Idrochimica lacustre e dei tributari, bilancio dei nutrienti

No abstract availabl

Geomorphology and hydrochemistry of 12 Alpine lakes in the Gran Paradiso National Park, Italy

Twelve Alpine lakes located in the Gran Paradiso National Park, in the western Italian Alps, were sampled during the ice free period in 2008 and analysed for the main morphological, chemical and physical variables in relation to the characteristics of their watershed, with the aim to create a reference database for present and future ecological studies and to support conservation politics with scientific data. The results highlighted that weathering process and direct precipitation input are the main factors determining the hydrochemistry of the studied lakes; moreover the morphological characteristics highly affects the physical properties of the lakes starting from stratification process. The acidification status, the atmospheric input of N compounds and the supply of nutrients were considered in detail. The studied lakes seem to be well preserved by acidification risk. Comparing data from Gran Paradiso National Park with data from European mountain regions ranging in N deposition rates, allows to consider long range anthropogenic impact: the detection of relative low Total Nitrogen (TN) concentration is not necessarily a synonym of a soft impact of long range pollutants, being the final nitrogen concentration dependent from retention process, closely related to catchment characteristics, besides N deposition rates; moreover the dominance of Inorganic Nitrogen (IN) on Organic Nitrogen (ON) highlights that the lakes are interested by N deposition and probably by long range transport of pollutants produced in the urbanized area surrounding the massif. However the Gran Paradiso National Park area is by far less affected by atmospheric pollutants than other Alpine regions, as the Central Alps. Total Phosphorus (TP) concentration in Gran Paradiso lakes (1-13 ?g L-1, mean level = 4 ?g L-1) is an index of oligotrophic and ultraoligotrophic conditions and according to Redfield's ratio phosphorus is mainly the phytoplankton growth limiting element, assuming a key role in biological processes and food-web dynamics; the high TN:TP ratio values detected in the studied lakes reflects the low N retention capacity of alpine sparse vegetation by comparison with prairies or forests

Geomorphology and hydrochemistry of 12 Alpine lakes in the Gran Paradiso National Park

Twelve Alpine lakes located in the Gran Paradiso National Park, in the western Italian Alps, were sampled during the ice free period in 2008 and analysed for the main morphological, chemical and physical variables in relation to the characteristics of their watershed, with the aim to create a reference database for present and future ecological studies and to support conservation politics with scientific data. The results highlighted that weathering process and direct precipitation input are the main factors determining the hydrochemistry of the studied lakes; moreover the morphological characteristics highly affects the physical properties of the lakes starting from stratification process. The acidification status, the atmospheric input of N compounds and the supply of nutrients were considered in detail. The studied lakes seem to be well preserved by acidification risk. Comparing data from Gran Paradiso National Park with data from European mountain regions ranging in N deposition rates, allows to consider long range anthropogenic impact: the detection of relative low Total Nitrogen (TN) concentration is not necessarily a synonym of a soft impact of long range pollutants, being the final nitrogen concentration dependent from retention process, closely related to catchment characteristics, besides N deposition rates; moreover the dominance of Inorganic Nitrogen (IN) on Organic Nitrogen (ON) highlights that the lakes are interested by N deposition and probably by long range transport of pollutants produced in the urbanized area surrounding the massif. However the Gran Paradiso National Park area is by far less affected by atmospheric pollutants than other Alpine regions, as the Central Alps. Total Phosphorus (TP) concentration in Gran Paradiso lakes (1-13 ?g L-1, mean level = 4 ?g L-1) is an index of oligotrophic and ultraoligotrophic conditions and according to Redfield\u27s ratio phosphorus is mainly the phytoplankton growth limiting element, assuming a key role in biological processes and food-web dynamics; the high TN:TP ratio values detected in the studied lakes reflects the low N retention capacity of alpine sparse vegetation by comparison with prairies or forests

Chimica lacustre

No abstract availableChimismo di base, composti dell\u27azoto, composti del forsforo, ossigeno disciolto, silicati reattiv

Idrochimica lacustre e dei tributari, bilancio dei nutrienti

No abstract availabl

Glacier surface-area changes in Sagarmatha national park, Nepal, in the second half of the 20th century, by comparison of historical maps

AbstractWe investigate variations in the surface area of glaciers in Sagarmatha national park, Nepal, during the second half of the 20th century through comparison of a map applicable to the late 1950s with the official map of Nepal in the early 1990s. The comparison reveals a slight overall decrease in glacier area (by 4.9%, from 403.9 to 384.6 km2), a result which, though potentially subject to errors arising from cartographic interpretation, is in line with the area reductions found by other studies of Asian glaciers. We find that the areas of some individual glaciers, the largest situated at higher altitudes, increased during the study period. This was most apparent for the glaciers oriented to the south, with the increase occurring mainly in the glacier accumulation zones while the fronts tended to recede. Meanwhile, the smaller glaciers, situated lower and on steep basins, experienced a reduction. For the smaller glaciers, the sections most affected by change were the accumulation zones, and these glaciers showed a tendency for the front to advance. In this region there is a lack of climate data for high altitudes. Nevertheless, observations from stations situated around the park suggest that, alongside temperature variations which are often considered the primary factor eliciting glacier response, changes in precipitation play a significant role

Valutazione esterna di qualit? in cromatografia ionica. Quality Control IC Proficiency Test. QC-IC 2010-2

No abstract availableUn esercizio di intercalibrazione ? stato organizzato in collaborazione con Dionex Italia SpA. Il programma e conforme alle linee guida internazionali dei proficiency test ISO e ILAC in tutte le sue fasi di preparazione dei campioni forniti, memorizzazione ed elaborazione dei dati statistici, refertazione. La valutazione di proficiency per ciascun laboratorio viene eseguita con lo z-score calcolato per ciascun analita dallo deviazione standard assegnata (SDa) ottenuta dai coefficienti di variazione percentuale indicati nelle metodiche analitiche ufficiali o da precedenti esperienze di intercalibrazione.Hanno partecipato circa 50 laboratori di paesi diversi

Evoluzione stagionale e a lungo termine delle caratteristiche chimiche del Lago Maggiore e bilancio dei nutrienti a Lago (Azoto e Fosforo)

Not availableRicerche sull\u27evoluzione del Lago Maggiore. Aspetti limnologici. Programma triennale 2013-2015. Campagna 2013. Evoluzione stagionale e a lungo termine delle caratteristiche chimiche del Lago Maggiore e bilancio dei nutrienti a Lago (Azoto e Fosforo). Chimica di base e contenuto ionico delle acque lacustri. Composti dell\u27Azoto e del Fosforo e silicati. Ossigeno disciolto. Metalli in tracce. Apporti chimici dai tributari: caratteristiche chimiche e chimico-fisiche; concentrazioni medie areali; carichi chimici e bilanci di Azoto e Fosforo

Valutazione esterna di qualit? in cromatografia ionica Quality Control IC Proficiency Test QC-IC 2011-2

A proficiency test for the analysis of chloride, nitrate, sulphate, calcium, magnesium, potassium, sodium was organised with 29 laboratories from Italy and The Netherland

The water chemistry of some shallow lakes in Northern Patagonian and their nitrogen status in comparison with remote lakes in different regions of the globe

Eighteen small shallow lakes located in the Northern Patagonian Lake District, in southern South America, were sampled in 2001 and analysed for the main chemical variables (pH, conductivity, alkalinity, major ions and nutrients). The study lakes span a wide geographical and altitudinal range and belong partly to the Pacific and partly to the Atlantic watershed. The main aim of this study was to investigate the relationships between water chemistry and physical/geographical properties of these lakes. Secondly, the nitrogen content of the lakes was considered in detail, and results compared to those obtained in previous studies carried out in other remote areas of the globe (the Central Southern Alps in Italy, the Sierra da Estrela region in Portugal, the Svalbard Islands in the Arctic, the Khumbu-Himal region in Nepal, and the Terra Nova Bay area in Antarctica). In the Alps, lakes are characterised by markedly high nitrogen concentrations, manly as nitrate, due to the high inputs of nitrogen compounds from downwind sources like the Po Plain in Northern Italy. Conversely, lakes at remote locations such as the Andes, Antarctica and Himalaya are characterised by a low nitrogen content, mainly as organic nitrogen. This status is related to the limited atmospheric inputs of nitrogen affecting these regions