Irena Ciglenečki

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The marine Lake Rogoznica is a small, karstic habitat with potential anthropogenic influence, situated in the eastern-central Adriatic coast. In this naturally eutrophic, hypoxic and periodically anoxic lake, an investigation of the microplankton community was performed during the 19951998 period when the ecology of the lake was greatly influenced by strong(More)
Recent publications have shown that the anodic reaction between FeS and Hg can be used for electrochemical detection of colloidal and particulate FeS in natural waters. Anodic waves that were recorded around -0.45 V (vs Ag/AgCl) in model solutions correspond to the electrochemical transformation of nanoparticulate FeS to HgS. Here, as a further step, the(More)
Voltammetric scans in sulfidic natural waters often reveal reduction peaks in the range -0.9 to -1.35 V versus Ag/AgCl. These peaks have been attributed to iron sulfide complexes or clusters. However, sols containing CuS nanoparticles now also are known to produce reduction peaks in this range. Here we investigate the voltammetric behavior of two additional(More)
Most stratified sulfidic holomictic lakes become oxygenated after annual turnover. In contrast, Lake Rogoznica, on the eastern Adriatic coast, has been observed to undergo a period of water column anoxia after water layer mixing and establishment of holomictic conditions. Although Lake Rogoznica's chemistry and hydrography have been studied extensively, it(More)
Highly stratified Mediterranean estuaries are unique environments where the tidal range is low and the tidal currents are almost negligible. The main characteristics of these environments are strong salinity gradients and other environmental parameters. In this study, 454 pyrosequencing of the 16S rRNA gene in combination with catalyzed reporter(More)
An association of Cu with sulfide in aerobic natural waters has been attributed to these components' coexistence in clusters of sizes intermediate between mononuclear complexes and colloidal particles. This hypothesis is investigated here. Copper sulfide solid phases display size-related voltammetric behavior at Hg electrodes. Suspensions of copper sulfide(More)
Dissolved organic carbon (DOC) is an essential component of the biogeochemical marine system, effecting biological and chemical reactions that take place in the sea. DOC represents a dynamic component of the global carbon cycle. This paper reports 25years of measurements of DOC content and distribution at seven stations along the transect Po River delta -(More)
Global change is determining the expansion of marine oxygen-depleted zones, which are hot spots of microbial-driven biogeochemical processes. However, information on the functioning of the microbial assemblages and the role of viruses in such low-oxygen systems remains largely unknown. Here, we used the marine Rogoznica Lake as a natural model to(More)
Electroanalytical (voltammetric, polarographic, chronoamperometric) methods on an Hg electrode were applied for studying of different sulfur compounds in model and natural water systems (anoxic lakes, waste water, rain precipitation, sea-aerosols). In all investigated samples typical HgS reduction voltammetric peak, characteristic for many different reduced(More)
Voltammetric and polarographic methods at the Hg electrode were used to study presence of sulfur species in different contrasting natural samples: stratified anoxic lakes, seawater lake Rogoznica Lake (Croatia) and crater lake Pavin Lake (France); rain precipitation and sea-aerosols. In all of these investigated samples typical HgS reduction voltammetric(More)
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