Igneous activity in central-southern Italy: Is the subduction paradigm still valid?

ABSTRACT The Pliocene–Quaternary igneous record of the Tyrrhenian Sea area features a surprisingly large range of compositions from subalkaline to ultra-alkaline and from ultrabasic to acid. These rocks, emplaced within the basin and along its margins, are characterized by strongly SiO2-undersaturated and CaO-rich to strongly SiO2-oversaturated and peraluminous compositions, with sodic to ultrapotassic alkaline and tholeiitic to calc-alkaline and high-K calc-alkaline affinities. We focused on the different models proposed to explain the famous Roman Comagmatic Region, part of the Quaternary volcanism that spreads along the eastern side of the Tyrrhenian area, in the stretched part of the Apennines thrust-and-fold belt. We reviewed data and hypotheses proposed in the literature that infer active to fossil subduction up to models that exclude subduction entirely. Many field geology observations sustain the interpretation that the evolution of the Tyrrhenian-Apennine system was related to subduction of the western margin of Adria continental lithosphere after minor recycling of oceanic lithosphere. However, the lateral extent of the subducting slab in the last millions of years, when magmatism flared up, remains debatable. The igneous activity that developed in the last millions of years along the Tyrrhenian margin is here explained as originating from a subduction-modified mantle, regardless of whether the large-scale subduction system is still active.

Factors Influencing the Interannual Variation in Biomass of Bottom-Cultured Yesso Scallop (Patinopecten yessoensis) in the Changhai Sea Area, China

Understanding how environmental factors impact the interannual variation in scallop growth and subsequently developing an easily obtained parameter to indicate this variation could provide a scientific basis for optimizing their aquaculture. In this study, we have set a growth scenario of uniformly sowed scallops of the same initial size in the Changhai sea area. The Yesso scallop culture ecosystem model was used to simulate the growth of bottom-cultured Yesso scallop each year from December 1, 2006 to November 30, 2017. The results show that the annual growth rate was higher in the northwest than in the southeast, and there were obvious high-value areas near the islands. The scallop biomass was significantly lower in 2009–2010 and reached its highest point in 2013–2014. Based on the match-mismatch conditions of bottom-water temperature, food availability, and the Yesso scallop growth process, three factors were determined: suitable growth days (SGD), restricted growth days (RGD), and food accumulation (FA). Subsequently, a multiple regression relationship was proposed with scallop biomass to explore the reasons affecting the interannual variations in scallop growth. We found that the anomaly of the contribution of SGD and FA for the scallop growth was small, and the interannual variation in scallop biomass was mainly regulated by RGD in winter. Our results indicated that the interannual variation in RGD in winter was closely related to the regional averaged air temperature in early winter. The air temperature in early winter is easily obtained in practice. Consequently, it could be used to predict the interannual growth of bottom-cultured scallops to improve aquaculture planning and management.

Estimating Sound Exposure Levels Due to a Broadband Source over Large Areas of Shallow Sea

3D sound propagation modeling in the context of acoustic noise monitoring problems is considered. A technique of effective source spectrum reconstruction from a reference single-hydrophone measurement is discussed, and the procedure of simulation of sound exposure level (SEL) distribution over a large sea area is described. The proposed technique is also used for the modeling of pulse signal waveforms at other receiver locations, and results of a direct comparison with the pulses observed in the experimental data is presented.

Influence of Bay o Bengal on winter monsoon rainfall

ABSTRACT. Utilizing marine meteorological data the values of 1 latent heat flux, sea surface temperature (SST) and sea minus air temperature have been computed on a grid mesh of 5° over the Bay of Bengal during September month of the contrasting Winter monsoon years 1987 and 1988. It has been found that the good winter monsoon of 1987 followed (I) higher SSTs over western Bay of Bengal; (ii) very high evaporation rate over the sea area bounded by 10°.20°N. 80°.90oE and (iii) instability in the surface layer over north and adjoining central Bay of Bengal, whereas, the bad winter monsoon of 1988 followed (i) lower SSTs over western Bay of Bengal; (ii) very low evaporation rate over the area I0°.20oN, 80°.90oE and (iii) stability in the surface layer over north and adjoining central Bay of Bengal.

Сurrent Trends in the Interaction Between the Black Sea Littoral States

The paper deals with the сurrent peculiarities of the relations between the Black Sea littoral states (Russia, Ukraine, Romania, Bulgaria, Georgia and Turkey) with the consideration of the coronavirus pandemic that to some extent has changed the ways of the external interaction. The author analyses the role of the Black Sea region in the political discourse of each littoral state and defines the trends of the economic and military-political interaction between the Black Sea states. It is shown that the pandemic has not led to the alleviation of the confrontation between the littoral states amidst the new common challenge. Neither has it stimulated them to reassess the current challenges and threats to maritime security. On the contrary, during the fight against the pandemic the conflicting nature of their interaction exacerbated under the conditions of the absence of the united strategic basis developed by the littoral states for their policy in the Black Sea region since the collapse of the USSR in 1991. The aspiration of Ukraine and Georgia to obtain military-political advantages in the Black Sea area prevailed with the support of the non-regional actors ‒ the United States, NATO and the EU.

COMPARISON OF TWO DATA ASSIMILATION METHODS USED TO ACCOUNT FOR OPEN BOUNDARIES IN SEA AREA HYDROTHERMODYNAMICS MODELING

The problems of modeling hydrothermodynamics of particular sea and coastal areas are of current interest, since the results of this modeling are often used in many applications. One of the methods allowing to take into account open boundaries and bring the simulation results closer to real data is the variational assimilation of observational data. In this paper the following approach is considered: it is supposed that there are observational data at a certain moment in time; the problem is considered as an inverse problem, in which the functions of fluxes across the open boundary are treated as additional unknowns. Comparison of methods for reconstructing unknown functions in boundary conditions at an open boundary using sea level and velocity observational data in a number of numerical experiments for a region of a simple shape is carried out.

Status of Indonesia's sovereign rights in the north natuna sea conflict area consequences of China's nine-dash line claim

The existence of sovereign rights in the North Natuna Sea has begun to be disturbed since China's claim of traditional fishing rights was strengthened by the nine-dash line claim. This claim includes the North Natuna Sea area into China's territorial sea, which makes this area a conflict area. The problem in this research is the existence of traditional fishing ground rights in UNCLOS III 1982 and the impact of the nine-dash line claim on Indonesia's sovereign rights in the conflict area of ??the North Natuna Sea. This study uses a normative legal research method with a statutory and conceptual approach. The results of the study explained that the 1982 UNCLOS III did not regulate traditional fishing ground, and the impact of the nine-dash line claim is very significant, as can be seen from the activities of Chinese fishers in the North Natuna Sea, which are supported by Chinese coast guard vessels, which have disrupted Indonesia's enjoyment of its sovereign rights. Thus, it can be concluded that the traditional fishing ground rights with the nine-dash line claim are not based on international law but are only based on China's unilateral claims and create conflicts that impact Indonesia.