scholarly journals Prokaryotic abundance and heterotrophic metabolism in the deep Mediterranean Sea

2010 ◽  
Vol 1 (1) ◽  
pp. 143 ◽  
Author(s):  
Rosabruna La Ferla ◽  
Maurizio Azzaro ◽  
Gabriella Caruso ◽  
Luis Salvador Monticelli ◽  
Giovanna Maimone ◽  
...  
Keyword(s):  
Carbon Cycle ◽  
Mediterranean Sea ◽  
Respiration Rate ◽  
Longitudinal Distribution ◽  
Large Spatial Scale ◽  
Prokaryotic Abundance ◽  
Changing Patterns ◽  
Gibraltar Strait ◽  
Heterotrophic Metabolism ◽  
The Mediterranean

A synthesis of field data carried out in the Mediterranean Sea are presented, aimed at contributing to the knowledge of three prokaryotic-mediated processes and their implications on the Carbon cycle. The distribution of exoenzymatic activities, secondary production and respiration rates was studied together with the prokaryotic abundances. Particular attention was paid to the meso- and bathypelagic layers which play an important role in the Mediterranean carbon cycle. The study is noteworthy because of its large spatial scale spanning the entire Mediterranean Sea over 4 years. In addition, two Atlantic stations in front of the Gibraltar Strait were investigated. The longitudinal distribution of prokaryotic activities and abundance along the MED showed different trends along the depthlayers. In particular, higher exoenzymatic rates were detected in the Eastern basin compared to the Western one; carbon respiration rate showed patterns variable with the sampling periods in the epipelagic and bathypelagic layers, while a consistent Westwards decreasing trend at the mesopelagic layers occurred. Specific enzyme activities per cell showed high values in the deepest layers for leucine aminopeptidase. Comparison with Carbon respiration rate data collected before the 2000s showed changing patterns of microbial heterotrophic processes in the Mediterranean Sea.

scholarly journals Decadal variability of net water flux at the Mediterranean Sea Gibraltar Strait

2013 ◽  
Vol 100 ◽  
pp. 1-10 ◽  
Author(s):  
L. Fenoglio-Marc ◽  
A. Mariotti ◽  
G. Sannino ◽  
B. Meyssignac ◽  
A. Carillo ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Decadal Variability ◽  
Water Flux ◽  
Gibraltar Strait ◽  
The Mediterranean ◽  
Net Water Flux

Prokaryotic abundance and heterotrophic metabolism in the deep Mediterranean Sea

2010 ◽  
Vol 1 (1) ◽  
pp. 143-166 ◽  
Author(s):  
Rosabruna La Ferla ◽  
Maurizio Azzaro ◽  
Gabriella Caruso ◽  
Luis Salvador Monticelli ◽  
Giovanna Maimone ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Prokaryotic Abundance ◽  
Heterotrophic Metabolism

scholarly journals De cerca medieval islámica a frente abaluartado: génesis y evolución del Frente de Tierra de Ceuta

X ◽  
2020 ◽  
Author(s):  
Fernando Villada Paredes
Keyword(s):  
Sixteenth Century ◽  
Atlantic Ocean ◽  
Mediterranean Sea ◽  
Archaeological Research ◽  
Strait Of Gibraltar ◽  
Research Project ◽  
Southern Shore ◽  
Archival Documents ◽  
Gibraltar Strait ◽  
The Mediterranean

From Medieval Islamic Wall to Bastioned Land Front: Genesis and evolution of the Land Front of CeutaCeuta is built on a peninsula at the southern shore of the Strait of Gibraltar. It’s a strategic point for communications between the Mediterranean Sea and the Atlantic Ocean and between two continents: Europe and Africa. As Ceuta ships rule the Gibraltar Strait in Medieval and Modern Ages, main defensive efforts were tuned of to Land Front. Consequently, in 950 ‘Abd al-Rahman III built a new fence in order to protect the madina reusing Roman and Byzantine fortifications. Although repaired and enlarged by Almohads, Marinids, and Portuguese, these walls and towers protected the Land Front of Ceuta until the sixteenth century. But, at this moment, pirobalistic artillery development had made this defensive device obsolete and a new bastioned front, an early and outstanding example of the new Renaissance ideas for the defense of the cities, was built. Archival documents, cartographic sources, etc., let us follow the main lines of this evolution. Recently, an archaeological research project has added new data on how this evolution, from Medieval to Renaissance fortifications, took place.

scholarly journals The influence of habitat complexity on fish assemblages associated with extractive platforms in the central Mediterranean Sea

2018 ◽  
Vol 9 (2) ◽  
Author(s):  
Pierpaolo Consoli ◽  
Maria Cristina Mangano ◽  
Gianluca Sarà ◽  
Teresa Romeo ◽  
Franco Andaloro
Keyword(s):  
Mediterranean Sea ◽  
Habitat Complexity ◽  
Fish Assemblages ◽  
Spatial Scales ◽  
Complex Structure ◽  
Attractive Potential ◽  
Water Volume ◽  
Large Spatial Scale ◽  
Internal Structures ◽  
The Mediterranean

In this work the influence of habitat complexity on fish assemblages associated with extractive platforms in the Mediterranean Sea was investigated. More specifically, at large spatial scale we tested the differences in fish assemblage between 4-legs vs 8-legs platforms, whereas at medium scale we evaluated, within each platform, the differences between internal structures with increasing complexity degrees (respectively: the water volume without any pillar - complexity “0”; the junction of two pillars - “1”; the junction of four pillars - “2”). Both univariate and multivariate analyses showed highly significant differences for each of the tested factors, as well as for their interaction. In general, at both medium and large spatial scales, mean species richness and abundance were positively correlated with the increasing habitat complexity with the highest values associated with 8-legs platforms and with the most complex internal structures within each platform. According to our findings, a more complex structure is able to attract more fish species and specimens than a less complex one, supporting previous studies carried out on different man-made structures outside the Mediterranean Sea. The study will integrate the still poor available knowledge baseline on the attractive potential of extractive platforms with strong implications for the environmental management under the incoming light of decommission in the basin.

Revision of the Alboran sea Tortonian-Pliocene record: possible new insights on Mediterranean-Atlantic connectivity during the Messinian Salinity Crises

2020 ◽  
Author(s):  
Francesca Bulian ◽  
Francisco J. Sierro
Keyword(s):  
Mediterranean Sea ◽  
High Amplitude ◽  
Atlantic Water ◽  
Time Interval ◽  
Alboran Sea ◽  
Base Level ◽  
Open Questions ◽  
Gibraltar Strait ◽  
The Mediterranean ◽  
Alborán Sea

<p>In August of 1970, during Mediterranean Sea Leg 13, when the Glomar challenger ventured Mediterranean waters, nobody was expecting to run into one of the most exiting scientific discoveries regarding the Mediterranean Sea evolution. Cores and seismic surveys made possible the discovery of a basin-wide Messinian evaporitic deposit buried beneath the deep-sea Pliocene sediments which was attributed to the Messinian Salinity Crises (MSC) already known and studied in onshore outcrops in the Apennines. Now, 50 years later the debate regarding the conditions and timing of the deposition of this salt giant is still ongoing as many theories are still open and in search for validating proof.</p><p>One of the main open questions certainly regards the base level drop during the MSC and the location, efficiency and dynamics of the Mediterranean – Atlantic connectivity. The Mediterranean level is thought to have dropped somewhere between a moderate 200 m up to an extreme high amplitude oscillation of 1500 m while according to different schools of thought the watergate to the Atlantic is considered as completely closed, intermittently open or to have been always open during the MSC. Gibraltar strait is the main candidate for a possible gateway during this time interval (5.96-5.33 Ma) as well as the leading cause of the re-establishment of open marine conditions in the Mediterranean. Consequently, understanding its evolution and opening is fundamental to endorse any of the MSC theories and a thorough investigation of the Messinian and early Pliocene sedimentological record of basins in its proximity is highly needed.</p><p>In this optic, the Alboran Sea is the place where many of those answers lie and its worth of further exploration. In the hope of a new oceanographic expedition in the near future, an effort should be made towards gathering and re-interpreting all the available data. We propose a refined planktonic foraminifer chronology of the Alboran DSDP and ODP sites 976B, 121 and 978A with a careful characterization of the main MSC facies that will clarify to a certain extent the MSC expression and the degree of Atlantic water influence in the Alboran basin.</p><p> </p>

scholarly journals First evidence of European eels exiting the Mediterranean Sea during their spawning migration

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Elsa Amilhat ◽  
Kim Aarestrup ◽  
Elisabeth Faliex ◽  
Gaël Simon ◽  
Håkan Westerberg ◽  
...  
Keyword(s):  
Atlantic Ocean ◽  
Mediterranean Sea ◽  
Anguilla Anguilla ◽  
European Eel ◽  
Migration Route ◽  
Spawning Site ◽  
Mediterranean Countries ◽  
Mesopelagic Zone ◽  
Gibraltar Strait ◽  
The Mediterranean

Abstract The migration route and the spawning site of the European eel Anguilla anguilla are still uncertain. It has been suggested that the Mediterranean eel stock does not contribute to spawning because there is no evidence of eels leaving the Mediterranean Sea. To test this hypothesis, we equipped eight female silver eels from the south of France with pop-up satellite tags during escapement from coastal waters. Once in deeper water, the eels quickly established diel vertical migration (DVM) between the upper and lower mesopelagic zone. Five tagged eels were taken by predators within the Mediterranean, but two eels reached the Atlantic Ocean after six months and at distances greater than 2000 km from release. These eels ceased their DVM while they negotiated the Gibraltar Strait, and remained in deep water until they reached the Atlantic Ocean, when they recommenced DVM. Our results are the first to show that eels from Mediterranean can cross the Strait of Gibraltar and continue their migration into the Atlantic Ocean. This finding suggests that Mediterranean countries, as for other EU states, have an important role to play in contributing to conservation efforts for the recovery of the European eel stock.

scholarly journals Catching the big picture of the Mediterranean Sea biodiversity with an end-to-end model of climate and fishing impacts

2019 ◽  
Author(s):  
Fabien Moullec ◽  
Laure Velez ◽  
Philippe Verley ◽  
Nicolas Barrier ◽  
Caroline Ulses ◽  
...  
Keyword(s):  
Global Change ◽  
Mediterranean Sea ◽  
Current Knowledge ◽  
Trophic Levels ◽  
Integrated Modelling ◽  
Marine Biodiversity ◽  
Large Spatial Scale ◽  
Management Actions ◽  
End To End ◽  
The Mediterranean

AbstractThe Mediterranean Sea is among the main hotspots of marine biodiversity in the world. Under combined pressures of fishing activities and climate change it has also become a hotspot of global change, with increased concern about the worsening status of marine exploited species. More integrated modelling approaches are needed to anticipate global change impacts in the Mediterranean Sea, in order to help decision makers prioritizing management actions and strategies, mitigating impacts and adapting to changes. Our challenge was to develop a holistic model of the marine biodiversity in the Mediterranean Sea with an explicit representation of the spatial multispecies dynamics of exploited resources under the combined influence of climate variability and fishing pressure. An individual-based ecosystem model OSMOSE (Object-oriented Simulator of Marine ecOSystEms), including 100 marine species (fish, cephalopods and crustaceans) and representing about 95 % of the total declared catches, has been implemented for the first time at a high spatial resolution (400 km2) and at a large spatial scale (whole Mediterranean basin). The coupling of OSMOSE to the NEMOMED 12 physical model, and to the Eco3M-S biogeochemical and low trophic level model has been achieved to build the OSMOSE-MED end-to-end model. We fitted OSMOSE-MED to observed and estimated data of biomass and commercial catches using a likelihood approach and an evolutionary optimization algorithm. The outputs of OSMOSE-MED were then verified against observed biomass and catches, and confronted to independent datasets (MEDITS data, diet compositions and trophic levels). Although some improvements are suggested for future developments, the model results at different hierarchical levels, from individuals up to the ecosystem scale, were consistent with current knowledge and observations on the structure, the functioning and the dynamics of the ecosystems in the Mediterranean Sea. All the modelling steps, from the comprehensive representation of key ecological processes and feedbacks, the careful parameterization of the model, the confrontation to observed data, and the positive outcome from the validation process, allowed to strengthen the degree of realism of OSMOSE-MED and its relevance as an impact model to explore the futures of marine biodiversity under scenarios of global change, and as a tool to support the implementation of ecosystem-based fisheries management in the Mediterranean Sea.

scholarly journals CO<sub>2</sub> exchange in a temperate marginal sea of the Mediterranean Sea: processes and carbon budget

2012 ◽  
Vol 9 (8) ◽  
pp. 10331-10370
Author(s):  
G. Cossarini ◽  
S. Querin ◽  
C. Solidoro
Keyword(s):  
Carbon Cycle ◽  
Continental Shelf ◽  
Mediterranean Sea ◽  
Adriatic Sea ◽  
Biogeochemical Model ◽  
Marginal Seas ◽  
Dense Water ◽  
Water Formation ◽  
Dense Water Formation ◽  
The Mediterranean

Abstract. Marginal seas play a potentially important role in the global carbon cycle; however, due to differences in the scales of variability and dynamics, marginal seas are seldom fully accounted for in global models or estimates. Specific high-resolution studies may elucidate the role of marginal seas and assist in the compilation of a complete global budget. In this study, we investigated the air-sea exchange and the carbon cycle dynamics in a marginal sub-basin of the Mediterranean Sea (the Adriatic Sea) by adopting a coupled transport-biogeochemical model of intermediate complexity including carbonate dynamics. The Adriatic Sea is a highly productive area owed to riverine fertilisation and is a site of intense dense water formation both on the northern continental shelf and in the southern sub-basin. Therefore, the study area may be an important site of CO2 sequestration in the Mediterranean Sea. The results of the model simulation show that the Adriatic Sea, as a whole, is a CO2 sink with a mean annual flux of 36 mg m−2 day−1. The northern part absorbs more carbon (68 mg m−2 day−1) due to an efficient continental shelf pump process, whereas the southern part behaves similar to an open ocean. Nonetheless, the Southern Adriatic Sea accumulates dense, southward-flowing, carbon-rich water produced on the northern shelf. During a warm year and despite an increase in aquatic primary productivity, the sequestration of atmospheric CO2 is reduced by approximately 15% due to alterations of the solubility pump and reduced dense water formation. The seasonal cycle of temperature and biological productivity modulates the efficiency of the carbon pump at the surface, whereas the intensity of winter cooling in the northern sub-basin leads to the export of C-rich dense water to the deep layer of the southern sub-basin and, subsequently, to the interior of the Mediterranean Sea.

scholarly journals Patterns in planktonic metabolism in the Mediterranean Sea

2009 ◽  
Vol 6 (4) ◽  
pp. 8569-8588
Author(s):  
A. Regaudie-de-Gioux ◽  
R. Vaquer-Sunyer ◽  
C. M. Duarte
Keyword(s):  
Mediterranean Sea ◽  
Gross Primary Production ◽  
Western Mediterranean ◽  
Community Respiration ◽  
Net Community Production ◽  
R Ratio ◽  
Heterotrophic Metabolism ◽  
The Mediterranean ◽  
Net Heterotrophy ◽  
Community Production

Abstract. Planktonic gross community production (GPP), net community production (NCP) and community respiration (CR) across the Mediterranean Sea was examined in two cruises, THRESHOLDS 2006 and 2007, each crossing the Mediterranean from West to East to test for consistent variation along this longitudinal gradient. GPP averaged 2.4±0.4 mmol O2m−3 d−1, CR averaged 3.8±0.5 mmol O2m−3 d−1, and NCP averaged -0.8&amp;plusmn0.6 mmol O2m−3 d−1across the studied sections, indicative of a tendency for a net heterotrophic metabolism, prevalent across studied sections of the Mediterranean Sea as reflected in 70% of negative NCP estimates. The median P/R ratio was 0.58, also indicating a strong prevalence of heterotrophic communities (P/R<1) along the studied sections of the Mediterranean Sea. The communities tended to be net heterotrophic (i.e. P/R<1) at GPP less than 3.5 mmol O2m−3 d−1. Although the Western Mediterranean supports a higher gross primary production than the Eastern basin does, it also supported a higher community respiration. The net heterotrophy nature of the studied sections of the Mediterranean Sea indicates that allochthonous carbon should be important to subsidise planktonic metabolism, and that the planktonic communities in the Mediterranean Sea acted as CO2 sources to the atmosphere during the study.

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