Climate change modifies carbon sequestration in copper-polluted forest soils

Soil carbon (C) storage is a key ecosystem function which can provide globally important services such as climate regulation. The effect of climate change on the restoration of soil C storage potential on post-mining land, where the development of both soil and vegetation starts de novo, is still insufficiently understood. In this work we discuss how the recent changes of climate, effectuating temperature increase and overall habitat xerophytization have, during about 40 years, markedy modified the course of spontaneous succession and concomitantly the soil C sequestration potental in a model floodplain severely altered by long-term deposition of sulphidic waste from a copper (Cu) mine. Excessive Cu strongly reduces turnover of soil organic matter and adversely affects the revegetation process. Natural floods in this complex geomorphic setup on the other hand bring both pollutants and deficient nutrients to the affected floodplain. As the recent climate changes reduce the intensity of natural floods, two very different but highly specialized forest types are developing along the microelevation gradient (transects perpendicular to water channel) with up to 3-fold different topsoil C sequestration. This work shows how climate change can increase the vunerability of spontaneous restoration process primarily by reducing nutrient fluxes

Cretaceous-Paleogene boundary Fish Clay at Højerup (Stevns Klint, Denmark): Zn, Pb and REE in kerogen

Geochemical analyses of Zn, Pb and rare earth elements (La, Ce, Nd, Sm, Eu, Tb, Yb and Lu) in the kerogen of the black marl at the Cretaceous - Paleogene boundary Fish Clay at Hojerup were performed. Substantial proportions of the Zn, Pb and rare earths were probably contained in terrestrial humic substances (the kerogen precursor) arriving at the marine sedimentary site. This is in accord with a previous hypothesis that kerogen is mainly derived from humic acids of an oxic soil in of the adjacent coastal areas of eastern Denmark. It is also suggested that humics enriched in Zn, Pb and rare earth elements were transported mainly through fluvial transport into the deposition site of the Fish Clay. Local weathering/leaching of the impact-eject fallout on the land surface and local terrestrial rocks by impact-induced? acid surface waters perhaps played an important role in providing Zn, Ph and rare earths to these humic substances. Apparently, chondritic and non-chondritic Zn originated from the impact fallout; Pb and rare earth elements were most likely sourced by exposed rocks in the coastal areas of eastern Denmark

Geochemistry of Fe3+ in the hydrothermal dickite from Jedlina Zdroj (Lower Silesia, Poland)

Geochemical analysis for Fe was made on a representative sample of dickite-rich hydrothermal clay from Jedlina Zdroj. The mineralogy of the sample is comparatively simple, dickite being the principal component (>95 wt. % of the total sample), with lesser amounts of goethite and barite. Geochemical fractionation and inductively coupled plasma-optical emission spectrometry indicated that most of the Fe (ca. 97 wt. % of the total metal) resides in the dickite. Electron spin resonance showed that some of the Fe in the dickite structure is in the form of Fe3+. A substantial proportion of these ions (as well as Fe) in the dickite matrix were probably contained in the original hydrothermal dickite-forming solution. From the geochemistry of Fe3+, it was deduced that the oxidation potential (Eh) and pH of the solution during the formation of dickite from the Jedlina Zdroj were approximately 0.45-0.95 V (highly oxygenated) and 0-4 (highly acidic), respectivel

Air oxidation of the kerogen/asphaltene vanadyl porphyrins: an electron spin resonance study

The thermal behavior of vanadyl porphyrins was studied by electron spin resonance during heating of kerogens, isolated from the La Luna (Venezuela) and Serpiano (Switzerland) bituminous rocks, at 25°C for 1 to 20 days in the presence of air. During the thermal treatment of the kerogens, the vanadyl porphyrins resonance signals decrease monotonically and become quite small after 6 days of heating. Concomitantly, new vanadyl signals appear and, at longer heating times, dominate the spectrum. It is suggested that the secondary vanadyl species must have been formed from vanadyl porphyrins. Similar conversions of vanadyl porphyrins are observed under the same experimental conditions for asphaltenes extracted from the La Luna and Serpiano rocks, and floating asphalt from the Dead Sea (Israel). A comparison of the spin-Hamiltonian parameters for vanadyl porphyrins and the vanadyl compounds obtained during pyrolysis of the kerogens/asphaltenes suggests that the latter are of a non-porphyrin type. For comparison a study was conducted on Western Kentucky No. 9 coal enriched with vanadium (>>400 ppm) from six mines. All the coal samples show only the presence of predominant by non-porphyrin vanadyl compounds, similar to those generated through laboratory heating of the kerogens/asphaltenes in air. In addition, some samples also contain a minor amount of vanadyl porphyrins

Geochemistry of Ni in the Cretaceous-Tertiary succession Fiskeler (Fish Clay) at Stevns Klint (Denmark): cheto-smectite of the black marl

The Cretaceus-Tertiary (KT) boundary at Stevns Klint (the Højerup succession), Fiskeler, consists of a thin red clay layer overlain by a thick one of black marl. These two layers are made up mainly from cheto-smectite and biogenic calcite. The black marl shows an enhanced concentration of Ni (655 ppm) within its smectite fraction. Additionally, its carbonate fraction also shows an enhanced concentration of Ni (245 ppm). It is reasoned that these enrichments represent a sudden and rapid input of high amounts of Ni into the late Cretaceus seawater at Stevns Klint. The ultimate source of Ni in both the carbonate and smectite fractions of the black marl was probably impact fallout, produced by the KT asteroidal impact, deposited on the nearby soil and leached by the (acid) surface waters. The geochemistry of the Ni supports the hypothesis that the smectite of this marl most likely has a local (marine or terrestrial) provenance and was probably redeposited, after its formation, from the original site to its present location at the KT boundary

Cretaceous – Paleogene boundary Fish Clay at Højerup (Stevns Klint, Denmark): Zn, Pb and REE in kerogen

Geochemical analyses of Zn, Pb and rare earth elements (La, Ce, Nd, Sm, Eu, Tb, Yb and Lu) in the kerogen of the black marl at the Cretaceous – Paleogene boundary Fish Clay at Højerup were performed. Substantial proportions of the Zn, Pb and rare earths were probably contained in terrestrial humic substances (the kerogen precursor) arriving at the marine sedimentary site. This is in accord with a previous hypothesis that kerogen is mainly derived from humic acids of an oxic soil in of the adjacent coastal areas of eastern Denmark. It is also suggested that humics enriched in Zn, Pb and rare earth elements were transported mainly through fluvial transport into the deposition site of the Fish Clay. Local weathering/leaching of the impact–eject fallout on the land surface and local terrestrial rocks by impact-induced? acid surface waters perhaps played an important role in providing Zn, Pb and rare earths to these humic substances. Apparently, chondritic and non-chondritic Zn originated from the impact fallout; Pb and rare earth elements were most likely sourced by exposed rocks in the coastal areas of eastern Denmark

Production process parameter optimization with a new model based on a genetic algorithm and ABC classification method

The difference between the production cost and selling price of the products may be viewed as a criterion that determines an organization’s competitiveness and market success. In such circumstances, it is necessary to impact these criteria in order to maximize this difference. The selling products’ price, in modern market conditions, is a category which may not be significantly affected. So organizations have one option, which is the production cost reduction. This is the motive for business organizations and the imperative of each organization. The key parameters that influence the costs of production and therefore influence the competitiveness of organizations are the parameters of production machines and processes used to create products. To define optimal parameter values for production machines and processes that will reduce production costs and increase competitiveness of production organizations, the authors have developed a new mathematical model. The model is based on application of the ABC classification method to classify production line processes based on their costs and an application of a genetic algorithm to find the optimal values of production machine parameters used in these processes. It has been applied in three different modern production line processes; the costs obtained by the model application have been compared with the real production costs

The vanadium isotopic constitution of petroleum asphaltenes: La Luna Formation (Venezuela)

High resolution mass spectrometry indicates that the isotopic abundance of 50vanadium (V) of the Late Cretaceous La Luna petroleum asphaltenes and related source kerogen of marine origin (both highly enriched with V >> 2000 ppm) is higher by about 3,5 % than that of an inorganic vanadium source (VOSO4 > 5H2O, Merck). It is proposed that the difference in the 50V/51V values between the La Luna source kerogen/the associated petroleum asphaltenes and the inorganic source can be best ascribed to the biological processing of seawater V. The fact that the isotopic compositions of V vary over a very narrow range (2.46-2.50) suggest an essentially same (or similar) and fixed bilogical source of V

Comparison of Preoperative Evaluation with the Pathological Report in Intraductal Papillary Mucinous Neoplasms: A Single-Center Experience

The key to the successful management of pancreatic cystic neoplasm (PCN), among which intraductal papillary mucinous neoplasm (IPMN) is the one with the highest risk of advanced neoplasia in resected patients, is a careful combination of clinical, radiological, and histopathological findings. This study aims to perform the comparison of a preoperative evaluation with pathological reports in IPMN and further, to evaluate and compare the diagnostic performance of European evidence-based guidelines on pancreatic cystic neoplasms (EEBGPCN) and Fukuoka Consensus guidelines (FCG). We analyzed 106 consecutive patients diagnosed with different types of PCN, among whom 68 had IPMN diagnosis, at the Clinical Center of Serbia. All the patients diagnosed with IPMNs were stratified concerning the presence of the absolute and relative indications according to EEBGPCN and high-risk stigmata and worrisome features according to FCG. Final histopathology revealed that IPMNs patients were further divided into malignant (50 patients) and benign (18 patients) groups, according to the pathological findings. The preoperative prediction of malignancy according to EEBGPCN criteria was higher than 70% with high sensitivity of at least one absolute or relative indication for resection. The diagnostic performance of FCG was shown as comparable to EEBGPCN. Nevertheless, the value of false-positive rate for surgical resection showed that in some cases, overtreating patients or treating them too early cannot be prevented. A multidisciplinary approach is essential to adequately select patients for the resection considering at the same time both the risks of surgery and malignancy