Complexity‐reduction modelling for assessing the macro‐scale patterns of historical soil moisture in the Euro‐Mediterranean region

Complexity‐reduction modelling can be useful for increasing the understanding of how the climate affects basin soil moisture response upon historical times not covered by detailed hydrological data. For this purpose, here is presented and assessed an empirical regression‐based model, the European Soil Moisture Empirical Downscaling (ESMED), in which different climatic variables, easily available on the web, are addressed for simplifying the inherent complexity in the long‐time studies. To accommodate this simplification, the Palmer Drought Severity Index, the precipitation, the elevation and the geographical location were used as input data in the ESMED model for predicting annual soil moisture budget. The test area was a large region including central Europe and Mediterranean countries, and the spatial resolution was initially set at 50 km. ESMED model calibration was made according to the soil moisture values retrieved from the Terrestrial Water Budget Data archive by selecting randomly 285 grid points (out of 2606). Once parameterized, ESMED model was performed at validation stage both spatially and temporally. The spatial validation was made for the grid points not selected in the calibration stage while the comparison with the soil moisture outputs of the Global Land Data Assimilation System–NOAH10 simulations upon the period 1950–2010 was carried out for the temporal validation. Moreover, ESMED results were found to be in good agreement with a root‐zone soil moisture product obtained from active and passive microwave sensors from various satellite missions. ESMED model was thus found to be reliable for both the temporal and spatial validations and, hence, it might represent a useful tool to characterize the long‐term dynamics of soil moisture–weather interaction. Copyright © 2013 John Wiley & Sons, Ltd.     

Mantle degassing on a near shore volcano,SE Tyrrhenian Sea

The presence of a seamount‐like structure, located a few nautical miles offshore the Capo Vaticano Promontory (western Calabria, S Italy), was revealed by combined geophysical and geochemical investigation. The edifice covers ~55 km², with a top located at a depth of about 70 m below sea level, and consists mainly of a NW‐trending structure orthogonally interrupted by minor ridges, the largest of which is affected by extensional faults. The top of the edifice hosts active vents, injected fluids that have been investigated for dissolved volatiles. Gas analyses revealed high CO₂ and CH₄ contents, several orders of magnitude above the atmospheric‐type values expected for shallow, coastal marine waters, and a noteworthy enrichment in mantle‐derived ³He, which is an unambiguous indicator of the mantle origin of the fluids. Our results, combined with available data from the literature, suggest that the edifice is a tectonically controlled volcanic system, which presence near the Calabria region changes the role played by faults in the frame of the subduction process.     

Identifying run‐off contributions during melt‐induced run‐off events in a glacierized alpine catchment

We analysed contributions to run‐off using hourly stream water samples from seven individual melt‐induced run‐off events (plus one rainfall event) during 2011, 2012 and 2013 in two nested glacierized catchments in the Eastern Italian Alps. Electrical conductivity and stable isotopes of water were used for mixing analysis and two‐component and three‐component hydrograph separation. High‐elevation snowmelt, glacier melt and autumn groundwater were identified as major end‐members. Discharge and tracers in the stream followed the diurnal variations of air temperature but markedly reacted to rainfall inputs. Hysteresis patterns between discharge and electrical conductivity during the melt‐induced run‐off events revealed contrasting loop directions at the two monitored stream sections. Snowmelt contribution to run‐off was highest in June and July (up to 33%), whereas the maximum contribution of glacier melt was reached in August (up to 65%). The maximum groundwater and rainfall contributions were 62% and 11%, respectively. Run‐off events were generally characterized by decreasing snowmelt and increasing glacier melt fractions from the beginning to the end of the summer 2012, while run‐off events in 2013 showed less variable snowmelt and lower glacier melt contributions than in 2012. The results provided essential insights into the complex dynamics of melt‐induced run‐off events and may be of further use in the context of water resource management in alpine catchments. Copyright © 2015 John Wiley & Sons, Ltd.     

Lysosomal and lipid-associated parameters in the livers of three species of arctic seabird chicks: species differences and relationships with contaminant levels

Lysosomal membrane stability, lipofuscin (LF), malondialdehyde (MDA), neutral lipid (NL) levels, as well as halogenated organic compounds (HOCs), Cr, Cd, Pb and Fe concentrations were analyzed in liver of black-legged kittiwake (BK), herring gull (HG), and northern fulmar (NF) chicks. There were significant species differences in the levels of NL, LF and lysosomal membrane stability. These parameters were not associated with the respective HOC concentrations. LF accumulation was associated with increasing Cr, Cd and Pb concentrations. HG presented the lowest lysosomal membrane stability and the highest.LF and NL levels, which indicated impaired lysosomes in HG compared to NF and BK. Lipid peroxidation was associated with HOC and Fe²⁺ levels. Specific HOCs showed positive and significant correlations with MDA levels in HG. The study indicates that contaminant exposure can affect lysosomal and lipid associated parameters in seabird chicks even at low exposure levels. These parameters may be suitable markers of contaminant induced stress in arctic seabirds.     

Seafloor mapping for geohazard assessment: state of the art

During the last two decades, increasing use of full-coverage sonic mapping of the seafloor has made us more aware of the large and different number of seafloor processes and events bearing significant geohazard potential. This awareness combines with the increasing use of the seafloor for infrastructure and with the high density of population and settlement on the coast. Seafloor mapping is the first step in making a census of the geohazard-bearing features present in a given offshore area. It often provides the only tool for a comprehensive, although non-specific, seafloor geohazard assessment over large areas that are scarcely groundtruthed by acoustic prospection and seafloor sampling. However, the characterization of geohazard features on a morphological basis alone is limited, and more detailed investigations are needed to define the character and state of activity of potentially hazardous features. Such investigations include the use of deep-tow or autonomous platforms designed to acquire high-resolution data at depth as well as in situ measurements, both being very expensive activities not applicable over large areas. Thus seafloor mapping is often not only the first and the main but also the only tool for a comprehensive seafloor geohazard assessment. This special issue represents an example of the diversity of approaches to seafloor geohazard assessment and summarizes the present state of this discipline. Both the diverse technologies applied and the specific aims of offshore geohazard assessment brought different communities to deal with the study of seafloor processes and events from remarkably distinct viewpoints. We identified three end members in offshore geohazard assessment: (1) geohazard assessment ??sensu stricto??, (2) ??engineering?? geohazard assessment, (3) ??non-specific?? geohazard assessment. These are being conducted by industry, academia and public agencies in charge of civil protection and land-use planning and management. Understanding the needs and geohazard perception of the different groups is a necessary step for a profitable collaboration in such an interesting and rapidly developing field of marine geology.     

Regional-scale seafloor mapping and geohazard assessment. The experience from the Italian project MaGIC (Marine Geohazards along the Italian Coasts)

Recent developments in seafloor imaging and mapping techniques greatly improved our capability of identifying marine geohazards affecting continental margins. Geomorphic features can be detected in great detail by high-resolution multibeam imaging and regarded as geohazard indicators; the most common include slide scars and deposits, canyon headscarps and steep erosional flanks, fault-related seafloor unevenness, mud volcanoes, pockmarks, gravity flow deposits, erosional scours and bedforms indicating sediment mobility at diverse temporal/spatial scale. These processes are widespread on Italian continental margins and are potential indicators of geohazard for human settlements and infrastructures in the offshore and coastal zones. The national Project MaGIC (Marine Geohazards along the Italian Coasts) aims at documenting potential geohazards based on the acquisition of high-resolution multibeam bathymetry and on the production of maps of the geohazard-related geomorphic features for most of the Italian continental margins. With reference to this issue, we discuss some of the most frequent problems dealing with reconnaissance, interpretation and cartographic representation of geohazard-related geomorphic features at a regional scale.     

The impact of metals on the reproductive mechanisms of the ascidian Ciona intestinalis

Environmental pollution due to anthropogenic activities may exert an adverse impact on the reproductive mechanisms of animals. In particular, environmental chemicals introduced into seawater are able to disrupt the normal development and function of the reproductive system of marine animals. In this study, we have used the whole‐cell voltage clamp technique to examine the effects of four metals – lead, cadmium, mercury, and zinc – on reproductive mechanisms of the marine ascidian Ciona intestinalis (tunicates). In particular, we measured the effect of metals on plasma membrane electrical properties, the steady‐state conductance, the fertilization current in the mature oocyte, and larval development. Results show that oocyte voltage‐gated sodium currents are significantly reduced by all four metals, steady‐state conductance is affected only by zinc, and post‐fertilization contraction is inhibited only by lead. The fertilization current is suppressed in the presence of zinc and mercury. Embryo development up to larval stage is inhibited by zinc and mercury exposure with a reversible effect; however, a long‐term effect on larval morphology was observed. After exposure to cadmium, fertilization occurs but gives rise to abnormal larval development. These findings highlight the point that exposure to metals represents a significant risk factor for the physiology of reproduction of marine species and suggest a possible role of the C. intestinalis as a bioindicator for marine pollution monitoring.