Yield and catch changes in a Mediterranean small tuna trap: a warming change effect?

Since the 17th century, the Tonnarella of Camogli, a small tuna trap, has been used to catch pelagic fish along the western coast of the Portofino Promontory (Ligurian Sea, Northwestern Mediterranean). The availability of long‐term datasets on fish yields (1950–1974 and 1996–2011), with information related to the seawater temperatures and the North Atlantic Oscillation (NAO), has allowed us to study the qualitative and quantitative changes in fish yields in the last decade and the possible relationships with the seasonal anomalies of temperature that have occurred in the Ligurian Sea. In 1950–1974, yields remained relatively constant over time (average of 35.6 ± 8.7 t·year^?1). From 1996 through 2011, yields were high (42.9 ± 15.9 t·year^?1) but inconsistent with strong annual variability in catches. The primary catches are Seriola dumerili, Auxis rochei, Trachurus spp. and Sarda sarda. Changes in species composition have occurred as well: S. dumerili, Sardinella sp. and Belone belone have appeared recently. Moreover, a significant decrease in the boreal scombroid (Scomber scombrus) and an increase of warm‐temperate carangids and other typically Southern Mediterranean species such as Coryphaena hippurus and Sphyraena viridensis, appear to be linked to the warming of the surface water layer, particularly evident in the Ligurian Sea, for the last 10 years. The analysis of this kind of trend may be a powerful tool for assessing structural changes of the pelagic fish community in the Ligurian Sea (Northwestern Mediterranean).     

A benthic mucilage event in North-Western Mediterranean Sea and its possible relationships with the summer 2003 European heatwave: short term effects on littoral rocky assemblages

In this contribution we document an anomalous mucilage growth which occurred in June 2003 along the rocky cliffs of the Portofino Promontory (Ligurian Sea, NW Mediterranean Sea), and we describe its dynamics and its negative effects on many benthic taxa. The zooxanthellate scleractinian Cladocora caespitosa underwent ‘bleaching’ and about 40% of biomass of the erect algae was detached by mucilage ‘lianas’ created and strengthened by bottom currents. The 2003 event differed from any other previously occurred in the northern Tyrrhenian Sea, in that the mucilage aggregates were formed by the free‐living form of the Phaeophyceae Acinetospora crinita (Harvey) Kornmann, a not usually dominant species in mucilage aggregates from the north Tyrrhenian Sea. The damage suffered by the benthic organisms living in this area was curtailed by a severe storm, occurred in July, which removed the mucilage to deeper depths, preventing irreversible damages. Only slow growing, perennant organisms, such as corallinales or scleractinians, were seriously affected, but a survey carried out 1 year later, in June 2004, allowed to appreciate a complete recovery of those organisms. This anomalous mucilage event occurred in coincidence of the 2003 European heatwave, and the anomalous temperature increase of seawater has to be regarded as the major contributing event that led to the mucilage outbreak.     

Hydrography, nutrients and chlorophyll during El Niño and La Niña 1997–99 winters in the Gulf of the Farallones, California

Nutrient and chlorophyll concentrations were measured in January 1997, 1998 and 1999 in the Gulf of the Farallones, CA at locations stretching north/south from Point Reyes to Half Moon Bay, and seaward from the Golden Gate to the Farallon Islands. The cruises were all carried out during periods of high river flow, but under different climatological conditions with 1997 conditions described as relatively typical or ‘neutral/normal’, compared to the El Niño warmer water temperatures in 1998, and the cooler La Niña conditions in 1999. Near-shore sea-surface temperatures ranged from cold (9.5–10.5°C) during La Niña 1999, to average (11–13°C) during 1997 to warm (13.5–15°C) during El Niño 1998. Nutrients are supplied to the Gulf of the Farallones both from San Francisco Bay (SFB) and from oceanic sources, e.g. coastal upwelling near Point Reyes. Nutrient supplies are strongly influenced by the seasonal cycle of fall calms, with storms (commencing in January), and the spring transition to high pressure and northerly upwelling favorable winds. The major effect of El Niño and La Niña climatic conditions was to modulate the relative contribution of SFB to nutrient concentrations in the coastal waters of the Gulf of the Farallones; this was intensified during the El Niño winter and reduced during La Niña. During January 1998 (El Niño) the oceanic water was warm and had low or undetectable nitrate, that did not reach the coast. Instead, SFB dominated the supply of nutrients to the coastal waters. Additionally, these data indicate that silicate may be a good tracker of SFB water. In January, delta outflow into SFB produces low salinity, high silicate, high nitrate water that exits the bay at the Golden Gate and is advected northward along the coast. This occurred in both 1997 and 1998. However during January 1999, a La Niña, this SFB feature was reduced and the near-shore water was more characteristic of high salinity oceanic water penetrated all the way to the coast and was cold (10°C) and nutrient rich (16 μM NO₃, 30 μM Si(OH)₄). January chlorophyll concentrations ranged from 1–1.5 μg l⁻¹ in all years with the highest values measured in 1999 (2.5–3 μg l⁻¹) as a result of elevated nutrients in the area. The impact of climatic conditions on chlorophyll concentrations was not as pronounced as might be expected from the high temperatures and low nutrient concentrations measured offshore during El Niño due to the sustained supply of nutrients from the Bay supporting continued primary production.     

Monitoring a Marine Coastal Area: Use of Mytilus galloprovincialis and Mullus barbatus as Bioindicators

Abstract. Samples of Mytilus galloprovincialis and Mullus barbatus were collected in eight coastal sites along the South Adriatic and Ionic coasts of Italy in spring 2000 for a survey of coastal pollution in the Mediterranean basin. Specimens were analysed using an integrated approach based on residue analysis of common aquatic pollutants like organochlorines such as hexachlorobenzene (HCB), DDTs and polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), heavy metals and nonylphenols (NPnE) and biomarker responses such as acetylcholinesterase (AChE) activity, and the two specific P450 activities benzo(a)pyrene monooxygenase (BPMO) and 7-ethoxyre-sorufin-(9-deethylase (EROD). Biological and morphological parameters like somatic liver index (SLI), gonadosomatic index (GSI) and gonadal and gamete histology (eggs and sperms) were also evaluated in red mullet samples. A contamination gradient in which several hot spots occur were revealed in this study. The hot spots account for high levels of organochlorines in both species near incinerators and of PAHs in harbour areas. Levels of both NPnE and AChE activity were highest in two protected marine areas and were within detectable limits in others. This finding was confirmed by P450 activities, in which maximum levels were detected in harbours and protected marine areas. No morphological alterations of male and female gonads were observed on the histological level.     

Forecasting the evolution in the mixing regime of a deep subalpine lake under climate change scenarios through numerical modelling (Lake Maggiore,Northern Italy/Southern Switzerland)

Climate Dynamics - The impact of air temperature rise is eminent for the large deep lakes in the Italian subalpine district, climate change being caused there by both natural phenomena and...     

Distribution and population structure of deep‐dwelling red coral in the Northwest Mediterranean

Commercially harvested since ancient times, the highly valuable red coral Corallium rubrum (Linnaeus, 1758) is an octocoral endemic to the Mediterranean Sea and adjacent Eastern Atlantic Ocean, where it occurs on rocky bottoms over a wide bathymetric range. Current knowledge is restricted to its shallow populations (15–50 m depth), with comparably little attention given to the deeper populations (50–200 m) that are nowadays the main target of exploitation. In this study, red coral distribution and population structure were assessed in three historically exploited areas (Amalfi, Ischia Island and Elba Island) in the Tyrrhenian Sea (Western Mediterranean Sea) between 50 and 130 m depth by means of ROV during a cruise carried out in the summer of 2010. Red coral populations showed a maximum patch frequency of 0.20 ± 0.04 SD patches·m^?1 and a density ranging between 28 and 204 colonies·m^?2, with a fairly continuous bathymetric distribution. The highest red coral densities in the investigated areas were found on cliffs and boulders mainly exposed to the east, at the greatest depth, and characterized by medium percentage sediment cover. The study populations contained a high percentage (46% on average) of harvestable colonies (>7 mm basal diameter). Moreover, some colonies with fifth‐order branches were also observed, highlighting the probable older age of some components of these populations. The Ischia population showed the highest colony occupancy, density and size, suggesting a better conservation status than the populations at the other study locations. These results indicate that deep dwelling red coral populations in non‐stressed or less‐harvested areas may diverge from the inverse size‐density relationship previously observed in red coral populations with increasing depth.     

Vesta's mineralogical composition as revealed by the visible and infrared spectrometer on Dawn

The Dawn spacecraft mission has provided extensive new and detailed data on Vesta that confirm and strengthen the Vesta–howardite–eucrite–diogenite (HED) meteorite link and the concept that Vesta is differentiated, as derived from earlier telescopic observations. Here, we present results derived by newly calibrated spectra of Vesta. The comparison between data from the Dawn imaging spectrometer—VIR—and the different class of HED meteorites shows that average spectrum of Vesta resembles howardite spectra. Nevertheless, the Vesta spectra at high spatial resolution reveal variations in the distribution of HED‐like mineralogies on the asteroid. The data have been used to derive HED distribution on Vesta, reported in Ammannito et al. (2013), and to compute the average Vestan spectra of the different HED lithologies, reported here. The spectra indicate that, not only are all the different HED lithologies present on Vesta, but also carbonaceous chondritic material, which constitutes the most abundant inclusion type found in howardites, is widespread. However, the hydration feature used to identify carbonaceous chondrite material varies significantly on Vesta, revealing different band shapes. The characteristic of these hydration features cannot be explained solely by infalling of carbonaceous chondrite meteorites and other possible origins must be considered. The relative proportion of HEDs on Vesta's surface is computed, and results show that most of the vestan surface is compatible with eucrite‐rich howardites and/or cumulate or polymict eucrites. A very small percentage of surface is covered by diogenite, and basaltic eucrite terrains are relatively few compared with the abundance of basaltic eucrites in the HED suite. The largest abundance of diogenitic material is found in the Rheasilvia region, a deep basin, where it clearly occurs below a basaltic upper crust. However, diogenite is also found elsewhere; although the depth to diogenite is consistent with one magma ocean model, its lateral extent is not well constrained.     

Scale- and orientation-invariant scene similarity metrics for image queries

In this paper we extend our previous work on shape-based queries to support queries on configurations of image objects. Here we consider spatial reasoning, especially directional and metric object relationships. Existing models for spatial reasoning tend to rely on pre-identified cardinal directions and minimal scale variations, assumptions that cannot be considered as given in our image applications, where orientations and scale may vary substantially, and are often unknown. Accordingly, we have developed the method of varying baselines to identify similarities in direction and distance relations. Our method allows us to evaluate directional similarities without a priori knowledge of cardinal directions, and to compare distance relations even when query scene and database content differ in scale by unknown amounts. We use our method to evaluate similarity between a user-defined query scene and object configurations. Here we present this new method, and discuss its role within a broader image retrieval framework.     

Benefits of the Proposed Magia Mission for Lunar Geology

Age of geological units, surface mineralogical composition, volcanism, tectonics and cratering are major keys for unravelling the geodynamic and geological history of a planet. Thanks to the extensive exploration of the 1960s and 1970s and the compositional mapping of the 1990s missions (Galileo, Clementine and Luna Prospector), the Moon has a unique geological dataset among the extraterrestrial Solar System bodies. The recent and on-going missions, along with the future plans for lunar exploration, will together acquire an extraordinary amount of data. This should provide a solid basis to meet broad objectives like the constraints on the heterogeneity of Lunar composition and the presence of water deposits, the understanding of volcanic and tectonic evolution as well as more specific issues such as the genetic classification of volcanic domes, origin of the dark-halos craters, lava flow emplacement mechanisms, and the kinematics and deformational styles of tectonic structures. The Italian small mission MAGIA (Missione Altimetrica Gravimetrica geochImica lunAre) will be equipped with an integrated context camera and imaging spectrometer, a high resolution camera and a radar altimeter. The spatial and spectral resolution of these instruments will provide data products complementing past and ongoing Lunar mission data, particularly for the polar regions where a full resolution coverage is planned. A general review of some still unanswered questions on lunar surface composition, cold traps, volcanism, tectonics and cratering records is presented here in order to illustrate the potential contribution of MAGIA to these subjects.     

Search for Steins’ surface inhomogeneities from OSIRIS Rosetta images

We investigate the possible presence of heterogeneous surface features on asteroid (2867) Steins, using the G-mode multivariate statistical method (Coradini et al., 1977) applied to Rosetta/OSIRIS images. We analyze both NAC and WAC images obtained near around the closest approach that occurred on September 5th, 2008, through different filters centered on wavelengths ranging from 295 to 986 nm. The shape of Steins is modeled as a polyhedron of almost 58 000 facets. Photometric corrections were performed using Hapke's (2002) model to compensate for the variable illuminations conditions at the surface. The G-mode classification method was performed on all visible and illuminated facets, i.e. in a region limited to [−50°,+60°] in latitude and [−40°,+90°] in longitude, that represents almost 30% of the total surface. The analyzed set of facets does not show any significant difference in the reflected light content, suggesting no surface inhomogeneities larger than 4% at the 95% confidence level.