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Oceanic ambient noise measurements can be analyzed to obtain qualitative and quantitative information about wind and rainfall phenomena over the ocean filling the existing gap of reliable meteorological observations at sea. The Ligurian Sea Acoustic Experiment was designed to collect long-term synergistic observations from a passive acoustic recorder and surface sensors (i.e., buoy mounted rain gauge and anemometer and weather radar) to support error analysis of rainfall rate and wind speed quantification techniques developed in past studies. The study period included combination of high and low wind and rainfall episodes and two storm events that caused two floods in the vicinity of La Spezia and in the city of Genoa in 2011. The availability of high resolution in situ meteorological data allows improving data processing technique to detect and especially to provide effective estimates of wind and rainfall at sea. Results show a very good correspondence between estimates provided by passive acoustic recorder algorithm and in situ observations for both rainfall and wind phenomena and demonstrate the potential of using measurements provided by passive acoustic instruments in open sea for early warning of approaching coastal storms, which for the Mediterranean coastal areas constitutes one of the main causes of recurrent floods. [ABSTRACT FROM AUTHOR]

Abstract: The trophic niche width and feeding strategy (FS) of juvenile European hake were studied during three trawl surveys in two different areas of the Mediterranean Sea. Both of these aspects of trophic behaviour were analysed as function of different biotic and abiotic factors. Prey were grouped by factors such as size, swimming behaviour and energy density. The trophic niche breadth values observed (2.25–2.89) were very similar regardless of the geographic area (geomorphology) and season. The FSs analysed were also quite similar regardless of the geographic area (geomorphology) and season, or predation environment (bottom or water column). Conversely, the FSs were linked with predator size. Increased predator size allowed changes in predatory behaviour through the development of preferences for larger and more energy-rich prey. The changes in FS from generalist to specialist began at a total length (TL) of approximately 12cm in both populations analysed. At larger sizes, the juveniles of both populations became more specialised, as confirmed by the reduction in the breadth of the individual trophic niche. The observed simultaneous changes in the FS, which occurred regardless of the geomorphology and seasonal characteristics, suggest that this shift is driven primarily by endogenous factors. The influence of body size on the foraging behaviour of European hake in the early life stages after bottom recruitment is a crucial information for the application of ecosystem mass-balance models. [Copyright &y& Elsevier]

This work regards a model evaluation exercise concerning the WRF meteorological model and in situ measurements collected both over land, at four WMO meteorological stations, and over open sea, by ODAS Italia 1, the only spar buoy in the Mediterranean Sea. In particular, this exercise is finalised to understand the ability of the model to act as meteorological pre-processor to simulate aerosol emissions from the sea, an important factor to correctly predict pollutant levels. The test is carried out for the August to December 2005 period over the Ligurian Sea region, a very complex area where the strong air-sea interactions and orography significantly affect the atmospheric circulation. Performances of two model versions, WRF-ARW 3.0 and WRF-ARW 3.2.1, applied at two different horizontal resolutions, have been compared. The results show that the new parameterisations introduced in WRF 3.2.1 improve the performance of the model with respect to version 3.2.0. Increasing the model domain resolution from 15 km to 5 km does not generally improve the model performance, except for the wind direction reconstruction. The model proved its reliability as meteorological processor, although further efforts are required to improve wind field simulation, mainly in order to reduce the low bias still affecting the reconstruction at high wind speed. [ABSTRACT FROM AUTHOR]

Feeding ecology was analysed for the first time in the larvae of the European hake ( Merluccius merluccius) to determine whether their diet and selectivity were constrained by environmental conditions and how these feeding characteristics were related to ontogeny, prey availability and visual capabilities. Larvae collected during both day and night were analysed, and it was found that feeding incidence was high, regardless of the time of day. Examination of the visual system corroborated the hypothesis that hake larvae should be able to cope with a wide range of photic conditions and to forage even at low light intensity. A clear preference for adult calanoid copepods and, especially, for Clausocalanus spp. was observed in all sizes analysed. Prey number increased with larval size, but prey size did not. This finding indicates that hake larvae behave as selective and specialist predators that consume an increasing number of prey rather than larger prey during larval growth. [ABSTRACT FROM AUTHOR]

Abstract: Wind above sea surface plays an important role in the Mediterranean Sea for a large variety of scientific applications (i.e., climatological, meteorological and oceanographic studies). In this work we compare wind vectors obtained from the SeaWinds scatterometer on board the National Aeronautics and Space Administration (NASA) QuikSCAT satellite with wind data measured in situ by an anemometer mounted on the offshore ODAS Italia 1 buoy. This platform is moored in the Central Ligurian Sea, a basin where the wind field is highly variable both in time and space due to the orographic constraints and the thermal contrast between land and sea that give rise to specific local effects. The work covers the period from July 2006 to June 2007. The comparison confirms that the QuikSCAT wind vectors satisfy the accuracy requirements for high wind speeds, but, QuikSCAT skill is less for low wind speed, especially for the direction assessment. These results are in agreement with those of previous investigations but the analysis evidences some issues mistreated until now. The most relevant is the scarceness of data. The satellite passes over the Ligurian Sea only twice a day and data taken under rainy condition and with wind speed lower than 3ms−1 are not valid. Thus, the temporal sampling may be not adequate to monitor wind fields and their evolution over this basin where calm condition often occurs and strong perturbations are generally associated to rain. Furthermore, the comparison shows that it may be difficult to recognize spurious values obtained from QuikSCAT when the true wind speed is lower than 3ms−1 without a reference at sea. [Copyright &y& Elsevier]

A network of three multi-sensor timeseries stations able to deliver real time physical and biochemical observations of the upper thermocline has been developed for the needs of the Mediterranean Forecasting System during the MFSTEP project. They follow the experience of the prototype M3A system that was developed during the MFSPP project and has been tested during a pilot pre-operational period of 22 months (2000-2001). The systems integrate sensors for physical (temperature, salinity, turbidity, current speed and direction) as well as optical and chemical observations (dissolved oxygen, chlorophyll-a, PAR, nitrate). The south Aegean system (E1-M3A) follows a modular design using independent mooring lines and collects biochemical data in the upper 100m and physical data in the upper 500m of the water column. The south Adriatic buoy system (E2- M3A) uses similar instrumentation but on a single mooring line and also tests a new method of pumping water samples from relatively deep layers, performing analysis in the protected "dry" environment of the buoy interior. The Ligurian Sea system (W1-M3A) is an ideal platform for air-sea interaction processes since it hosts a large number of meteorological sensors while its ocean instrumentation, with real time transmission capabilities, is confined in the upper 50m layer. Despite their different architecture, the three systems have common sampling strategy, quality control and data management procedures. The network operates in the Mediterranean Sea since autumn 2004 collecting timeseries data for calibration and validation of the forecasting system as well for process studies of regional dynamics. [ABSTRACT FROM AUTHOR]

The consumption rate of fishery discards is evaluated and the organisms involved in recycling discarded fish analysed. For this purpose, a fixed baited camera was deployed on the continental shelf and upper slope of the Catalan Sea (northwestern Mediterranean), where trawlers discard large quantities of non-target species. The results showed considerable bait consumption after 12 h of immersion. Between 48 and 64% of the bait was consumed within this period on the shelf, at a mean rate of 23.8±5.7 g h−1, and >90% of the bait on the slope, at a mean rate of 30.8±10.5 g h−1. After 24 h, generally just the bones of the bait were left. Amphipods, isopods, cephalopods, ophiuroids, nine species of fish, and seven decapods were identified feeding on the bait. Typical scavenger species stayed longer in the vicinity of the bait, but pelagic species exhibited only occasional scavenging behaviour, were slower to arrive at the bait, and remained for a shorter time. The snake eel, Ophichthus rufus, was the most abundant fish attracted to the bait, appearing in 75% of the photographic series. Isopods and amphipods reached the bait 80 minutes after camera deployment and were also involved in the recycling and dispersal of organic matter in the system. In fact, these organisms congregated at the bait and consumed it entirely in just a few hours. For scavenger species that live in areas where discarding is continuous, such additional inputs could be a major trophic resource. For this reason, continuous anthropogenic inputs may bring about environmental perturbations that can alter benthic ecology and community stability. [Copyright &y& Elsevier]

Abstract: Egg masses of oceanic squid accidently collected in the wild have been observed only from a few spawning events in aquaria, and as a consequence, the study of their embryos and hatchlings is very limited. Here, we used in vitro fertilization techniques to understand the abiotic factors that influenced egg development and hatchling performance of the ommastrephid squid Illex coindetii from the Mediterranean Sea. Egg and hatchling sizes of these ommastrephids are close to the minimum for cephalopod species, and therefore, short embryonic developmental periods were expected under a Mediterranean temperature regime. Low incubation densities and the use of antibiotics in the incubation medium resulted in relatively high survival rates to hatchling. Hatching time was inversely proportional to incubation temperature and ranged from 5 to 11days at 21°C and 13°C, respectively. The addition of oviducal jelly to the eggs immediately after fertilization, followed by another addition at the beginning of organogenesis, resulted in better chorionic expansion, with an increase in egg diameter, delayed hatching and higher hatchling weight, which suggests a better use of yolk reserves. Larger hatchlings in length and weight also tended to be produced at low temperature, probably also due to better yolk absorption. As this species spawns all year round, size differences between summer and winter hatchlings may be suspected. In vitro fertilization techniques used in the laboratory proved to be useful in shedding some light on the early life of this oceanic squid. Further research is needed to elaborate on tests to predict gamete quality and to develop methods to avoid premature hatching. [Copyright &y& Elsevier]