Slađana Strmečki

Slađana Strmečki
Ruđer Bošković Institute | RBI · Division for Marine and Environmental Research

PhD

About

33
Publications
2,016
Reads
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270
Citations
Introduction
As Guest Editor of the journal Water (EISSN 2073-4441, IF 2.544), I would like to invite you to submit a paper to the Special Issue “Characterization of Organic Matter in Marine and Freshwater Environment”. Keywords: organic matter; biogeochemistry; molecular composition; phytoplankton; pollution; climate change; interaction; analytical methods; water quality; monitoring. https://www.mdpi.com/journal/water/special_issues/characterization_organic_matter

Publications

Publications (33)
Article
Full-text available
We report a monthly distribution of Zn, Cd, Pb, Cu, Ni and Co, biologically relevant trace metals (TMs), within one year, in the productive surface layer at two stations with different trophic characters in the northern Adriatic (NA). The TM data was accompanied by a multivariable dataset, including dissolved organic carbon (DOC), surface-active or...
Article
We investigated the electrochemical properties of the models chitosan oligosaccharide (CHOS), an amino-glycan, and BSA protein, as major components of N-bearing polymeric organic material (N-POM) in seawater. The chronopotentiometric stripping method (CPS) and a hanging mercury drop working electrode (HMDE) were used to detect catalytic peaks (Ep a...
Article
In this work, we performed electrochemical investigations of Fe-binding ligands in water samples collected in autumn 2011 along the Australian GEOTRACES southwestern Pacific section (GP13, between 153°E and 170°W longitude along the 30°S line East of Australia, 0-1000 m depth). We determined the capacity of the bulk organic ligands to complex Fe us...
Article
Constant current chronopotentiometric stripping (CPS) peak H due to catalytic hydrogen evolution reaction on Hg‐containing electrodes appeared useful in the analysis of protein complexes with single‐stranded and double‐stranded DNA as well as with peptides. In dependence on stripping current (Istr), structural transition of the protein alone or in...
Article
Full-text available
The increased amount of organic matter (OM) accompanied with the development of hypoxia/anoxia and appearance of the sulphur species are indicators of eutrophication in natural waters. To predict biogeochemical and ecological changes, specific OM components in the Lake Brljan (the karst Krka River, Croatia; station B and station B2 downstream) were...
Conference Paper
On small karstic coastal island of Mljet in the South Adriatic Sea, Croatia, brackish lakes are the major source of fresh water. Mljet Island has not been connected with mainland water supply network and there is no surface watercourse of fresh water. In some areas on the island, water stays permanently on the surface forming small lakes created by...
Conference Paper
Full-text available
On small karstic coastal island of Mljet in the South Adriatic Sea, Croatia, brackish lakes are the major source of fresh water. Mljet Island has not been connected with mainland water supply network and there is no surface watercourse of fresh water. In some areas on the island, water stays permanently on the surface forming small lakes created by...
Article
Full-text available
On small and medium karstic coastal islands in the Adriatic Sea, brackish lakes are often the only source of freshwater. Therefore, it is important to adequately evaluate the biogeochemical processes occurring in these complex water systems, as well as to determine the origin of contaminants present. In this study, the distribution and origin of tr...
Article
Full-text available
Glaciers are dynamic, natural elements that are considered the best indicator of climate change and pollution due to their isolation, sensitivity and longevity. Dissolved water from the Briksdalsbreen glacier (Norway), a part of a larger glacier in the continental Europe, was sampled to determine the concentrations and types of toxic metals and org...
Article
Previously, it has been shown that proteins and some polysaccharides (PSs) catalyse hydrogen evolution, producing electrochemical signals on mercury electrodes. The catalytic hydrogen evolution reaction (CHER) of the above-mentioned biomacromolecules was studied by voltammetric and chronopotentiometric stripping (CPS) methods. To obtain more inform...
Article
Glycosylation of proteins plays an important role in health and diseases. At present new simple and inexpensive methods of glycoprotein analysis are sought. We developed a monoclonal antibody Manost 2.1 in mice after immunization with the adduct of mannan with Os(VI)temed complex (temed is N,N,N′,N′-tetramethylethylenediamine). The specificity of t...
Conference Paper
Full-text available
Polysaccharides (PS) are constituents of organic matter in seawater.They are surface active (accumulate at different phase boundaries), complex copper (and other metal ions) ions and could give catalytic hydrogen evolution wave (catalytic peak) in electrochemical measurement which could serve for their analytical determination
Article
The goal of this study was to investigate to which extent polysaccharides (PS) contribute to the complexing capacity for copper ion (LT), to determine their property of surface activity and evaluate their capability to cause the catalytic hydrogen evolution wave (peak “H”) due to their adsorption and the catalytic groups in their structure. Complex...
Article
Complex formation is among the mechanisms affecting metals’ bioaccessibility. Evaluating the extent of interactions between trace elements and several constituents of food items is of great interest. This paper examines the release of copper-complexing ligands in herbal infusions of 13 aromatic plants commonly used in Greece. The concentration of l...
Article
Sulphated polysaccharides κ-, ι-, and λ-carrageenan were analysed in seawater by applying adsorptive transfer constant current derivative chronopotentiometric stripping (AdT CPS) method on mercury electrode. Accelerated faradaic (catalytic) nature of the peak (peak HPS) recorded at negative potential was confirmed for all three carrageenans using s...
Article
Environmental context We determined seasonal changes in the organic matter content of the northern Adriatic with newly applied electrochemical techniques able to measure catalytically active organics. The inflow of the Po River and its nutrient load are responsible for the observed changes in the type and concentrations of organic matter in the are...
Article
Macroalgae are a significant source of extracellular organic material in the coastal areas of the Mediterranean, including organic ligands which serve as modulators of metal complexing capacity. This paper examines the release of copper-complexing ligands by 24 macroalgal species, including chlorophyta, rhodophyta, ochrophyta as well as Posidonia o...
Article
Full-text available
The Lake Shkodra - River Buna wetland complex (Albania) is included in Ramsar sites, and is one of the most important on the Adriatic coast. Dissolved organic carbon (DOC), particulate organic carbon (POC), surface active substances (SAS), copper complexing capacity (CuCC), and polymeric organic material containing nitrogen atoms (N-POM) were measu...
Article
In this communication an ex situ analysis of sulphated polysaccharide (S-PS) chondroitin sulphate (CS) on mercury electrode is reported for the first time. The analysis was performed using adsorptive transfer chronopotentiometric stripping (AdT CPS). AdT CPS included three major steps: adsorption, transfer and stripping. S-PS served as “presodium”...
Article
In May 2009, we characterized the organic matter in the area where Albanian shelf riverine plume waters enter the Southern Adriatic Pit region. Due to stable weather and hydrological conditions at the time of sampling a longitudinal thermal front was present around the Albanian shelf break. Our measurements point to the input of inorganic nutrients...
Article
Full-text available
Coastal systems are sensitive to eutrophication and organic matter (OM) produced in such systems influences the fate and distribution of other microconstituents and pollutants. The Boka Kotorska Bay is a jeopardized kar-stic area due to anthropogenic pressures. The concentrations of dissolved organic carbon (DOC) increase from spring to autumn mont...
Article
Full-text available
Coastal systems are sensitive to eutrophication and organic matter (OM) produced in such systems influences the fate and distribution of other microconstituents and pollutants. The Boka Kotorska Bay is a jeopardized kar-stic area due to anthropogenic pressures. The concentrations of dissolved organic carbon (DOC) increase from spring to autumn mont...
Article
Full-text available
Coastal systems are sensitive to eutrophication and organic matter (OM) produced in such systems influences the fate and distribution of other microconstituents and pollutants. The Boka Kotorska Bay is a jeopardized karstic area due to anthropogenic pressures. The concentrations of dissolved organic carbon (DOC) increase from spring to autumn month...
Article
Closed, isolated small systems, as the representatives of a “unique-environmental feature”, are valuable natural laboratories for studying different biogeochemical processes. The saline Rogoznica Lake (“Dragon Eye”), situated on the Eastern Adriatic coast is such a system (10 276 m2, 15 m deep) typical of many stratified, sulfide rich water bodies....
Article
Full-text available
The goal of this study was to investigate if transparent exopolymer particles (TEP), carbohydrates, surface-active substances (SAS), reduced sulfur species (RSS), or thio/amino groups contribute significantly to the complexing capacity of phytoplankton exudates for Cu (L-TOTCu), Cd (L-TOTCd), or Fe (L-TOTFe). Complexing capacities and apparent stab...
Article
Characterization of atmospheric surfactants in bulk precipitations was carried out by adsorption study at the mercury electrode/solution interface using phase sensitive AC voltammetry. The structure and permeability of the adsorbed organic films at the mercury electrode was tested using the redox processes of lead and cadmium ions as electrochemica...
Article
Catalytic properties and surface activity of nitrogen containing polymeric organic material (N-POM) were analyzed by constant current chronopotentiometric stripping analysis (CPSA) and alternating current (AC) voltammetry in sodium chloride solution (pH 8) and seawater. CPSA proved to be a suitable method for determination of low concentrations of...
Article
The study on dissolved organic ligands capable to complex copper ions (L T), surface-active substances (SAS) and dissolved organic carbon (DOC) in the Northern Adriatic Sea station (ST 101) under the influence of Po River was conducted in period from 2006–2008. The acidity of surface-active organic material (Ac r) was followed as well. The results...
Article
We show that electrochemically inactive molecules of polysaccharide (PS), if carrying sulphated groups (e.g. ι-carrageenan and dextran sulphate) produce in buffered solutions two well-developed chronopotentiometric peaks HPS and H′PS (due to catalytic hydrogen evolution) at hanging mercury drop electrode. Peak HPS of ι-carrageenan displayed a strik...
Article
Full-text available
The copper complexing capacities (CuCC), i.e. organic ligands capable to form stable organic complexes with copper ions, were measured in the Krka river estuary. Krka river estuary is a karstic, salt wedge estuary situated on the Eastern coast of middle Adriatic area. The measurements have been done in 1983, 1984 and 2008 at the same sampling stati...
Article
Organic complexation in atmospheric precipitation is an important control mechanism of the biogeochemistry of metal ions. We have measured complexation of copper ions in bulk precipitation by the method of differential pulse anodic stripping voltammetry (DPASV), which introduces least perturbation in the samples. The precipitation samples were coll...
Article
Voltammetry of selenium(+4)-rhodium(+3) system was studied in different electrolyte solutions with special attention paid to possible application of the observed effects in selenite determination at trace levels. Although the signals obtained from such mixtures can be more than 200 times higher than those resulting from simple selenium(+4) solution...
Article
Using square-wave voltammetry and linear scan voltammetry, some reduction processes, that take place on the hanging mercury drop electrode (HMDE) in rhodium(+3)–selenium(+4) mixtures, were studied in highly acidic sulfate, chloride and perchlorate solutions. The special attention was paid to the peak located at −1.1 V, that reflects catalytic hydro...

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Projects

Projects (3)
Project
BiREADI is designed to assess the impact of atmospheric deposition on complex biochemical responses of oligotrophic systems, considering the importance of promotion and inhibition effects on phytoplankton, and the consequent altering of the surface water chemistry, including the sea surface microlayer at the air-water interface.
Archived project
This project is designed to make scientific progress in the fundamental understanding of chemical composition and (trans)formation processes of marine organosulfur compounds (OS) and their role in the marine organic aerosol formation. Particulate inorganic sulfate influences aerosol acidity and cloud condensation activity and thus affects the radiative balance of the atmosphere and Earth’s climate. Recently, OS have come into the focus of atmospheric research as significant reservoirs of atmospheric sulfur, being potentially important in gas-to-particle conversion and the formation of secondary organic aerosols. The latter represent one of the largest uncertainties in state-of-the-art atmospheric models, which deviate substantially from field measurements.
Archived project
Recently documented oligotrophication of the Adriatic Sea caused by global changes opened questions how this reflects on the quality and quantity of organic matter (OM) produced by the phytoplankton and on the consequent influence on the micronutrient metals availability and cycling. Within the project, a progressive approach will be accomplished to reveal crucial alterations in the marine ecosystem. Initial investigations will imply model experiments on the interaction of selected OM with micronutrient metals. Additionally, phytoplankton monoculture incubation under various growth conditions will be included in order to comprehend multiple stressors on the phytoplankton OM production and micronutrients metals distribution. Model experiments will be followed by in-situ investigations at the selected oligotrophic and eutrophic areas of the Adriatic Sea.