Search results for " seawater"
showing 10 items of 42 documents
Vulnerability maps pollution to hydrocarbon and urban waste pollution in seawater intrusion areas
2004
De acuerdo con un proyecto nacional promovido por el Grupo Nacional Italiano para la Protección contra Riesgos Hidrogeológicos han sido publicados los mapas de vulnerabilidad (1:50.000) de parte del Territorio Italiano, particularmente algunos mapas de Sicilia: Montes Iblei, Moadonie, Sicani y el Monte Etna. Estos mapas se han vuelto documentos públicos para el manejo local del agua subterránea. Algunos fenómenos muy peligrosos han sido reportados en algunas áreas de Sicilia. Intervenciones antrópicas han creado basureros de residuos tóxicos sobre áreas vulnerables. Esta investigación explica las ventajas del uso de mapas de vulnerabilidad en estudio de tipos peligrosos de contaminación par…
Global distributions of diazotrophs nitrogen fixation rates - Depth integrated values computed from a collection of source datasets - Contribution to…
2013
The MAREDAT atlas covers 11 types of plankton, ranging in size from bacteria to jellyfish. Together, these plankton groups determine the health and productivity of the global ocean and play a vital role in the global carbon cycle. Working within a uniform and consistent spatial and depth grid (map) of the global ocean, the researchers compiled thousands and tens of thousands of data points to identify regions of plankton abundance and scarcity as well as areas of data abundance and scarcity. At many of the grid points, the MAREDAT team accomplished the difficult conversion from abundance (numbers of organisms) to biomass (carbon mass of organisms). The MAREDAT atlas provides an unprecedente…
Equilibrium studies in natural waters: Speciation of phenolic compounds in synthetic seawater at different salinities
1995
Interactions between some phenolic compounds and macro-constituents of synthetic seawater (Na{sup +}, K{sup +}, Ca{sup 2+}, Mg{sup 2+}, Cl{sup {minus}}, and SO{sub 4}{sup 2{minus}}), at 20, 35, and 45 {per_thousand} salinity, have been investigated potentiometrically by using the [H]-glass electrode. The formation constants of phenol, o- and p-cresol, o-a dn p-nitrophenol complexes with sodium, potassium, calcium, and magnesium ions have been determined in the ionic strength range 0 {le} I {le} 1 mol/L. A comparison between the apparent protonation constants of phenols determined in synthetic seawater, and those simulated by a suitable complex formation model, is discussed. The possibility …
Characterisation of submarine groundwater discharge offshore south-eastern Sicily
2005
A complex approach in characterisation of submarine groundwater discharge (SGD) off south-eastern Sicily comprising applications of radioactive and non-radioactive tracers, direct seepage measurements, geophysical surveys and a numerical modelling is presented. SGD fluxes in the Donnalucata boat basin were estimated by direct seepage measurements to be from 4 to 12Ls(-1), which are comparable with the total SGD flux in the basin of 17Ls(-1) obtained from radon measurements. The integrated SGD flux over the Donnalucata coast estimated on the basis of Ra isotopes was around 60m(3)s(-1) per km of the coast. Spatial variations of SGD were observed in the Donnalucata boat basin, the average (222…
A randomized multicenter study comparing seawater washes and carmellose artificial tears eyedrops in the treatment of dry eye syndrome.
2019
Purpose To investigate the safety and efficacy of sterile isotonic seawater washes vs standard treatment with carmellose artificial tears in dry eye syndrome (DES). Patients and methods This is a randomized multicenter prospective study with 12 weeks of follow-up. A group of patients with DES (N=60) were treated with seawater spray (Quinton®) five times daily, and another similar group (N=60) were treated with carmellose artificial tears eyedrops (Viscofresh® 0.5%) five times a day. The parameters studied and measured were as follows: Ocular Surface Disease Index questionnaire score, Schirmer I test (without anesthesia) score, tear osmolarity (TearLab®), tear breakup time, tear meniscus hei…
Hydrolysis and chemical speciation of (C2H5)2Sn2+, (C2H5)3Sn+ and (C3H7)3Sn+ in aqueous media simulating the major composition of natural waters
2001
The hydrolysis of (C 2 H 5 ) 2 Sn 2+ , (C 2 H 5 ) 3 Sn + and (n-C 3 H 7 ) 3 Sn + has been studied, by potentiometric measurements ([H + ]-glass electrode), in NaNO 3 , NaCl, NaCl/Na 2 SO 4 mixtures and in a synthetic seawater (SSWE), as an ionic medium simulating the major composition of natural seawater, at different ionic strengths (0 ≤ I ≤ 5 mol dm -3 ) and salinities (15 ≤ S ≤ 45), and at t = 25 °C. Five hydrolytic species for (C 2 H 5 ) 2 Sn 2+ , three for (C 2 H 5 ) 3 Sn + and two for (C 3 H 7 ) 3 Sn + are found. Interactions with the anion components of SSWE, considered as single-salt seawater, are determined by means of a complex formation model. A predictive equation for the calcul…
Genetics for Pseudoalteromonas provides tools to manipulate marine bacterial virus PM2
2008
ABSTRACT The genetic manipulation of marine double-stranded DNA (dsDNA) bacteriophage PM2 ( Corticoviridae ) has been limited so far. The isolation of an autonomously replicating DNA element of Pseudoalteromonas haloplanktis TAC125 and construction of a shuttle vector replicating in both Escherichia coli and Pseudoalteromonas enabled us to design a set of conjugative shuttle plasmids encoding tRNA suppressors for amber mutations. Using a host strain carrying a suppressor plasmid allows the introduction and analysis of nonsense mutations in PM2. Here, we describe the isolation and characterization of a suppressor-sensitive PM2 sus2 mutant deficient in the structural protein P10. To infect an…
Evaluation of the Purity of Magnesium Hydroxide Recovered from Saltwork Bitterns
2022
Magnesium has been listed among the 30 critical raw materials by the European Union. In recent years, many green and sustainable alternative Mg2+ sources have been sought to satisfy the EU’s demand and to avoid mineral ore consumption. In this context, saltwork bitterns, the by-products of solar sea salt production, have attracted much attention thanks to their high Mg2+ concentrations (up to 80 g/L) and low Ca2+ and bicarbonate contents (<0.5 g/L). Although investigations on Mg2+ extraction from bitterns in the form of Mg(OH)2(s) have already been performed, product purity has never been properly addressed. Mg(OH)2(s) is a chemical compound of great interest and extensive utility in num…
Modelling of natural and synthetic polyelectrolyte interactions in natural waters.
2006
In this paper SIT and Pitzer models are used for the first time to describe the interactions of natural and synthetic polyelectrolytes in natural waters. Measurements were made potentiometrically at 25 °C in single electrolyte media, such as Et4NI and NaCl (for fulvic acid 0.1 < I /mol L− 1 < 0.75), and in a multi-component medium simulating the composition of natural waters at a wide range of salinities (for fulvic and alginic acids: 5 < S < 45) with particular reference to sea water [Synthetic Sea Water for Equilibrium studies, SSWE]. In order to simplify calculations, SSWE was considered to be a “single salt” BA, with cation B and anion A representing all the major cations (Na+, K+, Mg2+…
Seawater carbonate chemistry and composition of intertidal and subtidal communities
2018
Rising atmospheric concentrations of carbon dioxide are causing surface seawater pH and carbonate ion concentrations to fall in a process known as ocean acidification. To assess the likely ecological effects of ocean acidification we compared intertidal and subtidal marine communities at increasing levels of pCO2 at recently discovered volcanic seeps off the Pacific coast of Japan (34° N). This study region is of particular interest for ocean acidification research as it has naturally low levels of surface seawater pCO2 (280–320 µatm) and is located at a transition zone between temperate and sub-tropical communities. We provide the first assessment of ocean acidification effects at a biogeo…