Effect of copper on the scope for growth of clams (Tapes philippinarum) from a farming area in the Northern Adriatic Sea

Copper is currently the most common biocide in antifouling paints. Levels of this metal were measured in the water, particulate matter and sediments from a shellfish farming area in the Sacca di Goro (Northern Adriatic Sea) over one year. With respect to the 1980s, copper environmental level increased twofold. The release of copper from shellfish farmers' boats was also estimated to be > 250 kg Cu y(-1). Clams Tapes philippinarum were collected in the same area and seasonally exposed to a sublethal (10 microg Cu l(-1)) concentration of copper. Physiological traits were significantly affected by copper exposure (scope for growth declined as a result of reduced clearance rate, increased oxygen consumption and a generally lower absorption efficiency). The results of this study are cause for concern for shellfish farming activities at least in Northern Adriatic, where shellfish farming is a monoculture of T. philippinarum. A strict interpretation of the precautionary principle might suggest that more rigorous regulatory action to control copper inputs in the field would be justified.     

The SAURON project – VII. Integral-field absorption and emission-line kinematics of 24 spiral galaxy bulges

We present observations of the stellar and gas kinematics for a representative sample of 24 Sa galaxies obtained with our custom-built integral-field spectrograph SAURON operating on the William Herschel Telescope. The data have been homogeneously reduced and analysed by means of a dedicated pipeline. All resulting data cubes were spatially binned to a minimum mean signal-to-noise ratio of 60 per spatial and spectral resolution element. Our maps typically cover the bulge-dominated region. We find a significant fraction of kinematically decoupled components (12/24), many of them displaying central velocity dispersion minima. They are mostly aligned and co-rotating with the main body of the galaxies, and are usually associated with dust discs and rings detected in unsharp-masked images. Almost all the galaxies in the sample (22/24) contain significant amounts of ionized gas which, in general, is accompanied by the presence of dust. The kinematics of the ionized gas are consistent with circular rotation in a disc co-rotating with respect to the stars. The distribution of mean misalignments between the stellar and gaseous angular momenta in the sample suggests that the gas has an internal origin. The [O  iii ]/Hβ ratio is usually very low, indicative of current star formation, and shows various morphologies (ring-like structures, alignments with dust lanes or amorphous shapes). The star formation rates (SFRs) in the sample are comparable with that of normal disc galaxies. Low gas velocity dispersion values appear to be linked to regions of intense star formation activity. We interpret this result as stars being formed from dynamically cold gas in those regions. In the case of NGC 5953, the data suggest that we are witnessing the formation of a kinematically decoupled component from cold gas being acquired during the ongoing interaction with NGC 5954.     

Star clusters with primordial binaries – I. Dynamical evolution of isolated models

In order to interpret the results of complex realistic star cluster simulations, which rely on many simplifying approximations and assumptions, it is essential to study the behaviour of even more idealized models, which can highlight the essential physical effects and are amenable to more exact methods. With this aim, we present the results of N -body calculations of the evolution of equal-mass models, starting with primordial binary fractions of 0–100 per cent, with values of N ranging from 256 to 16 384. This allows us to extrapolate the main features of the evolution to systems comparable in particle number with globular clusters.
In this range, we find that the steady-state 'deuterium main sequence' is characterized by a ratio of the core radius to half-mass radius that follows qualitatively the analytical estimate by Vesperini & Chernoff, although the N dependence is steeper than expected. Interestingly, for an initial binary fraction f greater than 10 per cent, the binary heating in the core during the post-collapse phase almost saturates (becoming nearly independent of f ), and so little variation in the structural properties is observed. Thus, although we observe a significantly lower binary abundance in the core with respect to the Fokker–Planck simulations by Gao et al., this is of little dynamical consequence.
At variance with the study of Gao et al., we see no sign of gravothermal oscillations before 150 half-mass relaxation times. At later times, however, oscillations become prominent. We demonstrate the gravothermal nature of these oscillations.     

Deep-water Circulation: Processes & Products (16�C18 June 2010, Baiona): introduction and future challenges

Deep-water circulation is a critical part of the global conveyor belt that regulates Earth??s climate. The bottom (contour)-current component of this circulation is of key significance in shaping the deep seafloor through erosion, transport, and deposition. As a result, there exists a high variety of large-scale erosional and depositional features (drifts) that together form more complex contourite depositional systems on continental slopes and rises as well as in ocean basins, generated by different water masses flowing at different depths and at different speeds either in the same or in opposite directions. Yet, the nature of these deep-water processes and the deposited contourites is still poorly understood in detail. Their ultimate decoding will undoubtedly yield information of fundamental importance to the earth and ocean sciences. The international congress Deep-water Circulation: Processes & Products was held from 16?C18 June 2010 in Baiona, Spain, hosted by the University of Vigo. Volume 31(5/6) of Geo-Marine Letters is a special double issue containing 17 selected contributions from the congress, guest edited by F.J. Hernández-Molina, D.A.V. Stow, E. Llave, M. Rebesco, G. Ercilla, D. Van Rooij, A. Mena, J.-T. Vázquez and A.H.L. Voelker. The papers and discussions at the congress and the articles in this special issue provide a truly multidisciplinary perspective of interest to both academic and industrial participants, contributing to the advancement of knowledge on deep-water bottom circulation and related processes, as well as contourite sedimentation. The multidisciplinary contributions (including geomorphology, tectonics, stratigraphy, sedimentology, paleoceanography, physical oceanography, and deep-water ecology) have demonstrated that advances in paleoceanographic reconstructions and our understanding of the ocean??s role in the global climate system depend largely on the feedbacks among disciplines. New insights into the link between the biota of deep-water ecosystems and bottom currents confirm the need for this field to be investigated and mapped in detail. Likewise, it is confirmed that deep-water contourites are not only of academic interest but also potential resources of economic value. Cumulatively, both the congress and the present volume serve to demonstrate that the role of bottom currents in shaping the seafloor has to date been generally underestimated, and that our understanding of such systems is still in its infancy. Future research on contourites, using new and more advanced techniques, should focus on a more detailed visualization of water-mass circulation and its variability, in order to decipher the physical processes involved and the associations between drifts and other common bedforms. Moreover, contourite facies models should be better established, including their associations with other deep-water sedimentary environments both in modern and ancient submarine domains. The rapid increase in deep-water exploration and the new deep-water technologies available to the oil industry and academic institutions will undoubtedly lead to spectacular advances in contourite research in terms of processes, morphology, sediment stacking patterns, facies, and their relationships with other deep-marine depositional systems.     

Global and regional factors responsible for the drowning of the Central Apennine Chattian carbonate platforms

This work discusses and interprets the factors responsible for the Oligocene–Miocene drowning of the Central Apennine platform deposits, based on facies and stable‐isotope analyses of two representative stratigraphic sections. The Mediterranean carbonate platforms were affected during the Oligocene–Miocene boundary by a carbonate production crisis that was induced by global factors and amplified by regional events, such as volcanic activity. The positive δ¹³C shift observed in the studied sections corresponds to vertical facies changes reflecting the evolution from middle carbonate ramp to outer ramp‐hemipelagic depositional environments. This drowning event is recorded not only in the Apennine platforms, but also in other Mediterranean platforms such as in southern Apulia, Sicily and Malta, and outside the Mediterranean Basin. The ~24–23.5 Ma Mi‐1 glacial maximum may have had a significant influence on this drowning event because it was associated with high rates of accumulation of continent‐derived sediments. The increased continental weathering and runoff sustained high trophic conditions. These probably were a consequence of the Aquitanian–Burdigalian volcanic activity in the Central‐Western Mediterranean, that may have led to an increase in nutrient content in seawater and an increase in atmospheric and marine CO₂ concentrations. Copyright © 2014 John Wiley & Sons, Ltd.