Search results for " CO2."

A comparison of growth, gas exchange and productivity in Olea europaea cultivars growing on Mediterranean hills.

2008

This work concerns the ecophysiology of olive cultivars growing on Mediterranean hills. Our aim was to quantify the photosynthetic efficiency of the cultivars in cultivation. In two hill areas, we tested the phenological and ecophysio- logical variability of olive cultivars grown on non-irrigated land, with different pedo-climatic characteristics. Cultivation area 1 falls within a natural protected area, while area 2 is on farming land. The cultivars selected (‘Biancolilla’, ‘Nocellara del Belice’ and ‘Giarraffa’) belong to the local genetic pool and require different amounts of water. We followed the phe- nological phases of shoot growth and drupe production. We studied leaf anatomy and ch…

First measurements of gas output from bubbling pools in a mud volcano at the periphery of Mt Etna (Italy): methodologies and implications for monitor…

2014

Gases and brines emitted in the southern sector of Mt Etna from mofettes, mud pools and mud volcanoes come from an hydrothermal reservoir hosted within the clayey formations of the sedimentary basement (Chiodini et al., 1996). The gas emitted consists mainly of CO2, with CH4, N2 and He as minor species. CO2 and He stable isotopes indicate a clear magmatic origin for these gases, and their compositional changes during either eruptive or rest periods closely parallel that of crater fumaroles (Paonita et al., 2012). Altough these manifestations are the most significant CO2 emitters outside the crater area, their mass output has never been measured. We present the first measurements of gas flux…

Electrochemical conversion of carbon dioxide in pressurized electrochemical cells

2019

To limit the negative effect of carbon dioxide as a greenhouse gas, an interesting approach is the utilization of Carbon Capture and Conversion (CCC) methodology, which is focused on the use of CO2 waste as a feedstock to produce added-value products by using the excess electric energy from renewable source [1]. In this framework, an increasing attention has been devoted to the electrochemical conversion of carbon dioxide to formic acid in water [2-3] or CO [1]. Since the main hurdle of the CO2 reduction from aqueous solution is the low CO2 solubility in water, in this work, the utilization of pressurized electrochemical cells is evaluated. The effect of various operating parameters, includ…

Diffuse degassing of carbon dioxide at Somma-Vesuvius volcanic complex (Southern Italy) and its relation with regional tectonics

2004

Abstract A systematic survey of soil CO 2 concentrations was carried out on the flanks of Somma–Vesuvius volcano in order to constrain possible pathways responsible of carbon dioxide diffuse degassing taking place during the present state of quiescence. Measurements were performed at 1162 sites in late winter–spring 2000, highlighting that soil CO 2 concentrations range from 50 to 10500 ppmV. A statistical analysis was developed in order to define the threshold value of anomaly and separate the biogenic CO 2 component, produced by soil respiration, from the inorganic component of deep provenance. A computer routine was also elaborated to interpret the grid of CO 2 anomalous concentration va…

Zirconium–hafnium and rare earth element signatures discriminating the effect of atmospheric fallout from hydrothermal input in volcanic lake water

2016

The geochemical behaviour of Rare Earth Elements, Zr and Hf was investigated in the thermal waters of Nevado del Ruiz volcano system. A wide range of pH, between 1.0 and 8.8, characterizes these fluids. The acidicwaters are sulphate dominatedwith different Cl/SO4 ratios. The important role of the pH and the ionic complexes for the distribution of REE, Zr a nd Hf in the aqueous phase was evidenced. The pH rules the precipitation of authigenic Fe and Al oxyhydroxides producing changes in REE, Zr, Hf amounts and strong anomalies of Cerium. The precipitation of alunite and jarosite removes LREE from the solution, changing the REE distribution in acidic waters. Y-Ho and Zr-Hf (twin pairs) have a…

Riduzione Fotocatalitica di CO2 in Presenza di Catalizzatori Compositi GaP/TiO2

2014

The duality of ocean acidification as a resource and a stressor

2018

Ecologically dominant species often define ecosystem states, but as human disturbances intensify, their subordinate counterparts increasingly displace them. We consider the duality of disturbance by examining how environmental drivers can simultaneously act as a stressor to dominant species and as a resource to subordinates. Using a model ecosystem, we demonstrate that CO2-driven interactions between species can account for such reversals in dominance; i.e., the displacement of dominants (kelp forests) by subordinates (turf algae). We established that CO2 enrichment had a direct positive effect on productivity of turfs, but a negligible effect on kelp. CO2 enrichment further suppressed the …

Ocean acidification as a driver of community simplification via the collapse of higher-order and rise of lower-order consumers

2017

AbstractIncreasing oceanic uptake of CO2 is predicted to drive ecological change as both a resource (i.e. CO2 enrichment on primary producers) and stressor (i.e. lower pH on consumers). We use the natural ecological complexity of a CO2 vent (i.e. a seagrass system) to assess the potential validity of conceptual models developed from laboratory and mesocosm research. Our observations suggest that the stressor-effect of CO2 enrichment combined with its resource-effect drives simplified food web structure of lower trophic diversity and shorter length. The transfer of CO2 enrichment from plants to herbivores through consumption (apparent resource-effect) was not compensated by predation, becaus…

Seagrass response to high CO2 in volcanic vents

2012

Study of the trophic and functional organization of fish assemblages in submarine shallow CO₂ vents

2014

Naturally acidified marine ecosystems are currently investigated to evaluate the effects of ocean acidification on species, communities and ecological processes. Among these, submarine shallow CO₂ vents represent a sort of natural mesocosms, where at small spatial scales marked gradient of pH are present. The aim of this project is to study the responses of fish assemblages to pH reduction in Mediterranean shallow CO₂ vents by using several descriptors such as community structure, trophic organization, chemical characteristics and composition of carbonic structures. Moreover as in CO₂ vents concentration and bio-availability of several trace elements, also toxic ones, may increase due to di…