Bolsena Lake Research Articles

A multi analytical characterization of a small bronze figurine from Gran Carro site (Bolsena Lake, Italy)

This paper presents the results of an archaeometric analysis carried out on an early Iron Age anthropomorphic figurine discovered in the area of the Gran Carro on Bolsena Lake (Latium, Italy) site, currently interpreted as a place of worship. This statuette is considered a unicum, both because of the context in which it was found and because of its stylistic characteristics similar to those of bronzes from the Nuragic civilization (Sardinia, Italy). Its discovery and the data obtained from this work provide further evidence in support of numerous previous studies suggesting the presence of trade and direct exchanges between Sardinia and southern Etruria. The research was performed through some non-destructive investigations such as Energy Dispersive X-Ray Fluorescence (EDXRF) combined with Monte Carlo Simulation (MC) and micro-invasive investigations such as Scanning Electron Microscopy coupled by Energy Dispersive Spectroscopy (SEM–EDS) and by Electron Probe Micro-Analysis (EPMA), metallography and lead isotope analyses (LIA), performed on a selected micro-fragment. The combination of non-destructive techniques (EDXRF-MCS) for the characterization of the artefact allowed us to obtain data similar to those obtained with micro-invasive surveys, further demonstrating the effectiveness of the method. The results indicate that the statuette is made of a bronze alloy and that the copper metal was extracted from Sardinian deposits.

The wels catfish Silurus glanis Linnaeus, 1758 (Actinopterygii Siluriformes) in Italian waters: a review with first report in the Bolsena lake (Italy)

The wels catfish Silurus glanis Linnaeus, 1758 (Actinopterygii Siluriformes) in Italian waters: a review with first report in the Bolsena lake (Italy)

Millets and Cereal Meals from the Early Iron Age Underwater Settlement of “Gran Carro” (Bolsena Lake, Central Italy)

Archeobotanical materials recovered from pottery vessels originating from the underwater archeological site of “Gran Carro”, located in Central Italy on the shore of Bolsena Lake, were analyzed to obtain new insight into the agricultural habits present in this Iron Age settlement. The archeobotanical study of cereal remains was combined with analytical data obtained from an amorphous organic residue using optical microscopy, SEM-EDS, ATR/FT-IR and Py-GC/MS. The cereal remains of emmer wheat (Triticum dicoccum), barley (Hordeum vulgare), broomcorn millet (Panicum miliaceum), and foxtail millet (Setaria italica) were identified as the preferred crops used for food and/or fodder at the site. The presence of charred millets, which have been directly dated by AMS, confirms consumption at the site and adds to the little-known background of millet use in central Italy. The find of millets in a perilacustrine pile-dwelling during a period when the water level of the Bolsena Lake was several meters lower than at present, attesting to a general dry period, suggests that the cultivation of millets, complementing more productive crops of wheat and barley, may have been favored by the availability of a large seasonally dry coastal plain, characterized by poor and sandy soils unsuitable for more demanding cereals.

Behaviour and eating habits as determinants for human opisthorchiasis in the Bolsena Lake area, Italy.

In Italy, food-borne outbreaks of opisthorchiasis have occurred since 2003, all of them originating from some lakes in Central Italy where the only European liver fluke, Opisthorchis felineus (Rivolta, 1884) is endemic. The aim of the present study is to investigate the factors that may facilitate the life cycle of O. felineus in the area of Bolsena Lake, the knowledge of the local population about opisthorchiasis, and preventative healthcare measures. We performed a descriptive observational study through the submission of questionnaires to three target populations: fishermen who fish exclusively in Bolsena Lake, restaurateurs whose businesses are close to the lake and general population living in the province of Viterbo. Results showed hazardous behaviours and eating habits in the three target populations, as well as a poor knowledge of opisthorchiasis and preventative healthcare measures.

NUTRITIONAL DECLARATION OF RAW AND PROCESSED FILLETS OF BOLSENA LAKE WHITEFISH (COREGONUS LAVARETUS L.)

The aim of the study was to investigate and compare the nutritional value of raw and processed fillets (marinated and smoked) of whitefish from Bolsena Lake (Italy). The study was carried out in collaboration with the “Lago vivo” Fisherman Cooperative using 40 whitefish caught by net. The chemical composition showed increased nutrient (protein, lipid and carbohydrate) concentration with processing due to dehydration. Regarding the fatty acid profile of fillets, marinating was associated with higher levels of n-6 PUFAs, whereas the smoked and raw fillets showed higher concentrations of ?-linolenic, eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids. Whitefish ?llets were characterized by high nutritional value and good oxidative stability, mainly as smoked products.

On the role of hydrological processes on the water balance of Lake Bolsena, Italy

AbstractLakes or reservoirs are complex environmental systems, and the sustainable management of their water resources requires advanced hydrological modelling techniques of the main state parameters (water levels and volumes, temperature, pollution level, etc.) to forecast the impacts of human activities on their natural context. Bolsena Lake in northern Lazio is a typical Italian lake environment, being a source of both environmental and economic wealth for the neighbouring area, drawing tourists and providing drinking and irrigation water. The complexity of this hydrogeological and anthropogenic system, and the current technical/scientific relevance of the several water emergencies that have occurred at the lake over the past decade, highlighted the need for a solid plan to manage the possible extreme scenarios that can affect the lake basin, including mitigation of decreases in the lake levels and for controlling lake water quality and water flow rates. The objective of this study was to assess the water budget of Lake Bolsena, accounting for the various jointly involved components, in order to model the lake levels, and to examine possible future scenarios that consider both natural and anthropogenic basin factors. Hydrometeorological data are analysed for setting such scenarios. An open‐source computational model (CEQUEAU) was calibrated with the available data and then used to evaluate possible outcomes. The model simulation results demonstrated the developed hydrological model is capable of predicting water‐level fluctuations with a good accuracy for both drought and flood events, identifying it as a valuable tool for basin/lake and lake/river management and simulations.

Soil gas radon assessment and development of a radon risk map in Bolsena, Central Italy.

Vulsini Volcanic district in Northern Latium (Central Italy) is characterized by high natural radiation background resulting from the high concentrations of uranium, thorium and potassium in the volcanic products. In order to estimate the radon radiation risk, a series of soil gas radon measurements were carried out in Bolsena, the principal urban settlement in this area NE of Rome. Soil gas radon concentration ranges between 7 and 176 kBq/m3 indicating a large degree of variability in the NORM content and behavior of the parent soil material related in particular to the occurrence of two different lithologies. Soil gas radon mapping confirmed the existence of two different areas: one along the shoreline of the Bolsena lake, characterized by low soil radon level, due to a prevailing alluvial lithology; another close to the Bolsena village with high soil radon level due to the presence of the high radioactive volcanic rocks of the Vulsini volcanic district. Radon risk assessment, based on soil gas radon and permeability data, results in a map where the alluvial area is characterized by a probability to be an area with high Radon Index lower than 20 %, while probabilities higher than 30 % and also above 50 % are found close to the Bolsena village.

The ISCR Project ‘Restoring Underwater’: An Evaluation of the Results After Ten Years

The project ‘Restoring Underwater’ launched and conducted by the Underwater Archaeology Operations Unit of the Istituto Superiore per la Conservazione ed il Restauro (ISCR, Rome, Italy) is aimed at the study and the experimentation of instruments, materials, methodologies, and techniques for the restoration, conservation, and in situ display of ancient submerged artefacts. The project commenced in 2001 with the restoration of the vivaria of the Roman villa of Torre Astura (Nettuno, Rome), since 2003 the main subject of researches has been the submerged archaeological site of Baiae (Naples, Italy), where, over the years, the restoration of sectors of certain buildings in the protected marine area has been carried out: the Villa con ingresso a Protiro, the Villa dei Pisoni, the Via Herculanea, and the Building with porticoed courtyard near Portus Iulius. In 2007, in 2009, and in 2010 three new archaeological targets have been added to the research: a group of nine cast iron cannons discovered offshore the coast of the Marettimo Island (Sicily, Italy), the Roman wreck carrying a load of sarcophagi discovered off the coast of San Pietro in Bevagna (Taranto, Italy), and the traditional fishing boat recently discovered off the cost of Martana Island (Bolsena Lake, Italy).The purpose of this paper is to sum up the work in progress and the results of these ten years of the project. The paper will shows as the conservation and museum display in situ of underwater heritage must not just be considered an opportune choice but may in itself provide a strong stimulus for experimenting new materials and technologies as well as representing a factor in the socio-economic development of the communities concerned, as shown by the example of Baiae.

Integrating habitat restoration and fisheries management : A small-scale case-study to support EEL conservation at the global scale

The aim of this work was to develop a methodological framework for the management of local eel stocks that integrates habitat restoration with optimal fishery management. The Bolsena lake (Viterbo, Italy) and its emissary, the river Marta, were taken as a reference system. The river flows in the Mediterranean sea but its course is fragmented by a number of dams built in the past century preventing eel migration from and to the sea. Eel fishery in the Bolsena lake is thus sustained by periodic stocking of glass eels caught at the Marta river estuary. A detailed demographic model was applied to simulate fishery yields and potential spawner escapement under different recruitment and management scenarios. It was estimated that the high exploitation rates occurring in the nineties reduced the potential spawner escapement from the Bolsena lake to less than 1 t; under current harvesting rates, the potential spawner escapement is estimated in about 12 t while in pristine conditions (i.e. high recruitment and no fishing) estimated spawner escapement is about 21 t. This analysis thus showed that current fishery management would comply with the 40% spawner escapement requirement of the EU regulation 1100/2007 if the connections between the Bolsena lake emissary and the sea were fully re-established. This confirms the opportunity of an integrated approach to management at the catchment area level scale for eel populations, that shall hopefully contribute to the conservation of the global stock.

Dendrogeomorphological analysis of shore erosion along Bolsena lake (Central Italy)

Dendrogeomorphological research was conducted along a volcanic caldera lake of Bolsena in central Italy, Latium region, in order to investigate the erosion process that affects its coastline. Most of the trees sampled were black poplars ( Populus nigra L.) with root systems differently exposed. The cores taken from trunks show growth stress (suppression) at different times according to the distance of the tree from the shoreline. Results of the morphological analysis of the root systems were used as a qualitative estimate of the erosion process developing an erosion map of the lake's shoreline. The dating of suppressions was used to calculate the main horizontal erosion rate at different shoreline sectors. The most intense erosion was recorded on the southern and northern shore, affected by the strongest and long-lasting winds (mean erosion rate at southern coast=0.092 m/year, northern coast=0.064 m/year, eastern coast=0.049 m/year, western coast=0.028 m/year). The age of the living trees along the shore points out that the erosion started at least in the 1970s (one of the highest lake level episode) and it is still in progress.

Description of Parastenocaris amalasuntae n. sp. and new data on Parastenocaris proserpina and Parastenocaris pasquinii from subterranean waters of central Italy (Copepoda, Harpacticoida)

This work concerns the description of Parastenocaris amalasuntae n. sp., the redescription of Parastenocaris proserpina, and the addition of new morphological features for Parastenocaris pasquinii. The characters have been detected using light and scanning electron microscopy. Parastenocaris amalasuntae has been collected in the interstitial psammal of Bolsena Lake (Latium), in hyporheic and groundwaters of northern Latium, and in phreatic habitats of southern Tuscany. The species belongs to the proserpina species group Lang, 1948 and shows the closest affinities with P. proserpina. This last species had previously been collected in Bolsena Lake, where nowadays it seems to have been substituted by P. amalasuntae. Updated information on the distribution and ecology of the three species is also presented and discussed.

Plinian fall deposits from Vulsini Volcanic District (Central Italy)

Stratigraphic investigations of the Vulsini Volcanic District indicate the existence of five prominent plinian fall deposits, deposited over a period of about 0.34 Ma. The oldest deposit (‘Basal pumices’) crops out mainly in the peripheral areas and is one of the largest plinian events in the Vulsini District, with a volume of about 9 km3 and a calculated column height exceeding 30 km. Subcircular patterns of isopachs and isopleths around the Bolsena lake indicate emplacement in wind-free conditions and suggest a source vent location in the northernmost sector of the present Bolsena lake, where it is possible that an older central volcanic structure existed. The four younger plinian fall deposits are related to Bolsena activity. The oldest of these, named the ‘Ponticello’ and ‘Orvieto-Bagnoregio’ pumices, are mainly distributed on the north-eastern sector of the Vulsini District. Their volumes are an order of magnitude lower than that of the basal unit, and the estimated column heights do not exceed 20 km. The younger ‘Ospedaletto’ pumice deposit has a NE-SW dispersal axis, whereas the youngest ‘Casetta’ pumice deposit is found only in the north-eastern sector of the district. Their estimated volumes are respectively 1.2 and 0.1 km3, whereas the inferred vent areas appear to be located slightly to the east of the Ponticello and Orvieto-Bagnoregio pumice deposit source areas. The chronology of the Ospedaletto and Casetta pumices indicates that the final plinian activity from the Bolsena complex is contemporaneous with the Latera activity. The decreasing volumes from the oldest to the youngest units, together with the progressive shifting northeastwards of the source vents, may be related to the volcano-tectonic subsidence of the Bolsena area. The source vents for the post-Basal pumices events are mainly clustered just north of Bolsena village where the greatest displacement during subsidence occurred. Accordingly, source vent shifting appears to be related to the progressive opening of normal faults from the inner to the outer margin of the Bolsena depression.

Soil gas survey in the geothermal area of Bolsena Lake (Vulsini Mts., Central Italy)

A soil gas survey has been carried out in the Vulsini Mts. volcanic area, around Bolsena Lake, with the objective of testing the reliability of this geochemical method for geothermal exploration. The thermal gradient is high all over the area; the He/Ne ratio, and He, CO 2, and H 2 concentrations have been determined in 259 samples (2 per km 2, over an area of 130 km 2). Compared with its surroundings, this area exhibits an overall positive CO 2 anomaly, but the distribution of diffusive gases (He and H 2) allows us to distinguish three different sectors around the lake: (1) a northern sector with high CO 2, and H 2/CO 2, He/CO 2, and He/Ne ratios close to the background value; (2) a south-eastern sector, characterized by the presence of cold fumaroles, with high He, H 2, CO 2 and He/Ne, and generally low H 2/CO 2 and He/CO 2; (3) a southern sector with generally atmospheric He and CO 2 and few high H 2 and CO 2 spots. Permeability is assumed to be the main factor controlling the differences between the above three sectors. In sector 1, the flysch (1 km thick) is intruced by a great number of sills and dikes, and the underlying limestones are completely metamorphosed into marbles; CO 2 (thermometamorphic?) is the late stage of a heavy degassing process. Sector 2 includes several volcanic spatter cones along the tectonic trends; the high permeability allows the deep gases to be ducted with minor changes. Sector 3 is an elongated strip with an anti-Apennine trend; diffusion of H 2 only is the result of the thick (>3 km) unaltered flysch cover. In sector 3 the underground outflow of the lake through shallow volcanics entrains large quantities of air and masks any deep gases; the few anomalous spots reproduce situations like that of sector 2. One of these spots is located near a producing well tapping the geothermal reservoir.

Evidence of incremental growth in the Vulsinian calderas (central Italy)

Abstract A comparative work on the Vulsini calderas has been carried out, fundamentally from volcanological field study, drilling and gravity anomalies data. On the basis of a detailed stratigraphy, four volcanic complexes have been recognized in the Vulsini Volcanic District from the oldest to the youngest: Paleo-Bolsena, Bolsena, Montefiascone and Latera, the latter two complexes having a contemporaneous evolution. In their activity, each complex gave rise to several little calderas caused by piecemeal collapses due to moderate-size explosive eruptions or coherent subsidence of a superficial piston-like block. Nevertheless, the extensional volcano-tectonic regime affecting this area could have accounted for as much of the total subsidence as the caldera-forming eruptions. Bolsena and Latera calderas, respectively 16 km and 8 km in average diameter, represent the main depressions of the Vulsini District and their topographic features are still well preserved. Several collapses forming the main poligenetic calderas of Bolsena and Latera are masked at present by the Bolsena Lake, the younger volcanic covering, the lacustrine deposits and erosion in a minor amount. Only the little Montefiascone and Vepe calderas, which represent the youngest collapses of the Vulsini area, have not been masked. Bolsena caldera could be considered a depression caused mostly by a subsidence hinged to the southwest, by down-sagging and by collapses which occurred after the most important explosive eruptions of the Paleo-Bolsena, Bolsena and Montefiascone volcanic complexes. Meanwhile, Latera caldera is mostly due to a piecemeal collapse linked to several moderate-size ignimbrite units which were emplaced throughout the explosive activity of the Latera complex. Therefore, the Vulsinian calderas did not form by catastrophic eruptions, because several and frequent moderate-size eruptions, downsagging and tectonic hinged subsidence concur, indicating an incremental growth.