Istituto di Scienze Marine - CNR

Experimental studies in recent years highlight the presence of an increasingly high quantity of microplastics worldwide [1]. The "resin pellets" represent a significant share among the first generation microplastics in the millimeter range (from 1 to 5 mm). They disperse in the environment, even unintentionally, during transport, storage and processing and recent studies show that their content varies from 3% to about 30% of all microplastics surveyed on beaches [2]. A three-years experiment was carried out on a simulated beach and in marine water in Santa Teresa Bay (Gulf of La Spezia, Italy). In detail, special cages have been installed on the underwater observatory, LabMARE coastal station [3], placed at ten meters deep. The submarine station is equipped with a sensor for monitoring environmental parameters, recording data every 10 min. The experiment, aimed at investigating the behavior of plastic items and HDPE, PP, PLA and PBAT pellets, began on March 3, 2020 and is still ongoing. Here, the comparison between the properties of the raw pellets and those placed in the two different environments after six months, is discussed. Through chemical, spectroscopic and thermal analyses (GPC, SEM, FTIR-ATR, DSC, TGA) of granules, variations in color, surface morphology, chemical composition, thermal properties and molecular weight, and polydispersity of materials are analysed to show the different influences of environmental conditions.

In this paper, we present two novel experimental setups specifically designed to perform in situ long-term monitoring of the aging behaviour of commercial plastic granules (HDPE, PP, PLA and PBAT). The results of the first six months of a three year monitoring campaign are presented. The two experimental setups consist of: (i) special cages positioned close to the sea floor at a depth of about 10 m, and (ii) a box containing sand exposed to atmospheric agents to simulate the surface of a beach. Starting from March 2020, plastic granules were put into the cages and plunged in sea water in two different locations in the sand boxes. Chemical spectroscopic and thermal analyses (GPC, SEM, FTIR-ATR, DSC, TGA) were performed on the granules before and after exposure to natural elements for six months, in order to identify the physical-chemical modifications occurring in marine environmental conditions (both in seawater and in sandy coastal conditions). Changes in colour, surface morphology, chemical composition, thermal properties and molecular weight, and the polydispersity of the materials, showed the different influences of the environmental conditions. Photooxidative reaction pathways were prevalent in the sandbox. Abrasive phenomena acted specially in the sea environment. PLA and PBAT did not show significant degradation after six months, making the possible reduction of marine pollution due to this process negligible

In questo articolo descriviamo l’importanza dell’attività ludico-didattica e del linguaggio visivo per facilitare l’apprendimento ed in particolare l’esperienza della sede INGV di Porto Venere all’interno del Gruppo di Lavoro La Spezia Golfo della Scienza [Locritani et al., 2015], nell’ambito dello sviluppo di giochi scientifici. Il gruppo di lavoro ormai da dieci anni collabora nell’organizzazione di eventi di divulgazione con l’obiettivo di accrescere la conoscenza sulle grandi tematiche ambientali per la salvaguardia del Pianeta. Le premesse che sostengono questa strategia hanno radici profonde provenienti da motivazioni politiche, economiche e sociali che sono alla base dello Sviluppo Sostenibile. In ambito Europeo l’educazione allo Sviluppo Sostenibile richiede il coinvolgimento di tutta la popolazione, nonostante queste linee guida i sondaggi dell’Eurobarometro evidenziano un basso interesse nei confronti delle scienze. In questo contesto è importante evidenziare il ruolo della divulgazione scientifica e delle diverse metodologie da impiegare. Nella semplificazione dei concetti svolge un ruolo chiave l’immagine e l’utilizzo di essa nella realizzazione di giochi scientifico-didattici. Nei prossimi paragrafi verranno descritti: il contesto economico, politico e sociale che sostiene l’importanza della divulgazione scientifica; la funzione del linguaggio visivo nella comunicazione scientifica; il ruolo del gioco nell’apprendimento; l’esperienza dell’INGV di Porto Venere all’interno dell’ambito territoriale e scientifico in cui opera; le strategie usate nella fase di progettazione del gioco, i contenuti dei giochi e le modalità stabilite per il loro utilizzo.

The presence in the Earth’s mantle of even small amounts of water and other volatiles has major effects: first, it lowers drastically mantle’s viscosity, thereby facilitating convection and plate tectonics; second, it lowers the melting temperature of the rising mantle affecting the formation of the oceanic crust. H2O concentration in oceanic basalts stays below 0.2 wt% except for basalts sampled near “hot spots” that contain significantly more H2O than normal MORB, implying that their mantle plume sources are unusually H2O-rich. Basalts sampled in the Equatorial Atlantic close to the Romanche transform, a thermal minimum in the Ridge system, have a H2O content that increases as the ridge is cooled approaching the transform offset. These basalts are Na-rich, being generated by low degrees of melting of the mantle, and contain unusually high ratios of light versus heavy rare earth elements implying the presence of garnet in the melting region. H2O enrichment is due not to an unusually H2O-rich mantle source, but to a low extent of melting of the upwelling mantle, confined to a deep wet melting region. Numerical models predict that this wet melting process takes place mostly in the mantle zone of stability of garnet. This prediction is verified by the geochemistry of our basalts showing that garnet must indeed have been present in their mantle source. Thus, oceanic basalts are H2O-rich not only near “hot spots”, but also at “cold spots”.