Observing and modeling long-term persistence of P. noctiluca in coupled complementary marine systems (Southern Tyrrhenian Sea and Messina Strait)

In the Mediterranean Sea, the Strait of Messina (MS) is a very peculiar area, connecting highly different regions and representing a privileged observatory for an early comprehension and assessment of ecosystems shifts. It is hypothesized that the outbreaks observed near the coast of many sites in the Mediterranean Sea may be the result of transport of permanent populations of P. noctiluca in pelagic waters to the coast, caused by specific hydrodynamic conditions. By both visual observations and numerical experiments our objective is twofold: (A) to help clarify whether the basin of the Aeolian Islands Archipelago (AIA), in the Southern Tyrrhenian Sea (STS), may be the site from which large populations of P. noctiluca are transported to the MS, and (B) to evaluate whether the upwelling turbulent system of the MS can be an energetic opportunity for this species. It should offer a rich habitat without jeopardizing the overall survival of the population, that is subject to stranding due to strong currents. Although very different, the two involved ecosystems (AIA and MS ) are complementary for the success of Pelagia noctiluca life cycle. Outputs obtained by coupling the 3D hydrodynamic model (SHYFEM) with a Lagrangian particle tracking model support the hypothesis of a connectivity between these two ecosystems, particularly in the first half of the year, indicating the coastal areas around the AIA as potential optimal source location for Pelagia larval stages. We support the very attractive hypothesis that two connected systems exist, the former one favours Pelagia's reproduction and acts as a nursery and the latter favours its growth due to higher productivity. We speculate that the reproductive population of the AIA is not permanent, but is renewed every year by individuals who have fed and quickly grown in the MS and who are passively transported by downwelling along canyon "corridors".

Patterns of invasive ctenophore Mnemiopsis leidyi distribution and variability in different recipient environments of the Eurasian seas: A review

Harmful invader ctenophore Mnemiopsis leidyi's expansions in the Eurasian Seas, its spatio-temporal population dynamics depending on environmental conditions in recipient habitats have been synthesized. M. leidyi found suitable temperature, salinity and productivity conditions in the temperate and subtropical environments of the semi-enclosed seas, in the coastal areas of open basins and in closed water bodies, where it created autonomous populations. M. leidyi changes its phenology depending on seasonal temperature regime in different environments. We assessed ranges of sea surface temperature, sea surface salinity and sea surface chlorophyll values, sufficient for M. leidyi general occurrence and reproduction based on comprehensive long-term datasets, contributed by co-authors. This assessment revealed that there are at least two eco-types (Southern and Northern) in the recipient seas of Eurasia with features specific for their donor areas. The range of thresholds for M. leidyi establishment, occurrence and life cycle in both eco-types depends on variability of environmental parameters in their native habitats.

Redescription of Pelagia benovici into a new jellyfish genus, Mawia, gen. nov., and its phylogenetic position within Pelagiidae (Cnidaria : Scyphozoa : Semaeostomeae)

This study provides new and additional data on morphology and a phylogenetic analysis of the recently described species Pelagia benovici Piraino, Aglieri, Scorrano & Boero, 2014 from the Northern Adriatic (Mediterranean Sea). Comprehensive morphological analyses of diagnostic characters, of which the most significant are marginal tentacles anatomy, basal pillars, gonad pattern, subgenital ostia and exumbrellar sensory pits, revealed significant differences from the currently known genera Sanderia, Chrysaora and Pelagia in the family Pelagiidae. A phylogenetic analysis of mitochondrial genes (COI, 16S rRNA, 12S rRNA) and nuclear ribosomal genes (28S rRNA, ITS1/ITS2 regions), together with cladistic analysis of morphological characters, positioned Pelagia benovici as a sister taxon with Sanderia malayensis, and both share a common ancestor with Chrysaora hysoscella. Pelagia benovici does not share a direct common ancestor with the genus Pelagia, and thus we propose it should not belong to this genus. Therefore, a new genus Mawia, gen. nov. (Semaeostomeae : Pelagiidae) is described, and Pelagia benovici is renamed as Mawia benovici, comb, nov.

A MSFD complementary approach for the assessment of pressures, knowledge and data gaps in Southern European Seas: The PERSEUS experience

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.

Main meiofauna taxa as an indicator for assessing the spatial and seasonal impact of fish farming

The present study aimed to establish potential indicators of fish farming pollution in muddy substrate, by means of meiofauna, and to test whether the effect of the fish farm is more important to determine the meiofauna community than the seasonal environmental conditions. Sampling was performed in spring, after several months of light feeding, and in summer, at high food supply. Samples were collected in three directions at various distances from the floating cages. Harpacticoid copepods and kinorhynchs, whose abundance decreased under the cages, were put forward as indicator taxa. However, harpacticoid copepods were sensitive to fish farm only, while kinorhynchs showed responsiveness to fish farm and to seasonal environmental conditions. Total meiofauna density was dependent on season sensu stricto. The nMDS clearly showed a 'cage community' and 'control community' in both sampling occasions; therefore it is a good tool for impact assessment.

Application of eutrophication indices for assessment of the Bulgarian Black Sea coastal ecosystem ecological quality

The present paper is an attempt to test the applicability of the trophic state index (TRIX) for scaling the eutrophication along the Bulgarian Black Sea coastal zone in concert with a number of chemical and biological descriptors aimed at selection of relevant indicators of marine coastal area ecological quality. The following environmental parameters have been considered: t(o), salinity, nutrients--inorganic P, N and dissolved Si, dissolved oxygen and oxygen saturation, phytoplankton--taxonomic structure, abundance and biomass, chlorophyll a, zooplankton--taxonomic structure, abundance and biomass. Principal Component Analysis was applied in order to figure out and score the most relevant combination of parameters to discriminate between sites and select representative descriptors (pressure/state) of eutrophication. The following variables are defined as relevant descriptors for classification of the sites: nutrients (N, P, Si) and their molar ratios (N:P and Si:P), the capacity of the system to produce and sustain organic matter (chlorophyll a, phytoplankton biomass), phytoplankton taxonomic dominance (Bacilariophyceae:Dinophyceae biomass ratio), grazing pressure (phytoplankton:zooplankton biomass, Bacilariophyceae:Copepoda), plankton diversity index (Hb and Ha) and the trophic state index (TRIX). The investigated sites under a different anthropogenic impact are classified according to selected descriptors and their water quality state.

The mucilage phenomenon in the northern Adriatic Sea. A critical review of the present scientific hypotheses

In the summers of 1988, 1989, and 1991 large quantities of sticky mucilaginous masses occurred in the Adriatic Sea, particularly in its northern part. The mucilage phenomenon has been studied by scientists during past events, but the previous scientific reports back to the thirties of this century. Great efforts have been made since 1988 to understand the nature of the phenomenon. Although remarkable scientific results have been achieved, many questions related to such a complex phenomenon have remained open. In this paper results and hypotheses related to the chemical and biological composition, causes, triggering mechanisms, and responsible organisms for the mucilage phenomenon are briefly reviewed. Finally, some suggestions for future researches are proposed.