scholarly journals The role of atmospheric deposition in the biogeochemistry of the Mediterranean Sea

1999 ◽  
Vol 44 (1-3) ◽  
pp. 147-190 ◽  
Author(s):  
Stefano Guerzoni ◽  
Roy Chester ◽  
François Dulac ◽  
Barak Herut ◽  
Marie-Dominique Loÿe-Pilot ◽  
...  
Keyword(s):  
Atmospheric Deposition ◽  
Mediterranean Sea ◽  
The Mediterranean

scholarly journals Introduction to the project DUNE, a DUst experiment in a low Nutrient, low chlorophyll Ecosystem

2013 ◽  
Vol 10 (7) ◽  
pp. 12491-12527 ◽  
Author(s):  
C. Guieu ◽  
F. Dulac ◽  
C. Ridame ◽  
P. Pondaven
Keyword(s):  
Trace Elements ◽  
Atmospheric Deposition ◽  
Mediterranean Sea ◽  
Surface Waters ◽  
Carbon Pump ◽  
Mesocosm Experiments ◽  
The Mediterranean ◽  
Atmospheric Inputs ◽  
Oligotrophic Ecosystem ◽  
The Impact

Abstract. The main goal of the project DUNE was to estimate the impact of atmospheric deposition on an oligotrophic ecosystem based on mesocosm experiments simulating strong atmospheric inputs of Aeolian dust. Atmospheric deposition is now recognized as a significant source of macro- and micro-nutrients for the surface ocean, but the quantification of its role on the biological carbon pump is still poorly determined. We proposed in DUNE to investigate the role of atmospheric inputs on the functioning of an oligotrophic system particularly well adapted to this kind of study: the Mediterranean Sea. The Mediterranean Sea – etymologically, sea surrounded by land – is submitted to atmospheric inputs that are very variable both in frequency and intensity. During the thermal stratification period, only atmospheric deposition is prone to fertilize Mediterranean surface waters which has become very oligotrophic due to the nutrient depletion (after the spring bloom). This paper describes the objectives of DUNE and the implementation plan of a series of mesocosms experiments during which either wet or dry and a succession of two wet deposition fluxes of 10 g m−2 of Saharan dust have been simulated. After the presentation of the main biogeochemical initial conditions of the site at the time of each experiment, a general overview of the papers published in this special issue is presented, including laboratory results on the solubility of trace elements in erodible soils in addition to results from the mesocosm experiments. Our mesocosm experiments aimed at being representative of real atmospheric deposition events onto the surface of oligotrophic marine waters and were an original attempt to consider the vertical dimension in the study of the fate of atmospheric deposition within surface waters. Results obtained can be more easily extrapolated to quantify budgets and parameterize processes such as particle migration through a "captured water column". The strong simulated dust deposition events were found to impact the dissolved concentrations of inorganic dissolved phosphorus, nitrogen, iron and other trace elements. In the case of Fe, adsorption on sinking particles yields a decrease in dissolved concentration unless binding ligands were produced following a former deposition input and associated fertilization. For the first time, a quantification of the C export induced by the aerosol addition was possible. Description and parameterization of biotic (heterotrophs and autotrophs, including diazotrophs) and abiotic processes (ballast effect due to lithogenic particles) after dust addition in sea surface water, result in a net particulate organic carbon export in part controlled by the "lithogenic carbon pump".

Migration and ‘pull factor’ traps

2020 ◽  
Author(s):  
Glenda Garelli ◽  
Martina Tazzioli
Keyword(s):  
Mediterranean Sea ◽  
Migration Studies ◽  
Pull Factors ◽  
The Past ◽  
Critical Knowledge ◽  
Political Outcomes ◽  
History Of ◽  
The Mediterranean ◽  
History Books

Abstract This article engages with the centrality that the push–pull theory regained in the context of border deaths in the Mediterranean Sea and particularly as part of the debate against the criminalization of nongovernment organizations (NGOs’) rescue missions at sea. The article opens by illustrating the context in which the push–pull theory re-emerged—after having been part of migration studies’ history books for over a decade—as part of an effort to defend non-state actors engaged in rescue missions in the Mediterranean Sea against an aggressive campaign of illegalilzation conducted by European states. We then take a step back to trace the history of the push–pull theory and its role as a foil for critical migration studies in the past 20 years. Building on this history, the article then turns to interrogating the epistemic and political outcomes that result from bringing evidence against the NGOs’ role as pull factors for migrants. The article closes by advocating for a transformative, rather than evidencing, role of critical knowledge in the current political context where migrants and actors who fight against border deaths are increasingly criminalized.

scholarly journals The role of the Strait of Gibraltar in shaping the genetic structure of the Mediterranean Grenadier, Coryphaenoides mediterraneus, between the Atlantic and Mediterranean Sea

PLoS ONE ◽  
2017 ◽  
Vol 12 (5) ◽  
pp. e0174988 ◽  
Author(s):  
Diana Catarino ◽  
Sergio Stefanni ◽  
Per Erik Jorde ◽  
Gui M. Menezes ◽  
Joan B. Company ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Mediterranean Sea ◽  
Strait Of Gibraltar ◽  
The Mediterranean

A scale-independent model for land-locked seas with application to the Messinian salinity crisis

2020 ◽  
Author(s):  
Paul Meijer
Keyword(s):  
Mediterranean Sea ◽  
Independent Solution ◽  
Aegean Sea ◽  
Basic Element ◽  
Messinian Salinity Crisis ◽  
Elevated Salinity ◽  
Levantine Basin ◽  
The Mediterranean ◽  
Atmospheric Heat

<p>While the Mediterranean Sea is, since the Middle Miocene, a nearly completely land-locked basin indeed, it is itself comprised of several smaller semi-enclosed seas. What the Mediterranean Sea as a whole is to the Atlantic Ocean, are the Adriatic Sea or Aegean Sea to the Ionian-Levantine basin, for example. In the discussions regarding the Messinian salinity crisis the marginal basins of the Mediterranean play a prominent role because it is from these parts that the sedimentary record has been uplifted and become exposed.</p><p>In view of this and with an aim to contribute insight from the field of modelling, we focus on the basic element: a single marginal basin, subject to atmospheric forcing and exchanging water through a seaway with an adjacent larger basin. The equations are derived in dimensionless form and a universal, scale-independent, solution for basin salinity obtained. The analysis yields two dimensionless ratios which control basin behaviour in terms of salinity and response time. </p><p>Application of the theoretical model to the Messinian salinity crisis sheds new light on the formation of gypsum in marginal basins that were separated from the main Mediterranean by a sill, gives insight about the role of atmospheric heat exchange, and underlines the previous finding that, at elevated salinity, marginal basins respond to periodic climate variation (e.g. due to precession) with a significant lag.</p>

scholarly journals Assessing the role of submarine groundwater discharge as a source of Sr to the Mediterranean Sea

2017 ◽  
Vol 200 ◽  
pp. 42-54 ◽  
Author(s):  
Giada Trezzi ◽  
Jordi Garcia-Orellana ◽  
Valentí Rodellas ◽  
Pere Masqué ◽  
Ester Garcia-Solsona ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Submarine Groundwater Discharge ◽  
Groundwater Discharge ◽  
Submarine Groundwater ◽  
The Mediterranean

scholarly journals Distribution and host diversity of Amoebophryidae parasites across oligotrophic waters of the Mediterranean Sea

2011 ◽  
Vol 8 (2) ◽  
pp. 267-278 ◽  
Author(s):  
R. Siano ◽  
C. Alves-de-Souza ◽  
E. Foulon ◽  
El M. Bendif ◽  
N. Simon ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Marine Ecosystems ◽  
Natural Environments ◽  
Coastal Station ◽  
Host Diversity ◽  
Eukaryotic Community ◽  
Wide Range ◽  
The Mediterranean ◽  
Host Infection

Abstract. Sequences affiliated to Syndiniales (Marine alveolate, MALV) regularly dominate 18S rDNA genetic libraries of nearly all marine ecosystems investigated so far. Among them, Amoebophryidae (MALV group II) is composed of numerous and genetically distant environmental sequences, where Amoebophrya is the only known and formally described genus. Amoebophrya species include virulent pathogens for a wide range of dinoflagellate species. Beside their regular occurrence in marine ecosystems, their quantitative distribution and the environmental factors triggering host infection have barely been studied in open oligotrophic waters. In order to understand the functional role of these parasites in natural environments, we studied the distribution and contribution to the eukaryotic community of the small free-living stage of Amoebophryidae (the dinospores) along a transect in the Mediterranean Sea, as well as their host diversity at three oligotrophic stations. Dinospores were more abundant at a coastal station (max. 1.5 × 103 cells ml−1) than in oligotrophic waters (max. 51 ± 16.3 cells ml−1), where they represented 10.3 to 34.9% of the total eukaryotic community at 40 and 30 m depth, respectively and 21.2% on average along the water column. Positive correlation was found between dinospore occurrence and higher concentration of NO3 + NO2 at the coastal station. At selected stations, out of 38 different dinoflagellates taxa identified, 15 were infected, among which a majority were not recognized as Amoebophryidae host so far. Prevalences (percentage of infected cells) generally varied between 1% and 10%, with a notable exception for Blepharocysta paulsenii for which 25% of cells were infected at the most oligotrophic station. The present study shows that dinospores are able to thrive and infect dinoflagellates both in coastal and ultra-oligotrophic open waters. Our results emphasize the role of parasitism in microbial food web dynamics and ultimately on biogeochemical cycles.

Foraminifers epibiontic on Eudendrium (Cnidaria: Hydrozoa) from the Mediterranean Sea

2008 ◽  
Vol 88 (3) ◽  
pp. 485-489 ◽  
Author(s):  
C. Di Camillo ◽  
M. BO ◽  
A. Lavorato ◽  
C. Morigi ◽  
M. Segre Reinach ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Life Histories ◽  
Evolutionary Relationships ◽  
The Mediterranean ◽  
Shape And Size

Four species of foraminifers Rosalina globularis, Lobatula lobatula, Acervulina inhaerens and Miniacina miniacea were observed as epibionts on some species of the athecate hydroids of the genus Eudendrium—E. armatum, E. glomeratum, E. moulouyensis and E. racemosum—from the Mediterranean Sea. The abundance and the distribution of the protozoans were determined for each hydroid and considered in relation to the shape and size of the Eudendrium branches. Results revealed differences in the composition of the epibiontic assemblage among different species of Eudendrium which were dependent on several factors, but were mainly related to the habitat and to the morphology of the host.The interactions between Eudendrium and its epibionts were considered to emphasize the role of the Eudendrium colonies as a hotspot not only of poorly known species but also of co-evolutionary relationships and life histories.

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