Aurelia aurita Ephyrae Reshape a Coastal Microbial Community

Over the last two decades, increasing attention has been paid to the impact of jellyfish blooms on marine communities. Aurelia aurita is one of the most studied of the Scyphozoans, and several studies have been carried out to describe its role as a topdown controller within the classical food web. However, little data are available to define the effects of these jellyfish on microbial communities. The aims of this study were to describe the predation impact of A. aurita ephyrae on a natural microplanktonic assemblage, and to determine any reshaping effects on the prokaryote community composition and functioning. Surface coastal water was used to set up a 24-h grazing experiment in microcosms. Samples were collected to determine the variations in prey biomass, heterotrophic carbon production (HCP), extracellular leucine aminopeptidase activity, and grazing pressure. A next-generation sequencing technique was used to investigate biodiversity shifts within the prokaryote and protist communities through the small subunit rRNA tag approach. This study shows that A. aurita ephyrae were responsible for large decreases in the abundances of the more motile microplankton groups, such as tintinnids, Dinophyceae, and aloricate ciliates. Bacillariophyceae and Mediophyceae showed smaller reductions. No evidence of selective predation emerged in the analysis of the community diversity down to the family level. The heterotrophic prokaryote biomass increased significantly (by up to 45%), in parallel with increases in HCP and leucine aminopeptidase activity (40%). Significant modifications were detected in prokaryotic community composition. Some classes of Gammaproteobacteria and Flavobacteriia showed higher relative abundances when exposed to A. aurita ephyrae, while there was a net decrease for Alphaproteobacteria. Overall, this study provides new insight into the effects of A. aurita on microbial communities, underlining their selective predation toward the more motile groups of microplankton and their impact on prokaryotic assemblages, by favoring blooms of copiotrophic taxa

The Impact of Treated Urban Wastewaters and Flood Discharge on the Quality of Bathing Water

What do we know about the Adriatic Sea and the state of its health [...

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

Water column monitoring at CO2 leaking sites near Panarea Island

The fate and transport of geologically produced CO2 that leaks from the sea floor into the overlying water column has numerous important implications related to large scale carbon cycling and potential impact on marine organisms, and is of interest for the development of improved monitoring techniques and strategies for offshore Carbon Capture and Storage (CCS) sites. The CO2 leakage areas off the east coast of Panarea Island, Italy provides an excellent environment to study these processes given the wide range of different flux rates in relatively shallow water. The water column at this site was monitored using two completely different but complementary approaches, continuous monitoring along short 2D transects using GasPro pCO2 sensors and discrete seasonal sampling along a 700 m transect crossing multiple leakage areas. Results are discussed in terms of the movement of CO2, and associated tracers, in the water column

The Panarea natural CO2 seeps: fate and impact of the leaking gas (PaCO2) ; R/V URANIA, Cruise No. U10/2011, 27 July – 01 August 2011, Naples (Italy) – Naples (Italy)

Carbon capture and storage (CCS), both on- and offshore, is expected to be an important technique to mitigate anthropogenic effects on global climate by isolating man-made carbon dioxide (CO2) in deep geological formations. In marine environments, however, the potential impacts of CO2 leakage, appropriate detection methods, and risk and pathways of atmospheric emissions are poorly defined. The natural CO2 gas seeps that occur in the relatively shallow waters off the coast of Panarea Island (Aeolian Islands, Italy) can be studied as a large-scale, real-world analogue of what might occur at a leaking offshore CCS site and what tools can be used to study it. The oceanographic survey PaCO2 was performed aboard R/V Urania from 27 July – 01 August 2011 (Naples – Naples). The project’s ship-time was funded by Eurofleets, with work being performed as a sub-project of the Seventh Framework Programme projects “ECO2” and “RISCS”, which provided subsidiary funding. Large amounts of data and samples were collected during the cruise which will be interpreted in the coming months, with preliminary results detailed here. Of particular importance was the discovery of much larger areas showing gas seepage than previously reported. Interdisciplinary measurements were performed at the Panarea seepage site. The international team of scientists onboard R/V Urania performed complementary sampling and measurements for biological, chemical, and physical parameters throughout the area. Together with the dedication of R/V Urania’s Captain and crew, and the eagerness and cooperation of the scientific crew, we were able to obtain excellent scientific results during this six-day cruise

Linking lifestyle and foraging strategies of marine bacteria: selfish behaviour of particle-attached bacteria in the northern Adriatic Sea

Microbe-mediated enzymatic hydrolysis of organic matter entails the production of hydrolysate, the recovery of which may be more or less efficient. The selfish uptake mechanism, recently discovered, allows microbes to hydrolyze polysaccharides and take up large oligomers, which are then degraded in the periplasmic space. By minimizing the hydrolysate loss, selfish behaviour may be profitable for free-living cells dwelling in a patchy substrate landscape. However, selfish uptake seems to be tailored to algal-derived polysaccharides, abundant in organic particles, suggesting that particle-attached microbes may use this strategy. We tracked selfish polysaccharides uptake in surface microbial communities of the northeastern Mediterranean Sea, linking the occurrence of this processing mode with microbial lifestyle. Additionally, we set up fluorescently labelled polysaccharides incubations supplying phytodetritus to investigate a ‘pioneer’ scenario for particle-attached microbes. Under both conditions, selfish behaviour was almost exclusively carried out by particle-attached microbes, suggesting that this mechanism may represent an advantage in the race for particle exploitation. Our findings shed light on the selfish potential of particle-attached microbes, suggesting multifaceted foraging strategies exerted by particle colonizers

Psychosocial and biological determinants of ill health in relation to deprivation

Background: Despite public health campaigns and improvements in healthcare, socioeconomic gradients in health and life expectancy persist, and in many cases are becoming more marked – the gradient in coronary heart disease being a prime example. Classic cardiovascular risk factors (e.g. smoking, cholesterol and blood pressure) only partially explain the deprivation effect, and attempts to narrow the health gap by focussing on such risk factors do not appear to be succeeding. There also appear to be socioeconomic differences in uptake of healthy lifestyle advice. The work described in this thesis aimed to expand current understanding of the deprivation-based gap in health and life expectancy, focussing particularly on the socioeconomic gradient in cardiovascular risk. Methods: Using a cross-sectional, population-based study design based in the Greater Glasgow area, 666 participants were selected on the basis of area-level social deprivation (Scottish Index for Multiple Deprivation ranking). The study was designed to include approximately equal numbers from most deprived and least deprived areas; equal numbers of male and female participants and equal numbers of participants from each age group studied (35-44; 45-54 and 55-64 years). Participants completed an extensive questionnaire on health, lifestyle and early life experiences. Anthropometric measures (height, leg length, weight, waist, hip and thigh circumferences) were recorded. Blood pressure, heart rate and parameters of lung function (Forced Expiratory Volume in 1 second [FEV1] and Forced Vital Capacity [FVC]) were recorded. Psychological assessments (General Health Questionnaire-28, Generalised Self-Efficacy Scale, Sense of Coherence Scale, Beck Hopelessness Scale, Eysenck Personality Scale and Rosenberg Self-Esteem Scale) and assessments of cognitive function (Auditory Verbal Learning Test, Choice Reaction Time and Stroop Test) were undertaken. Fasting blood samples were obtained for classic and emerging cardiovascular risk factors including lipid profile, glucose, insulin, leptin, adiponectin, C-reactive protein, interleukin-6, soluble intercellular adhesion molecule-1, von Willebrand Factor, fibrinogen, D-dimer and tissue plasminogen activator antigen. Carotid ultrasound assessment of intima-media thickness (cIMT), plaque score and arterial stiffness was performed. Results: Total and low density lipoprotein cholesterol were significantly higher in the least deprived group (both p<0.0001). Triglycerides were higher and high density lipoprotein cholesterol lower in the most deprived group (both p<0.0001). Fasting glucose, insulin and leptin were higher in the most deprived group. C-reactive protein, interleukin-6 and soluble intercellular adhesion molecule-1 were higher in the most deprived group (all p<0.0001). Von Willebrand factor, fibrinogen and D-dimer were higher in the most deprived group. Age- and sex-adjusted cIMT was significantly higher in the most deprived group, but on subgroup analysis this difference was only apparent in the highest age tertile in males (>56.3 years). Plaque score showed a much more highly significant deprivation difference in the group as a whole (p<0.0001). No differences in parameters of arterial stiffness were found between the most deprived and least deprived groups. Neither adjustment for classic nor emerging cardiovascular risk factors, either alone or in combination, abolished the area-level deprivation-based difference in plaque presence or cIMT. Adjustment for early life markers of socioeconomic status in addition to classic cardiovascular risk factors abolished the deprivation-based difference in plaque presence. Further associations between early life factors and health outcomes were noted: lung function (FEV1) and cognitive performance appeared to be influenced by father’s occupation, whether the parents/guardians were owner-occupiers or tenants, and by degree of overcrowding; cIMT was modestly related to father’s occupation and carotid plaque was related strongly to father’s occupation and parental home status. Socioeconomic differences were noted in the impact of personality in determining mental wellbeing, and also in relation to the health behaviours of fruit and vegetable consumption and smoking cessation. Conclusions: The relationship between social deprivation and health is complex and multifactorial and appears to involve the interplay of early life factors, biological mediators, psychological parameters such as personality and cognitive function, health behaviours and outcomes such as atherosclerosis. Approaches aiming to narrow the deprivation gap in health will need to be designed to take into account this complexity, addressing factors such as early life experiences and personality, as well as the more classically recognised factors such as smoking, cholesterol and blood pressure, if they are to have a chance of succeeding in improving the health of those most in need.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

The Interreg Project AdSWiM: Managed Use of Treated Wastewater for the Quality of the Adriatic Sea

The Italy-Croatia Cross Border Cooperation (CBC) Programme is the financial instrument supporting the cooperation between the two European Member States overlooking the Adriatic Sea. The first call for proposals was launched in 2017, identifying four priority axes of intervention. Subsequently, in 2019, the kick-off of the AdSWiM project “Managed use of treated urban wastewater for the quality of the Adriatic Sea” took place in Udine (IT). Adriatic marine waters are generally classified as good to excellent based on the Bathing Water Directive (2006/7/EC). Nevertheless, issues of low productivity or the lack of nutrients have been often suggested, especially on the Italian side. The project addresses the question of whether wastewater treatment plants (WWTPs) discharging to the sea, after applying appropriate pollution control and management technologies, can modulate the nutrient content of their effluents to support localized depleted areas. This idea is borrowed from one of the motivations that support the reuse of treated wastewater for irrigation, thus leading to the return of nutrients (nitrogen, phosphorus, potassium, etc.) to natural biogeochemical cycles. However, the hypothesis of modulating the nutrient composition of wastewater opens up to several critical aspects, including legislative and technological ones. Being aware of the delicate environmental implications, we have undertaken the project involving WWTPs, research centers, municipalities, and legal experts with the aim of investigating in detail the problems related to wastewater reuse, especially with regard to the content of nutrients. Our experimental approach aimed to evaluate appropriate and possibly new treatment technologies to reduce the microbial load and to implement chemical and microbiological tests on the treated wastewater. Results have shown that it can be tricky to draw decisive conclusions because (i) the wastewater management systems differ between the two sides of the Adriatic sea due to the different levels of technological development of WWTPs; (ii) the Italian and Croatian coasts deeply differ in geographic characteristics (i.e., topography, orography, current circuits, presence of rivers) and anthropogenic pressure (i.e., exploitation levels, population density); (iii) the new treatment technologies to lower bacterial contamination need further efforts to raise their technological level of readiness (TRL) and make them implementable in the existing WWTPs. However, in terms of chemical control methodologies, the proposed sensors and biosensors gave positive results, managing to decrease the detection limits for the measured parameters, and the tested technologies for microbiological monitoring were also effective. In particular, the latter was carried out by using recent molecular biology techniques, capable of resolving the microbiota in treated wastewater, which emerged to be strictly related to the features of the WWTPs

Leucine Aminopeptidase, β-Glucosidase and Alkaline Phosphatase Activity Rates and Their Significance in Nutrient Cycles in Some Coastal Mediterranean Sites

In aquatic microbial ecology, knowledge of the processes involved in the turnover of organic matter is of utmost importance to understand ecosystem functioning. Microorganisms are major players in the cycling of nutrients (nitrogen, phosphorus) and carbon, thanks to their enzymatic activities (leucine aminopeptidase, LAP, alkaline phosphatase, AP, and β-glucosidase, β-GLU) on organic polymers (proteins, organic phosphates and polysaccharides, respectively). Estimates of the decomposition rates of organic polymers are performed using fluorogenic compounds, whose hydrolysis rate allow us to obtain information on the “potential” metabolic activity of the prokaryotic community. This paper refers the enzyme patterns measured during recent oceanographic cruises performed in some coastal Mediterranean sites, not yet fully investigated in terms of microbial biogeochemical processes. Mean enzyme activity rates ranged from 5.24 to 5558.1 nM/h, from 12.68 to 244.73 nM/h and from 0.006 to 9.51 nM/h for LAP, AP and β-GLU, respectively. The highest LAP and AP activity rates were measured in the Gulf of Milazzo (Tyrrhenian Sea) and in the Straits of Messina, in association with the lowest bacterioplankton abundance; in contrast, the lowest ones were found in the northern Adriatic Sea. β-GLU was more active in the Straits of Messina. Activity rates were analysed in relation to the main environmental variables. Along the northern Adriatic coastal side affected by the Po river, significant inverse relationships linked LAP and AP with salinity, pointing out that fluvial inputs provided organic substrates for microbial metabolism. Both in the Gulf of Manfredonia and in the Straits of Messina, LAP and AP levels were inversely related with the concentration of nitrate and inorganic phosphorus, respectively. In the Gulf of Milazzo, high cell-specific AP measured in spite of phosphorus availability suggested the role of this enzyme not only in phosphorus, but also in carbon release

Dynamics and enzymatic degradation of exopolymer particles under increasing concentrations of silver ions and nanoparticles during a marine mesocosm experiment

Pollution of the marine environment is an emerging threat. Nowadays, engineered nanoparticles (<100 nm) such as zinc, copper and silver are widely used as antimicrobial agents, therefore often present in daily-life products. Consequently, the demand and production of nanoparticles are expected to increase. Here, we specifically focus on silver nanoparticles (AgNP). Once released into the environment, AgNPs pose an obvious ecotoxicological risk, potentially affecting ecosystem structure and functioning. For instance, phytoplankton-derived exudates, rich in acidic polysaccharides and amino acids, can abiotically aggregate into microgels such as transparent exopolymer particles (TEP) and Coomassie stainable particles (CSP). Hence, microgels can bridge dissolved and particulate size fractions and facilitate aggregate formation with organic and mineral particles. Both physical and chemical properties make TEP and CSP attractive nutrient hotspots for heterotrophic bacterioplankton. Bacteria, in turn, utilize extracellular enzymes to access these carbon and nitrogen pools. However, knowledge about the mechanisms by which AgNPs might interact with and affect the biogeochemical cycling of TEP and CSP is still insufficient. Therefore, we conducted a mesocosm experiment in the Eastern Mediterranean Sea and investigated the effects of environmentally relevant concentrations of silver ions (Ag+) and AgNP on the properties of TEP and CSP (i.e., area and abundance) along with enzymatic activity measurements. Our results showed that cyanobacteria were likely the primary source of CSP in the ultra-oligotrophic Mediterranean Sea. Also, CSP contributed more to the microgel pool than TEP, as indicated by a strong relationship between CSP and heterotrophic microbial dynamics. While silver (i.e., Ag+ or AgNP) had overall only marginal effects, both species affected the relationships between cell-specific LAPase activity and CSP and cell-specific APase activity and phosphate levels. Thus, Ag+ and AgNP have the potential to regulate microgel dynamics. However, future studies are needed to derive a robust understanding of the effects of silver pollution on the coupling of microgel formation and degradation and the follow-on effect on biogeochemical cycles