The biogeochemical vertical structure renders a meromictic volcanic lake a trap for geogenic CO2 (Lake Averno, Italy).

Volcanic lakes are characterized by physicochemical favorable conditions for the development of reservoirs of C-bearing greenhouse gases that can be dispersed to air during occasional rollover events. By combining a microbiological and geochemical approach, we showed that the chemistry of the CO2- and CH4-rich gas reservoir hosted within the meromictic Lake Averno (Campi Flegrei, southern Italy) are related to the microbial niche differentiation along the vertical water column. The simultaneous occurrence of diverse functional groups of microbes operating under different conditions suggests that these habitats harbor complex microbial consortia that impact on the production and consumption of greenhouse gases. In the epilimnion, the activity of aerobic methanotrophic bacteria and photosynthetic biota, together with CO2 dissolution at relatively high pH, enhanced CO2- and CH4 consumption, which also occurred in the hypolimnion. Moreover, results from computations carried out to evaluate the dependence of the lake stability on the CO2/CH4 ratios, suggested that the water density vertical gradient was mainly controlled by salinity and temperature, whereas the effect of dissolved gases was minor, excepting if extremely high increases of CH4 are admitted. Therefore, biological processes, controlling the composition of CO2 and CH4, contributed to stabilize the lake stratification of the lake. Overall, Lake Averno, and supposedly the numerous worldwide distributed volcanic lakes having similar features (namely bio-activity lakes), acts as a sink for the CO2 supplied from the hydrothermal/magmatic system, displaying a significant influence on the local carbon budget.

Complexity in internal medicine wards: A novel screening method and implications for management.

RATIONALE: Complexity is increasingly recognized as a critical variable in health care. However, there is still lack of practical tools to assess it and tackle the challenges that stem from it, particularly within hospitals. AIMS AND OBJECTIVE: To validate a simple novel screening method based on both objective and subjective criteria to identify patients with clinically complex hospitalization events. To evaluate the prevalence of patients with complex events, identify their features, and compare them with those of the other patients and to those of patients with multimorbidities. METHOD: We monitored the level of complexity of the hospitalization events of 240 patients admitted to an internal medicine ward in Tuscany over the course of 56 days. We compared the demographic features, the length of stay, and the prognosis of patients with and without complex events. RESULTS: Sixty-nine patients (28.8% of the sample) had a complex episode during their stay, and 115 (47.9%) had phases of low complexity. Patients with complex episodes were younger and more comorbid than patients without. They stayed longer in-hospital (+4.5 days; 95% CI: 2.5-6.5) and had higher mortality (OR: 24.93; 95% CI: 6.97-171.63) and a lower probability of home discharge (OR: 0.25; 95% CI: 0.13-0.48). CONCLUSIONS: The results show that using a simple screening method is possible to identify complex patients within IM wards and that every day, about one-third of the patients are complex. The results are discussed in implications for the dynamic management of patients with complex and simple phases during hospitalization.