Lake Bolsena Research Articles

Towards a cooperative governance. Lessons learned from the only Italian “River, Lake, and Coastal” Contract

This paper is a contribution to a special issue of “Interdisciplinarity and governance in water landscapes” with a critical reflection on the “Marta-Bolsena-Tarquinia” River, Lake, and Coast Contract research experience in the Lazio Region. This Contract is the only one in Italy that covers three different water landscapes, from lake to coast (Lake Bolsena, the river Marta and the Tarquinia coastline), all in the same water basin. However, despite the ambitious premises, research shows how this Contract has partially failed. Indeed, the in-depth study offers a commentary not only to better understand what did not work in this River, Lake, and Coast Contract process, but also to suggest how to move on from a formal coalition, towards much more cooperative practices by reforming the redistribution of responsibilities, power, and knowledge.

Opportunities for development of agro and family tourism in the area of lake Ohrid in the example of lake Bolsena – Italy

Opportunities for development of agro and family tourism in the area of lake Ohrid in the example of lake Bolsena – Italy

Long-term change in the trophic status and mixing regime of a deep volcanic lake (Lake Bolsena, Central Italy)

Lake Bolsena, the fourth Italian lake for volume (9.2 × 109 m3), must be considered as highly sensitive to eutrophication for its extremely long water renewal time. In this paper, temperature and chemical characteristics of the lake measured in the period 2003–2017 are used to discuss the mixing pattern and the variation in the oxygen and algal nutrient concentrations, as indicators of the trophic level. In the analysed period the lake showed oligomictic characteristics, reaching the full overturn, with homogenization of the chemical profile over the whole water column, only in 4 out of the 15 considered years. A regular decrease of oxygen and increase of phosphorus concentrations in the deepest layers has been observed in the non-circulating multi-year periods. The mean total phosphorus concentration showed a regular increase, reaching values close to 16 μg P L−1 in early spring 2017, mostly because of the urban discharge from the watershed, not adequately collected from an existing sewage pipe. Chemical and mixing patterns are discussed in relation with a previous study, carried out in 1966–1971, confirming the recent increase of phosphorus concentrations and the lower frequency of full circulation. The progressive deterioration of lake water quality indicates the need of prompt actions to reduce the external nutrient load and of further studies on the physical and biological characteristics of the lake, still strongly missing.

Micro-morphological, physical and thermogravimetric analyses of waterlogged archaeological wood from the prehistoric village of Gran Carro (Lake Bolsena-Italy)

Abstract Oak disks from pile dwellings of the prehistoric site of Gran Carro (lake Bolsena, Italy) were analysed in order to estimate wood degradation. Micro-morphological observations showed that the microbial decay could be mainly attributed to erosion bacteria. The most important physical properties, i.e. Maximum Water Content (MWC), Residual basal Density (RDb), and the calculation of the Lost Wood Substance (LWS) highlighted that heartwood (HW) was moderately preserved, with MWC values slightly higher or comparable to that of recent oak, whereas sapwood (SW) was very degraded. Thermogravimetric analysis (TGA) was tested as an alternative method for the chemical characterisation of archaeological wood. The TGA profiles were critically discussed taking into account the results of the physical and micro-morphological analyses. Potentialities and drawbacks of TGA were underlined.

Beyond the mean: A comparison of trace- and macroelement correlation profiles of two lacustrine populations of the crayfish Procambarus clarkii

In invertebrate biomonitors of chemical pollution, emphasis has been generally given to mean accumulation patterns and how they reflect varying environmental levels of contamination. Intra-population variability, and how it relates with individual phenotypic traits, has received less attention. Here, a set of analytes including trace elements (B, Ba, Cd, Cr, Cu, Fe, Li, Mn, Ni, Pb, Sr, V, and Zn), macroelements (C, Ca, K, Mg, N, Na), and carbon and nitrogen stable isotopes (δ13C and δ15N) was measured in two populations of the crayfish Procambarus clarkii from Lake Trasimeno and Lake Bolsena (Central Italy). The influence of location, sex, body size, and condition factor was assessed; in addition, the analyte correlation profiles of the two populations were compared to verify their congruence. In general, significant inter-lake differences were observed in the concentration of both trace- and macroelements in crayfish tissues, generally mirroring the local chemistry of water and of benthic non-living matrices (sediment and plant detritus). Crayfish CN isotopic signatures excluded the occurrence of inter-lake variations in their omnivorous trophic habits. Correlation profiles varied considerably between the two populations in the nature and strength of bivariate relationships. However, Mantel tests and procrustean analyses indicated a general, significant congruence; C, N, and, to a lesser extent K, Li, Ni, Pb, and δ13C showed the highest procrustean residuals, suggesting that their associations with other analytes may be partially influenced by inter-population differences in growing phases. Our study indicates that the local geochemistry of the lacustrine environment influences the elemental fingerprint of Procambarus clarkii; the considerable inter-individual variability in the concentration of analytes, however, does not significantly reflect on their association, thus corroborating its effectiveness as an indicator species.

Evidence for sub-lacustrine volcanic activity in Lake Bolsena (central Italy) revealed by high resolution seismic data sets

The Bolsena caldera that formed between 0.6 and 0.2Ma has a well preserved structural rim, which makes it an ideal site to study the tectonic and volcanic evolution of calderas. However, the main area is covered by a 150m deep lake which makes it rather difficult to investigate the subsurface structure directly. To overcome this problem new high resolution hydro-acoustic surveys using a multichannel reflection seismic system and a sediment echo-sounder system were conducted in September 2012. As space was limited we used a rowing boat towed by a rubber boat to handle a 36m long and 24 channel streamer to receive seismic reflections produced using a Mini GI-Gun (0.25 l).The subsurface structure of Lake Bolsena was imaged up to a sediment depth of ~190m, which is estimated to have filled over a period of 333kyrs. However, massive pyroclastic flow deposits found in the deeper parts of the basin indicate an initial infill of volcanic deposits from two adjacent younger calderas, the Latera (W) and Montefiascone (SE) calderas. Our data suggest that the caldera has a long history of active volcanism, because the lacustrine sediments show post-sedimentary influences of geothermal fluids. We mapped several mound structures at various stratigraphic depths. Two volcanic structures outcrop at the modern lake surface implying recent activity. One of these structures is hardly covered by sediments and has a crater-like feature in its summit. The other structure shows a pockmark-like depression on top. Another observable feature is a partially sediment filled crater located in the western part of the lake which further implies the existence of a magma chamber located beneath the Bolsena caldera. Since the late Pleistocene and Holocene, the sedimentation was mainly hemipelagic evidenced by a sediment drape of up to 10m thick sediment drape on the uppermost sediments. Beneath the drape we found evidence for a distal tephra layer likely related to an explosive eruption from the Campanian Volcanic Province occurring as the Neapolitan Yellow Tuff. Our new geophysical data set is a valuable record with a potential to constrain the sedimentary and volcanic evolution of the Vulsini Volcanic District in areas that have not been assessed previously due to logistical challenges of conducting surveys in water-filled settings.

Microplastic pollution in lakes and lake shoreline sediments – A case study on Lake Bolsena and Lake Chiusi (central Italy)

Rivers and effluents have been identified as major pathways for microplastics of terrestrial sources. Moreover, lakes of different dimensions and even in remote locations contain microplastics in striking abundances. This study investigates concentrations of microplastic particles at two lakes in central Italy (Lake Bolsena, Lake Chiusi). A total number of six Manta Trawls have been carried out, two of them one day after heavy winds occurred on Lake Bolsena showing effects on particle distribution of fragments and fibers of varying size categories. Additionally, 36 sediment samples from lakeshores were analyzed for microplastic content. In the surface waters 2.68 to 3.36 particles/m3 (Lake Chiusi) and 0.82 to 4.42 particles/m3 (Lake Bolsena) were detected, respectively. Main differences between the lakes are attributed to lake characteristics such as surface and catchment area, depth and the presence of local wind patterns and tide range at Lake Bolsena. An event of heavy winds and moderate rainfall prior to one sampling led to an increase of concentrations at Lake Bolsena which is most probable related to lateral land-based and sewage effluent inputs. The abundances of microplastic particles in sediments vary from mean values of 112 (Lake Bolsena) to 234 particles/kg dry weight (Lake Chiusi). Lake Chiusi results reveal elevated fiber concentrations compared to those of Lake Bolsena what might be a result of higher organic content and a shift in grain size distribution towards the silt and clay fraction at the shallow and highly eutrophic Lake Chiusi. The distribution of particles along different beach levels revealed no significant differences.

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.

An unhealthy holiday on Lake Bolsena

A 70-year old man (OL) was hospitalized due to fever (up to 40°C) associated with malaise and abdominal pain. Tests showed hypereosinophilic syndrome, and increased liver and inflammation indexes. Abdominal echography showed a nonhomogeneous liver and the spleen was enlarged. Abdominal computed tomography showed multiple abscesses on the liver. The patient reported that he had recently gone on holiday to Lake Bolsena where he had eaten raw fish. A specialist in infectious diseases confirmed that in that area there is an infestation of Opisthorchis felineus. Analysis of blood and stool samples confirmed the presence of this parasite. The patient was treated with praziquantel with resolution of fever and improvement in clinical tests and general condition. Opisthorchis felineus is a parasite that commonly infects dogs and cats. Infection is sometimes transmitted to man and is usually related to eating raw fish. The parasite enters the liver and its eggs are found in the patient’s stool samples. Acute symptoms are: fever, diarrhea, abdominal pain, and malaise. Hypereosinophilic syndrome and increase in liver index are typical. Chronic infection could result in cholangiocarcinoma. Presence of the parasite is confirmed through specific analysis of blood and stool. Therapy consists of praziquantel or, as second choice, abendazol. In the 20th century, there were 4 epidemics in Italy, on Lakes Trasimeno and Bolsena in Central Italy. The latest epidemic was reported in that area in summer 2012.

Foodborne Trematodiasis andOpisthorchis felineusAcquired in Italy

To the editor: Opisthorchiasis comprises diverse clinical manifestations caused by infections with Opisthorchis felineus or O. viverrini liver flukes, which are transmitted by eating infected raw or undercooked fish and other aquatic products. In regions outside Western Europe where human opisthorchiasis is endemic, the disease is mainly described as being chronic and asymptomatic. Recent studies indicate cases of O. felineus infection in the Mediterranean region, particularly Italy (1–4). Patients with acute infection have signs/symptoms ranging from fever to hepatitis-like signs/symptoms (e.g., pain in upper right abdominal quadrant, weakness, fatigue, loss of appetite, diarrhea, weight loss); sign/symptom onset occurs ≈2–3 weeks after infection, depending on the number of ingested flukes (2–4).

Littoral Trichoptera of volcanic lakes Vico and Bolsena (Central Italy)

The first list of Trichoptera from lakes Vico and Bolsena is reported. It is the result of research carried out in 1955 and 1971-1979 in lake Vico, and in 1957 and 1959-1990 in lake Bolsena. The distribution of caddisflies around the littoral zone depends on the environmental characteristics of the microhabitats. Overall, 16 species from 7 families were collected, 8 of which were found in both lakes, whereas 5 were only collected in Lake Vico, and 3 only occurred in Lake Bolsena. Hydroptila aegyptia and Ecnomus tenellus were the most abundant species in Vico, Tinodes waeneri and T. maclachlani in Bolsena. The trophic categories of the larvae and their gregarines were identified.

Lake Bolsena (Central Italy): an updating study on its water chemistry

In spite of its importance as regards size (volume 9.2 106 m3, max depth 151 m) and as a source of drinking water, Lake Bolsena has not been studied from a hydrochemical point of view since the second half of the 60s, when a group of researchers from the Istituto Italiano di Idrobiologia co-ordinated a complete study of the limnology of the Latium lakes Bolsena, Albano, Vico, and Bracciano. In the following years analyses were performed sporadically; since the 90s, temperature and oxygen profiles and other studies were made by the Associazione Lago di Bolsena. Based on chemical profiles made in 2001-2003, this paper discusses the present chemical composition of Lake Bolsena waters, and compares them with those of other volcanic lakes in Latium (Bracciano, Albano, Nemi and Vico). The paper briefly considers the main factors influencing the water chemistry of Lake Bolsena, the variations observed from the analyses of the 60s, and the main sources of risk to water quality.

Modelling the radionuclide balance in some water bodies of central Italy

This article illustrates the quantitative analysis of the radionuclide behaviour in some lakes of central Italy and in their outlets. The migration rates and the effective transport velocities of the radionuclides to sediment were estimated. In the examined lakes (Albano, Bolsena, Bracciano, Nemi and Vico), the concentrations of 90Sr and 137Cs show a marked exponential time decay due to the radioactive decay, the radionuclide removal by the outlets and the radionuclide migration from water to bottom sediments. It was estimated that the 137Cs average migration rate to sediment is 1.2 × 10 −9 s −1 corresponding to an effective migration velocity of 5.8 × 10 −8 m s −1. The radionuclide concentrations in watercourses Marta (outlet of Lake Bolsena) and Rio Vicano (outlet of Lake Vico) were fitted by exponential (decay) functions of the distance from the lake. The ‘half-distance’ of the above process (‘half-distance’ = the distance for the radionuclide concentration reduces to one half) is 12.6 km and 3.9 km for 137Cs in river Marta and Rio Vicano, respectively. The half-distances for 90Sr in the above watercourses are, respectively, 30 km and 5.8 km. The half-distances were quantitatively related to the effects of water dilution and to the radionuclide contribution from catchment. The analysed data offered the opportunity of calculating that the 90Sr contribution from catchment to the examined watercourses is in the order of 10 −3–10 −4 Bqs −1m −1 (radionuclide flowing per second and per metre of river).

Fatty acid composition of some coregonid species (Coregonus spp.) from different European lakes

The muscle tissue of coregonid ‘lavarello’ (Coregonus forma hybrida) from Lake Bolsena (Central Italy), ‘bondella’ (C. macrophthalmus) from Lake Maggiore (Northern Italy) and ‘bondelle’ (C. macrophthalmus) from Lake Neuchatel (Switzerland), sampled during the whitefishes' growth season, were analysed to evaluate the fat content and the fatty acid composition. In fact, the lipid profile of the muscle is strongly subjected to environmental influence and, as a consequence, its use as a parameter allowing ‘identification of origin’ of the fish products may be possible. ω3 HUFA (highly unsaturated fatty acids = C 20:5 + C 22:5 + C 22:6) content of fish from Lake Bolsena was lower than in coregonid from Lake Maggiore, while the saturated fraction (SFA) was higher. Fish from Lake Neuchatel showed a lower ω3 HUFA proportion than in the two other lakes. These data demonstrate that significant differences in fatty acid composition occur in similar fish species living in different lakes. Further studies are required to identify the role of each environmental variable, with special attention to temperature and food range.

Gastrotrichs from Lakes Bolsena, Chiusi and Montepulciano (central Italy), with the description of four new species

Abstract Twenty‐one species of gastrotrichs were found in samples collected from Lakes Bolsena, Chiusi and Montepulciano. Four are new species: Chaetonotus (Zonochaeta) dracunculus, C. (Z.) cestacanthus, C. trispinosus and C. pungens. Two, C. poznaniensis and Aspidiophorus oculifer, were recorded for the first time in Italy. Sperms are reported in C. (Z.) dracunculus. Qualitative differences exist between gastrotrichs of Lake Chiusi, an eutrophic environment rich in vegetation, and those of Lake Bolsena, an oligotrophic environment with sandy bottom. There is a consistent relationship between the cuticular characteristics of a species and the habitat in which it was found: species with reduced scales and spines live interstitially in detritus, whereas species with elaborate scales and long spines live on the surface of plants.

A Heteromorph of Venanzite

Venanzite. Venanzite is a volcanic rock consisting essentially of y melilite, leucite, olivine, and a little phlogopitic biotite, which occurs as small lava-flows of late- or post-Pliocene age near San Venanzo, Umbria, Italy. This isolated centre of activity lies north-west of Lake Bolsena and is regarded as an outlying part of the Vulsinian district of the Roman netroaranhic nrovince.