Exploring copepod distribution patterns at three nested spatial scales in a spring system. Habitat partitioning and potential for hydrological bioindication

In groundwater-fed springs, habitat characteristics are primarily determined by a complex combination of geomorphic features and physico-chemical parameters, while species assemblages are even more intricate. Springs host species either inhabiting the spring mouth, or colonizing spring habitats from the surface or from the aquifers which feed the springs. Groundwater species living in springs have been claimed as good candidates for identifying dual aquifer flowpaths or changes in groundwater pathways before reaching the spring outlets. However, the reliability of spring species as hydrological biotracers has not been widely investigated so far. Our study was aimed at analysing a large karstic spring system at three nested spatial scales in order: i) to assess, at whole spring system scale, the presence of a groundwater divide separating two aquifers feeding two spring units within a single spring system, by combining isotope analyses, physico-chemistry, and copepod distribution patterns; ii) to test, at vertical spring system scale, the effectiveness of copepods in discriminating surface and subsurface habitat patches within the complex mosaic spring environment; iii) to explore, at local spring unit level, the relative role of hydrochemistry and sediment texture as describers of copepod distribution among microhabitats. The results obtained demonstrated the presence of a hierarchical spatial structure, interestingly reflected in significant differences in assemblage compositions. Copepod assemblages differed between the two contiguous spring units, which were clearly characterized by their hydrochemistry and by significant differences in the groundwater flowpaths and recharge areas, as derived by the isotope analyses. The biological results suggested that stygobiotic species seem to be related to the origin of groundwater, suggesting their potential role as hydrological biotracers. At vertical scale, assemblage composition in surface and subsurface habitats was significantly different, both between spring units and among microhabitats, supporting strong habitat preferences of copepod species. At the smaller local scale, the response to habitat patchiness of subsurface copepod assemblages resulted in distribution patterns primarily defined by sediment texture, while the sensitivity to differences in hydrochemistry was negligible

The water mites (Acari: Hydrachnidia) of the standing waters of Corsica, Sardinia and Sicily: review and new data

A compilation of our present knowledge of the water mites (Acari: Hydrachnidia) adapted to life in standing waters on the three large islands in the western Mediterranean (Corsica, Sardinia and Sicily) is provided. In addition to published data, this study deals with a rich volume of new material from recent field work, mostly deriving from intermittent ponds and pools, an extremely poorly investigated yet peculiar habitat type in the Mediterranean area. Species richness of water mites reported for the standing waters of the three islands amounts to 91 species. Out of the 47 species for which we present new distributional data, Hydrachna incisa Halbert, 1903, Hydrachna leegei Koenike, 1895, Piersigia limophila Protz, 1896, Hydryphantes crassipalpis Koenike, 1914 and Piona laminata (Thor, 1900) have not been recorded previously from the Mediterranean area. Most of these species were believed to have typical North European distributions. In addition to these, a further 13 species are recorded for the first time from the area covered. In total, 11 species are new for Italy, seven more are new for Sicily, three for Sardinia and seven for Corsica. Redescriptions are given of Axonopsis complanata (Müller, 1776) (A. graeca, nov. syn), Brachypoda baderi (reported for the first time after the original description from Abruzzo, Italy, synonymization with B. mutila rejected) and B. mutila (recorded for the first time outside Algeria with certainty). For each species, information is given on habitat preference and geographical distribution; the significance of the data is discussed under perspectives of zoogeography and nature protection. The completeness of our knowledge for the three investigated island is assessed using rarefaction curves and non-parametric estimators of species richness; while Sicily can be considered fairly well known, Corsica and Sardinia require further sampling to assess their water mite diversity

Diversity and Distribution of the Inland Water Decapods of Sicily (Crustacea, Malacostraca)

The current knowledge of Sicilian inland water decapod malacostracans is scarce and an updated synopsis on species distribution is lacking. Therefore, we reviewed the checklist and recent distribution of Sicilian inland water decapods based on published and unpublished records and novel observations with the aim of providing an exhaustive repository, also to be used as a sound baseline for future surveys. Overall, five native decapod species occur in the study area, i.e., the atyid shrimp Atyaephyra desmarestii, the palaemonid shrimps Palaemon adspersus, P. antennarius, and P. elegans, and the freshwater crab Potamon fluviatile, and their current local distributions are described. In addition, three alien species were recorded: the common yabby Cherax destructor and the red swamp crayfish Procambarus clarkii, strictly linked to inland waters, and the Atlantic blue crab Callinectes sapidus, a mainly marine species that can also colonise the lower stretches of rivers and coastal brackish waters. The collected data suggest the existence of a partial segregation of native versus non-native species, with the latter currently confined to coastal water bodies and the lower stretches of rivers. Moreover, the exclusively freshwater caridean A. desmarestii and P. antennarius show a parapatric distribution in the study area, which may suggest the existence of mutual exclusion phenomena. The results obtained raise some concerns about the effects of alien species on the native biota, and dedicated monitoring and management strategies should be implemented in order to better understand and mitigate their impact

An updated checklist and biogeography of the Sardinian large branchiopods, with a focus on Spinicaudata (Crustacea, Branchiopoda)

The large branchiopod fauna of Sardinia is reviewed based both on literature and newly collected data. Based on the available evidence, 13 taxa are present on the island (8 Anostraca, 2 Notostraca, and 3 Spinicaudata). Among them, the finding of the spinicaudatan Leptestheria dahalacensis is new for Sardinia, while the spinicaudatans Cyzicus bucheti and Eulimnadia sp. were overlooked in the most recent synopses on the fauna of the island due to misidentifications. Conversely, Cyzicus tetracerus and Limnadia lenticularis, previously erroneously reported based on misidentifications, must be excluded from the fauna of Sardinia. The finding of Eulimnadia sp. is the first record in Europe and the northernmost record of the genus. The occurrence of Leptestheria dahalacensis in Sardinia is rather unexpected and probably due to its accidental introduction linked with rice cultures. At least four of the 13 Sardinian large branchiopod species are absent from the Italian mainland and Sicily, stressing the uniqueness of its fauna and its significant contribution to the Mediterranean inland water crustacean diversity

Anti-dumping proceedings in metallurgical brand

Dumping can be generally defined as an unfair trade practice, in which a manufacturer sells identical products or very similar products in the foreign market at price that is lower than their normal value in the domestic market. Metallurgical materials and products are among those products which the anti-dumping duty is often imposed on. The market with metallurgical products and the methodology used for calculating the dumping range have certain specific features related to the decisions on possible dumping and its amount, as presented in the article

Karakterizacija i korozione karakteristike elektrohemijski taložene legure Ni-W

Ni-W alloys electrodeposited from citrate solution consist of three different phases, which are all present in high W-content alloys: a solid solution of W in a Ni matrix; an intermetallic compound Ni4W, as well as another solid solution of W in Ni with a W content higher than 20 mol. %. XPS analysis revealed that the alloys were covered with a surface layer of complex structure containing the pure metals Ni and W, Ni(OH)2 andWO3, on the very surface as well as some partially reduced oxideWO2.72 (most probably a solid solution ofWO2.72 in Ni) and tungsten carbide in the layer underneath. It is highly likely that some of the oxide species in the layer act as intermediates in the cathodic deposition process. Identifying these species should be the clue to a more detailed understanding of the mechanism of induced deposition of W than has been achieved so far. Corrosion of Ni-W alloys in sulfuric acid solution at OCP, occurs by the preferential dissolution of nickel from the surface layer. The longer the corrosion process lasts, the more the surface behaves like pure W. The lowest initial corrosion rates were recorded with alloys rich in W, but after aging at OCP the lowest corrosion c.d. was found for the Ni-W alloy with the most homogenous phase structure, consisting of the solid solution only.Elektrohemijski taložene legure Ni-W iz citratnog rastvora sadrže tri različite faze, koje su prisutne pri visokom sadržaju W u leguri: čvrst rastvor W u Ni; intermetalno jedinjenje Ni4Wi čvrst rastvor Wu Ni sa sadržajem W većim od 20 mol %. XPS analizom je pokazano da su legure pokrivene slojem složene strukture. Ovaj sloj sadrži čiste metale Ni i W, Ni(OH)2 i WO3, na samoj površini. U sloju ispod same površine nađeni su i delimično redukovan oksid WO2,72 (najverovatnije čvrst rastvor WO2,72 u Ni) i volfram-karbid. Vrlo je verovatno da neka od oksidnih vrsta u sloju učestvuje kao intermedijer u procesu katodnog taloženja. Identifikacija te vrste mogla bi doprineti boljem razumevanju mehanizma indukovanog taloženja volframa. Na potencijalu otvorenog kola u sumpornoj kiselini korozioni proces se odigrava tako što se preferencijalno rastvara Ni iz površinskog sloja legure. Ukoliko korozioni proces traje duže utoliko korozione karakteristike postaju sve sličnije onima za čist W. Niže početne brzine korozije dobijene su za legure sa većim sadržajem W. Međutim, nakon stajanja na potencijalu otvorenog kola niže korozione struje su dobijene za Ni-W leguru homogene fazne strukture koja sadrži samo čvrst rastvor

Deuteron spin-lattice relaxation in the presence of an activation energy distribution: Application to methanols in zeolite NaX

A new method is introduced for analyzing deuteron spin-lattice relaxation in molecular systems with a broad distribution of activation energies and correlation times. In such samples the magnetization recovery is strongly non-exponential but can be fitted quite accurately by three exponentials. The considered system may consist of molecular groups with different mobility. For each group a Gaussian distribution of the activation energy is introduced. By assuming for every subsystem three parameters: the mean activation energy E-0, the distribution width sigma and the pre-exponential factor tau(0) for the Arrhenius equation defining the correlation time, the relaxation rate is calculated for every part of the distribution. Experiment-based limiting values allow the grouping of the rates into three classes. For each class the relaxation rate and weight is calculated and compared with experiment. The parameters E-0, sigma and tau(0) are determined iteratively by repeating the whole cycle many times. The temperature dependence of the deuteron relaxation was observed in three samples containing CD3OH (200% and 100% loading) and CD3OD (200%) in NaX zeolite and analyzed by the described method between 20 K and 170 K. The obtained parameters, equal for all the three samples, characterize the methyl and hydroxyl mobilities of the methanol molecules at two different locations. (C) 2012 Elsevier Inc. All rights reserved