Environment health and intraspecific biodiversity in T. tubifex: a preliminary analysis of a population from Apennines springs

The cosmopolitan freshwater oligochaete Tubifex tubifex is an important health indicator of the aquatic environment. Water pollutants can affect the intraspecific biodiversity grade of local Tubifex colonies. A genetic profile of specimens collected in an environment with reduced anthropic presence is particularly important to define genetic variability in unperturbed Tubifex populations, and it is still missing in the international literature. Therefore, it has been performed the analysis of lineage composition in a T. tubifex colony from high mountain spring ponds in Central Italy, characterized by a very low concentration of heavy metals. The sampling was performed during spring 2010 and 2011, in the Sett’acque valley (1,900 m above mean sea level), within the township of Lucoli. Data presented in this work depicted a peculiar composition of the population, characterized by a reduced complexity compared to other urban environments, and with no specimens belonging to the lineage I, largely described in many European populations. Interestingly, lineage 2e, previously discovered only in a natural reserve, results to be the most common lineage in this population. Considerations on environmental health and genetic evolution are discussed.     

Integration of local and scientific knowledge to support drought impact monitoring: some hints from an Italian case study

According to the Hyogo Framework for Action, increasing resilience to drought requires the development of a people-centered monitoring and early warning system, or in other words, a system capable of providing useful and understandable information to the community at risk. To achieve this objective, it is crucial to negotiate a credible and legitimate knowledge system, which should include both expert and local knowledge. Although several benefits can be obtained, the integration of local and scientific knowledge to support drought monitoring is still far from being the standard in drought monitoring and early warning. This is due to many reasons, that is, the reciprocal skepticism of local communities and decision makers, and the limits in the capacity to understand and assess the complex web of drought impacts. This work describes a methodology based on the sequential implementation of Cognitive Mapping and Bayesian Belief Networks to collect, structure and analyze stakeholders’ perceptions of drought impacts. The methodology was applied to analyze drought impacts at Lake Trasimeno (central Italy). A set of drought indicators was developed based on stakeholders’ perceptions. A validation phase was carried out comparing the perceived indicators of drought and the physical indicators (i.e., Standard Precipitation Index and the level of the lake). Some preliminary conclusions were drawn concerning the reliability of local knowledge to support drought monitoring and early warning.     

Imaging of the Antarctic ionosphere: Experimental results

Ground-based dual-frequency GPS observations can be used to create images of electron density. This is well established for the Arctic ionosphere; here one of the first results is presented for the Antarctic. In this study, the GPS receivers in the Antarctic are supplemented with another GPS receiver onboard CHAMP. The aim of the study is to demonstrate the technique for investigating geophysical events, for example, an ionospheric disturbance period on 11 February 2004. The images have been validated by in-situ measurements from DMSP and CHAMP satellites, as well as Super Dual Auroral Radar Network (SuperDARN) convection patterns, which are able to confirm the location, presence, and transportation of large-scale plasma patches. This study indicates that although the convection still dominates in the high-latitude ionosphere, soft precipitation within the polar cap may play a role in the evolution of the polar patches. It also illustrates the potential for future multi-instrument studies of the Antarctic.     

Multi-wavelength observations of flares and eruptive filaments

In this paper we report some results obtained from multi-wavelength observations carried out to study the mechanisms operating in flares and filament eruptions. Most of these studies have given indication of the presence of phenomena that might be considered signatures of magnetic reconnection, while others have pointed out the important role played by magnetic helicity transport in corona before the eruptive phase.     

Emergence and evolution of active and ephemeral regions: Comparison between observations and models

This work aims to describe some aspects relevant to the emergence of magnetic structures on the solar surface. Using high resolution photospheric and chromospheric data, besides than EUV images acquired by space telescopes, the dynamics of rising flux tubes is studied. It is shown that, for both long-lived and short-lived magnetic regions, the flux tubes are initially characterized by a high rising velocity, which eventually decreases as the region develops. Other results concern the timeline of the active regions appearance in the atmospheric layers and the asymmetries in plasma downflows between preceding and following legs of the flux tubes. These results are briefly discussed in the light of most recent models.     

Relict nebkhas (pimple mounds) record prolonged late Holocene drought in the forested region of south-central United States

The origin and significance of pimple mounds (low, elliptical to circular dune-like features found across much of the south-central United States) have been debated for nearly two centuries. We cored pimple mounds at four sites spanning the Ozark Plateau, Arkansas River Valley, and Gulf of Mexico Coastal Plain and found that these mounds have a regionally consistent textural asymmetry such that there is a significant excess of coarse-grained sediment within their northwest flanks. We interpret this asymmetry as evidence of an eolian depositional origin of these mounds and conclude they are relict nebkhas (coppice dunes) deposited during protracted middle to late Holocene droughts. These four mounds yield optically stimulated luminescence ages between 2400 and 700 yr that correlate with well-documented periods of eolian activity and droughts on the southern Great Plains, including the Medieval Climate Anomaly. We conclude vegetation loss during extended droughts led to local eolian deflation and pimple mound deposition. These mounds reflect landscape response to multi-decadal droughts for the south-central U.S. The spatial extent of pimple mounds across this region further underscores the severity and duration of late Holocene droughts, which were significantly greater than historic droughts.     

Fake quakes in Italy through parametric catalogues and seismological compilations: case histories and typologies

The Italian catalogue contains many earthquakes of moderate to high epicentral intensity which are located in areas of low seismicity and near big cities. Some of them have been inserted in the catalogue after one historical record only. This study investigates many such events in the 1000–1690 time-window showing that a great number of them are fake. Starting by an operational definition of ‘fake quake’, this paper shows the procedures adopted, and the main results which contribute in a significant way to the reassessment of seismicity and seismic hazard.     

Copper complexing capacity of phytoplanktonic cell exudates

Copper complexing capacity of cell exudates of Dunaliella salina in natural seawater culture medium was investigated in order to evaluate the influence of this organism on speciation of trace metals in seawater.Seawater samples were collected at 200 m and 2 miles off the coast and immediately filtered. Copper complexing capacity (CC_Cu) and stability constants (K′) of related cupric complexes were then measured. They were, respectively, 27.1 × 10⁻⁸ mol l⁻¹ and 0.56 × 10⁷ l mol⁻¹ for the samples collected at 200 m and 12.8 × 10⁻⁸ mol l⁻¹ and 6.10 × 10⁷ l mol⁻¹ for those collected 2 miles off the coast. A stock culture (20 ml, 10⁶ cells ml⁻¹) in log-phase was inoculated in 2 l of each sample of filtered natural seawater. The trend of cell influence was estimated on filtered culture medium by measuring CC_Cu and K′ after 1 h, 3 and 7 days. From the results it appears that CC_Cu increased with respect to time and this was related to the growth rate, indicating a certain relationship with cell metabolic activity.It can be concluded that a comparison between the culture referring to 200 m and 2 miles, respectively, shows that the former presents a CC_Cu two times higher than the latter while the K′ is ten times higher at 2 miles than that at 200 m.     

Green‐Ampt Curve‐Number mixed procedure as an empirical tool for rainfall–runoff modelling in small and ungauged basins

The Soil Conservation Service Curve Number (SCS‐CN) method is a popular rainfall–runoff model that is widely used to estimate direct runoff from small and ungauged basins. The SCS‐CN is a simple and valuable approach to quantify the total streamflow volume generated by storm rainfall, but its use is not appropriate for estimating the sub‐daily incremental rainfall excess. To overcome this drawback, we propose to include the Green‐Ampt (GA) infiltration model into a mixed procedure, which is referred to as Curve Number for Green‐Ampt (CN4GA), aiming to distribute in time the information provided by the SCS‐CN method. For a given storm, the computed SCS‐CN total net rainfall amount is employed to calibrate the soil hydraulic conductivity parameter of the GA model. The proposed procedure is evaluated by analysing 100 rainfall–runoff events that were observed in four small catchments of varying size. CN4GA appears to provide encouraging results for predicting the net rainfall peak and duration values and has shown, at least for the test cases considered in this study, better agreement with the observed hydrographs than the classic SCS‐CN method. Copyright © 2012 John Wiley & Sons, Ltd.     

Global nature of the Paleoproterozoic Lomagundi carbon isotope excursion: A review of occurrences in Brazil,India, and Uruguay

Positive carbon isotope excursion is reported from Paleoproterozoic carbonates of the Aravalli Supergroup (northwestern India), the Minas Supergroup (Brazil), and new sections of the Paso Severino Formation (Uruguay). The 2.42 Ga Gandarela Formation, Minas Gerais, Brazil, contains red carbonate-facies BIF grading into dolostones and limestones and yielding δ¹³C values ranging from −1.6 to +0.4‰ V-PDB. The positive C-isotope excursion (up to + 11‰ V-PDB) in marine shallow-water carbonates in India and Brazil (Jhamarkotra Formation in northwestern India, and Cercadinho and Fecho do Funil formations in Minas Gerais State, Brazil) is comparable to that observed in 2.22–2.1 Ga carbonate successions worldwide that were deposited during the Lomagundi excursion. In Uruguay, δ¹³C values up to +11.6‰ V-PDB in the deep-water Paso Severino Formation of the Piedra Alta Terrane are compatible with deposition at ca. 2.15 Ga, as indicated by the 2146 ± 7 Ma U–Pb age of dacites occurring at the top of the unit. Negative δ¹³C values are also present in carbonates of the Paso Severino Formation, but an origin related to organic-matter remineralization cannot be ruled out. Thin carbonate beds in the Rio Itapicuru greenstone belt, Bahia State, Brazil, are associated, as in the Paso Severino Formation, with deep-water black shales and have carbon isotope values up to +9‰ V-PDB. High metamorphic grade carbonates of the Jacurici terrane in the Medrado-Ipueira area, Bahia, Brazil, have carbon isotope values up to +6.9‰ V-PDB, consistent with their minimum age of 2085 ± 5 Ma inferred from the intrusive contact with and the age of the Medrado norite. No evidence was found in India, Brazil, or Uruguay for Paleoproterozoic glacial events recognized in the 2.45–2.22 Ga sedimentary successions worldwide. Unconformities between the Gandarela and Cercadinho formations in Brazil and the banded gneissic Complex and the Lower Aravalli Supergroup in India might explain the absence of glacial record. Compositional and isotopic data presented here for studied Paleoproterozoic carbonate successions allow their integration into the global record of the Paleoproterozoic evolution as well as correlation with other successions of similar age. The study highlights the global nature of the Lomagundi excursion. Furthermore, it indicates that the Lomagundi excursion is recorded in both shallow-water (Aravalli and Minas supergroups) and deep-water carbonates (Paso Severino Formation and Rio Itapicuru greenstone belt) negating a significant impact of stromatolite productivity and hypersaline conditions on carbon isotope values of carbonates deposited in shallow-water, open-marine and isolated basins.