scholarly journals Quantifying the Variability of Phytoplankton Blooms in the NW Mediterranean Sea with the Robust Satellite Techniques (RST)

2021 ◽  
Vol 13 (24) ◽  
pp. 5151
Author(s):  
Emanuele Ciancia ◽  
Teodosio Lacava ◽  
Nicola Pergola ◽  
Vincenzo Vellucci ◽  
David Antoine ◽  
...  

Investigating the variability of phytoplankton phenology plays a key role in regions characterized by cyclonic circulation regimes or convective events, like the north-western Mediterranean Sea (NWM). The main goal of this study is to assess the potential of the robust satellite techniques (RST) in identifying anomalous phytoplankton blooms in the NWM by using 9 years (2008–2017) of multi-sensor chlorophyll-a (chl-a) products from the CMEMS and OC-CCI datasets. Further application of the RST approach on a corresponding time-series of in situ chl-a measurements acquired at the BOUSSOLE site allows evaluation ofthe accuracy of the satellite-based change detection indices and selecting the best indicator. The OC-CCI derived chl-a anomaly index shows the best performances when compared to in situ data (R2 and RMSE of 0.75 and 0.48, respectively). Thus, it has been used to characterize an anomalous chl-a bloom that occurred in March 2012 at regional scale. Results show positive chl-a anomalies between the BOUSSOLE site and the Center of Convection Zone (CCZ) as a possible consequence of an intense convection episode that occurred in February 2012.

2010 ◽  
Vol 60 (1) ◽  
pp. 209-213 ◽  
Author(s):  
Laurent Urios ◽  
Valérie Michotey ◽  
Laurent Intertaglia ◽  
Françoise Lesongeur ◽  
Philippe Lebaron

A novel Gram-negative bacteria, named CZ41_10aT, was isolated from coastal surface waters of the north-western Mediterranean Sea. Cells were motile, pleomorphic rods, 1.6 μm long and 0.7 μm wide and formed cream colonies on marine agar medium. The G+C content of the genomic DNA was 65 mol%. Phylogenetic analysis of 16S rRNA gene sequences placed the new isolate in the genus Thalassobaculum, a member of the family Rhodospirillaceae, class Alphaproteobacteria. Unlike Thalassobaculum litoreum CL-GR58T, its closest relative, strain CZ41_10aT was unable to grow anaerobically and did not exhibit nitrate reductase activity. On the basis of DNA–DNA hybridization, fatty acid content and physiological and biochemical characteristics, this isolate represents a novel species for which the name Thalassobaculum salexigens sp. nov. is proposed. The type strain is CZ41_10aT (=DSM 19539T=CIP 109064T=MOLA 84T). An emended description of the genus Thalassobaculum is also given.


2021 ◽  
Vol 9 (2) ◽  
pp. 208
Author(s):  
Valentina Vannucchi ◽  
Stefano Taddei ◽  
Valerio Capecchi ◽  
Michele Bendoni ◽  
Carlo Brandini

A 29-year wind/wave hindcast is produced over the Mediterranean Sea for the period 1990–2018. The dataset is obtained by downscaling the ERA5 global atmospheric reanalyses, which provide the initial and boundary conditions for a numerical chain based on limited-area weather and wave models: the BOLAM, MOLOCH and WaveWatch III (WW3) models. In the WW3 computational domain, an unstructured mesh is used. The variable resolutions reach up to 500 m along the coasts of the Ligurian and Tyrrhenian seas (Italy), the main objects of the study. The wind/wave hindcast is validated using observations from coastal weather stations and buoys. The wind validation provides velocity correlations between 0.45 and 0.76, while significant wave height correlations are much higher—between 0.89 and 0.96. The results are also compared to the original low-resolution ERA5 dataset, based on assimilated models. The comparison shows that the downscaling improves the hindcast reliability, particularly in the coastal regions, and especially with regard to wind and wave directions.


2015 ◽  
Author(s):  
Jasmine Ferrario ◽  
Agnese Marchini ◽  
Martina Marić ◽  
Dan Minchin ◽  
Anna Occhipinti-Ambrogi

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.


ZooKeys ◽  
2019 ◽  
Vol 838 ◽  
pp. 71-84
Author(s):  
Céline Labrune ◽  
Nicolas Lavesque ◽  
Paulo Bonifácio ◽  
Pat Hutchings

A new species of Terebellidae, Pistacolinisp. n., has been identified from the harbour of Banyuls-sur-Mer, north-western Mediterranean Sea. This new species was found in very high densities, exclusively in gravelly sand deposited manually, and was not found in the original source habitat of the gravel. This species is characterized by the colour of the ventral shields with pinkish anterior part and a blood red posterior part in live specimens, a pair of unequal-sized plumose branchiae inserted on segment II and anterior thoracic neuropodia with long-handled uncini. The presence of long-handled uncini even in the smallest specimens constitutes the major difference between Pistacolinisp. n. and other Pista species with a single pair of branchiae such as P.lornensis and P.bansei.


2016 ◽  
Vol 12 (1) ◽  
pp. 91-101 ◽  
Author(s):  
B. Jalali ◽  
M.-A. Sicre ◽  
M.-A. Bassetti ◽  
N. Kallel

Abstract. Sea surface temperatures (SSTs) and land-derived input time series were generated from the Gulf of Lions inner-shelf sediments (NW Mediterranean Sea) using alkenones and high-molecular-weight odd-carbon numbered n-alkanes (TERR-alkanes), respectively. The SST record depicts three main phases: a warm Early Holocene ( ∼  18 ± 0.4  °C) followed by a cooling of  ∼  3  °C between 7000 and 1000 BP, and rapid warming from  ∼  1850 AD onwards. Several superimposed multi-decadal to centennial-scale cold events of  ∼  1  °C amplitude were also identified. TERR-alkanes were quantified in the same sedimentary horizons to identify periods of high Rhone River discharge and compare them with regional flood reconstructions. Concentrations show a broad increase from the Early Holocene towards the present with a pronounced minimum around 2500 BP and large fluctuations during the Late Holocene. Comparison with Holocene flood activity reconstructions across the Alps region suggests that sediments of the inner shelf originate mainly from the Upper Rhone River catchment basin and that they are primarily delivered during positive North Atlantic Oscillation (NAO).


2020 ◽  
Vol 159 ◽  
pp. 105021
Author(s):  
Marta Albo-Puigserver ◽  
Sonia Sánchez ◽  
Marta Coll ◽  
Miguel Bernal ◽  
Raquel Sáez-Liante ◽  
...  

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