CARATTERISTICHE PALEOAMBIENTALI IN AMBIENTI MARINI ATTUALI E SUBATTUALI MEDIANTE L'USO DI MARKERS BIOGEOCHIMICI

2002/2003Le interazioni che avvengono nella regione antartica tra atmosfera, ghiaccio, oceano e comunità biologiche influenzano il sistema globale attraverso meccanismi a feedback che coinvolgono i cicli biogeochimici, la circolazione oceanica profonda, il trasporto atmosferico dell'energia e degli agenti inquinanti e le variazioni nel bilancio di massa glaciale (SCAR, 1992). Lo studio del ghiaccio e del sedimento consentono pertanto di ricostruire sia le sequenze climatiche sia, dall'analisi delle loro caratteristiche, ottenere informazioni paleoambientali, importanti in particolare per valutare le modificazioni del ciclo del carbonio. Vista l'assenza di input antropici e continentali, la matrice organica sedimentata risulta tipicamente marina ed è riconducibile ai processi biologici che avvengono lungo la colonna d'acqua. E' possibile ipotizzare, pertanto, che le caratteristiche composizionale della sostanza organica sedimentata, stante i processi di degradazione e rimineralizzazione, riflettano le condizioni ambientali nelle quali c'è stata la produzione. Va comunque rimarcato che, per quanto riguarda l'ambiente antartico, sono note le quantità complessive di sostanza organica nelle successioni plioquaternarie, ma quasi esclusivamente in termini di Carbonio organico e Silice biogenica, mentre sono scarsissimi le informazioni sulla composizione qualitativa. Alla luce di queste osservazioni il lavoro della presente tesi è stato rivolto allo studio della composizione biopolimerica della sostanza organica dei sedimenti profondi antartici al fine di: 1. ottenere informazioni sulla distribuzione, lungo il sedimento della frazione labile (proteine, lipidi, carboidrati) maggiormente legata ai processi biologici della colonna d'acqua 2. definire se le quantità in gioco sono associate a processi di produzione o a processi di preservazione/degradazione 3. verificare la possibilità di utilizzare le informazioni derivanti dalla composizione biochimica della sostanza organica in chiave paleoambientale Il protocollo sperimentale ha previsto il campionamento di due carote di sedimento nel bacino Joides, caratterizzato da elevati tassi di sedimentazione di materiale biogenico, a loro volta legati ad un intenso sviluppo delle comunità planctoniche. Vista l'ipotesi di partenza che prevedeva di utilizzare parametri di tipo biologico, generalmente non considerati nel corso degli studi sedimentologici, si è scelto di operare in un'area in cui esistesse una conoscenza pregressa dei processi sedimentari e dell'evoluzione paleoambientale. Le carote studiate sono state raccolte nel corso di due diverse campagne oceanografiche effettuate nell'ambito del Progetto Nazionale di Ricerca in Antartide (PNRA). Durante la XVI campagna (2000-2001) è stata campionata la carota ANTAOl-07 mentre la carota ANTA03-01 è stata prelevata nel corso della XVIII spedizione (2002-2003). Il campionamento è stato realizzato utilizzando un carotiere a gravità da 2.3 ton, con diametro interno di 90 mm. Dopo la misura della suscettività magnetica, le carote sono state sezionate, descritte, fotografate e successivamente campionate. I campioni sono stati sottoposti alle classiche analisi sedimentologiche (contenuto d'acqua, granulometria, carbonio organico, azoto totale) e alla determinazione dei biopolimeri (lipidi, proteine, carboidrati). Sulla carota ANTA03-01 è stata eseguita, immediatamente dopo il campionamento, anche la valutazione dell'attività enzimatica degradativa. Dai risultati ottenuti emerge che la sostanza organica di origine biogenica, sedimentata nel bacino Joides, è costituita, per circa il 10%, da biopolimeri (lipidi, proteine, carboidrati), concentrazioni analoghe a quanto rilevato in sedimenti profondi di zone temperate fortemente produttive. Questa frazione labile della sostanza organica subisce degli intensi processi di degradazione ai livelli superficiali che si protraggono fino a profondità che raggiungono il metro. La presenza di ossigeno nelle acque di fondo facilita, infatti, la degradazione aerobia diminuendo la preservabilità delle molecole più labili. La sostanza organica sedimentata risulta fortemente arricchita in materiale proteico che viene velocemente degradato poiché rappresenta un'importante serbatoio di azoto. Il rapporto C/N, infatti, aumenta con la profondità del sedimento a dimostrazione del progressivo arricchimento in carbonio. / I maggiori input di materiale organico corrispondono ai periodi di optimum climatico e si riflettono in una più elevata concentrazione della frazione biopolimerica. I carboidrati, in particolare, sembrano fornire buone indicazioni paleoambientali facendo ipotizzare una loro possibile utilizzazione come marker. Questa frazione organica risulta diversamente concentrata nelle due carote studiate sottolineando le differenze esistenti tra il bacino Joides settentrionale e quello meridionale. · I risultati ottenuti rappresentano un primo approccio ad una problematica estremamente complessa che riguarda, nell'aspetto più ampio, il ciclo del carbonio ed il ruolo del sedimento come serbatoio sia di molecole organiche che, e forse soprattutto, di informazioni pregresse.XV Ciclo1959Versione digitalizzata della tesi di dottorato cartacea

Microbial processing of sedimentary organic matter at a shallow LTER site in the northern Adriatic Sea: an 8-year case study

Benthic prokaryotes are the key-players in C-cycling at the sediment-seawater interface, one of the largest biologically active interfaces on Earth. Here, microbial-mediated processes, such as the degradation of organic matter and the incorporation of mobilized C into microbial biomass, depend on several factors such as environmental temperature and substrate availability, especially in shallow sediments at mid-high latitudes where seasonal fluctuations of these variables occur. In the present study, four degradative activities (β-glucosidase, lipase, chitinase and aminopeptidase), Heterotrophic C Production (HCP), Total Organic C (TOC), Total Nitrogen (TN) and Biopolymeric C (BPC) were investigated seasonally from April 2010 to April 2018 in the surface sediments of a shallow Long-Term Ecological Research (LTER) station of the northern Adriatic Sea. Significant temperature-dependences were described by Arrhenius-type equations for HCP and each of the degradative activities tested with the exception of aminopeptidase. The relatively low apparent Activation Energies suggested that these microbial-mediated processes were enhanced by the availability of palatable substrates over the study period. Nevertheless, a clear and tight dependence from such substrates was detected only for aminopeptidase, the most pronounced degradative activity observed. TN was identified by the stepwise multiple regression analysis as the environmental variable that mainly drove this exoenzymatic activity. Enhanced aminopeptidase rates mirrored peaks of TN that seemed, in turn, linked to the seasonal proliferation of benthic microalgae. By supplying prokaryotes with promptly available substrates, these autotrophs, represented mainly by diatoms, seemed to play an important role in the C-cycling regulation at the studied LTER station

Use of deferoxamine (DFO) in transfusion-dependent β-thalassemia during pregnancy: A retrospective study.

Objective: To report cases of use of chelation therapy during pregnancy which resulted in favorable outcomes for the babies. Materials and methods: In this retrospective cohort study, we described the evolution and outcome of 9 pregnancies in Italian thalassemic women who received deferoxamine (DFO) inadvertently during early pregnancy. Results: The use of deferoxamine during first trimester did not lead to adverse effects on the fetus or cause major complications for the gestation, although an increase in iron burden was observed after suspending chelation therapy. Conclusion: In our experience, iron-chelation therapy might be administrated in pregnancy where the benefits to the mother outweigh the potential risks to the baby. Keywords: Deferoxamine, Iron chelation therapy, Magnetic resonance T2*, Pregnancy, Thalassemi

Socio-Economic Analysis, Ecological Impacts and Sustainability of Long Line Mussel-Farming in the Gulf of Trieste

Mussels aquaculture is a relevant activity for the fishery sector of the North Adriatic. Around 15 km of coastal water of the Gulf of Trieste, Italy, are used for the mussel long line farming, for a production of about 5000 tonn/year. The aim of this work is to assess sustainability of this activity in a Ecological-Socio-Economical (ESE) perspective by evaluating the role of mussels farming in the socio economic system and in the ecological system. A socio economic analysis has been conducted involving local stakeholders in meetings, and also by contacting them with bilateral interviews and questionnaires. Results of questionners, together with mussels production data declared at the Sanitary authority, and official economic data, have been used to quantify the economic relevance of the activity, and problems perceived by local farmers. For the ecological analysis, we monitored -on monthly basis- mussels growth and water quality parameters in 6 sites along the gulf. Feeding preference and faeces/pseudofaeces production, impact on surface sediment ad its reversibility have been investigated, too. Results have been used to calibrate a bioenergetic model representing the mussel physiology and growth in relation to environmental conditions, and the impact of mussel aquaculture on water column. The integration of the whole set of models and information will be used to give an evaluation of the ecological footprint of the activity and as a tool for coastal management.Keywords: Fisheries Economics, Modeling and Economic Theory, Integrated Modeling Approach of Social and Environmental Interactions in Support of Marine Resource ManagementKeywords: Fisheries Economics, Modeling and Economic Theory, Integrated Modeling Approach of Social and Environmental Interactions in Support of Marine Resource Managemen

Stable carbon isotopes of phytoplankton as a tool to monitor anthropogenic CO2 submarine leakages

This study aims to validate the stable carbon isotopic composition (d13C) of phytoplankton as a tool for detecting submarine leakages of anthropogenic CO2(g), since it is characterised by d13C values significantly lower than the natural CO2 dissolved in oceans. Three culture experiments were carried out to investigate the changes in d13C of the diatom Thalassiosira rotula during growth in an artificially modified medium (ASW). Three different dissolved inorganic carbon (DIC) concentrations were tested to verify if carbon availability affects phytoplankton d13C. Simultaneously, at each experiment, T. rotula was cultured under natural DIC isotopic composition (d13C DIC) and carbonate system conditions. The available DIC pool for diatoms grown in ASW was characterised by d13C DIC values (-44.2 ± 0.9‰) significantly lower than the typical marine range. Through photosynthetic DIC uptake, microalgae d13C rapidly changed, reaching significantly low values (until -43.4‰). Moreover, the different DIC concentrations did not affect the diatom d13C, exhibiting the same trend in d13C values in the three ASW experiments. The experiments prove that phytoplankton isotopic composition quickly responds to changes in the d13C of the medium, making this approach a promising and low-impact tool for detecting CO2(g) submarine leakages from CO2(g) deposits

Status of faecal pollution in ports: A basin-wide investigation in the Adriatic Sea

Ports are subject to a variety of anthropogenic impacts, and there is mounting evidence of faecal contamination through several routes. Yet, little is known about pollution in ports by faecal indicator bacteria (FIB). FIB spatio-temporal dynamics were assessed in 12 ports of the Adriatic Sea, a semi-enclosed basin under strong anthropogenic pressure, and their relationships with environmental variables were explored to gain insight into pollution sources. FIB were abundant in ports, often more so than in adjacent areas ; their abundance patterns were related to salinity, oxygen, and nutrient levels. In addition, a molecular method, quantitative (q)PCR, was used to quantify FIB. qPCR enabled faster FIB determination and water quality monitoring that culture-based methods. These data provide robust baseline evidence of faecal contamination in ports and can be used to improve the management of routine port activities (dredging and ballast water exchange), having potential to spread pathogens in the sea

Prescription appropriateness of anti-diabetes drugs in elderly patients hospitalized in a clinical setting: evidence from the REPOSI Register

Diabetes is an increasing global health burden with the highest prevalence (24.0%) observed in elderly people. Older diabetic adults have a greater risk of hospitalization and several geriatric syndromes than older nondiabetic adults. For these conditions, special care is required in prescribing therapies including anti- diabetes drugs. Aim of this study was to evaluate the appropriateness and the adherence to safety recommendations in the prescriptions of glucose-lowering drugs in hospitalized elderly patients with diabetes. Data for this cross-sectional study were obtained from the REgistro POliterapie-Società Italiana Medicina Interna (REPOSI) that collected clinical information on patients aged ≥ 65 years acutely admitted to Italian internal medicine and geriatric non-intensive care units (ICU) from 2010 up to 2019. Prescription appropriateness was assessed according to the 2019 AGS Beers Criteria and anti-diabetes drug data sheets.Among 5349 patients, 1624 (30.3%) had diagnosis of type 2 diabetes. At admission, 37.7% of diabetic patients received treatment with metformin, 37.3% insulin therapy, 16.4% sulfonylureas, and 11.4% glinides. Surprisingly, only 3.1% of diabetic patients were treated with new classes of anti- diabetes drugs. According to prescription criteria, at admission 15.4% of patients treated with metformin and 2.6% with sulfonylureas received inappropriately these treatments. At discharge, the inappropriateness of metformin therapy decreased (10.2%, P < 0.0001). According to Beers criteria, the inappropriate prescriptions of sulfonylureas raised to 29% both at admission and at discharge. This study shows a poor adherence to current guidelines on diabetes management in hospitalized elderly people with a high prevalence of inappropriate use of sulfonylureas according to the Beers criteria

Clinical features and outcomes of elderly hospitalised patients with chronic obstructive pulmonary disease, heart failure or both

Background and objective: Chronic obstructive pulmonary disease (COPD) and heart failure (HF) mutually increase the risk of being present in the same patient, especially if older. Whether or not this coexistence may be associated with a worse prognosis is debated. Therefore, employing data derived from the REPOSI register, we evaluated the clinical features and outcomes in a population of elderly patients admitted to internal medicine wards and having COPD, HF or COPD + HF. Methods: We measured socio-demographic and anthropometric characteristics, severity and prevalence of comorbidities, clinical and laboratory features during hospitalization, mood disorders, functional independence, drug prescriptions and discharge destination. The primary study outcome was the risk of death. Results: We considered 2,343 elderly hospitalized patients (median age 81 years), of whom 1,154 (49%) had COPD, 813 (35%) HF, and 376 (16%) COPD + HF. Patients with COPD + HF had different characteristics than those with COPD or HF, such as a higher prevalence of previous hospitalizations, comorbidities (especially chronic kidney disease), higher respiratory rate at admission and number of prescribed drugs. Patients with COPD + HF (hazard ratio HR 1.74, 95% confidence intervals CI 1.16-2.61) and patients with dementia (HR 1.75, 95% CI 1.06-2.90) had a higher risk of death at one year. The Kaplan-Meier curves showed a higher mortality risk in the group of patients with COPD + HF for all causes (p = 0.010), respiratory causes (p = 0.006), cardiovascular causes (p = 0.046) and respiratory plus cardiovascular causes (p = 0.009). Conclusion: In this real-life cohort of hospitalized elderly patients, the coexistence of COPD and HF significantly worsened prognosis at one year. This finding may help to better define the care needs of this population