Conceptual models for the biogeochemical role of the photic zone microbial food web, with particular reference to the Mediterranean Sea

1999 ◽  
Vol 44 (1-3) ◽  
pp. 271-286 ◽  
Author(s):  
T.Frede Thingstad ◽  
Fereidoun Rassoulzadegan
Keyword(s):  
Food Web ◽  
Mediterranean Sea ◽  
Conceptual Models ◽  
Microbial Food Web ◽  
Photic Zone ◽  
The Mediterranean

scholarly journals The impact of anticyclonic mesoscale structures on microbial food webs in the Mediterranean Sea

2011 ◽  
Vol 8 (1) ◽  
pp. 185-220 ◽  
Author(s):  
U. Christaki ◽  
F. Van Wambeke ◽  
D. Lefevre ◽  
A. Lagaria ◽  
L. Prieur ◽  
...  
Keyword(s):  
Food Web ◽  
Mediterranean Sea ◽  
Microbial Food Web ◽  
Community Respiration ◽  
Net Community Production ◽  
Mesoscale Structures ◽  
The Mediterranean ◽  
And Function ◽  
The Impact ◽  
Community Production

Abstract. The abundance and activity of the major members of the heterotrophic microbial community – from viruses to ciliates – were studied along a longitudinal transect across the Mediterranean Sea in the summer of 2008. The Mediterranean Sea is characterized by a west to the east gradient of deepening of DCM (deep chlorophyll maximum) and increasing oligotrophy reflected in gradients of heterotrophic microbial biomass and production. However, within this longitudinal trend, hydrological mesoscale features exist and likely influence microbial dynamics. We show here the importance of mesoscale structures by a description of the structure and function of the microbial food web through an investigation of 3 geographically distant eddies within a longitudinal transect. Three selected sites each located in the center of an anticyclonic eddy were intensively investigated: in the Algero-Provencal Basin (St. A), the Ionian Basin (St. B), and the Levantine Basin (St. C). The 3 geographically distant eddies showed the lowest values of the different heterotrophic compartments of the microbial food web, and except for viruses in site C, all stocks were higher in the neighboring stations outside the eddies. During our study the 3 eddies showed equilibrium between GCP (Gross Community Production) and DCR (Dark Community Respiration); moreover, the west-east (W-E) gradient was evident in terms of heterotrophic biomass but not in terms of production. Means of integrated PPp values were higher at site B (~190 mg C m−2 d−1) and about 15% lower at sites A and C (~160 mg C m−2 d−1). Net community production fluxes were similar at all three stations exhibiting equilibrium between gross community production and dark community respiration.

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 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 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
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