Development of a sliding device for extended measurements in coastal waters

Extensive measurements of main sea water parameters (e.g. temperature, salinity, dissolved oxygen, nutrients, bacterial abundance...) are required to investigate marine environment, both to evaluate its state and to quickly detect possible perturbations (arrival of pollutants, anthropogenic contaminants...). Traditional observing methods cannot offer the flexibility and cost effectiveness needed for extensive monitoring and water quality assessment in coastal areas where important health and economic issues are involved (e.g. aquaculture, tourism). As a part of the MFSTEP program (EU FP5) a new device was designed and built for pelagic use, the SAVE (Sliding Advanced VEhicle), able to perform continuous profiles of physical and optical measurements on the upper 200 m of the water column. The original system consists mainly in a depressor, towed at a fixed depth, using a cable on which the main unit slides. Both the depressor and the sliding unit can be equipped with various kinds of sensors. The new goal was to obtain a coastal version, to be towed from small boats. A smaller prototype is now under development and test, able to be towed by a very small (8-10 m.) boat, like those commonly used in aquaculture plants, and also fitted with modular water samplers for bacterial or chemical determinations. The paper gives some first results of this development.L'articolo è disponibile sul sito dell'editore http://library.witpress.com

Studio sull’impatto ambientale delle attività di maricoltura nel Golfo di Oristano

L’obiettivo del presente lavoro è stato di simulare la dispersione e il tempo di residenza delle sostanze organiche immesse nell’ambiente a seguito delle attività di acquacoltura all’interno del Golfo di Oristano (Sardegna, Italia). A questo scopo è stato implementato un modello numerico di circolazione, con moduli di dispersione e diffusione euleriana e lagrangiana. Il modello ha evidenziato il ruolo fondamentale della direzione e dell’intensità del vento sulla dispersione dei rifiuti organici. A parità d’intensità, la direzione del vento influenza in maniera decisiva la distanza alla quale i rifiuti organici vengono trasportati e depositati. In tutti gli scenari di vento, il mangime non consumato, indipendentemente dalla sua dimensione, si deposita in un’area direttamente sotto le gabbie ma con una distribuzione spaziale che dipende dalle correnti indotte. In tutti i casi, la materia organica disciolta si diluisce ed è trasportata al di fuori del golfo. Con i venti da Maestrale i rifiuti organici sono spinti verso, l’interno del golfo per poi uscirne in forma disciolta da sud. Negli scenari di Libeccio e Scirocco i rifiuti organici disciolti tendono a diluirsi ed essere trasportati al di fuori del golfo dalla parte nord. In tutti gli scenari, la capacità di ricambio delle acque interne al golfo risulta elevata, con la maggior parte delle sostanze organiche disciolte presenti in concentrazioni molto basse dopo dieci ore dalla loro produzione. Dal punto di vista del ricambio d’acqua e conseguentemente per la dispersone di agenti inquinanti, quasi tutti i 13 siti simulati, ad esclusione dei due in prossimità dei capi, hanno tempi di residenza idonei per il posizionamento delle gabbie. Sono comunque da preferire le regioni più a sud perché i tempi di transito sono più bassi creando un impatto minore. Infine considerando che il golfo è ricoperto quasi interamente da Posidonia, i siti meno impattanti sono quelli che si trovano su un fondale fangoso e in prossimità del fiume Tirso (Sito 3 e 4). L’utilizzo di modelli numerici ha permesso di portare a termine studi a priori (tempi di transito, zone di deposizione, dispersioni inquinanti) per la pianificazione della disposizione ottimale delle gabbie, avente come conseguenza una più proficua produzione (maggiore redditività) e un minore impatto ambientale. Si può infine affermare che nonostante l’assenza di studi antecedenti al presente, le gabbie all’interno del Golfo di Oristano siano state posizionate correttamente, in una regione ottimale per produzione e impatto ambientale

Anthropogenic impact on river basins: temporal evolution of sediment classes and accumulation rates in the Northern Tyrrhenian Sea, Italy

Abstract In this study, sedimentological and geochronological data from sections of a core (GRT50) collected in the Northern Latium coastal area were compared to data on pluviometric (rainfall) trends, river flows and the temporal evolution of human interventions in the three most important hydrographic basins (Mignone, Marta and Fiora) of this coastal area. The statistical analysis of pluviometric trends identified variations due to a decreasing trend in the Fiora river basin, whereas in the two other locations the decrease was not so significant. Data from the sedimentological analysis of the core confirmed a progressive decrease in the sandy component, which declined from about 30% to the current level of 7% over the last 36 years. There was no significant variation in the sediment mass accumulation rates (MAR), which were characterized by an almost cyclic trend that was probably determined by the most intense floods in the study area. The results revealed that the variations caused by the fluvial processes have affected the water runoff of the Fiora River, and that the consequent decrease in the sand production has been responsible for the recession of beaches in the coastal area between Tarquinia and Montalto di Castro

Development of a new expendable probe for the study of pelagic ecosystems from voluntary observing ships

Physical and biological processes of the marine ecosystem have a high spatial and temporal variability, whose study is possible only through high resolution and synoptic observations. The Temperature and Fluorescence Launchable Probe was charted in order to answer to the claim of a cost effective temperature and fluorescence expendable profiler, to be used in ships of opportunity. The development of the expendable fluorometer has followed similar concepts of the XBT (a wire conducting the signal to a computer card), but differently from the latter it was developed with an electronic system which can be improved and adapted to several variables measure channels. To reach the aim of a low-cost probe, were utilized commercial components:a glass bulb temperature resistor for the temperature measurement, blue LEDs, a photodiode and available selective glass filters, for the fluorescence measurement. The measurement principle employed to detect phytoplankton’s biomass is the active fluorescence. This method is an in vivo chlorophyll estimation, that can get the immediate biophysical reaction of phytoplankton inside the aquatic environment; it is a non-disruptive method which gives real time estimation and avoids the implicit errors due to the manipulation of samples. The possibility of using a continuous profiling probe, with an active fluorescence measurement, is very important in real time phytoplankton’s study; it is the best way to follow the variability of sea productivity. In fact, because of the high time and space variability of phytoplankton, due to its capability to answer in a relatively short time to ecological variations in its environment and because of its characteristic patchiness, there isn’t a precise quantitative estimation of the biomass present in the Mediterranean Sea.L'articolo è disponibile sul sito dell'editore http://publications.copernicus.org

Macular ganglion cell layer thickness after macula-off rhegmatogenous retinal detachment repair: scleral buckling versus pars plana vitrectomy

(1) Background: We evaluated macular ganglion cell layer-inner plexiform layer (GCL-IPL) thickness in patients with primary macula-off rhegmatogenous retinal detachment (RRD) treated with scleral buckling (SB) or pars plana vitrectomy (PPV) using spectral domain optical coherence tomography (SD-OCT). (2) Methods: In this retrospective, observational study, we reviewed the medical records of patients undergoing SB or PPV surgery for macula-off RRD. SD-OCT was performed at three and 12 months after surgery. The central and parafoveal GCL-IPL thicknesses in treated eyes were compared with those of healthy fellow eyes. OCT measurements between the SB and PPV group were also compared using the analysis of covariance. (3) Results: Seventy-one eyes of 71 patients with a mean age of 61.2 ± 11.7 years were included. The parafoveal GCL-IPL thickness of the PPV group was significantly reduced, with respect to fellow eyes, at three and 12 months (p < 0.01). After adjusting for age, axial length, spherical equivalent, RD extent, preoperative intraretinal cysts, duration of symptoms and postoperative IOP, the parafoveal GCL-IPL thickness in the PPV group was significantly reduced with respect to the SB group, both at three and 12 months (F = 11.45, p = 0.001 and F = 12.37, p = 0.001, respectively). (4) Conclusions: In conclusion, the GCL-IPL is reduced in thickness in eyes with macula-off RRD treated with vitrectomy and is significantly thinner compared to eyes undergoing scleral buckling surgery

Computational modeling of immune system of the fish for a more effective vaccination in aquaculture

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Interlayer potassium and its neighboring atoms in micas : Crystal-chemical modeling and XANES spectroscopy

A detailed description of the interlayer site in trioctahedral true micas is presented based on a statistical appraisal of crystal-chemical, structural, and spectroscopic data determined on two sets of trioctahedral micas extensively studied by both X-ray diffraction refinement on single crystals (SC-XRD) and X-ray absorption fine spectroscopy (XAFS) at the potassium K -edge. Spectroscopy was carried out on both random powders and oriented cleavage flakes, the latter setting taking advantage of the polarized character of synchrotron radiation. Such an approach (AXANES) is shown to be complementary to crystal-chemical investigation based on SC-XRD refinement. However, the results are not definitive as they focus on few samples having extreme features only (e.g., end-members, unusual compositions, and samples with extreme and well-identified substitution mechanisms). The experimental absorption K -edge (XANES) for potassium was decomposed by calculation and extrapolated into a full in-plane absorption component (σ||) and a full out-of-plane absorption component (σ⊥). These two patterns reflect different structural features: σ|| represents the arrangement of the atoms located in the mica interlayer space and facing tetrahedral sheets; σ⊥ is associated with multiple-scattering interactions entering deep into the mica structure, thus also reflecting interactions with the heavy atoms (essentially Fe) located in the octahedral sheet. The out-of-plane patterns also provide insights into the electronic properties of the octahedral cations, such as their oxidation states (e.g., Fe2+ and Fe3+) and their ordering (e.g., trans - vs. cis -setting). It is also possible to distinguish between F- and OH-rich micas due to peculiar absorption features originating from the F vs. OH occupancy of the O4 octahedral site. Thus, combining crystal-chemical, structural, and spectroscopic information is shown to be a practical method that allows, on one hand, assignment of the observed spectroscopic features to precise structural pathways followed by the photoelectron within the mica structure and, on the other hand, clarification of the amount of electronic interactions and forces acting onto the individual atoms at the various structural sites