Radioactivity of the soil in Vojvodina (northern province of Serbia and Montenegro)

The widespread public belief that during the bombardment of Vojvodina (Yugoslavia) this region was contaminated by depleted uranium has recently raised public concern with respect to the potential contamination of agricultural products due to soil radioactivity. Based on the gamma-spectrometric analysis of 50 soil samples taken from the region of Vojvodina we concluded that there is no increase of radioactivity that could endanger the food production. Taking into account the transfer factors of 137Cs to plants, the measured activity concentrations of this isotope should not endanger the health safety of the produced food. No traces of depleted uranium have been found. The natural radioactivity levels are compared with the results form other countries.     

Influence of suspended clay minerals and humic matter on the solid phase extraction efficiency of selected pesticides from water

The purpose of this investigation was to determine the influence of humic acids (HA) and Ca-montmorillonite (CaM) on the solid-phase extraction (SPE) efficiency of atrazine, alachlor and alpha-cypermethrin from water samples at various pH-values. The nature and intensity of binding of the studied pesticides to CaM were determined by X-ray diffraction analysis and termogravimetric analysis (TGA) test. The studied pesticides eluted from discs were analysed by thin-layer chromatography (TLC). The effects of CaM and humic acid were generally pH-dependent and acted independently in extraction efficiency influence. Lower recovery of pesticides was observed at higher pH values when CaM was > or =0.1 g and was attributed to greater dispersion of clay, increased surface area and subsequent adsorption. Concentrations of dissolved organic carbon (DOC) in humic acid had less effect on the extraction efficiency when water was at pH 8 compared to water at pH 2, which was probably due to greater nonpolar interactions of the pesticides to the charge-neutralized humic acid molecule.     

Impact of a severe flood on large-scale contamination of arable soils by potentially toxic elements (Serbia)

Environmental Geochemistry and Health - Extreme flooding in May, 2014 affected the sub-catchments of six major rivers in Serbia. The goal of the study was to evaluate the contents of potentially...     

Microphytoplankton in the Strait of Otranto (eastern Mediterranean)

The Strait of Otranto is the connection between the Adriatic and Ionian Seas. Low nutrient concentrations, high transparency, and low phytoplankton cell density and biomass reflect the oligotrophic character of the area. Enrichment of the euphotic layer with nutrients is mainly due to discharge of Albanian and Greek rivers, as well as mixing and upwelling in winter/early spring. Following phytoplankton bloom in April, a progressive decrease of phytoplankton cell density is due to the consumption of nutrients throughout the proceeding summer and autumn. Nitrogen was a strong limiting factor for phytoplankton growth in summer. Deep biomass maxima were detected in the 50 to 100 m layer and corresponded mostly to cells smaller than 20 m. The eastern part of the strait is mostly influenced by the northerly inflowing current from the Ionian Sea, and the western part by the southerly outflowing current from the Adriatic Sea. This typical circulation could be disturbed by inertial oscillations in the current field, generated by the strong oscillating winds and cyclonic eddies. The type of circulation determined the distribution of thermohaline characteristics, abundance, biomass, as well as taxonomic composition of phytoplankton, across the strait. Ecological characteristics of the water masses on two sides of the strait were significantly different during the formation of a longitudinal thermohaline front in May 1990.     

Benefits of protected areas for nonbreeding waterbirds adjusting their distributions under climate warming

Climate warming is driving changes in species distributions and community composition. Many species have a so-called climatic debt, that is, shifts in range lag behind shifts in temperature isoclines. Inside protected areas (PAs), community changes in response to climate warming can be facilitated by greater colonization rates by warm-dwelling species, but also mitigated by lowering extirpation rates of cold-dwelling species. An evaluation of the relative importance of colonization-extirpation processes is important to inform conservation strategies that aim for both climate debt reduction and species conservation. We assessed the colonization-extirpation dynamics involved in community changes in response to climate inside and outside PAs. To do so, we used 25 years of occurrence data of nonbreeding waterbirds in the western Palearctic (97 species, 7071 sites, 39 countries, 1993–2017). We used a community temperature index (CTI) framework based on species thermal affinities to investigate species turnover induced by temperature increase. We determined whether thermal community adjustment was associated with colonization by warm-dwelling species or extirpation of cold-dwelling species by modeling change in standard deviation of the CTI (CTI_SD). Using linear mixed-effects models, we investigated whether communities in PAs had lower climatic debt and different patterns of community change than communities outside PAs. For CTI and CTI_SD combined, communities inside PAs had more species, higher colonization, lower extirpation, and lower climatic debt (16%) than communities outside PAs. Thus, our results suggest that PAs facilitate 2 independent processes that shape community dynamics and maintain biodiversity. The community adjustment was, however, not sufficiently fast to keep pace with the large temperature increases in the central and northeastern western Palearctic. Our results underline the potential of combining CTI and CTI_SD metrics to improve understanding of the colonization-extirpation patterns driven by climate warming.