scholarly journals Summertime surface PM<sub>1</sub> aerosol composition and size by source region at the Lampedusa island in the central Mediterranean Sea

2019 ◽  
Vol 19 (17) ◽  
pp. 11123-11142 ◽  
Author(s):  
Marc D. Mallet ◽  
Barbara D'Anna ◽  
Aurélie Même ◽  
Maria Chiara Bove ◽  
Federico Cassola ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Ammonium Sulfate ◽  
Organic Aerosol ◽  
Western Mediterranean ◽  
Central Mediterranean ◽  
Aerosol Composition ◽  
Air Masses ◽  
Westerly Winds ◽  
Central Mediterranean Sea ◽  
The Mediterranean

Abstract. Measurements of aerosol composition and size distributions were taken during the summer of 2013 at the remote island of Lampedusa in the southern central Mediterranean Sea. These measurements were part of the ChArMEx/ADRIMED (Chemistry and Aerosol Mediterranean Experiment/Aerosol Direct Radiative Forcing on the Mediterranean Climate) framework and took place during Special Observation Period 1a (SOP-1a) from 11 June to 5 July 2013. From compact time-of-flight aerosol mass spectrometer (cToF-AMS) measurements in the size range below 1 µm in aerodynamic diameter (PM1), particles were predominately comprised of ammonium and sulfate. On average, ammonium sulfate contributed 63 % to the non-refractory PM1 mass, followed by organics (33 %). The organic aerosol was generally very highly oxidized (f44 values were typically between 0.25 and 0.26). The contribution of ammonium sulfate was generally higher than organic aerosol in comparison to measurements taken in the western Mediterranean but is consistent with studies undertaken in the eastern basin. Source apportionment of organics using a statistical (positive matrix factorization) model revealed four factors: a hydrocarbon-like organic aerosol (HOA), a methanesulfonic-acid-related oxygenated organic aerosol (MSA-OOA), a more oxidized oxygenated organic aerosol (MO-OOA) and a less oxidized oxygenated organic aerosol (LO-OOA). The MO-OOA was the dominant factor for most of the campaign (53 % of the PM1 OA mass). It was well correlated with SO42-, highly oxidized and generally more dominant during easterly air masses originating from the eastern Mediterranean and central Europe. The LO-OOA factor had a very similar composition to the MO-OOA factor but was more prevalent during westerly winds, with air masses originating from the Atlantic Ocean, the western Mediterranean and at high altitudes over France and Spain from mistral winds. The MSA-OOA factor contributed an average 12 % to the PM1 OA and was more dominant during the mistral winds. The HOA, representing observed primary organic aerosol, only contributed 8 % of the average PM1 OA during the campaign. Even though Lampedusa is one of the most remote sites in the Mediterranean, PM1 concentrations (10 ± 5 µg m−3) were comparable to those observed in coastal cities and sites closer to continental Europe. Cleaner conditions corresponded to higher wind speeds. Nucleation and growth of new aerosol particles was observed during periods of north-westerly winds. From a climatology analysis from 1999 to 2012, these periods were much more prevalent during the measurement campaign than during the preceding 13 years. These results support previous findings that highlight the importance of different large-scale synoptic conditions in determining the regional and local aerosol composition and oxidation and also suggest that a non-polluted surface atmosphere over the Mediterranean is rare.

scholarly journals Summertime surface PM<sub>1</sub> aerosol composition and size by source region at the Lampedusa island in the central Mediterranean Sea

2019 ◽  
Author(s):  
Marc D. Mallet ◽  
Barbara D'Anna ◽  
Aurélie Même ◽  
Maria Chiara Bove ◽  
Federico Cassola ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Ammonium Sulphate ◽  
Organic Aerosol ◽  
Western Mediterranean ◽  
Dominant Factor ◽  
Central Mediterranean ◽  
Aerosol Composition ◽  
Air Masses ◽  
Central Mediterranean Sea ◽  
The Mediterranean

Abstract. Measurements of aerosol composition and size distributions were taken during the summer of 2013 at the remote island of Lampedusa in the southern central Mediterranean Sea. These measurements were part of the ChArMEx/ADRIMED (Chemistry and Aerosol Mediterranean Experiment/Aerosol Direct Radiative Forcing on the Mediterranean Climate) framework and took place during the Special Observation Period 1a (SOP-1a) from 11 June until 5 July 2013. From compact time-of-flight aerosol mass spectrometer (cToF-AMS) measurements in the size range below 1 μm in aerodynamic diameter (PM1), particles were predominately comprised of ammonium and sulphate. On average, ammonium sulphate contributed 63 % to the non-refractory PM1 mass, followed by organics (33 %). The organic aerosol was generally very highly oxidised (f44 values were typically between 0.25 and 0.26). The contribution of ammonium sulphate was generally higher than organic aerosol in comparison to measurements taken in the western Mediterranean but is consistent with studies undertaken in the eastern basin. Source apportionment of organics using a statistical (positive matrix factorisation) model revealed four factors; a hydrocarbon-like organic aerosol (HOA), a methanesulfonic acid related oxygenated organic aerosol (MSA-OOA), a more oxidised oxygenated organic aerosol (MO-OOA) and a less oxidised oxygenated organic aerosol we label (LO-OOA). The MO-OOA was the dominant factor for most of the campaign (53 % of the PM1 OA mass). It was well correlated with SO42−, highly oxidised, and generally more dominant during easterly air masses originating from the eastern Mediterranean and central Europe. The LO-OOA factor had a very similar composition to the MO-OOA factor, but was more prevalent during westerly winds with air masses originating from the Atlantic Ocean, the western Mediterranean, and in high altitudes over France and Spain from mistral winds. The MSA-OOA factor contributed an average 12 % to the PM1 OA and was more dominant during the mistral winds. The HOA, representing observed primary organic aerosol only contributed 8 % of the average PM1 OA during the campaign. Even though Lampedusa is one of the most remote sites in the Mediterranean, PM1 concentrations (10 ± 5 μg m−3) were comparable to those observed in coastal cities and sites closer to continental Europe. Cleaner conditions corresponded to higher wind speeds. Nucleation and growth of new aerosol particles was observed during periods of northwesterly winds. From a climatology analysis from 1999 until 2012, these periods were much more prevalent during the measurement campaign than during the preceding 13 years. These results support previous findings that highlight the importance of different large-scale synoptic conditions in determining the regional and local aerosol composition and oxidation and also suggest that a non-polluted surface atmosphere over the Mediterranean is rare.

scholarly journals Particulate biogenic barium tracer of mesopelagic carbon remineralization in the Mediterranean Sea (PEACETIME project)

2021 ◽  
Vol 18 (22) ◽  
pp. 5891-5902
Author(s):  
Stéphanie H. M. Jacquet ◽  
Christian Tamburini ◽  
Marc Garel ◽  
Aurélie Dufour ◽  
France Van Vambeke ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Deep Convection ◽  
Western Mediterranean ◽  
Late Spring ◽  
Small Scale ◽  
Dust Deposition ◽  
Central Mediterranean ◽  
Central Mediterranean Sea ◽  
The Mediterranean ◽  
The Impact

Abstract. We report on the sub-basin variability in particulate organic carbon (POC) remineralization in the western and central Mediterranean Sea in late spring during the PEACETIME (ProcEss studies at the Air–sEa Interface after dust deposition in the MEditerranean sea) cruise. POC remineralization rates were estimated using the excess biogenic particulate barium (Baxs) inventories in the mesopelagic layers (100–1000 m depth) and compared with prokaryotic heterotrophic production (PHP). Baxs-based mesopelagic remineralization rates (MRs) ranged from 25±2 to 306±70 mgCm-2d-1. MRs were larger in the Algero-Provençal (ALG) Basin than in the Tyrrhenian (TYR) and Ionian (ION) basins. Our Baxs inventories and integrated PHP data also indicated that significant mesopelagic remineralization occurred down to 1000 m depth in the ALG Basin in contrast to the ION and TYR basins, where remineralization was mainly located above 500 m depth. We propose that the higher and deeper MRs in the ALG Basin were sustained by an additional particle export event driven by deep convection. The TYR Basin (in contrast to the ALG and ION basins) presented the impact of a previous dust event, as reflected by our particulate Al water column concentrations. The ION and TYR basins showed small-scale heterogeneity in remineralization processes, reflected by our Baxs inventories and integrated PHP data at the Tyrr long-duration station. This heterogeneity was linked to the mosaic of blooming and non-blooming patches reported in this area during the cruise. In contrast to the western Mediterranean Sea (ALG Basin), the central Mediterranean Sea (ION and TYR basins) showed lower remineralization rates restricted to the upper mesopelagic layer during the late spring PEACETIME cruise.

scholarly journals Remarks on Echinodermata from the South Central Mediterranean Sea based upon collections made during the MARCOS cruise (10 to 20th April, 2007)

2009 ◽  
Vol 10 (2) ◽  
pp. 63 ◽  
Author(s):  
C. MIFSUD ◽  
M. TAVIANI ◽  
S. STOHR
Keyword(s):  
Mediterranean Sea ◽  
The South ◽  
Central Mediterranean ◽  
Management Zone ◽  
Maltese Islands ◽  
South Central ◽  
Central Mediterranean Sea ◽  
The Mediterranean ◽  
First Time ◽  
The Mediterranean Basin

The MARCOS cruise, which took place in the South Central Mediterranean Sea on board the RV ‘Urania’, resulted in the collection of 27 species of Echinodermata from shallow to bathyal depths, many from around Malta (the Fisheries Management Zone). The fauna is represented by common to rare taxa already reported from the Mediterranean with the exception of the amphi-Atlantic ophiuroid Ophiotreta valenciennesi rufescens (Koehler, 1896), recorded from the Mediterranean Basin for the first time. Odontaster mediterraneus (von Marenzeller, 1893) and Luidia sarsi Lutken, 1858 are also first records for the Maltese Islands.

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

2010 ◽  
Vol 7 (6) ◽  
pp. 8779-8816 ◽  
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.

First record of Dosima fascicularis (Ellis & Solander, 1786) (Crustacea, Cirripedia) in the Strait of Messina (Central Mediterranean Sea)

Zootaxa ◽  
2020 ◽  
Vol 4743 (3) ◽  
pp. 447-450
Author(s):  
M. CAVALLARO ◽  
G. AMMENDOLIA ◽  
P. BATTAGLIA
Keyword(s):  
Mediterranean Sea ◽  
Mediterranean Basin ◽  
First Record ◽  
Central Mediterranean ◽  
Central Mediterranean Sea ◽  
The Mediterranean

Four specimens of Dosima fascicularis were collected from the Strait of Messina (Central Mediterranean Basin), representing the first record of the species from this locality, the second from Italian waters, and the most eastern indication of the species in the Mediterranean Sea. 

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

2011 ◽  
Vol 8 (3) ◽  
pp. 827-840 ◽  
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.

Large-scale seasonal distribution of fin whales (Balaenoptera physalus) in the central Mediterranean Sea

2008 ◽  
Vol 88 (6) ◽  
pp. 1253-1261 ◽  
Author(s):  
Mehdi Aïssi ◽  
Antonio Celona ◽  
Giorgia Comparetto ◽  
Renata Mangano ◽  
Maurizio Würtz ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Western Mediterranean ◽  
High Abundance ◽  
Central Mediterranean ◽  
Balaenoptera Physalus ◽  
Feeding Ground ◽  
The North ◽  
Central Mediterranean Sea ◽  
Fin Whales ◽  
North Western

Fin whales (Balaenoptera physalus) are the only mysticete regularly found in the Mediterranean Sea. Its exceptional high abundance during the summer period in the north-western Mediterranean is essentially due to productive waters, but outside of this spatio-temporal window its distribution still remains quite unknown. This paper investigates the distribution of the fin whale on large-scales during the 2002–2006 period. Three areas of the central Mediterranean Sea were selected: the Ligurian Sea in the north-western Mediterranean belonging to the Pelagos Sanctuary; the area connecting both Mediterranean basins in the south-western Mediterranean, the Strait of Messina; and the waters surrounding the island of Lampedusa, in the central Mediterranean. Of the 41,270 km covered by the three surveys, a total of 98 sightings was recorded corresponding to 198 fin whales. Results display a year round distribution along synchronic seasonal dispatching, with a feeding behaviour occurrence in the northern part of the Pelagos Sanctuary during late spring and summer. They indicate high abundance in the Lampedusa area from late winter to early spring manifesting feeding activity. In the Strait of Messina, our results point out the importance of this area as a seasonal feeding ground and an important location for regular autumn transfers between both Mediterranean basins. According to the feeding ground in the two Mediterranean basins, whales change foraging strategy, one being single animals or animal pairs searching for prey in the water column while the other strategy is associated with more individuals feeding on the surface. The strategies differ also by their ecological conditions, such as depth affinity and shoreline distance.

scholarly journals Paleoenvironmental changes, climate and human impact in the Western Mediterranean Sea during the 4.2 Kyr event along a North-South Transect

2020 ◽  
Author(s):  
Nathalie Combourieu-Nebout ◽  
Vincent Coussin ◽  
Yannick Miras ◽  
Aurélie Penaud ◽  
Sandra Picard Casal ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Human Impact ◽  
Water Depth ◽  
Western Mediterranean ◽  
Time Lags ◽  
Central Mediterranean ◽  
Western Mediterranean Sea ◽  
Sequence Of Events ◽  
Dry Conditions ◽  
The Mediterranean

&lt;p&gt;The 4.2 ka event is considered a key-period of the Mediterranean climate because of its potential impact on human societies over the Holocene. Numerous records provide a detailed description on its expression in continental and marine archives (e.g. Bini et al, 2019). They generally indicate cold/dry conditions, although not uniformly expressed across the Mediterranean, and summer dryness reinforced by dry winters. Palynological data from the central Mediterranean basin show a complex response of the vegetation during this climatic event that seems to be more pronounced in the southern sites.&lt;/p&gt;&lt;p&gt;In this study, we developed a multidisciplinary approach on two sequences collected in the Western Mediterranean Sea to insight the response of the W-Mediterranean forest along a North-South transect. The two marine records, KSGC-31 (43&amp;#176;N - 3&amp;#176;17.9&amp;#8217;E; 60 m water depth, Gulf of Lion margin at 20 km from the coast) and MD04-2801 (36&amp;#176;30.99&amp;#8217; N - 0&amp;#176;30.03&amp;#8217; W, 2067 m water depth, 12km from the Algerian coast) were used to document regional changes in the basin between 5 and 3 kyr BP at a multi-decadal to centennial scale temporal resolution.&lt;/p&gt;&lt;p&gt;Information derived from palynological (pollen, spores, dinocysts, microalgae and non-pollen palynomorphs) and marine proxy data (alkenone-derived SSTs, isotopes...) are combined to evaluate environmental and hydrological changes and how this relate to human activities. Our findings highlight coherent climatic patterns and time-lags along a South-North transect in the Western Mediterranean during the establishment of droughts. They also reveal the first indications of human impact in the two areas. Overall, our study shows the effectively of our approach based on cross-analysis of continental palynological and marine evidences to decipher the chronology of sequence of events embedded in multiproxy records.&lt;/p&gt;&lt;p&gt;Bini, M., Zanchetta, G., Per&amp;#351;oiu, A., et al. : The 4.2&amp;#8201;ka&amp;#8201;BP Event in the Mediterranean region: an overview, Clim. Past, 15, 555&amp;#8211;577, https://doi.org/10.5194/cp-15-555-2019, 2019.&lt;/p&gt;

scholarly journals Alien species in the Mediterranean Sea by 2010. A contribution to the application of European Union’s Marine Strategy Framework Directive (MSFD). Part I. Spatial distribution

2010 ◽  
Vol 11 (2) ◽  
pp. 381 ◽  
Author(s):  
A. ZENETOS ◽  
S. GOFAS ◽  
M. VERLAQUE ◽  
M.E. CINAR ◽  
J.E. GARCIA RASO ◽  
...  
Keyword(s):  
Alien Species ◽  
Mediterranean Sea ◽  
Introduced Species ◽  
Cold Water ◽  
Eastern Mediterranean ◽  
Western Mediterranean ◽  
Marine Strategy Framework Directive ◽  
Central Mediterranean ◽  
Total Species Richness ◽  
The Mediterranean

The state-of-art on alien species in the Mediterranean Sea is presented, making distinctions among the four subregions defined in the EU Marine Strategy Framework Directive: (i) the Western Mediterranean Sea (WMED); (ii) the Central Mediterranean Sea (CMED); (iii) the Adriatic Sea (ADRIA); and (iv) the Eastern Mediterranean Sea (EMED). The updated checklist (December 2010) of marine alien species within each subregion, along with their acclimatization status and origin, is provided. A total of 955 alien species is known in the Mediterranean, the vast majority of them having being introduced in the EMED (718), less in the WMED (328) and CMED (267) and least in the Adriatic (171). Of these, 535 species (56%) are established in at least one area.Despite the collective effort of experts who attempted in this work, the number of introduced species remains probably underestimated. Excluding microalgae, for which knowledge is still insufficient, aliens have increased the total species richness of the Mediterranean Sea by 5.9%. This figure should not be directly read as an indication of higher biodiversity, as spreading of so many aliens within the basin is possibly causing biotic homogenization. Thermophilic species, i.e. Indo-Pacific, Indian Ocean, Red Sea, Tropical Atlantic, Tropical Pacific, and circum(sub)tropical, account for 88.4% of the introduced species in the EMED, 72.8% in the CMED, 59.3% in the WMED and 56.1% in the Adriatic. Cold water species, i.e. circumboreal, N Atlantic, and N Pacific, make up a small percentage of the introduced species, ranging between 4.2% and 21.6% and being more numerous in the Adriatic and less so in the EMED.Species that are classified as invasive or potentially invasive are 134 in the whole of the Mediterranean: 108 are present in the EMED, 76 in the CMED, 53 in the Adriatic and 64 in the WMED. The WMED hosts most invasive macrophytes, whereas the EMED has the lion’s share in polychaetes, crustaceans, molluscs and fish.

scholarly journals Criminalizing solidarity: Search and rescue in a neo-colonial sea

2021 ◽  
pp. 239965442097931
Author(s):  
Ċetta Mainwaring ◽  
Daniela DeBono
Keyword(s):  
Mediterranean Sea ◽  
Search And Rescue ◽  
Central Mediterranean ◽  
Eu Member States ◽  
Governmental Organizations ◽  
Non Governmental Organizations ◽  
Legal Geographies ◽  
Central Mediterranean Sea ◽  
The Mediterranean ◽  
Trade And Exchange

Non-governmental organizations (NGOs) rescued over 110,000 people in the Central Mediterranean Sea between 2015 and 2017. From 2017, EU member states and agencies increasingly criminalized these organizations, accusing them of ‘colluding with smugglers’ and acting as a pull factor. In this climate, as Italy, Malta and the EU increased cooperation with Libya to stop people from taking to the seas, many suspended their operations. This article explores the search and rescue efforts of NGOs in the Central Mediterranean Sea between 2014 and 2018. We examine the criminalization of this NGO activity and argue that it is made possible through an oscillating neo-colonial imagination of the sea as mare nostrum and mare nullius, our sea and nobody’s sea, respectively. We build on the work of other scholars who have pointed to the activation of the Mediterranean as ‘empty’ in response to migration flows, erasing the historical connections of colonialism, empire, trade, and exchange in the Mediterranean as well as the contemporary legal geographies that govern the space. Here, we go further to develop the idea of a neo-colonial sea, which is alternately imagined as empty and ‘European’. We explore how NGOs disrupt these depictions, as well as the disappearing figures of the migrant and refugee amidst the contestations between NGOs and states.

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