Alberto Ribotti

Screen-printed electrodes for environmental monitoring of heavy metal ions: a review

AbstractHeavy metals such as lead, mercury, cadmium, zinc and copper are among the most important pollutants because of their non-biodegradability and toxicity above certain thresholds. Here, we review methods for sensing heavy metal ions (HMI) in water samples using screen-printed electrodes (SPEs) as transducers. The review (with 107 refs.) starts with an introduction into the topic, and this is followed by sections on (a) mercury-coated SPEs, (b) bismuth-coated SPEs, (c) gold-coated SPEs (d) chemically modified and non-modified carbon SPEs, (e) enzyme inhibition-based SPEs, and (f) an overview of commercially available electrochemical portable heavy metal analyzers. The review reveals the significance of SPEs in terms of decentralized and of in situ analysis of heavy metal ions in environmental monitoring. Graphical AbstractThis review summarises recent advances in the use of screen-printed electrodes (SPEs) for the electrochemical detection of heavy metal ions in water samples. Research proofs of concept and commercially available portable equipments for ‘in situ analysis’ are discussed.

Multiscale Observations of Deep Convection in the Northwestern Mediterranean Sea during Winter 2012–2013 Using Multiple Platforms

During winter 2012–2013, open‐ocean deep convection which is a major driver for the thermohaline circulation and ventilation of the ocean, occurred in the Gulf of Lions (Northwestern Mediterranean Sea) and has been thoroughly documented thanks in particular to the deployment of several gliders, Argo profiling floats, several dedicated ship cruises, and a mooring array during a period of about a year. Thanks to these intense observational efforts, we show that deep convection reached the bottom in winter early in February 2013 in a area of maximum 28 ± 3 109 m2. We present new quantitative results with estimates of heat and salt content at the subbasin scale at different time scales (on the seasonal scale to a 10 days basis) through optimal interpolation techniques, and robust estimates of the deep water formation rate of 2.0 ± 0.2 Sv. We provide an overview of the spatiotemporal coverage that has been reached throughout the seasons this year and we highlight some results based on data analysis and numerical modeling that are presented in this special issue. They concern key circulation features for the deep convection and the subsequent bloom such as Submesoscale Coherent Vortices (SCVs), the plumes, and symmetric instability at the edge of the deep convection area.

Monitoring the marine environment operational practices in Europe

Abstract A survey of existing environmental monitoring networks operated in European waters and a review of their main characteristics has been completed. Individual questionnaires have been filled out by persons in charge of operations enabling gathering of up-to-date, accurate information about equipment used and actual operational practices. A map of the location of these networks is shown and a table gives their main characteristics. These data have been used to conduct the analysis of practices employed to maintain these installations. The various difficulties met by operators as well as the costs of these operations are analysed. Methods and procedures are specific to the geographic situations and to the physical characteristics of the monitored sites. The means and resources used for maintenance operations and the related costs are strongly dependent on the distance between the monitoring site and the closest harbour (logistic bases). In the same way, the frequency of on-site interventions are heavily dependant on the bio-productivity of the surrounding environment, bringing a heavy constraint on the choice of the technique for biofouling prevention. Last but not least, the level of data quality seems to be related to the method- ology used for maintenance (both procedure and frequency). The choice of the archi- tecture of measurement systems is also an important factor in the efficiency of the systems.

Effects of protection rules and measures in an important international strait area: the Bonifacio Strait

The Strait of Bonifacio, between Sardinia and Corsica, is an area with environmental characteristics of great importance and uniqueness in the Mediterranean. Since the early ‘90s Italy and France have been trying to preserve the area through the creation of national and international marine parks, activating understandings to limit the danger of environmental emergencies and ensuring compliance with international agreements, both from the EC and IMO. The bilateral agreement of 1993 prohibits the passage through the Strait of Italian and French tankers and other ships with hazardous and noxious substances at full load, but it does not restrict the transit of ships from other countries or when empty. The analysis of 2000–2009 data of transits through the Strait of Bonifacio, derived from the Vessel Traffic Service provided by the Coast Guard of La Maddalena, shows the fulfilment of agreements within this maritime sector and their limits, and possible remedies are suggested.

Impact of different initialisation methods on the quality of sea forecasts for the Sicily Channel

ABSTRACT An operational ocean forecasting system provided numerical predictions on the main hydrodynamics in the seas around Sicily. The system is evaluated using an independent dataset of sea surface temperature (SST) satellite observations. A set of specific numerical experiments are carried and the simulated SST data was compared with the satellite data observed at selected dates. Two kinds of initialisation techniques are adopted to generate different initial conditions: ‘slave mode’ and ‘partially active mode’. The accuracy of both approaches is analysed to individuate the optimal nesting strategy. The results show that the partially active mode improves the forecasts, resulting in a model accuracy increase of up to about 30%.

Frontal dynamics boost primary production in the summer stratified Mediterranean sea

Bio-physical glider measurements from a unique process-oriented experiment in the Eastern Alboran Sea (AlborEx) allowed us to observe the distribution of the deep chlorophyll maximum (DCM) across an intense density front, with a resolution (∼ 400 m) suitable for investigating sub-mesoscale dynamics. This front, at the interface between Atlantic and Mediterranean waters, had a sharp density gradient (Δρ ∼ 1 kg/m3 in ∼ 10 km) and showed imprints of (sub-)mesoscale phenomena on tracer distributions. Specifically, the chlorophyll-a concentration within the DCM showed a disrupted pattern along isopycnal surfaces, with patches bearing a relationship to the stratification (buoyancy frequency) at depths between 30 and 60 m. In order to estimate the primary production (PP) rate within the chlorophyll patches observed at the sub-surface, we applied the Morel and Andrè (J Geophys Res 96:685–698 1991) bio-optical model using the photosynthetic active radiation (PAR) from Argo profiles collected simultaneously with glider data. The highest production was located concurrently with domed isopycnals on the fresh side of the front, suggestive that (sub-)mesoscale upwelling is carrying phytoplankton patches from less to more illuminated levels, with a contemporaneous delivering of nutrients. Integrated estimations of PP (1.3 g C m−2d−1) along the glider path are two to four times larger than the estimations obtained from satellite-based algorithms, i.e., derived from the 8-day composite fields extracted over the glider trip path. Despite the differences in spatial and temporal sampling between instruments, the differences in PP estimations are mainly due to the inability of the satellite to measure DCM patches responsible for the high production. The deepest (depth > 60 m) chlorophyll patches are almost unproductive and probably transported passively (subducted) from upper productive layers. Finally, the relationship between primary production and oxygen is also investigated. The logarithm of the primary production in the DCM interior (chlorophyll (Chl) > 0.5 mg/m3) shows a linear negative relationship with the apparent oxygen utilization, confirming that high chlorophyll patches are productive. The slope of this relationship is different for Atlantic, mixed interface waters and Mediterranean waters, suggesting the presence of differences in planktonic communities (whether physiological, population, or community level should be object of further investigation) on the different sides of the front. In addition, the ratio of optical backscatter to Chl is high within the intermediate (mixed) waters, which is suggestive of large phytoplankton cells, and lower within the core of the Atlantic and Mediterranean waters. These observations highlight the relevance of fronts in triggering primary production at DCM level and shaping the characteristic patchiness of the pelagic domain. This gains further relevance considering the inadequacy of optical satellite sensors to observe DCM concentrations at such fine scales.

COMMON SENSE: Cost-effective sensors, interoperable with international existing ocean observing systems, to meet EU policies requirements

The COMMON SENSE (CS) project aims to develop cost-effective, multi-functional innovative sensors to perform reliable in-situ measurements in the marine environment. The COMMON SENSE sensors will focus on key parameters including eutrophication, heavy metals, marine litter (microplastics) and underwater noise. The project will focus on increasing the availability of sensor data and observations through the development and implementation of the Common Sensor Web Platform (CSWP), a software platform that will integrate the COMMON SENSE sensor data and observations and deliver them to the Web, in standard formats and through standard interfaces.

Seasonal variability of the levantine intermediate waters in the Western Mediterranean-Algerian/Provençal basin

The Levantine Intermediate Water (LIW) circulation in the Algerian basin is studied by mean of an analysis of the Mediterranean Oceanic Data Base (MODB). The results show that LIW circulates in the area following two seasonal branches: the first going northward along the western Sardinian coast and the second directly westward in the middle of the Algerian/Provencal basin. This background information will be useful for future design of operational monitoring, networks in the region.