Aggregation dynamics and foraging behaviour of striped red mullet Mullus surmuletus in the western Mediterranean Sea

Habitat-related heterogeneity of striped red mullet Mullus surmuletus heterospecific foraging assemblages was examined off the coast of Spain. Video-based focal-follows conducted on 122 M. surmuletus assemblages (446 total individuals) revealed an array of attendant species (n = 7) with composition linked to benthic habitat complexity; bare sandy substrata were characterized by homospecific groups of M. surmuletus, while habitats with rock and vegetation attracted a variety of scrounging labrids and sparids. Although the nature of the relationship between M. surmuletus and attendants requires further exploration, the present study indicates that substratum composition can be a driving factor explaining the dynamics of this heterospecific assemblage.

Cyclically-arranged, storm-controlled, prograding lithosomes in Messinian terrigenous shelves (Bajo Segura Basin, western Mediterranean)

This work focuses on a Messinian shallow-marine terrigenous unit, termed the La Virgen Formation, which forms part of the sedimentary infill of the Bajo Segura Basin (Betic margin of the western Mediterranean). This formation was deposited during a high sea level phase prior to the onset of the Messinian Salinity Crisis. Stratigraphically, it comprises a prograding stack of sandstone lithosomes alternating with marly intervals (1st-order cyclicity). These lithosomes are characterized by a homoclinal geometry that tapers distally, and interfinger with pelagic sediments rich in planktonic and benthic microfauna (Torremendo Formation). An analysis of sedimentary facies of each lithosome reveals a repetitive succession of sandy storm beds (tempestites), occasionally amalgamated, which are separated by thin marly layers (2nd-order cyclicity). Each storm bed contains internal erosional surfaces (3rd-order cyclicity) that delimit sets of laminae. Two categories of storm beds have been differentiated. The first one includes layers formed below storm wave base (SWB), characterized by traction structures associated to unidirectional flows (scoured base, planar lamination, and parting lineation). The second category consists of layers deposited above the SWB which display typical high regime oscillatory flow structures (swaley and hummocky cross lamination). In both cases, the ichnological record is characterized by an oligotypic association of Ophiomorpha nodosa, which can be interpreted as the result of allochthonous tracemakers (crustaceans) transported during storm events together with the sediment. The benthic microfauna in the marly intervals that separate the sandstone lithosomes (1st-order cyclicity) indicates that the storm ebb surges were deposited at depths ranging from those of inner shelf settings (with Elphidium spp. and Cibicides lobatulus) to those of outer shelf (with Valvulineria complanata and Uvigerina cylindrica). At the distal end of the sandstone lithosomes, the planktonic microfauna is characterized by a high content of taxa indicative of warm-oligotrophic waters (Globigerinoides obliquus and Globigerinoides bulloideus). In contrast, in the marly intervals, the microfauna is dominated by species typical of cold-eutrophic waters (Globigerina and Neogloboquadrina). This alternation of planktic foraminiferal assemblages is interpreted as being the expression of climatic cycles, in which every episode of progradation of tempestite-dominated lithosomes corresponds to maximum insolation and warm waters, whereas episodes of marly deposition correspond to minimal insolation and cold waters. The 1st-order cyclicity recorded in the La Virgen Formation, in a context of terrigenous storm-dominated shelf, corresponds to sapropel/homogeneous marl cycles formed in a pelagic basin (Torremendo Fm). These cycles in pelagic sediments are commonplace throughout the Mediterranean during the Messinian and reflect precession orbital changes: repeated periods of maximum insolation – minimum precession (sapropels) and minimal insolation – maximum precession (homogeneous marls). The fact that the example of terrigenous unit studied herein is coetaneous with the well-developed reef complexes in the Mediterranean basins points out the importance of sediment supply in the formation of large-scale sandy lithosomes. This is a crucial aspect to understanding reservoir genesis as well as lateral stratigraphic relationships with potential seal and/or source rocks.

Amphipoda assemblages in a disturbed area (Alicante, Spain, Western Mediterranean)

The distribution and composition of Amphipoda assemblages were analysed off the coasts of Alicante (Spain, Western Mediterranean), a disturbed area affected by several co-occurring anthropogenic impacts. Although differences among sampled stations were mainly related to natural parameters, anthropogenic activities were linked with changes in amphipod assemblages. Expansion of the Port of Alicante, a sewage outfall and a high salinity brine discharge could be causing the disappearance of amphipods at stations closer to these disturbances. However, the completion of port enlargement works and mitigatory dilution of the brine discharge has led to the recovery of the amphipod assemblage. Among the natural parameters, depth determines the distribution of some of the species. While Siphonoecetes sabatieri was abundant at shallow stations, Ampelisca spp., Photis longipes, Pseudolirius kroyeri, Apherusa chiereghinii and Phtisica marina were more abundant at deeper stations. Grain size and percentage of organic matter also influenced amphipod distribution, resulting in changes in species composition and in the relative percentages of different trophic groups. Species such as Ampelisca brevicornis, Perioculodes longimanus, Urothoe hesperiae and Urothoe elegans were more abundant at stations with a high content of fine sand. Carnivorous species, mainly of the Oedicerotidae family, were more abundant at those stations with a low organic matter content, while detritivorous species were more abundant at stations with a higher mud content. Among 62 identified species, three were reported for the first time from the Spanish Mediterranean coast, two species were recorded for the second time and a new species of Siphonoecetes was found, Siphonoecetes (Centraloecetes) bulborostrum. These results confirm the need for further data on amphipods from the Mediterranean Spanish coast.

Steric and mass-induced sea level variations in the Mediterranean Sea revisited

The total sea level variation (SLV) is the combination of steric and mass␣induced SLV, whose exact shares are key to understanding the oceanic response to climate system changes. Total SLV can be observed by radar altimetry satellites such as TOPEX/POSEIDON and Jason 1/2. The steric SLV can be computed through temperature and salinity profiles from in situ measurements or from ocean general circulation models (OGCM), which can assimilate the said observations. The mass-induced SLV can be estimated from its time-variable gravity (TVG) signals. We revisit this problem in the Mediterranean Sea estimating the observed, steric, and mass-induced SLV, for the latter we analyze the latest TVG data set from the GRACE (Gravity Recovery and Climate Experiment) satellite mission launched in 2002, which is 3.5 times longer than in previous studies, with the application of a two-stage anisotropic filter to reduce the noise in high-degree and -order spherical harmonic coefficients. We confirm that the intra-annual total SLV are only produced by water mass changes, a fact explained in the literature as a result of the wind field around the Gibraltar Strait. The steric SLV estimated from the residual of “altimetry minus GRACE” agrees in phase with that estimated from OGCMs and in situ measurements, although showing a higher amplitude. The net water fluxes through both the straits of Gibraltar and Sicily have also been estimated accordingly.

On the steric and mass-induced contributions to the annual sea level variations in the Mediterranean Sea

The sea level variation (SLVtotal) is the sum of two major contributions: steric and mass-induced. The steric SLVsteric is that resulting from the thermal and salinity changes in a given water column. It only involves volume change, hence has no gravitational effect. The mass-induced SLVmass, on the other hand, arises from adding or subtracting water mass to or from the water column and has direct gravitational signature. We examine the closure of the seasonal SLV budget and estimate the relative importance of the two contributions in the Mediterranean Sea as a function of time. We use ocean altimetry data (from TOPEX/Poseidon, Jason 1, ERS, and ENVISAT missions) to estimate SLVtotal, temperature, and salinity data (from the Estimating the Circulation and Climate of the Ocean ocean model) to estimate SLVsteric, and time variable gravity data (from Gravity Recovery and Climate Experiment (GRACE) Project, April 2002 to July 2004) to estimate SLVmass. We find that the annual cycle of SLVtotal in the Mediterranean is mainly driven by SLVsteric but moderately offset by SLVmass. The agreement between the seasonal SLVmass estimations from SLVtotal – SLVsteric and from GRACE is quite remarkable; the annual cycle reaches the maximum value in mid-February, almost half a cycle later than SLVtotal or SLVsteric, which peak by mid-October and mid-September, respectively. Thus, when sea level is rising (falling), the Mediterranean Sea is actually losing (gaining) mass. Furthermore, as SLVmass is balanced by vertical (precipitation minus evaporation, P–E) and horizontal (exchange of water with the Atlantic, Black Sea, and river runoff) mass fluxes, we compared it with the P–E determined from meteorological data to estimate the annual cycle of the horizontal flux.

Reply to comment by L. Fenoglio-Marc et al. on “On the steric and mass-induced contributions to the annual sea level variations in the Mediterranean Sea”

Reply to comment by L. Fenoglio-Marc et al. on “On the steric and mass-induced contributions to the annual sea level variations in the Mediterranean Sea”.

Tectono-sedimentary evolution of the ’Numidian Formation’ and Lateral Facies (southern branch of the western Tethys): constraints for central-western Mediterranean geodynamics

The origin of the Numidian Formation (latest Oligocene to middle Miocene), characterized by ultra-mature quartzose arenites with abundant well-rounded frosted quartz grains, remains controversial. This formation, sedimented in the external domain of the Maghrebian Flysch Basin, displays three characteristic stratigraphic members with marked longitudinal (proximal–distal) and transverse (along-chain) variations with palaeogeographical importance. The origin of the Numidian supply is related to the outward tectogenetic propagation when a forebulge evolved in the African foreland, leading to the erosion of African cratonic areas rich in quartzose arenites (Nubian Sandstone-like). The ages of the Numidian Formation checked by Betic, Maghrebian and Southern Apennine data suggest a timing for the accretionary orogenic wedge, earlier in the Betic-Rifian Arc (after middle Burdigalian), later in the Algerian-Tunisian Tell (after late Burdigalian) and afterwards in Sicily and the Southern Apennines (after Langhian). A geodynamic evolutionary model for the central-western Mediterranean is proposed.

Polychaete distribution pattern on the Valencian Community coast, Spanish Mediterranean

Changes in benthic community structure are strongly related to environmental factors, and we need to determine how these natural changes occur in order to interpret the possible changes associated with anthropogenic impacts. The aim of this survey was to characterize and classify the polychaete assemblages inhabiting unpolluted soft bottoms in the Spanish Mediterranean in relation to environmental factors. Thirteen localities were sampled at depths between 9 and 31 m, from 2004 to 2006. Multivariate techniques showed that the structure of polychaete assemblages detected in 2004 was consistent over time and correlations between polychaetes and environmental factors were detected. The study area comprises four kinds of communities mainly characterized by polychaete assemblages, sediment types, and depth.

Breve apunte acerca de un manuscrito ornitológico redactado por Philip W. Munn durante su exilio en Portugal (1941-1945): The birds of the Balearic Islands (June, 1943)

Se presenta un bosquejo acerca de un documento de excepcional valor histórico para la ornitología balear: el manuscrito de Las Aves de las Islas Baleares (1943), redactado en inglés por el ornitólogo británico Philip Winchester Munn durante su exilio lisboeta.

Carybdea marsupialis (Cubozoa) in the Mediterranean Sea: The first case of a sting causing cutaneous and systemic manifestations

A woman stung by the box jellyfish Carybdea marsupialis (Cnidaria, Cubozoa) at a Spanish Mediterranean beach, showed systemic manifestations over several months (pain far from the inoculation point, arthralgia, paresthesia, hyperesthesia, increase of eosinophils and IgE) in addition to the skin condition.

The Early Miocene “Bisciaro volcaniclastic event” (northern Apennines, Italy): a key study for the geodynamic evolution of the central-western Mediterranean

The Early Miocene Bisciaro Fm., a marly limestone succession cropping out widely in the Umbria–Romagna–Marche Apennines, is characterized by a high amount of volcaniclastic content, characterizing this unit as a peculiar event of the Adria Plate margin. Because of this volcaniclastic event, also recognizable in different sectors of the central-western Mediterranean chains, this formation is proposed as a “marker” for the geodynamic evolution of the area. In the Bisciaro Fm., the volcaniclastic supply starts with the “Raffaello” bed (Earliest Aquitanian) that marks the base of the formation and ends in the lower portion of the Schlier Fm. (Late Burdigalian–Langhian p.p.). Forty-one studied successions allowed the recognition of three main petrofacies: (1) Pyroclastic Deposits (volcanic materials more than 90 %) including the sub-petrofacies 1A, Vitroclastic/crystallo-vitroclastic tuffs; 1B, Bentonitic deposits; and 1C, Ocraceous and blackish layers; (2) Resedimented Syn-Eruptive Volcanogenic Deposits (volcanic material 30–90 %) including the sub-petrofacies 2A, High-density volcanogenic turbidites; 2B, Low-density volcanogenic turbidites; 2C, Crystal-rich volcanogenic deposits; and 2D, Glauconitic-rich volcaniclastites; (3) Mixing of Volcaniclastic Sediments with Marine Deposits (volcanic material 5–30 %, mixed with marine sediments: marls, calcareous marls, and marly limestones). Coeval volcaniclastic deposits recognizable in different tectonic units of the Apennines, Maghrebian, and Betic Chains show petrofacies and chemical–geochemical features related to a similar calc-alkaline magmatism. The characterization of this event led to the hypothesis of a co-genetic relationship between volcanic activity centres (primary volcanic systems) and depositional basins (depositional processes) in the Early Miocene palaeogeographic and palaeotectonic evolution of the central-western Mediterranean region. The results support the proposal of a geodynamic model of this area that considers previously proposed interpretations.