scholarly journals ​Impact of changes in rivers inputs during the last decades on the biogeochemistry of the eastern Mediterranean basin

2020 ◽  
Author(s):  
Rémi Pagès ◽  
Melika Baklouti ◽  
Nicloas Barrier ◽  
Camille Richon ◽  
Jean-Claude Dutay ◽  
...  
Keyword(s):  
Surface Layer ◽  
Mediterranean Sea ◽  
Mediterranean Basin ◽  
Large Scale ◽  
Eastern Mediterranean ◽  
Phosphate Availability ◽  
Eastern Mediterranean Basin ◽  
The Mediterranean ◽  
Long Term Impact ◽  
First Time

<p>The Mediterranean Sea (MS) is a semi-enclosed sea characterized by a zonal west-east gradient of oligotrophy, where microbial growth is controlled by phosphate availability in most situations. External inputs of nutrients including Gibraltar inputs, river inputs and atmospheric deposition are therefore of major importance for the biogeochemistry of the MS. The latter has long been considered to be driven mainly by nutrient exchanges at Gibraltar. However, recent studies indicate that river inputs significantly affect nutrients concentrations in the Mediterranean Sea, although their resulting impact on its biogeochemistry remains poorly understood. In this study, our aim was to help fill this knowledge gap by addressing the large-scale and long-term impact of variations in river inputs on the biogeochemistry of the Mediterranean Sea over the last decades, using a coupled physical- biogeochemical 3D model (NEMO-MED12/Eco3M-Med). As a first result, it has been shown by the model that the strong diminution (60%) of phosphate (PO4) in river inputs into the Mediterranean Sea since the end of the 1980s induced a significant lowering of PO4 availability in the sub-surface layer of the Eastern Mediterranean Basin (EMB). One of the main consequences of PO4 diminution is the rise, never previously documented, of dissolved organic carbon (DOC) concentrations in the surface layer (by 20% on average over the EMB). Another main result concerns the gradual deepening of the top of the phosphacline during the period studied, thus generating a shift between the top of the nitracline and the top of the phosphacline in the EMB. This shift has already been observed in situ and documented in literature, but we propose here a new explanation for its occurrence in the EMB. The last main result is the evidence of the decline in abundance and the reduction of size of copepods calculated by the model over the years 1985–2010, that could partially explain the reduction in size of anchovy and sardine recently recorded in the MS. In this study, it is shown for the first time that the variations in river inputs that occurred in the last decades may have significantly altered the biogeochemical cycles of two key elements (P and C), in particular in the EMB.</p>

scholarly journals On the Finding of the Rare Crab Paragalene longicrura (Nardo, 1868) (Crustacea, Decapoda, Brachyura, Progeryonidae) from Thermaikos Gulf, Northwest Aegean Sea, Greece

Fishes ◽  
2018 ◽  
Vol 3 (3) ◽  
pp. 30 ◽  
Author(s):  
Thodoros Kampouris ◽  
Debora Milenkova ◽  
Ioannis Batjakas
Keyword(s):  
Mediterranean Basin ◽  
Eastern Mediterranean ◽  
Aegean Sea ◽  
Eastern Mediterranean Basin ◽  
The Mediterranean ◽  
First Time

The finding of a rare crab, Paragalene longicrura, is herein recorded from Thermaikos Gulf. This constitutes the northmost record of the species in Greek waters. The species is only known from sporadic records in the eastern Mediterranean basin. Ecological remarks on the habitat of P. longicrura and other decapod species are described for the first time for the Mediterranean.

scholarly journals Satellite Observations of the Seasonal Evolution of Total Precipitable Water Vapour over the Mediterranean Sea

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
J. L. Palau ◽  
F. Rovira ◽  
M. J. Sales
Keyword(s):  
Mediterranean Sea ◽  
Mediterranean Basin ◽  
Eastern Mediterranean ◽  
Precipitable Water ◽  
Satellite Observations ◽  
Annual Variability ◽  
Total Precipitable Water ◽  
New Findings ◽  
Precipitation Regimes ◽  
The Mediterranean

This study shows satellite observations and new findings on the time and spatial distribution of the Total Precipitable Water (TPW) column over the Mediterranean Sea throughout the year. Annual evolution and seasonality of the TPW column are shown and compared to the estimated net evaporation over the Mediterranean Sea. Daily spatiotemporal means are in good agreement with previous short-term field campaigns and also corroborate hypothesis and conclusions reached from previous mesoscale modelling studies: (a) from a meteorological point of view, Mediterranean Basin should be considered as two different subbasins (the Western and the Eastern Mediterranean); (b) accumulation processes may affect the radiative balance at regional scale and the summer precipitation regimes. Furthermore, these satellite observations constitute strong empirical evidences that, (a) from late May to early October, contrary to what happens in the Eastern Mediterranean Basin (EMB), there is a net accumulation of TPW on the Western Mediterranean Basin (WMB) that favours the instability of the atmosphere, (b) there is a seasonal anticorrelation between the seasonal variability of the TPW column over the two Mediterranean subbasins, (c) solar radiation can not be the only driver for the annual variability of the TPW column over the Mediterranean Sea, and (d) both previous features are seasonally dependent and, therefore, their effects on the TPW column are attenuated by annual variability.

scholarly journals Tritonia nilsodhneri Marcus Ev., 1983 (Gastropoda, Heterobranchia, Tritoniidae)

2017 ◽  
Vol 58 (2) ◽  
pp. 261-269 ◽  
Author(s):  
Giulia Furfaro ◽  
Egidio Trainito ◽  
Franco De Lorenzi ◽  
Marco Fantin ◽  
Mauro Doneddu
Keyword(s):  
Host Species ◽  
Mediterranean Basin ◽  
Eastern Mediterranean ◽  
Feeding Habits ◽  
New Host ◽  
Host Preferences ◽  
Mediterranean Populations ◽  
Eastern Atlantic Ocean ◽  
Eastern Mediterranean Basin ◽  
The Mediterranean

The nudibranch Tritonia nilsodhneri, usually feeding on a variety of gorgoniacean species, is known from different localities of the eastern Atlantic Ocean and the Mediterranean Sea. Knowledge of the host preferences of the Mediterranean populations is still scarce. Few records of this nudibranch have been reported from the eastern Mediterranean basin. With this report, the occurrence of T. nilsodhneri within the Mediterranean basin is extended to the Adriatic Sea. Furthermore, the list of the host species associated to the Mediterranean populations for feeding habits is increased from two up to five. Mediterranean specimens of T. nilsodhneri were observed for the first time feeding and spawning on Leptogorgia sarmentosa, Eunicella cavolini and E. labiata. Finally, these last two Gorgoniidae species are also reported here as a new host species for T. nilsodhneri.

scholarly journals Precipitation climatology over Mediterranean Basin from ten years of TRMM measurements

2008 ◽  
Vol 17 ◽  
pp. 87-91 ◽  
Author(s):  
A. V. Mehta ◽  
S. Yang
Keyword(s):  
Mediterranean Sea ◽  
Rainy Season ◽  
Mediterranean Region ◽  
Large Scale ◽  
Eastern Mediterranean ◽  
Tropical Rainfall Measuring Mission ◽  
Western Mediterranean ◽  
Sea Temperature ◽  
Maximum Rainfall ◽  
The Mediterranean

Abstract. Climatological features of mesoscale rain activities over the Mediterranean region between 5° W–40° E and 28° N–48° N are examined using the Tropical Rainfall Measuring Mission (TRMM) 3B42 and 2A25 rain products. The 3B42 rainrates at 3-hourly, 0.25°×0.25° spatial resolution for the last 10 years (January 1998 to July 2007) are used to form and analyze the 5-day mean and monthly mean climatology of rainfall. Results show considerable regional and seasonal differences of rainfall over the Mediterranean Region. The maximum rainfall (3–5 mm day−1) occurs over the mountain regions of Europe, while the minimum rainfall is observed over North Africa (~0.5 mm day−1). The main rainy season over the Mediterranean Sea extends from October to March, with maximum rainfall occurring during November–December. Over the Mediterranean Sea, an average rainrate of ~1–2 mm day−1 is observed, but during the rainy season there is 20% larger rainfall over the western Mediterranean Sea than that over the eastern Mediterranean Sea. During the rainy season, mesoscale rain systems generally propagate from west to east and from north to south over the Mediterranean region, likely to be associated with Mediterranean cyclonic disturbances resulting from interactions among large-scale circulation, orography, and land-sea temperature contrast.

scholarly journals Diversity and Distribution of the Dinoflagellates Brachidinium, Asterodinium and Microceratium (Brachidiniales, Dinophyceae) in the open Mediterranean Sea

2011 ◽  
Vol 70 (2) ◽  
pp. 209-214 ◽  
Author(s):  
Fernando Gómez
Keyword(s):  
Mediterranean Sea ◽  
Eastern Mediterranean ◽  
Life Stage ◽  
Western Mediterranean ◽  
The South ◽  
Levantine Basin ◽  
First Occurrence ◽  
Local Species ◽  
The Mediterranean ◽  
First Time

Diversity and Distribution of the DinoflagellatesBrachidinium, AsterodiniumandMicroceratium(Brachidiniales, Dinophyceae) in the open Mediterranean SeaBrachidiniacean dinoflagellates have been investigated in the open waters of the Mediterranean Sea, along a transect from the south of France to the south of Cyprus (20 June-18 July 2008).BrachidiniumandKarenia papilionaceaoften co-occurred,B. capitatumpredominating in the surface waters. The highest abundance ofBrachidiniumwere found in the upper 25min the western Mediterranean with amaximum (24 cells L-1) at a depth of 5 m in the Balearic Sea.Asterodinium(up to 4 cells L-1) was recorded below of deep chlorophyll maxima. The genusMicroceratium, only known from the tropical Indo-Pacific region, is reported for the first time in the Mediterranean Sea.Microceratiumwas found below 100min the eastern Mediterranean Sea, with the highest abundance of 8 cells L-1at 125 m depth, in the Levantine Basin. This study also illustrates for the first time specimens under the division ofBrachidiniumandMicroceratium. This first occurrence ofMicroceratiumin the Mediterranean Sea should be considered an indicator of climate warming. However, it should not be considered a non-indigenous taxon.Microceratiumis the ‘tropical morphotype’, the adaptation of a local species (a life stage ofKarenia - Brachidinium - Asterodinium) to the tropical environmental conditions that prevail in summer in the open Mediterranean Sea.

scholarly journals Evidence of a prolonged drought ca. 4200 yr BP correlated with prehistoric settlement abandonment from the Gueldaman GLD1 Cave, Northern Algeria

2016 ◽  
Vol 12 (1) ◽  
pp. 1-14 ◽  
Author(s):  
J. Ruan ◽  
F. Kherbouche ◽  
D. Genty ◽  
D. Blamart ◽  
H. Cheng ◽  
...  
Keyword(s):  
Mediterranean Basin ◽  
Eastern Mediterranean ◽  
Western Mediterranean ◽  
Faunal Remains ◽  
Carbon And Oxygen Isotopes ◽  
Northern Algeria ◽  
Western Mediterranean Basin ◽  
Prolonged Drought ◽  
Eastern Mediterranean Basin ◽  
The Mediterranean

Abstract. Middle Holocene cultures have been widely studied around the Eastern-Mediterranean basin in the last 30 years and past cultural activities have been commonly linked with regional climate changes. However, in many cases such linkage is equivocal, in part due to existing climatic evidence that has been derived from areas outside the distribution of ancient settlements, leading to uncertainty from complex spatial heterogeneity in both climate and demography. A few high-resolution well-dated paleoclimate records were recently established using speleothems in the Central and Eastern-Mediterranean basin, however, the scarcity of such records in the western part of the Mediterranean prevents us from correlating past climate evolutions across the basin and deciphering climate–culture relation at fine timescales. Here we report the first decadal-resolved Mid-Holocene climate proxy records from the Western-Mediterranean basin based on the stable carbon and oxygen isotopes analyses of two U/Th dated stalagmites from the Gueldaman GLD1 Cave in Northern Algeria. Comparison of our records with those from Italy and Israel reveals synchronous (multi) centennial dry phases centered at ca. 5600, ca. 5200 and ca. 4200 yr BP across the Mediterranean basin. New calibrated radiocarbon dating constrains reasonably well the age of rich anthropogenic deposits (e.g., faunal remains, pottery, charcoal) excavated inside the cave, which allows the comparison between in situ evidence of human occupation and of climate change. This approach shows that the timing of a prolonged drought at ca. 4400–3800 yr BP blankets the onset of cave abandonment shortly after ca. 4403 cal yr BP, supporting the hypothesis that a climate anomaly may have played a role in this cultural disruption.

scholarly journals Intercomparison of intense cyclogenesis events over the Mediterranean basin based on baroclinic and diabatic influences

2006 ◽  
Vol 7 ◽  
pp. 333-342 ◽  
Author(s):  
Ll. Fita ◽  
R. Romero ◽  
C. Ramis
Keyword(s):  
Mediterranean Sea ◽  
Mediterranean Basin ◽  
Numerical Study ◽  
Eastern Mediterranean ◽  
Geographical Area ◽  
Relative Weight ◽  
High Impact ◽  
The Mediterranean ◽  
The Mediterranean Basin

Abstract. A large number of high impact cyclones all over the Mediterranean basin have been reported on the data base of the MEDEX project (http://medex.inm.uib.es). A numerical study on the impacts and interactions of baroclinic and diabatic factors is carried out through a PV-based system of prognostic equations for 11 intense MEDEX cyclone episodes occurred in different zones of the basin (Western, Central and Eastern Mediterranean). The main aim of the study is to investigate the possible similarities and differences among the selected cases of the relative weight of the considered cyclogenetic factors on the cyclone evolutions as function of cyclone type and geographical area. A crucial role of the baroclinicity over the Mediterranean zone is obtained in most of the cases. A certain distinction can be also established in terms of the cyclogenesis areas (Africa, Mediterranean Sea, and Alpine region), and between west-central and eastern Mediterranean basins. It is generally observed that the considered baroclinic and diabatic factors cooperate most strongly for the cyclone deepening process when the disturbance reaches the Mediterranean sea.

scholarly journals Spring distribution of shelled pteropods across the Mediterranean Sea

2020 ◽  
Author(s):  
Roberta Johnson ◽  
Clara Manno ◽  
Patrizia Ziveri
Keyword(s):  
Climate Change ◽  
Mediterranean Sea ◽  
Eastern Mediterranean ◽  
Hot Spot ◽  
Environmental Parameters ◽  
Saturation State ◽  
Eastern Mediterranean Sea ◽  
The Mediterranean ◽  
First Time ◽  
Natural Laboratory

Abstract. Shelled pteropods represent an excellent sentinel for indicating exposure to ocean acidification (OA). Here, for the first time, we characterise spring pteropod distribution throughout the Mediterranean Sea, a region that has been identified as a climate change hot-spot. The presence of a west–east natural biogeochemical gradient makes this region a natural laboratory to investigate how the variability in environmental parameters may affect pteropod distribution. Results show that pteropod abundance is significantly higher in the eastern Mediterranean Sea where there is a higher aragonite saturation state (Ωar), showing that distribution is positively correlated with Ωar. We also observed a resilience of pteropods to higher temperatures and low nutrient conditions, including phosphorous limitation. The higher abundance of pteropods in ultra-oligotrophic conditions (eastern Mediterranean Sea) suggests that this organism can play an important role as the prime calcifying zooplankton within specific oligotrophic regions.

scholarly journals Hydrographic situation during cruise M84/3 and P414 (spring 2011) in the Mediterranean Sea

2013 ◽  
Vol 10 (6) ◽  
pp. 2399-2432 ◽  
Author(s):  
D. Hainbucher ◽  
A. Rubino ◽  
V. Cardin ◽  
T. Tanhua ◽  
K. Schroeder ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Large Scale ◽  
Water Mass ◽  
Eastern Mediterranean ◽  
Physical Parameters ◽  
Strait Of Gibraltar ◽  
Mass Properties ◽  
The Mediterranean ◽  
Geostrophic Velocities ◽  
Lebanese Coast

Abstract. Hydrography and large scale circulation observed in the Mediterranean Sea during the M84/3 and P414 cruises (April and June 2011, respectively) are presented. In contrast to most of the recent expeditions, which were limited to special areas of the basin, these two cruises, especially the M84/3, offered the opportunity of delineating a quasi-synoptic picture of the distribution of the relevant physical parameters through the whole Mediterranean. A section was observed from the Lebanese coast up to the Strait of Gibraltar. The focus of our analysis are the water mass properties, also in the context of the recently observed variability, and a comparison between the velocity fields observed using a vessel-mounted ADCP and those calculated from the observed density fields. Overall, a distribution of temperature, salinity, and geostrophic velocities emerges, which seems far from that observed before the beginning of the so-called "Eastern Mediterranean Transient", a major climatic shift in the hydrography and circulation of the Mediterranean Sea occurred at the end of 1980s. Here, our focus is a discussion of the observed water mass properties analysed through T–S diagrams and through an Optimum Multiparameter (OMP) analysis. Additionally, ADCP velocities are compared to geostrophic calculations.

scholarly journals New records of amphipod crustaceans along the Israeli Mediterranean coast, including a rare Mediterranean endemic species, Maera schieckei Karaman & Ruffo, 1971

2020 ◽  
Vol 8 ◽  
Author(s):  
Sabrina Lo Brutto ◽  
Davide Iaciofano
Keyword(s):  
Mediterranean Sea ◽  
Mediterranean Basin ◽  
Eastern Mediterranean ◽  
Aegean Sea ◽  
Western Mediterranean ◽  
Mediterranean Coast ◽  
Tyrrhenian Sea ◽  
Western Mediterranean Basin ◽  
The Mediterranean ◽  
Distribution And Ecology

A survey has been carried out at four Israeli rocky sites to evaluate the diversity of the amphipod fauna on various hard substrates, still scarcely monitored, as potential pabulum for amphipod crustacean species. A survey of shallow rocky reefs along the Mediterranean coast of Israel recovered 28 species and integrated the Amphipoda checklist for the country ofIsrael with 12 newly-recorded species. Such renewed national list includes Maera schieckei Karaman & Ruffo, 1971, a rare species endemic to the Mediterranean Sea, recorded here for the first time from the southern Levant Basin. The species, described from specimens collected in the Tyrrhenian Sea in 1970, has been only recorded eight times within the whole Mediterranean Sea. A revision of the bibliography on the distribution and ecology of M. schieckei showed that, although mentioned only for the western Mediterranean basin by some authors, it is listed in the checklist of amphipods of the Aegean Sea and neighbouring seas and has been found in the eastern Mediterranean basin since 1978. Maera schieckei was rarely found in the Mediterranean, one of the most studied marine biogeographic region as concerns the amphipod fauna; and the species seems to prefer bays or gulf areas. The role of updating and monitoring faunal composition should be re-evaluated.

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