Inventory and the biogeographical affinities of Annelida Polychaeta in theAlgerian coastline (Western Mediterranean)

The data analyzed to inventory of all polychaetes in Algerian waters make it possible to estimate the diversity of this group to 534 species. The most diversified families are Syllidae (66 species), Spionidae (37 species) and Terebellidae (27 species).The presence of these listed species along the Algerian coast is compared with their occurrence in nine other areas of the Mediterranean Sea, in the Black Sea and in four other areas of the World Ocean. Comparison are also made with respect to the indications of the biogeographical origin for each species. The polychaete fauna of the Algerian coast is among the richest of the Mediterranean Sea and comparable to that reported for the French Mediterranean continental shelf and the Aegean Sea, but higher that that found in the bordering coastlines of Morocco and Tunisia. Most of the species have an Atlantic origin and are present in the western Mediterranean Sea; this inventory includes eight Non-Indigenous Polychaete Species in the Algerian waters.

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Further spreading of the non-indigenous bryozoan Celleporaria brunnea in the Mediterranean Sea: port to port morphological variations

10.7287/peerj.preprints.1592 ◽

2015 ◽

Author(s):

Jasmine Ferrario ◽

Agnese Marchini ◽

Martina Marić ◽

Dan Minchin ◽

Anna Occhipinti-Ambrogi

Keyword(s):

Mediterranean Sea ◽

Western Mediterranean ◽

Indigenous Species ◽

Large Variability ◽

Morphometric Characters ◽

Morphological Variations ◽

The North ◽

Western Mediterranean Sea ◽

The Pacific ◽

The Mediterranean

The Pacific cheilostome bryozoan Celleporaria brunnea (Hincks, 1884), a non-indigenous species already known for the Mediterranean Sea, was recorded in 2013-2014 from nine Italian port localities (Genoa, Santa Margherita Ligure, La Spezia, Leghorn, Viareggio, Olbia, Porto Rotondo, Porto Torres and Castelsardo) in the North-western Mediterranean Sea; in 2014 it was also found for the first time in the Adriatic Sea, in the marina “Kornati”, Biograd na Moru (Croatia). In Italy, specimens of C. brunnea were found in 44 out of 105 samples (48% from harbour sites ad 52% from marinas). These data confirm and update the distribution of C. brunnea in the Mediterranean Sea, and provide evidence that recreational boating is a vector responsible for the successful spread of this species. Previous literature data have shown the existence of differences in orifice and interzooidal avicularia length and width among different localities of the invaded range of C. brunnea. Therefore, measurements of orifice and avicularia were assessed for respectively 30 zooids and 8 to 30 interzooidal avicularia for both Italian and Croatian localities, and compared with literature data, in order to verify the existence of differences in the populations of C. brunnea that could reflect the geographic pattern of its invasion range. Our data show high variability of orifice measures among and within localities: zooids with broader than long orifice coexisted with others displaying longer than broad orifice, or similar values for both length and width. The morphological variation of C. brunnea in these localities, and above all the large variability of samples within single localities or even within colonies poses questions on the reliability of such morphometric characters for inter and intraspecific evaluations.

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Carbonate System and Acidification of the Adriatic Sea

10.5194/egusphere-egu2020-10977 ◽

2020 ◽

Author(s):

Valentina Turk ◽

Nina Bednarsek ◽

Jadran Faganeli ◽

Blaženka Gasparovic ◽

Michele Giani ◽

...

Keyword(s):

Mediterranean Sea ◽

Adriatic Sea ◽

Microbial Community Composition ◽

Aegean Sea ◽

Total Alkalinity ◽

The Black Sea ◽

Po River ◽

Saturation State ◽

Northern Adriatic ◽

The Mediterranean

Although the marginal seas represent only 7% of the total ocean area, the CO2 fluxes are intensive and important for the carbon budget, exposing to an intense process of anthropogenic ocean acidification (OA). A decline in pH, especially in the estuarine waters, results also from the eutrophication-induced acidification. The Adriatic Sea is currently a CO2 sink with an annual flux of approximately -1.2 to -3 mol C m-2 yr-1 which is twice as low compared to the net sink rates in the NW Mediterranean (-4 to -5 mol C m-2 yr-1). Based on the comparison of two winter cruises carried out in in the 25-year interval between 1983 and 2008, acidification rate of 0.003 pHT units yr&#8722;1 was estimated in the northern Adriatic which is similar to the Mediterranean open waters (with recent estimations of &#8722;0.0028 &#177; 0.0003 units pHT yr&#8722;1) and the surface coastal waters (-0.003 &#177; 0.001 and -0.0044 &#177; 0.00006 pHT units yr&#8722;1). The computed Revelle factor for the Adriatic Sea, with the value of about 10, indicates that the buffer capacity is rather high and that the waters should not be particularly exposed to acidification. Total alkalinity (TA) in the Adriatic (2.6-2.7 mM) is in the upper range of TA measured in the Mediterranean Sea because riverine inputs transport carbonates dissolved from the Alpine dolomites and karstic watersheds. The Adriatic Sea is the second sub-basin (319 Gmol yr-1), following the Aegean Sea (which receives the TA contribution from the Black Sea), that contribute to the riverine TA discharges into the Mediterranean Sea. About 60% of the TA inflow into the Adriatic Sea is attributed to the Po river discharge with TA of ~3 mM and TA decreases with increasing salinity. Saturation state indicates that the waters of the Adriatic are supersaturated with respect to calcite (&#937;Ca) and aragonite (&#937;Ar) throughout the year. However, saturation states are considerably lower in the bottom water layers, due to the prevalence of benthic remineralization processes in the stratification period. The seasonal changes of the chemical and environmental conditions and relatively small size of the Adriatic Sea area the microbial community composition, function (growth, enzymatic activity) and carbon and nitrogen biogeochemical cycles. Significant effects on calcifying organisms and phytoplankton are expected while the effects of possible OA on microbially-driven processes are not known yet.

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Two live sightings of Sowerby's beaked whale (Mesoplodon bidens) from the western Mediterranean (Tyrrhenian Sea)

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315416001892 ◽

2017 ◽

Vol 98 (5) ◽

pp. 1003-1009 ◽

Cited By ~ 1

Author(s):

Luca Bittau ◽

Mattia Leone ◽

Adrien Gannier ◽

Alexandre Gannier ◽

Renata Manconi

Keyword(s):

Mediterranean Sea ◽

Western Mediterranean ◽

Tyrrhenian Sea ◽

Beaked Whale ◽

Long Distance ◽

The North ◽

Western Mediterranean Sea ◽

Beaked Whales ◽

Species Groups ◽

The Mediterranean

Sowerby's beaked whale (Mesoplodon bidens) was previously known in the Mediterranean Sea from a single live stranding of two individuals in the French Riviera. We report here on two live sightings in the western Mediterranean, central-western Tyrrhenian Sea off eastern Corsica (Montecristo Trough) and off eastern Sardinia (Caprera Canyon) in 2010 and 2012, respectively. In both cases single individuals, possibly the same individual, occurred within groups of Cuvier's beaked whales (Ziphius cavirostris) suggesting inter-specific interactions. Based on our close observations of mixed-species groups of Sowerby's and Cuvier's beaked whales, we hypothesize that some previous long-distance sightings of beaked whales in the Mediterranean may not be reliably attributed to Z. cavirostris. The present sightings and previous live stranding indicate that the western Mediterranean Sea is the easternmost marginal area of M. bidens within the North Atlantic geographic range. Notes on behaviour are also provided.

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Observing Winter Mixing and Spring Bloom in the Mediterranean

Eos ◽

10.1029/2018eo105887 ◽

2018 ◽

Vol 99 ◽

Author(s):

Pascal Conan ◽

Pierre Testor ◽

Claude Estournel ◽

Fabrizio D'Ortenzio ◽

Xavier Durrieu de Madron

Keyword(s):

Mediterranean Sea ◽

Spring Bloom ◽

Western Mediterranean ◽

Special Issue ◽

Dense Water ◽

Western Mediterranean Sea ◽

Water Formation ◽

Dense Water Formation ◽

The Mediterranean

A new special issue of JGR: Oceans and JGR: Atmospheres presents new insights into the dynamics of dense water formation in the western Mediterranean Sea and its biogeochemical consequences.

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Impact of moderately energetic fine-scale dynamics on the phytoplankton community structure in the western Mediterranean Sea

Biogeosciences ◽

10.5194/bg-18-6455-2021 ◽

2021 ◽

Vol 18 (24) ◽

pp. 6455-6477

Author(s):

Roxane Tzortzis ◽

Andrea M. Doglioli ◽

Stéphanie Barrillon ◽

Anne A. Petrenko ◽

Francesco d'Ovidio ◽

...

Keyword(s):

Mediterranean Sea ◽

Phytoplankton Community ◽

World Ocean ◽

Western Mediterranean ◽

Water Masses ◽

Ocean Dynamics ◽

Western Boundary ◽

Fine Scale ◽

Western Mediterranean Sea

Abstract. Model simulations and remote sensing observations show that ocean dynamics at fine scales (1–100 km in space, day–weeks in time) strongly influence the distribution of phytoplankton. However, only a few in situ-based studies at fine scales have been performed, and most of them concern western boundary currents which may not be representative of less energetic regions. The PROTEVSMED-SWOT cruise took place in the moderately energetic waters of the western Mediterranean Sea (WMS), in the region south of the Balearic Islands. Taking advantage of near-real-time satellite information, we defined a sampling strategy in order to cross a frontal zone separating different water masses. Multi-parametric in situ sensors mounted on the research vessel, on a towed vehicle and on an ocean glider were used to sample physical and biogeochemical variables at a high spatial resolution. Particular attention was given to adapting the sampling route in order to estimate the vertical velocities in the frontal area also. This strategy was successful in sampling quasi-synoptically an oceanic area characterized by the presence of a narrow front with an associated vertical circulation. A multiparametric statistical analysis of the collected data identifies two water masses characterized by different abundances of several phytoplankton cytometric functional groups, as well as different concentrations of chlorophyll a and O2. Here, we focus on moderately energetic fronts induced by fine-scale circulation. Moreover, we explore physical–biological coupling in an oligotrophic region. Our results show that the fronts induced by the fine-scale circulation, even if weaker than the fronts occurring in energetic and nutrient-rich boundary current systems, maintain nevertheless a strong structuring effect on the phytoplankton community by segregating different groups at the surface. Since oligotrophic and moderately energetic regions are representative of a very large part of the world ocean, our results may have global significance when extrapolated.

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Climatological distribution of dissolved inorganic nutrients in the Western Mediterranean Sea (1981–2017)

10.5194/essd-2021-149 ◽

2021 ◽

Author(s):

Malek Belgacem ◽

Katrin Schroeder ◽

Alexander Barth ◽

Charles Troupin ◽

Bruno Pavoni ◽

...

Keyword(s):

Mediterranean Sea ◽

World Ocean ◽

Western Mediterranean ◽

Inorganic Nutrients ◽

Data Product ◽

Western Mediterranean Sea ◽

Dissolved Inorganic Nutrients ◽

In Situ Observations ◽

Nutrient Variability

Abstract. The Western MEDiterranean Sea BioGeochemical Climatology (BGC-WMED) presented here is a product derived from in situ observations. Annual mean gridded nutrient fields for the period 1981–2017, and its sub-periods 1981–2004 and 2005–2017, on a horizontal 1/4° × 1/4° grid have been produced. The biogeochemical climatology is built on 19 depth levels and for the dissolved inorganic nutrients nitrate, phosphate and orthosilicate. To generate smooth and homogeneous interpolated fields, the method of the Variational Inverse Model (VIM) was applied. A sensitivity analysis was carried out to assess the comparability of the data product with the observational data. The BGC-WMED has then been compared to other available data products, i.e. the medBFM biogeochemical reanalysis of the Mediterranean Sea and the World Ocean Atlas18 (WOA18) (its biogeochemical part). The BGC-WMED product supports the understanding of inorganic nutrient variability in the western Mediterranean Sea, in space and in time, but can also be used to validate numerical simulations making it a reference data product.

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Characterising the surface microlayer in the Mediterranean Sea: trace metals concentration and microbial plankton abundance

10.5194/bg-2019-290 ◽

2019 ◽

Author(s):

Antonio Tovar-Sánchez ◽

Araceli Rodríguez-Romero ◽

Anja Engel ◽

Birthe Zäncker ◽

Franck Fu ◽

...

Keyword(s):

Trace Metals ◽

Mediterranean Sea ◽

Surface Waters ◽

Bacterial Community Composition ◽

Western Mediterranean ◽

Surface Microlayer ◽

Dissolved Metals ◽

Western Mediterranean Sea ◽

Sea Surface Microlayer ◽

The Mediterranean

Abstract. The Sea Surface Microlayer (SML) is known to be enriched in trace metals relative to the underlaying water and to harbor diverse microbial communities (i.e. neuston). However, the processes linking metals and biota in the SML are not yet fully understood. In this study, we analyzed the metal (Cd, Co, Cu, Fe, Ni, Mo, V, Zn and Pb) concentrations in aerosol samples, SML (dissolved and total fractions) and in subsurface waters (SSW; dissolved fraction at ~ 1 m depth) from the Western Mediterranean Sea during a cruise in May–June 2017. The bacterial community composition and abundance in the SML and SSW, and the primary production and Chl-a in the SSW were measured simultaneously at all stations during the cruise. Residence times of particulate metals derived from aerosols deposition ranged from a couple of minutes for Co (2.7 ± 0.9 min; more affected by wind conditions) to a few hours for Cu (3.0 ± 1.9 h). Concentration of most dissolved metals in both, the SML and SSW, were well correlated with the salinity gradient and showed the characteristic eastward increase in surface waters of the Mediterranean Sea (MS). Contrarily, the total fraction of some reactive metals in the SML (i.e. Cu, Fe, Pb and Zn) showed negative trends with salinity, these trends of concentrations seem to be associate to microbial uptake. Our results suggest a toxic effect of Ni on neuston and microbiology community’s abundance of the top meter of the surface waters of the Western Mediterranean Sea.

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Intriguing diversity among diazotrophic picoplankton along a Mediterranean transect: from the origin of plastids to the dominance of rhizobia

Biogeosciences Discussions ◽

10.5194/bgd-7-8779-2010 ◽

2010 ◽

Vol 7 (6) ◽

pp. 8779-8816 ◽

Cited By ~ 2

Author(s):

M. Le Moal ◽

H. Collin ◽

I. C. Biegala

Keyword(s):

Mediterranean Sea ◽

Nifh Gene ◽

Western Mediterranean ◽

Central Mediterranean ◽

Plastid Evolution ◽

Surface Distribution ◽

Western Mediterranean Sea ◽

Diazotrophic Cyanobacteria ◽

The Mediterranean ◽

Marine Areas

Abstract. The Mediterranean Sea is one of the most oligotrophic marine areas on earth where nitrogen fixation has been formally believed to play an important role in carbon and nitrogen fluxes. Although this view is under debate, the diazotrophs responsible for this activity have still not been investigated in the open sea. In this study we characterised the surface distribution and species richness of unicellular and filamentous diazotrophs across the Mediterranean Sea by combining microscopic counts with size fractionated in situ hybridization (TSA-FISH), and 16S rDNA and nifH phylogenies. These genetic analyses were possible owning to the development of a new PCR protocol adapted for scarce microorganisms (0.2 cell ml−1). Low concentrations of diazotrophic cyanobacteria were detected and this community was dominated at 99.9% by picoplankton hybridized with Nitro821 probe, specific for unicellular diazotrophic cyanobacteria (UCYN). Among filamentous cyanobacteria only 0.02 filament ml−1 of Richelia were detected in the eastern basin, while small (0.7–1.5 μm) and large (2.5–3.2 μm) Nitro821-targeted cells were recovered at all stations and averaged 3.5 cell ml−1. The affiliation of the small Nitro821-targeted cells to UCYN-A was confirmed by 16S and nifH phylogenies in the western Mediterranean Sea. Surprisingly, the larger hybridized cells were not belonging to UCYN-B and C but to plastids of picoeukaryote. NifH gene was not recovered among picoeukaryotes, when rhizobia sequences, including the ones of Bradyrhizobia, were dominating nifH clone libraries from picoplanktonic size fractions. Few sequences of γ-proteobacteria were also detected in central Mediterranean Sea. While low phosphate and iron concentrations could explain the absence of Trichodesmium sp., the factors that prevent the development of UCYN-B and C remain unknown. We also propose that the dominating picoplankters probably developed specific strategies, such as associations with protists or particles and photosynthetic activity to acquire carbon for sustaining diazotrophy. Among UCYN further work will be necessary to understand their suggested role in plastid evolution.

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Intriguing diversity among diazotrophic picoplankton along a Mediterranean transect: a dominance of rhizobia

Biogeosciences ◽

10.5194/bg-8-827-2011 ◽

2011 ◽

Vol 8 (3) ◽

pp. 827-840 ◽

Cited By ~ 27

Author(s):

M. Le Moal ◽

H. Collin ◽

I. C. Biegala

Keyword(s):

Mediterranean Sea ◽

16S Rdna ◽

Eastern Mediterranean ◽

Western Mediterranean ◽

Central Mediterranean ◽

Surface Distribution ◽

Western Mediterranean Sea ◽

Diazotrophic Cyanobacteria ◽

The Mediterranean ◽

Marine Areas

Abstract. The Mediterranean Sea is one of the most oligotrophic marine areas on earth where nitrogen fixation has formally believed to play an important role in carbon and nitrogen fluxes. Although this view is under debate, the diazotrophs responsible for this activity have still not been investigated in the open sea. In this study, we characterised the surface distribution and species richness of unicellular and filamentous diazotrophs across the Mediterranean Sea by combining microscopic counts with size fractionated in situ hybridization (TSA-FISH), and 16S rDNA and nifH genes phylogenies. These genetic analyses were possible owing to the development of a new PCR protocol adapted to scarce microorganisms that can detect as few as 1 cell ml−1 in cultures. Low concentrations of diazotrophic cyanobacteria were detected and this community was dominated at 99.9% by picoplankton hybridized to the Nitro821 probe, specific for unicellular diazotrophic cyanobacteria (UCYN). Among filamentous cyanobacteria only 0.02 filament ml−1 of Richelia were detected in the eastern basin, while small (0.7–1.5 μm) and large (2.5–3.2 μm) Nitro821-targeted cells were recovered at all stations with a mean concentration of 3.5 cell ml−1. The affiliation of the small Nitro821-targeted cells to UCYN-A was confirmed by 16S and nifH phylogenies in the western Mediterranean Sea. In the central and the eastern Mediterranean Sea no 16S rDNA and nifH sequence from UCYN was obtained as cells concentration were close to, or below PCR detection limit. Bradyrhizobium sequences dominated nifH clone libraries from picoplanktonic size fractions. A few sequences of γ-proteobacteria were also detected in the central Mediterranean Sea. While low phosphate and iron concentrations could explain the absence of Trichodesmium sp., the factors that prevent the development of UCYN-B and C remain unknown. We also propose that the dominating picoplankters probably developed specific strategies, such as associations with protists or particles, and/or photosynthetic activity, to acquire carbon for sustaining diazotrophy.

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Inventory and new records of polychaete species from the Cap Bon Peninsula, north-east coast of Tunisia, Western Mediterranean Sea

Mediterranean Marine Science ◽

10.12681/mms.22 ◽

2012 ◽

Vol 13 (1) ◽

pp. 36 ◽

Cited By ~ 3

Author(s):

S. ZAABI ◽

P. GILLET ◽

S. CHAMBERS ◽

A. AFLI ◽

M. BOUMAIZA

Keyword(s):

Mediterranean Sea ◽

East Coast ◽

Western Mediterranean ◽

Baseline Survey ◽

Polychaete Species ◽

Future Studies ◽

North East ◽

The North ◽

Western Mediterranean Sea ◽

Historic Review

An inventory of Polychaete species is recorded from the North east coast of Tunisia with an historic review of the previous literature from Tunisian coasts. Altogether 40 families, 146 genera, and 238 species are currently known from the area in which 86 taxa, 4 families (Chrysopetalidae, Pilargidae, Protodrilidae and Saccocirridae) and 40 genera (Saccocirrus, Protodrilus, Parathelepus, Thelepus, Petta, Isolda, Brada, Tharyx, Paraprionospio, Jasmineira, Hypsicomus, Euchone, Pseudobranchiomma, Laonome, Galathowenia, Lugia, Pseudomystides, Protomystides, Pirakia, Mysta, Eurysyllis, Parapionosyllis, Streptosyllis, Paraehlersia, Sigambra, Ancistrosyllis, Kefersteinia, Chrysopetalum, Bhawania, Fimbriosthenelais, Subadyte, Panthalis, Dorvillea, Scalibregma, Paradoneis, Cirrophorus, Metasychis, Websterinereis, Euniphysa and Mastobranchus) are new additions to the Polychaete fauna of Tunisia. The list, which provides a synthesis of the regional taxonomica work, including coastal areas from Sidi Daoud to the area of Menzel Hurr (Cap Bon Peninsula, Western Mediterranean Sea), can serve as a baseline survey for future studies.

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