' composition) and quantitatively (abundance, biomass and size-distribution). To achieve this goal, bulk zooplankton samples are first scanned and analyzed with ZooImage and then massively sequenced for a selected fragment of the mitochondrial 16S rRNA gene. Through a bioinformatic pipeline, sequences are compared to a reference genetic database, constructed within the project, and identified at species- level. The methodology was calibrated by using both mock and taxonomically identified samples and demonstrated on samples collected monthly from monitoring stations across the Mediterranean Sea. It is currently optimized for higher integration and accuracy and is expected to become a powerful tool for monitoring zooplankton in the long term and for early warning of bioinvasions and other ecosystem change

Global versus local changes in upwelling systems

Dans ce travail, nous analysons les principales caractéristiques des pêcheries marines grecques (composition des captures et densités) pour la période 1982-1989 ; les résultats sont discutés en termes de potentiel trophique des eaux maritimes grecques (abondance et productivité du phytoplancton et du zooplancton) et comparés à ceux obtenus dans d'autres zones (d'upwelling ou non). Des analyses multivariées (classification et hiérarchisation) sont faites sur les captures commerciales moyennes de 66 espèces (ou groupes d'espèces) de 16 zones de pêche appartenant à trois groupes : la zone S-SE de la mer Egée (et NW de la mer du Levantin), la mer Ionienne et la zone centrale de la mer Egée, et le N-NW de la mer Egée. La composition des captures diffère beaucoup d'une zone à l'autre. La capture moyenne de la zone S-SE de la mer Egée est dominée par les brochets et les bogues et, dans une moindre mesure, par les chinchards ; celle de la partie centrale de la mer Egée et de la mer Ionienne par les sardines, les chinchards, les bogues et les brochets ; et celle de la zone N-NW de la mer Egée par les anchois et les sardines. Les densités moyennes des captures de poissons pélagiques, démersaux et des captures totales diminuent entre 1982 et 1989 de 1,3, 0,83 et 2,13 t/km2 respectivement dans le N-NW de la mer Egée, à 0,25, 0,37 et 1,23 t/km2 dans le S-SE de la mer Egée, ces dernières valeurs se retrouvent aussi dans le mer Ionienne. De plus, un tel accroissement va de pair avec une décroissance de l'importance relative dans chacune des zones des espèces démersales. La densité des captures de poissons pélagiques dans la mer Ionienne et dans le S-SE de la mer Egée est de 3 à 150 fois plus faible que celle d'autres zones marines... (D'après résumé d'auteur

Analysis of the biological cycle of Acartia clausi (Copepoda) in a meso-oligotrophic coastal area of the eastern Mediterranean Sea using time-series analysis

We evaluated the duration of Copepodite Stages C1 to C6, the biological cycle and the number of annual generations of the planktonic copepod Acartia clausi in a meso-oligotrophic area of the eastern Mediterranean Sea (Saronikos Gulf, Greece). The results were based on 95 zooplankton samples collected during the period November 1988 through June 1990, at intervals of 1, 2, 7 and 15 d, the sampling intervals being dependent on the abundance of A. clausi. Time-series analysis (cross-correlation) of fluctuations in the comparative abundance (percentages) of the copepodite stages present was used to determine the duration of the development stages and generation length. This methodology could significantly contribute to the identification of cohorts, and hence to the estimation of stage duration, from field data for a given copepod species. The development of A. clausi stages was not isochronal; duration of the first copepodite stage was shorter than that of the last three stages. The mean generation length estimated (28.6 d) is among the highest recorded in the literature for A. clausi at the range of temperatures prevailing in the area (13 to 25°C). Throughout the year there were four or five generations. The possible limiting role of food availability on the duration of each stage and hence on generation length is also discussed. © 1993 Springer-Verlag

Length, weight and condition factor of acartia clausi (copepoda) in the eastern mediterranean

Cephalothorax length and dry weight of copepodite stages and adults of the planktonic copepod Acartia clausi Giesbrecht in the Saronikos Gulf, Greece, were measured. Length-weight relationships and condition factor were also determined. The results were based on 17 zooplankton samples collected between November 1989 and June 1990, a period in which the abundance of A. clausi is significant. There was an inverse relationship between temperature and length, a pattern shown by many copepods. Temperature had the most significant effect on length, which was also affected by chlorophyll level. This strong temporal variation in length might possibly be considered as an adaptation of A. clausi to a continuously fluctuating environment. Length-weight regressions displayed high coefficients of determination (r2=0.98). Food, expressed as chlorophyll, affected the size and condition factor, and could act as a limiting factor on length and weight of A. clausi in the study area. © 1993, Marine Biological Association of the United Kingdom. All rights reserved

Comparison of marine copepod outfluxes: Nature, rate, fate and role in the carbon and nitrogen cycles

We compare the nature of copepod outfluxes of nonliving matter, the factors controlling their rate (aid their Jaw, and finally their role, particularly their relative importance in the carbon and nitrogen cycle. Copepods release dissolved matter through excretion and respiration and particulate matter through production of faecal pellets, carcasses, moults, and (lead eggs. Excretion liberates several organic C, N, and P compounds and inorganic N and P compounds, with inorganic compounds constituting the larger part. The faecal pellets of copepods are covered by a peritrophic membrane and have a highly variable size and content. There is less information on the nature of other copepod particulate products. The weight-specific rates of posthatch mortality, respiration, excretion, and faecal pellet production have similar C or N levels and are higher than those of moulting and egg mortality. In general, most important factors controlling these rates are temperature, body mass, food concentration, food quality, and faunistic composition. Physical and biological factors govern the vertical fate of copepod products by affecting their sedimentation speed and concentration gradient. The physical factors are sinking speed, advection, stratification, turbulent diffiusion, and molecular diffusion. They influence the sedimentation speed and degradation of the copepod products. The biological factors are production, biodegradation (by zooplankton, nekton, and microorganisms) and vertical migration of copepods (diel or seasonal). Physical degradation and biodegradation by zooplankton and nekton are faster than biodegradation by microorganisms. The most important copepod outfluxes are excretion and fecal pellet production. Excretion offers inorganic nutrients that can be directly used by . Excretion of primary producers. Faecal pellets have a more important role in the vertical transport of elements than the other particulate products. Most investigation has focused on carbon burial in the form of copepod faecal pellets, measured by sediment traps, and on the role of ammonia excretion in nutrient recycling. Full evaluation of the role of copepod products in the transport and recycling of elements and compounds requires a quantification of all copepod products and their different fates, particularly detritiphagy, remineralization, and integration as marine snow

Copepod communities, production and grazing in the Turkish Straits System and the adjacent northern Aegean Sea during spring

The Mediterranean and the Black Seas are connected through Bosphorus, Marmara Sea and Dardanelles (Turkish Straits System, TSS). In this study, we examined the spatial distribution of copepods and investigate their production and grazing. The aim was to understand the transfer of phytoplankton/microzooplankton production up the food chain in TSS and Aegean Sea during spring. The phytoplankton and microzooplankton biomass and production showed a clear decreasing trend from Bosphorus to the Aegean Sea, whereas copepod biomass did not reveal any distinct trend and only the number of copepod species increased from Bosphorus to the Aegean Sea. Production of copepods and egg production showed similar trends except for the Bosphorus, where production of copepods was very low due to the low copepod biomass in this area. In all areas, the copepod carbon demand was largely met by phytoplankton and microzooplankton production. However, only a low amount of primary production was consumed by copepods and production appeared to flow mostly through other pathways (microbial loop) and/or sediment on the bottom. The results of this study confirm the hypothesis that there is a substantial differentiation within pelagic food web structure and carbon flow from Bosphorus to the Aegean Sea. © 2010 Elsevier B.V.36949We thank the captain and the crew of R/V ‘Aegaeo’ and R/V ‘Bilim’ for shipboard assistance. We also thank T.G. Nielsen for commenting on a draft version of the manuscript and the three anonymous reviewers for their very valuable comments on the manuscript. Research for this paper was supported by the SESAME project (contract no. 036949 ), supported by the European Commission's Sixth Framework Programme on Sustainable Development, Global Change and Ecosystem