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.

scholarly journals On the mesoscale monitoring capability of Argo floats in the Mediterranean Sea

2016 ◽  
Author(s):  
Antonio Sánchez-Román ◽  
Simón Ruiz ◽  
Ananda Pascual ◽  
Baptiste Mourre ◽  
Stéphanie Guinehut
Keyword(s):  
Mediterranean Sea ◽  
Large Scale ◽  
Spatial Scales ◽  
Altimeter Data ◽  
Simulation Experiments ◽  
Argo Data ◽  
Sea Level Anomalies ◽  
The Mediterranean ◽  
Observing System Simulation Experiment ◽  
Initial Objective

Abstract. In this work an Observing System Simulation Experiment (OSSE) approach is used to investigate the Argo array spatial sampling necessary in the Mediterranean Sea to recover the mesoscale signal as seen by altimetry. The monitoring of the mesoscale features is not an initial objective of the Argo network. However, it is an interesting question in the perspective of future network extensions in order to improve the ocean state estimates. A quality assessment of the performances of the altimeter product is carried out to quantify the differences between Argo and altimetry needed to conduct the simulation experiments. The method used here to evaluate the altimeter data is based on the comparison of Sea Level Anomalies (SLA) from altimetry and Dynamic Height Anomalies (DHA) referred to both 400 and 900 dbar computed from the in-situ Argo network. A standard deviation of the differences between SLA and DHA of 4.92 cm is obtained when comparing altimetry and Argo data referred to 400 dbar. The simulation experiments show that a configuration similar to the current Argo array in the Mediterranean (with a spatial resolution of 2° × 2°) is only able to recover the large-scale signals of the basin. On the contrary, the SLA field reconstructed from a 0.75° x 0.75° Argo network can retrieve most of the mesoscale signal. Such an Argo array of around 450 floats in the Mediterranean Sea would be enough to recover the SLA field with an RMSE of 3 cm for spatial scales higher than 150 km, similar to those captured by the altimetry.

scholarly journals Parallel pattern of differentiation at a genomic island shared between clinal and mosaic hybrid zones in a complex of cryptic seahorse lineages

2017 ◽  
Author(s):  
Florentine Riquet ◽  
Cathy Liautard-Haag ◽  
Lucy Woodall ◽  
Carmen Bouza ◽  
Patrick Louisy ◽  
...  
Keyword(s):  
Reproductive Isolation ◽  
Mediterranean Sea ◽  
Genomic Island ◽  
Spatial Scales ◽  
Hybrid Zones ◽  
Single Chromosome ◽  
Marine Habitats ◽  
Habitat Variation ◽  
The Mediterranean ◽  
Mosaic Distribution

AbstractDiverging semi-isolated lineages either meet in narrow clinal hybrid zones, or have a mosaic distribution associated with environmental variation. Intrinsic reproductive isolation is often emphasized in the former and local adaptation in the latter, although both can contribute to isolation. Rarely these two patterns of spatial distribution are reported in the same study system. Here we report that the long-snouted seahorse Hippocampus guttulatus is subdivided into discrete panmictic entities by both types of hybrid zones. Along the European Atlantic coasts, a northern and a southern lineage meet in the southwest of France where they coexist in sympatry with little hybridization. In the Mediterranean Sea, two lineages have a mosaic distribution, associated with lagoon-like and marine habitats. A fifth lineage was identified in the Black Sea. Genetic homogeneity over large spatial scales contrasts with isolation maintained in sympatry or close parapatry at a fine scale. A high variation in locus-specific introgression rates provides additional evidence that partial reproductive isolation must be maintaining the divergence. Surprisingly, fixed differences between lagoon and marine populations in the Mediterranean Sea belong to the most differentiated SNPs between the two Atlantic lineages, against the genome-wide pattern of structure. These parallel outlier SNPs cluster on a single chromosome-wide island of differentiation. Since Atlantic lineages do not match the lagoon-sea habitat variation, genetic parallelism at the genomic island suggests a shared genetic barrier contributes to reproductive isolation in contrasting contexts -i.e. spatial vs. ecological. We discuss how a genomic hotspot of parallel differentiation could have evolved and become associated either with space or with a patchy environment in a single study system.

scholarly journals Hydrodynamic controls on connectivity of the high commercial value shrimp Parapenaeus longirostris (Lucas, 1846) in the Mediterranean Sea

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Giovanni Quattrocchi ◽  
Matteo Sinerchia ◽  
Francesco Colloca ◽  
Fabio Fiorentino ◽  
Germana Garofalo ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Current Knowledge ◽  
Stock Assessment ◽  
Spatial Scales ◽  
Management Plan ◽  
Nursery Areas ◽  
The North ◽  
North Side ◽  
Parapenaeus Longirostris ◽  
The Mediterranean

AbstractIn the Strait of Sicily (SoS), a wide passage of the Mediterranean Sea, Parapenaeus longirostris, (Lucas, 1846; DPS hereafter) is the main target species of trawl fisheries, with an estimated annual market value of about 80 million euro. The exploitation of this resource is shared between Italian, Tunisian and Maltese bottom trawlers and its management raises social, economic and environmental interests. Recent stock assessment revealed high fishing mortalities and low size at first capture, thus promoting the adoption of a strategic plan for a sustainable management. However, the current knowledge of the geographical boundaries of the stock, supporting  the implementation of such management plan is still poor. In this respect, under different hydrodynamic regimes, particle-tracking modelling was used to explore connectivity between both, known and unexplored, spawning and nursery areas of DPS in the SoS. Ensembles scenarios derived by model outcomes displayed decadal changes in connectivity between spawning and nursery areas in the north side of the SoS, hence confirming the presence of a single stock in this area. Expanding the area of investigation, the model results showed weak connectivity between spawning ground in the north side of SoS and nurseries on the African shelf-break. This method could support the spatial management of the stock, such as the protection of the nursery and spawning areas, by providing estimates of how connectivity is influenced by hydrodynamic regimes at different temporal and spatial scales.

scholarly journals Deep-water fish assemblages in the Mediterranean Sea

2004 ◽  
Vol 68 (S3) ◽  
pp. 87-99 ◽  
Author(s):  
Gianfranco D'Onghia ◽  
Chrissi Yianna Politou ◽  
Anna Bozzano ◽  
Domingo Lloris ◽  
Guiomar Rotllant ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Deep Water ◽  
Fish Assemblages ◽  
Water Fish ◽  
The Mediterranean

Can mineralogical features affect the distribution patterns of sessile gastropods? The Vermetidae case in the Mediterranean Sea

2003 ◽  
Vol 83 (6) ◽  
pp. 1267-1268 ◽  
Author(s):  
S. Schiaparelli ◽  
P. Guidetti ◽  
R. Cattaneo-Vietti
Keyword(s):  
Spatial Distribution ◽  
Mediterranean Sea ◽  
Rock Type ◽  
Spatial Scales ◽  
Distribution Patterns ◽  
Spatial Distribution Patterns ◽  
Rocky Substrate ◽  
North Eastern ◽  
The Mediterranean

Spatial distribution patterns of two sessile gastropods belonging to Vermetidae, Vermetus triquetrus and Dendropoma petraeum, were studied in June 2001 in north-eastern Sardinia (Mediterranean Sea, Italy). Density of individuals was assessed within quadrats positioned on a shallow (0·1–1 m depth) rocky substrate of different lithological types (limestone and granite), at a hierarchy of spatial scales. Density of D. petraeum is significantly greater on granite than on limestone, while V. triquetrus does not show any differences related to rock type.

Modelling alpha-diversities of coastal lagoon fish assemblages from the Mediterranean Sea

2018 ◽  
Vol 165 ◽  
pp. 100-109 ◽  
Author(s):  
R. Riera ◽  
V.M. Tuset ◽  
R. Betancur-R ◽  
A. Lombarte ◽  
C. Marcos ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Coastal Lagoon ◽  
Fish Assemblages ◽  
The Mediterranean

scholarly journals On the mesoscale monitoring capability of Argo floats in the Mediterranean Sea

Ocean Science ◽  
2017 ◽  
Vol 13 (2) ◽  
pp. 223-234 ◽  
Author(s):  
Antonio Sánchez-Román ◽  
Simón Ruiz ◽  
Ananda Pascual ◽  
Baptiste Mourre ◽  
Stéphanie Guinehut
Keyword(s):  
Mediterranean Sea ◽  
Spatial Resolution ◽  
Large Scale ◽  
Spatial Scales ◽  
Mesoscale Dynamics ◽  
Sea Level Anomalies ◽  
Network Cost ◽  
The Mediterranean ◽  
Observing System Simulation Experiment ◽  
Initial Objective

Abstract. In this work a simplified observing system simulation experiment (OSSE) approach is used to investigate which Argo design sampling in the Mediterranean Sea would be necessary to properly capture the mesoscale dynamics in this basin. The monitoring of the mesoscale features is not an initial objective of the Argo network. However, it is an interesting question from the perspective of future network extensions in order to improve the ocean state estimates. The true field used to conduct the OSSEs is provided by a specific altimetry-gridded merged product for the Mediterranean Sea. Synthetic observations were obtained by sub-sampling this Nature Run according to different configurations of the ARGO network. The observation errors required to perform the OSSEs were obtained through the comparison of sea level anomalies (SLAs) from altimetry and dynamic height anomalies (DHAs) computed from the real in situ Argo network. This analysis also contributes to validate satellite SLAs with an increased confidence. The simulation experiments show that a configuration similar to the current Argo array in the Mediterranean (with a spatial resolution of 2°  ×  2°) is only able to recover the large-scale signals of the basin. Increasing the spatial resolution to nearly 75 km  ×  75 km, allows the capture of most of the mesoscale signal in the basin and to retrieve the SLA field with a RMSE of 3 cm for spatial scales larger than 150 km, similar to those presently captured by the altimetry. This would represent a theoretical reduction of 40 % of the actual RMSE. Such a high-resolution Argo array composed of around 450 floats, cycling every 10 days, is expected to increase the actual network cost by approximately a factor of 6.

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 Hydrological Cycle of the Mediterranean-Black Sea System

2021 ◽  
Author(s):  
David García-García ◽  
Isabel M. Vigo ◽  
Mario Trottini ◽  
Juan A. Vargas ◽  
Juan-Manuel Sayol
Keyword(s):  
Atlantic Ocean ◽  
Mediterranean Sea ◽  
Black Sea ◽  
Hydrological Cycle ◽  
Global Climate ◽  
Water Flux ◽  
Meridional Overturning Circulation ◽  
Water Volume ◽  
The Black Sea ◽  
The Mediterranean

Abstract The Mediterranean-Black Sea system consists of two semi-enclosed basins connected by the Turkish Straits. In turn, the Mediterranean Sea is connected to the Atlantic Ocean through the narrow Strait of Gibraltar. The hydrological cycle of the system is driven by fresh water exchanges between the atmosphere, continents and oceans, and by salty water mass exchange among the ocean basins. Monitoring such water fluxes, especially its time evolution, is essential to understand the water cycle in the region, which is very sensitive to global climate changes and influences the variability of the Atlantic Meridional Overturning Circulation (AMOC), which in turn affects the global climate. In this study, we have estimated the hydrological cycle of the Mediterranean-Black Sea system from the time-variable gravity observations performed by the Gravity Recovery and Climate Experiment (GRACE) and GRACE Follow-On satellites, and precipitation and evaporation from ERA5 atmospheric reanalysis data for the period 2002-2020. In the Black Sea, rivers introduce an average water volume of 391±12 km3/year, one third of which escape through the atmosphere and two thirds go to the Mediterranean Sea. In the latter, 1787 ± 23 km3/year are lost via net evaporation. The rivers runoff (502 ± 27 km3/year), and the inflow of Atlantic waters (1020 ± 56 km3/year; 0.0323 ± 0.0018 Sv), finally restore the Mediterranean water budget. The balance is not reached instantaneously, and this delay introduces a seasonal variability in all the fluxes. In particular, the net water flux from the Atlantic Ocean increases up to 2660 ± 111 km3/year in August/September, and reverses to – 407 ± 140 km3/year in April/May. On top of the climatology, the mean annual Atlantic water flux varies significantly between 706 and 1262 km3/year.

scholarly journals Nematode diversity patterns at different spatial scales in bathyal sediments of the Mediterranean Sea

2013 ◽  
Vol 10 (8) ◽  
pp. 5465-5479 ◽  
Author(s):  
S. Bianchelli ◽  
C. Gambi ◽  
M. Mea ◽  
A. Pusceddu ◽  
R. Danovaro
Keyword(s):  
Mediterranean Sea ◽  
Deep Sea ◽  
Spatial Scales ◽  
High Turnover ◽  
Trophic Conditions ◽  
Bathymetric Range ◽  
Β Diversity ◽  
Α Diversity ◽  
Nematode Diversity ◽  
The Mediterranean

Abstract. Understanding biodiversity patterns and how they are driven at different spatial scales is a crucial issue in ecological studies. This is particularly evident for the deep sea, the largest biome of the biosphere, where information on the scales of spatial variation is very scant. Here, we investigated deep-sea nematodes species richness, turnover and functional diversity, and life strategies at different spatial scales (from local to macro-regional) to identify the factors that shape regional (γ) and macro-regional (ε) deep-sea diversity. This study was conducted in several deep-sea habitats (canyons, open slopes, deep-water corals, and bathyal plains) over > 2000 km across the whole Mediterranean Basin, at a bathymetric range comprised between ca. 600 and 1300 m. Our results indicate that the patterns of local (α) diversity across the deep Mediterranean follow the gradients of the trophic conditions, which decrease from the western to the eastern basins. For all of the sites and habitats, the α diversity is generally low. Conversely, the turnover diversity changes significantly among habitats (β diversity) and between regions (δ diversity), showing values of dissimilarity (based on species presence/absence matrixes) between 59 and 90% for β diversity and between 81 and 89% for δ diversity. This suggests that patterns and values of γ and ε diversities in the deep Mediterranean Sea are related to turnover diversity among habitats and between regions (β and δ diversities), rather than to the local biodiversity (α diversity). These results indicate also that the differences in β and δ diversities are even more important than those in α diversity for the comprehension of the drivers of biodiversity in the deep Mediterranean Sea. We conclude that the presence of different habitats and gradients in environmental conditions, by promoting a high turnover diversity across the Mediterranean Sea, may play a crucial role in the levels of γ diversity of deep-sea nematodes.

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