Physical forcing and physical/biochemical variability of the Mediterranean Sea: a review of unresolved issues and directions for future research

This paper is the outcome of a workshop held in Rome in November 2011 on the occasion of the 25th anniversary of the POEM (Physical Oceanography of the Eastern Mediterranean) program. In the workshop discussions, a number of unresolved issues were identified for the physical and biogeochemical properties of the Mediterranean Sea as a whole, i.e., comprising the Western and Eastern sub-basins. Over the successive two years, the related ideas were discussed among the group of scientists who participated in the workshop and who have contributed to the writing of this paper. Three major topics were identified, each of them being the object of a section divided into a number of different sub-sections, each addressing a specific physical, chemical or biological issue: 1. Assessment of basin-wide physical/biochemical properties, of their variability and interactions. 2. Relative importance of external forcing functions (wind stress, heat/moisture fluxes, forcing through straits) vs. internal variability. 3. Shelf/deep sea interactions and exchanges of physical/biogeochemical properties and how they affect the sub-basin circulation and property distribution. Furthermore, a number of unresolved scientific/methodological issues were also identified and are reported in each sub-section after a short discussion of the present knowledge. They represent the collegial consensus of the scientists contributing to the paper. Naturally, the unresolved issues presented here constitute the choice of the authors and therefore they may not be exhaustive and/or complete. The overall goal is to stimulate a broader interdisciplinary discussion among the scientists of the Mediterranean oceanographic community, leading to enhanced collaborative efforts and exciting future discoveries

Revising the taxonomic status and distribution of the Paracalanus parvus species complex in the Mediterranean and Black seas through an integrated analysis of morphology and mlecular taxonomy

The marine copepod Paracalanus parvus has long been considered the most abundant representative of the genus and one of the main components of coastal zooplankton in the Mediterranean and Black Seas. However, subtle morphological differences between P. parvus, P. indicus and P. quasimodo hamper correct taxonomic identification. To clarify the taxonomic status and distribution of this species complex in the Mediterranean and Black Seas, DNA barcoding as well as an integrated morphological and molecular analysis was conducted on samples collected across these two basins. DNA barcoding confirmed the presence of P. parvus s.s. in the Black Sea and revealed four Paracalanus species in the Mediterranean Sea, including the morphologically undescribed Paracalanus sp. F. The most abundant species in all coastal areas was P. quasimodo, while P. parvus s.s. was confined to areas of the northern Mediterranean Sea. The phylogeographic analysis indicated that the boreal species P. parvus s.s. has a relic distribution in the Mediterranean and may have been displaced by the subtropical P. quasimodo during the last interglacial period. The integrated analysis revealed inconsistencies between morphological and molecular taxonomic identification and indicated that the taxonomic characters traditionally used are not adequate to discriminate between these species.The marine copepod Paracalanus parvus has long been considered the most abundant representative of the genus and one of the main components of coastal zooplankton in the Mediterranean and Black Seas. However, subtle morphological differences between P. parvus, P. indicus and P. quasimodo hamper correct taxonomic identification. To clarify the taxonomic status and distribution of this species complex in the Mediterranean and Black Seas, DNA barcoding as well as an integrated morphological and molecular analysis was conducted on samples collected across these two basins. DNA barcoding confirmed the presence of P. parvus s.s. in the Black Sea and revealed four Paracalanus species in the Mediterranean Sea, including the morphologically undescribed Paracalanus sp. F. The most abundant species in all coastal areas was P. quasimodo, while P. parvus s.s. was confined to areas of the northern Mediterranean Sea. The phylogeographic analysis indicated that the boreal species P. parvus s.s. has a relic distribution in the Mediterranean and may have been displaced by the subtropical P. quasimodo during the last interglacial period. The integrated analysis revealed inconsistencies between morphological and molecular taxonomic identification and indicated that the taxonomic characters traditionally used are not adequate to discriminate between these species

Temporal variability of Centropages typicus in the Mediterranean sea seasonal-to-decadal scales

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Zooplankton of the Mediterranean Sea (ICES Zooplankton Status Report 2008/2009)

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Zooplankton of the Mediterranean Sea. ICES Zooplankton Status Report 2010/2011.

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Intercomparison of six Mediterranean zooplankton time series

We analyzed and compared Mediterranean mesozooplankton time series spanning 1957–2006 from six coastal stations in the Balearic, Ligurian, Tyrrhenian, North and Middle Adriatic and Aegean Sea. Our analysis focused on fluctuations of major zooplankton taxonomic groups and their relation with environmental and climatic variability. Average seasonal cycles and interannual trends were derived. Stations spanned a large range of trophic status from oligotrophic to moderately eutrophic. Intra-station analyses showed (1) coherent multi-taxa trends off Villefranche sur mer that diverge from the previous results found at species level, (2) in Baleares, covariation of zooplankton and water masses as a consequence of the boundary hydrographic regime in the middle Western Mediterranean, (3) decrease in trophic status and abundance of some taxonomic groups off Naples, and (4) off Athens, an increase of zooplankton abundance and decrease in chlorophyll possibly caused by reduction of anthropogenic nutrient input, increase of microbial components, and more efficient grazing control on phytoplankton. (5) At basin scale, the analysis of temperature revealed significant positive correlations between Villefranche, Trieste and Naples for annual and/or winter average, and synchronous abrupt cooling and warming events centered in 1987 at the same three sites. After correction for multiple comparisons, we found no significant correlations between climate indices and local temperature or zooplankton abundance, nor between stations for zooplankton abundance, therefore we suggest that for these coastal stations local drivers (climatic, anthropogenic) are dominant and that the link between local and larger scale of climate should be investigated further if we are to understand zooplankton fluctuationsPublicado

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