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Ricerche sull\u27evoluzione del Lago Maggiore. Aspetti limnologici. Programma triennale 2013-2015. Campagna 2015 e rapporto triennale 2013-2015. Conclusioni
No full textNot availableConclusioni del volume "Ricerche sull\u27evoluzione del Lago Maggiore. Aspetti limnologici. Programma triennale 2013-2015. Campagna 2015 e rapporto triennale 2013-2015
Development of a full-life cycle and reproduction bioassay with the freshwater cyclopoid Eucyclops serrulatus
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Status quo of knowledges on Italian high altitude lacustrine macroinvertebrates
No full textHigh altitude lakes and their fauna are one of the most threatened and less investigated ecosystems in Italy. Alpine lakes are highly influenced by climate harshness and by air pollution, and because of their small dimensions are extremely vulnerable to global climate warming. Italy, in addition to the Alps, hosts another mountain range: the Apennines, reaching in some cases comparable altitudes, and therefore subject to the same risks. Moreover, the gentler slope of the Apennines makes them extremely vulnerable even to direct human impacts. In the present work, for the first time, high altitude lakes belonging to the Alps and to the Apennines are compared to highlight which meteo-climatic or chemical characteristics could be considered key drivers for their macroinvertebrate structure. The study area was explicitly focused on natural lakes placed above 1300 m of altitude and above the 44? parallel, thus in the alpine area and subject to a continental climate. 25 lakes were chosen (19 in the central-western Alps and 6 in the Modenese Apennines) with surface areas lower than 1 km2 and with maximum depths lower than 15 m. Physico-chemical parameters and macroinvertebrates were studied and compared. Samples were taken through the use of a hand-net (250 ?m mesh size) along the littorals on different substrates following standardised methodologies during the richerfauna season to allow an easier identification of species. Parallel to that, water samples were collected and analysed. Species richness and the Taxonomic Distinctness Indices were applied to underline the different complexity of the community structure of the two areas. Results showed different macroinvertebrates communities with peculiar characteristics and highlighted a more structured and diverse composition on the Apennines. Predictive models on the future climate scenarios show how the peninsular portion of Italy will be even more affected by the increase in temperatures than the Alpine area. Thus, this work could be highly informative, mainly for central Italy, where proximity to towns encourage tourists to reach these type of lakes, even if placed in protected areas or parks. Therefore, protection and management plans, and conservation efforts of high altitudes cannot overlooked a thorough understanding of the biological diversity of these environments, which still appears fragmented and limited to some sector of the Alps. Furthermore, the fundamental role of high altitude lakes as water resource needs a specific management regime, as they are not included under the monitoring programs of the Water Framework Directive legislation
Macrogels in a deep oligotrophic lake: their role in the organic carbon cycle
No full textMacrogels such as transparent exopolymer particles (TEP) can be especially significant in freshwaters as in the oceans because they constitute microenvironments that exhibit peculiar physical, chemical, and biological properties. In addition, in inland waters TEP can affect carbon export and sequestration in sediments because they appear to be critical for the formation of particles aggregates. Previous studies show that TEP concentrations can be large relative to the organic carbon pool in both marine and freshwaters. Despite this apparent relevance of TEP for their role as microbial substrate or by product and for carbon export to sediments, no studies exist on TEP in southern alpine large oligotrophic and deep lakes. We started the first extensive analysis on TEP concentrations in Lake Maggiore, where in recent years the presence of TEP become evident, associated to diatoms in spring or as wind accumulated foams. We determined the significance of TEP in terms of carbon in comparison to total organic carbon (TOC), and bacterial and phytoplanktonic carbon. In addition, we explored the persistence in time and space of TEP and the potential influence of biological and chemical factors as drivers of TEP concentrations in the water. Our two-year study showed that in the oligotrophic Lake Maggiore, characterized by low TOC concentration (summer max ~ 1.6 mg L-1), TEP can reach the 36% of TOC in the photic layer never exceeding the 2% in the hypolimnion, below 50 m depth. TEP concentration also exhibit clear seasonal variability mirroring that of phytoplankton, ranging 0-489 mg L-1
Long-term persistence of sedimentary copper contamination in Lake Orta: potential environmental risks 20 years after liming
Get PDFLake Orta, northern Italy, has suffered from severe copper pollution and human-induced acidification between the 1920s and the 1990s because of discharges from a rayon factory and electroplating industries located in its water basin. Following liming operations in the late 1990s, the chemical quality of the water column has been restored and signs of, still ongoing, biological recovery observed. Examination of two sediment cores collected close to the main historical Cu discharge and in the central part of the Lake shows that Cu concentrations in the uppermost layers of bottom sediments remain 10 to 40-fold higher than background levels. Past studies demonstrated the toxic potential of Lake Orta sediments to a variety of organisms at Cu concentrations comparable to present ones. Comparison with published results suggests that current level of Cu contamination may still pose a risk to sediment-ingesting organisms and slow down further ecological recovery of Lake Orta. Particular attention should be given to understand the effects of dietary ingestion of Cu from sediments which, unlike in previous ecotoxicological studies, may now represent the main route of Cu exposure for sediment-ingesting benthic organisms
Micro-players for macro-roles: aquatic microbes in deep lakes
Get PDFDespite their relative low volume on a global scale, lakes represent a valuable reserve of accessible freshwaters. Any increase in our understanding of their functioning is a step towards their better exploitation and preservation. Microorganisms drive the metabolic processes that regulate the biogeochemical cycles in lakes; here, I will focus on Archaea and Cyanobacteria as micro-players playing macro-roles in lake ecosystems. In particular, I will present two examples to demonstrate the importance of prokaryotes in lakes: picocyanobacteria and mesophilic archaea. The role of prokaryotes in lakes will be discussed in relation to their taxonomy, dynamics and ecology using these two examples. The challenge, now, is to better understand the relationship between the diversity and the physiology of various ecotypes, how these interact with each other and with environmental factors allowing the proliferation of the most competitive genotypes
Exploring copepod distribution patterns at three nested spatial scales in a spring system: habitat partitioning and potential for hydrological bioindication
Get PDFIn groundwater-fed springs, habitat characteristics are primarily determined by a complex combination of geomorphic features and physico-chemical parameters, while species assemblages are even more intricate. Springs host species either inhabiting the spring mouth, or colonizing spring habitats from the surface or from the aquifers which feed the springs. Groundwater species living in springs have been claimed as good candidates for identifying dual aquifer flowpaths or changes in groundwater pathways before reaching the spring outlets. However, the reliability of spring species as hydrological biotracers has not been widely investigated so far. Our study was aimed at analysing a large karstic spring system at three nested spatial scales in order: i) to assess, at whole spring system scale, the presence of a groundwater divide separating two aquifers feeding two spring units within a single spring system, by combining isotope analyses, physico-chemistry, and copepod distribution patterns; ii) to test, at vertical spring system scale, the effectiveness of copepods in discriminating surface and subsurface habitat patches within the complex mosaic spring environment; iii) to explore, at local spring unit level, the relative role of hydrochemistry and sediment texture as describers of copepod distribution among microhabitats. The results obtained demonstrated the presence of a hierarchical spatial structure, interestingly reflected in significant differences in assemblage compositions. Copepod assemblages differed between the two contiguous spring units, which were clearly characterized by their hydrochemistry and by significant differences in the groundwater flowpaths and recharge areas, as derived by the isotope analyses. The biological results suggested that stygobiotic species seem to be related to the origin of groundwater, suggesting their potential role as hydrological biotracers. At vertical scale, assemblage composition in surface and subsurface habitats was significantly different, both between spring units and among microhabitats, supporting strong habitat preferences of copepod species. At the smaller local scale, the response to habitat patchiness of subsurface copepod assemblages resulted in distribution patterns primarily defined by sediment texture, while the sensitivity to differences in hydrochemistry was negligible
Italian classification method for phytoplancton in lakes. Method summary and boundary setting protocol
No full textThis document outlines how status is assigned for the biological quality element phytoplankton and how boundaries have been assigned in Italy. The metrics included in the Italian phytoplankton assessment method developed for Alpine lakes are the biomass metrics chlorophyll a and total biovolume and the taxonomic composition metric PTIot. The reference value and HG boundary for each metric and each type were set from the median and the 90th %ile of the AlpGIG reference sites (lake-years) respectively. The GM, MP and PB metric boundaries were set using equidistant class widths on a log scale
Rilascio e insediamento di Torymus sinensis (Hymenoptera Torymidae) in Sardegna
No full textThe classical biological control based on the release of the parasitoid Torymus sinensis Kamijo (Hymenoptera, Torymidae) is considered to be the only effective method of controlling Dryocosmus kuriphilus ((Hymenoptera, Cynipidae), a major pest of Castanea species worldwide. In our multi-year study, performed between 2009 and 2015, we confirm the establishment of T. sinensis in Sardinia (Italy) and its effectiveness in controlling gall wasp infestation
KPI Ontology and Learners Assessment Mechanisms
No full textPublic Administrations need to ensure that their employees (civil servants) are able to learn fast how to correctly execute relevant business processes and hence meet their business goals on strategic and operational levels. Concerning the strategic business goals, they hence need to derive operational goals and learning goals, i.e. for each organisational goal, they need to answer the question: hich competencies do civil servants need to acquire in order to help achieve that business goal? Having identified the learning goals, Public Administrations - in order to take appropriate actions and implement suitable measures for learning - must be able to identify the gaps in civil servants\u27 competencies, to track progress in closing them and to provide guidance and support to employees in the learning process. Tracking progress can be done e.g. via suitable (learning) KPIs. This deliverable describes the design of a comprehensive solution to the above challenges: it outlines how we studied the example of the Titolo Unico process to understand typical goals and KPIs that were required to plan and track learning in a real workplace environment. Based on the insights from this domain analysis, we elaborate a meta-model, suited to model all relevant aspects of a learning scorecard - a tool that helps to model learning goals, connect them to organisational goals and define KPIs for assessing their achievement. To illustrate the approach, we have created a learning scorecard with strategic, operational and learning goals and corresponding KPIs for the Titolo Unico process. We have taken care to keep the elements generic such that they will suit different business processes in different Public Administrations. Finally, we describe the design of a dashboard to visualise goal achievements. In addition to these concepts, we also introduce methods for assessing learning outcomes, i.e. for measuring KPI values: we show how learners\u27 achievements can be measured on the basis of traces from the collaborative workspace and simulation environment and we discuss the design of questionnaires that can be used to test civil servants\u27 knowledge about certain relationships captured in domain and process models. A prototypical implementation of these methods has been performed