ALBERT

Description: "With so much media and political criticism of their shortcomings and failures, it is easy to overlook the fact that many governments work pretty well much of the time. Great Policy Successes turns the spotlight on instances of public policy that are remarkably successful. It develops a framework for identifying and assessing policy successes, paying attention not just to their programmatic outcomes but also to the quality of the processes by which policies are designed and delivered, the level of support and legitimacy they attain, and the extent to which successful performance endures over time. The bulk of the book is then devoted to 15 detailed case studies of striking policy successes from around the world, including Singapore's public health system, Copenhagen and Melbourne's rise from stilted backwaters to the highly liveable and dynamic urban centres they are today, Brazil's Bolsa Familia poverty relief scheme, the US's GI Bill, and Germany's breakthrough labour market reforms of the 2000s. Each case is set in context, its main actors are introduced, key events and decisions are described, the assessment framework is applied to gauge the nature and level of its success, key contributing factors to success are identified, and potential lessons and future challenges are identified. Purposefully avoiding the kind of heavy theorizing that characterizes many accounts of public policy processes, each case is written in an accessible and narrative style ideally suited for classroom use in conjunction with mainstream textbooks on public policy design, implementation, and evaluation.

Description: The Pomici di Avellino eruption is the Plinian event of Vesuvius with the highest territorial impact. It affected an area densely inhabited by Early Bronze Age human communities and resulted in the long- term abandonment of an extensive zone surrounding the volcano. Traces of human life beneath the eruption products are very common throughout the Campania Region. A systematic review of the available archaeological data, the study of geological and archaeological sequences exposed in excava- tions, and the reconstruction of the volcanic phenomena affecting single sites has yielded an under- standing of local effects and their duration. The archaeological and volcanological analyses have shown that the territory was rapidly abandoned before and during the eruption, with rare post-eruption at- tempts at resettlement of the same sites inhabited previously. The definition of the distribution and stratigraphy of alluvial deposits in many of the studied sequences leads us to hypothesise that the scarce presence of humans during phases 1 and 2 of the Middle Bronze Age in the wide area affected by the eruption was due to diffuse phenomena of remobilisation of the eruption products, generating long- lasting alluvial processes. These were favoured by the deposition of loose fine pyroclastic material on the slopes of the volcano and the Apennines, and by climatic conditions. A significant resettlement of the territory occurred only hundreds of years after the Pomici di Avellino eruption, during phase 3 of the Middle Bronze Age. This study show the role of volcanic and related phenomena from a Plinian event in the settlement dynamics of a complex territory like Campania.

Description: Published

Description: 231-244

Description: 1V. Storia eruttiva

Description: 5V. Dinamica dei processi eruttivi e post-eruttivi

Description: 6V. Pericolosità vulcanica e contributi alla stima del rischio

Description: JCR Journal

Description: Ground deformations are among the main volcanic phenomena occurring within the caldera system and pres- ently recorded at different volcanoes worldwide including the Campi Flegrei active caldera (southern Italy). A new stratigraphic, sedimentological and paleontological survey carried out in the central sector of the Campi Flegrei caldera both along the already known La Starza succession and through a new excavated tunnel provided new insights into the ground movement episodes occurred in the last 15 kyr. This study, which has also benefited of unpublished boreholes stratigraphic data, shows that the most uplifted sector of the Campi Flegrei caldera, presently marked by the morphological structure of the La Starza cliff close to the Pozzuoli coastline, was charac- terized by a complex sedimentary evolution. It results from different phases of alternating marine transgressions and regressions, the latter marked by both continental volcanic and/or palustrine/lacustrine sediments. These al- ternations result from the interplay between (i) subsidence and uplift episodes of the caldera floor and (ii) sea level variations during the Holocene. A rest period of volcanism accompanied by a sea level rise determined a sig- nificant submersion phase in about 3000 years between 8.59 and 5.5 ka. This phase was defined by a sea level with a maximum water depth value of 60–80 m and a late stage recording significant episodes of ground move- ments. Subsequently, between 5.5 and 3.5 ka, a ground uplift of about 100 m occurred, with short subsidence around 4.5 ka following the Plinian Agnano-Monte Spina eruption. The net vertical displacement represents the recorded deformation linked with a volcanism period in which ~2.5 km3 of magma were erupted by different vents within the caldera. It is worth to note as the general trend of ground movement through the time indicates a similarity in the pattern, beyond its scale.

Description: Published

Description: 143-158

Description: 1V. Storia eruttiva

Description: JCR Journal

Description: In this study we combine seismological and GOCE satellite gravity information by using a Bayesian-like technique, with the aim of inferring the density structure of the Pacific (90°N 90°S) (121°E 60°W) lithosphere and upper mantle. We recover a 1° × 1° 3-D density model, down to 300 km depth, which explains gravity observations with a variance reduction of 67.41%. The model, with an associated a posteriori standard deviation, provides a significant contribution to understanding the evolution of the Pacific lithosphere and answers to some debated geodynamic questions. Our methodology enables us to combine the recovery of density parameters with the optimum density-vSV scalings. The latter account for both seismological and gravity observations in order to identify the regions characterized by chemically-induced density heterogeneities which add to the thermally-induced anoma- lies. Chemically-modified structures are found west of the East Pacific Rise (EPR) and are of relevant amplitude both below the north-western side of the Pacific Plate, at the base of the lithosphere, and up to 100 km depth beneath the Hawaiian and Super Swell regions, thus explaining the anomalous shallow regions without invoking the thermal buoyancy as the sole justification. Coherently with the chemically modified structures, our results a) support a lighter and more buoyant lithosphere than that predicted by the cooling models and b) are in favor of the hypothesized crustal underplating beneath the Hawaiian chain and be- neath the volcanic units in the southern branch of the Super Swell region. The comparison between calculated mantle gravity residuals and residual topography a) suggests a lateral viscosity growth associated with the increasing thickness and density of the Plate and b) correlates well with sub-lithospheric mantle flow from the EPR towards west, up to the Kermadec and Tonga Trench in the south and the Kuril-Kamchatka Trench in the north.

Description: Published

Description: 101-115

Description: 7T. Struttura della Terra e geodinamica

Description: JCR Journal

Description: During the last few decades, 4D volcano gravimetry has shown great potential for illuminating subsurface processes at active volcanoes (including some that might otherwise remain “hidden”), especially when combined with other methods (e.g., ground deformation, seismicity, and gas emissions). By supplying information on changes in the distribution of bulk mass over time, gravimetry can provide unique information regarding such processes as magma accumulation in void space, gas segregation at shallow depths, and mechanisms driving volcanic uplift and subsidence. Despite its potential, 4D volcano gravimetry is an underexploited method, not widely adopted by volcano researchers or observatories. The cost of instrumentation and the difficulty in using it under harsh environmental conditions is a significant impediment to the exploitation of gravity at many volcanoes. In addition, retrieving useful information from gravity changes in noisy volcanic environments is a major challenge. While these difficulties are not trivial, neither are they insurmountable; indeed, creative efforts in a variety of volcanic settings highlight the value of 4D gravimetry for understanding hazards as well as revealing fundamental insights into how volcanoes work. Building on previous work, we provide a comprehensive review of 4D volcano gravimetry, including discussions of instrumentation, modeling and analysis techniques, and case studies that emphasize what can be learned from, campaign, continuous, and hybrid gravity observations. We are hopeful that this exploration of 4D volcano gravimetry will excite more scientists about the potential of the method, spurring further application, development, and innovation.

Description: Published

Description: 146-179

Description: 4V. Dinamica dei processi pre-eruttivi

Description: JCR Journal

Description: San Cristóbal volcano in northwest Nicaragua is one of the most active basaltic–andesitic stratovolcanoes of the Central American Volcanic Arc (CAVA). Here we provide novel constraints on the volcano's magmatic plumbing system, by presenting the first direct measurements of major volatile contents in mafic-to-intermediate glass inclusions from Holocene and historic-present volcanic activity. Olivine-hosted (forsterite [Fo] b80; Fob80) glass inclusions from Holocene tephra layers contain moderate amounts of H2O (0.1–3.3 wt%) and S and Cl up to 2500 μg/g, and define the mafic (basaltic) endmember component. Historic-present scoriae and tephra layers exhibit more-evolved olivines (Fo69–72) that contain distinctly lower volatile contents (0.1–2.2 wt% H2O, 760–1675 μg/g S, and 1021–1970 μg/g Cl), and represent a more-evolved basaltic–andesitic magma. All glass inclusions are relatively poor in CO2, with contents reaching 527 μg/g (as measured by nanoscale secondary ion mass spectrometry), suggesting pre- to postentrapment CO2 loss to a magmatic vapor. We use results of Raman spectroscopy obtained in a population of small (b50 μm) inclusions with CO2-bearing shrinkage bubbles (3–12 μm) to correct for postentrapment CO2 loss to bubbles, and to estimate the original minimumCO2 content in San Cristóbal parental melts at ~1889 μg/g, which is consistent with the less-CO2-degassed melt inclusions (MI) (N1500 μg/g) found in Nicaragua at Cerro Negro, Nejapa, and Granada. Models of H2O and CO2 solubilities constrain the degassing pathway of magmas up to 425 MPa (~16 km depth), which includes a deep CO2 degassing step (only partially preserved in the MI record), followed by coupled degassing of H2O and S plus crystal fractionation at magma volatile saturation pressures from ∼195 to b10 MPa. The variation in volatile contents from San Cristóbal MI is interpreted to reflect (1) Holocene eruptive cycles characterized by the rapid emplacement of basaltic magma batches, saturated in volatiles, at depths of 3.8–7.4 km, and (2) the ascent of more-differentiated and cogenetic volatile-poor basaltic andesites during historic-present eruptions, having longer residence times in the shallowest (b3.4 km) and hence coolest regions of the magmatic plumbing system. We also report the first measurements of the compositions of noble-gas isotopes (He, Ne, and Ar) in fluid inclusions in olivine and pyroxene crystals. While the measured 40Ar/36Ar ratios (300–304) and 4He/20Ne ratios (9–373) indicate some degree of air contamination, the 3He/4He ratios (7.01–7.20 Ra) support a common mantle source for Holocene basalts and historic-present basaltic andesites. The magmatic source is interpreted as generated by a primitive MORB-like mantle, that is influenced to variable extents by distinct slab fluid components for basalts (Ba/La ~ 76 and U/Th ~ 0.8) and basaltic andesites (Ba/La ~ 86 and U/Th ~ 1.0) in addition to effects of magma differentiation. These values for the geochemical markers are particularly high, and their correlation with strong plume CO2/S ratios from San Cristóbal is highly consistent with volatile recycling at the CAVA subduction zone, where sediment involvement in mantle fluids influences the typical relatively C-rich signature of volcanic gases in Nicaragua.

Description: Published

Description: 131-148

Description: 1V. Storia eruttiva

Description: JCR Journal

Description: The Nevado del Ruiz volcano is considered one of the most active volcanoes in Colombia, which can potentially threaten approximately 600,000 inhabitants. The existence of a glacier and several streams channelling in some main rivers, flowing downslope, increases the risk for the population living on the flank of the volcano in case of unrest, because of the generation of lahars and mudflows. Indeed, during the November 1985 subplinian eruption, a lahar generated by the sudden melting of the glacier killed twenty thousand people in the town of Armero. Moreover, the involvement of the local hydrothermal system has produced in the past phreatic and phreatomagmatic activity, as occurred in 1989. Therefore, the physico-chemical conditions of the hydrothermal system as well as its contribution to the shallow thermal groundwater and freshwater in terms of enthalpy and chemicals require a close monitoring. The phase of unrest occurred since 2010 and culminated with an eruption in 2012, after several years of relative stability, stillmaintains amoderate alert, as required by the high seismicity and SO2 degassing. In October 2013, a sampling campaign has been performed on thermal springs and stream water, located at 2600–5000 m of elevation on the slope of Nevado del Ruiz, analyzed for water chemistry and stable isotopes. Some of these waters are typically steam-heated (low pH and high sulfate content) by the vapour probably separating from a zoned hydrothermal system. By applying a model of steam-heating, based on mass and enthalpy balances, we have estimated themass rate of hydrothermal steam discharging in the different springs. The composition of the hottest thermal spring (Botero Londono) is probably representative of a marginal part of the hydrothermal system, having a temperature of 250 °C and low salinity (Cl ~1500 mg/l), which suggest, along with the retrieved isotope composition, a chiefly meteoric origin. The vapour discharged at the steam vent “Nereidas” (3600 m asl) is hypothesized to be separated from a high temperature hydrothermal system. Based on its composition and on literature data on fluid inclusions, we have retrieved the P-T-X conditions of the deep hydrothermal system, aswell as its pH and fO2. The vapour feeding Nereidas would separate from a biphasic hydrothermal system characterized by the following parameters: t= 315 °C, P= 15 MPa, NaCl = 10 wt%, CO2=5 wt%, and similar proportion between liquid and vapour. Considering also the equilibria involving S-bearing gases and HCl, pH would approach the value of 1.5 while fO2 would correspond to the FeO-Fe2O3 buffer. Chlorine content is estimated at 10,300mg/l. Changes in the magmatic input into the hydrothermal system couldmodify its degree of vapourization and/or P-T-X conditions, thus inducing corresponding variations in vapour discharges and thermal waters. These findings, paralleled by contemporary measurements of water flow rates, could give significant clues on risk evaluation.

Description: Published

Description: 40-53

Description: 2V. Struttura e sistema di alimentazione dei vulcani

Description: JCR Journal

Description: Since hydrofracking is used for shale gas production, human caused seismicity have become a subject of increasing interest. Seismic monitoring is common for earthquakes generated by human operations like mining, reservoir impoundments, hydrocarbon and geothermal production, as well as reinjection of fluids. In Italy the Mw6.1 Reggio-Emilia earthquake of 20 May 2012 triggered particular interest in anthropogenic seismicity. It also raised the question of whether hydrocarbon exploitation induced variations in crustal stress that influenced the generation of these earthquakes. The Italian government commissioned a technical report compiling cases of documented and hypothesized anthropogenic seismicity. Following a governmental request, a technical report was compiled, describing the relation between anthropogenic activities and induced or triggered seismicity in Italy. This paper reviews these cases, on the basis of previously published works, and additional new analyses. Three cases of seismicity in Central Italy, occurring close to anthropogenic activities, are: (i) extraction of carbon dioxide (CO_2) from a borehole near Pieve Santo Stefano, (ii) the impoundment of the Montedoglio reservoir and (iii) geothermal energy production at Mt. Amiata. Since the sites are situated in the seismically active area of the Northern Apennines, we illustrate both by standard seismological analysis as well as by modeling to tackle the challenge of discriminating anthropogenic from natural seismicity.

Description: Published

Description: 80-94

Description: 5T. Sismologia, geofisica e geologia per l'ingegneria sismica

Description: JCR Journal

Description: Extreme and inaccessible environments are a new frontier that unmanned and remotely operated ve-hicles can today safely access and monitor. The Lusi mud eruption (NE Java Island, Indonesia) representsone of these harsh environments that are totally unreachable with traditional techniques. Here boilingmud is constantly spewed tens of meters in height and tall gas clouds surround the 100 m wide activecrater. The crater is surrounded by a ~600 m diameter circular zone of hot mud that prevents anyapproach to investigate and sample the eruption site. In order to access this active crater we designedand assembled a multipurpose drone.The Lusi drone is equipped with numerous airborne devices suitable for use on board of other mul-ticopters. During the missions, three cameras can complete 1) video survey, 2) high resolution photo-grammetry of desired and preselected polygons, and 3) thermal photogrammetry surveys with infra-redcamera to locate hotfluids seepage areas or faulted zones. Crater sampling and monitoring operationscan be pre-planned with aflight software, and the pilot is required only for take-off and landing. A winchallows the deployment of gas, mud and water samplers and contact thermometers to be operated withno risk for the aircraft. During the winch operations (that can be performed automatically), the aircrafthovers at a safety height until the tasks controlled by the winch-embedded processor are completed. Thedrone is also equipped with GPS-connected CO2and CH4sensors. Gridded surveys using these devicesallowed obtaining 2D maps of the concentration and distribution of various gasses over the area coveredby theflight path.The device is solid, stable even with significant wind, affordable, and easy to transport. The Lusi dronesuccessfully operated during several expeditions at the ongoing active Lusi eruption site and proved to bean excellent tool to study other harsh or unreachable sites, where operations with more conventionalmethods are too expensive, dangerous or simply impossible

Description: LUSI LAB project, PI A. Mazzini; esearch Council of Norway through itsCenters of Excellence funding scheme, Project Number 223272; BPLS (Badan Penanggulangan Lumpur Sidoarjo, Sidoarjo Mudflow Management Agency)

Description: Published

Description: 26-37

Description: 2IT. Laboratori sperimentali e analitici

Description: JCR Journal

Description: Syneruptive gas flux time series can, in principle, be retrieved from satellite maps of SO2 collected during and immediately after volcanic eruptions, and used to gain insights into the volcanic processes which drive the volcanic activity. Determination of the age and height of volcanic plumes are key prerequisites for such calculations. However, these parameters are challenging to constrain using satellite-based techniques. Here, we use imagery from OMI and GOME-2 satellite sensors and a novel numerical procedure based on back-trajectory analysis to calculate plume height as a function of position at the satellite measurement time together with plume injection height and time at a volcanic vent location. We applied this new procedure to three Etna eruptions (12 August 2011, 18 March 2012 and 12 April 2013) and compared our results with independent satellite and ground-based estimations. We also compare our injection height time-series with measurements of volcanic tremor, which reflects the eruption intensity, showing a good match between these two datasets. Our results are a milestone in progressing towards reliable determination of gas flux data from satellite-derived SO2 maps during volcanic eruptions, which would be of great value for operational management of explosive eruptions.

Description: 1) European Research Council under the European Union's Seventh Framework Programme (FP/2.007-2013)/ERC Grant Agreement no. 279802, project 283 CO2Volc. 2) MEDiterranean SUpersite Volcanoes 280 (MED-SUV) WP 3.3.3

Description: Published

Description: 79-91

Description: 5V. Dinamica dei processi eruttivi e post-eruttivi

Description: JCR Journal

Description: We present the analysis of rotational and translational ground motions from earthquakes recorded during October–November 2016, in association with the Central Italy seismic sequence. We use co-located measurements of the vertical ground rotation rate from a large ring laser gyroscope and the three components of ground velocity from a broad-band seismometer. Both instruments are positioned in a deep underground environment, within the Gran Sasso National Laboratories of the Istituto Nazionale di Fisica Nucleare. We collected dozens of events spanning the 3.5–5.9 magnitude range and epicentral distances between 30 and 70 km. This data set constitutes an unprecedented observation of the vertical rotational motions associated with an intense seismic sequence at local distance. Under the plane-wave approximation we process the data set in order to get an experimental estimation of the events backazimuth. Peak values of rotation rate (PRR) and horizontal acceleration (PGA) are markedly correlated, according to a scaling constant which is consistent with previous measurements from different earthquake sequences. We used a prediction model in use for Italy to calculate the expected PGA at the recording site, obtaining consequently predictions for PRR. Within the modelling uncertainties, predicted rotations are consistent with the observed ones, suggesting the possibility of establishing specific attenuation models for ground rotations, like the scaling of peak velocity and peak acceleration in empirical ground-motion prediction relationships. In a second step, after identifying the direction of the incoming wavefield, we extract phase-velocity data using the spectral ratio of the translational and rotational components. This analysis is performed over time windows associated with the P-coda, S-coda and Lg phase. Results are consistent with independent estimates of shear wave velocities in the shallow crust of the Central Apennines

Description: Published

Description: 705-715

Description: 4T. Sismicità dell'Italia

Description: JCR Journal

Description: An Mw 6.1, devastating earthquake, on April 6, 2009, struck the Middle Aterno Valley (Abruzzi Apennines, Italy) due to the activation of a poorly known normal fault system. Structural analysis of the fault population and investigation of the relationships with the Quaternary continental deposits through integrated field and laboratory techniques were conducted in order to reconstruct the long-term, tectono-sedimentary evolution of the basin and hypothesize the size of the fault segment. A polyphasic evolution of the Middle Aterno Valley is characterized by a conjugate, ∼E-W and ∼NS-striking fault system, during the early stage of basin development, and by a dip-slip, NW-striking fault system in a later phase. The old conjugate fault system controlled the generation of the largest sedimentary traps in the area and is responsible for the horst and graben structures within the basin. During the Early Pleistocene the E-W and NS system reactivated with dip-slip kinematics. This gave rise to intra-basin bedrock highs and a significant syn-tectonic deposition, causing variable thickness and hiatuses of the continental infill. Subsequently, since the end of the Early Pleistocene, with the inception of the NW-striking fault system, several NW-strands linked into longer splays and their activity migrated toward a leading segment affecting the Paganica-San Demetrio basin: the Paganica-San Demetrio fault alignment. The findings from this work constrain and are consistent with the subsurface basin geometry inferred from previous geophysical investigations. Notably, two major elements of the ∼E-W and ∼NS-striking faults likely act as transfer to the nearby stepping active fault systems or form the boundaries, as geometric complexities, that limit the Paganica-San Demetrio fault segment overall length to 19 ± 3 km. The resulting size of the leading fault segment is coherent with the extent of the 6 April 2009 L'Aquila earthquake causative fault. The positive match between the geologic long-term and coseismic images of the 2009 seismogenic fault highlights that the comprehensive reconstruction of the deformation history offers a unique contribution to the understanding faults seismic potential.

Description: MIUR (Italian Ministry of Education, University and Research) project “FIRB Abruzzo - High-resolution analyses for assessing the seismic hazard and risk of the areas affected by the 6 April 2009 earthquake”, ref. RBAP10ZC8K_005 and RBAP10ZC8K_007, and by Agreement INGV-DPC 2012–2021

Description: Published

Description: 30-66

Description: 2T. Deformazione crostale attiva

Description: JCR Journal

Description: Soil CO2 flux and 222Rn activity measurements may positively contribute to the geochemicalmonitoring of active volcanoes. The influence of several environmental parameters on the gas signals has been substantially demonstrated. Therefore, the implementation of tools capable of removing (or minimising) the contribution of the atmospheric effects from the acquired time series is a challenge in volcano surveillance. Here, we present 4 years-long continuousmonitoring (fromApril 2007 to September 2011) of radon activity and soil CO2 flux collected on the NE flank of Stromboli volcano. Both gases record higher emissions during fall–winter (up to 2700 Bq * m−3 for radon and 750 g m−2 day−1 for CO2) than during spring–summer seasons. Short-time variations on 222Rn activity aremodulated by changes in soil humidity (rainfall), and changes in soil CO2 flux that may be ascribed to variations in wind speed and direction. The spectral analyses reveal diurnal and semi-diurnal cycles on both gases, outlining that atmospheric variations are capable to modify the gas release rate fromthe soil. The long-termsoil CO2 flux shows a slow decreasing trend, not visible in 222Rn activity, suggesting a possible difference in the source depth of the of the gases, CO2 being deeper and likely related to degassing at depth of the magma batch involved in the February–April 2007 effusive eruption. To minimise the effect of the environmental parameters on the 222Rn concentrations and soil CO2 fluxes, two different statistical treatments were applied: the Multiple Linear Regression (MLR) and the Principal Component Regression (PCR). These approaches allow to quantify theweight of each environmental factor on the two gas species and showa strong influence of some parameters on the gas transfer processes through soils. The residual values of radon and CO2 flux, i.e. the values obtained after correction for the environmental influence, were then compared with the eruptive episodes that occurred at Stromboli during the analysed time span (2007–2011) but no clear correlations emerge between soil gas release and volcanic activity. This is probably due to i) the distal location of the monitoring stations with respect to the active craters and to ii) the fact that during the investigated period no major eruptive phenomena (paroxysmal explosion, flank eruption) occurred. Comparison of MLR and PCR methods in time-series analysis indicates thatMLR can bemore easily applied to real time data processing in monitoring of open conduit active volcanoes (like Stromboli) where the transition to an eruptive phase may occur in relatively short times.

Description: This researchwas partly funded by ItalianMinistry of University and Research (MIUR) and by University of Torino-Fondazione Compagnia di San Paolo. Additional fundswere provided by the Italian “Presidenza del Consiglio dei Ministri–Dipartimento della Protezione Civile (DPC)” through the DEVnet Project (a cooperative program between the Departments of Earth Sciences of the University of Torino and the University of Florence) and through the “Potenziamento Monitoraggio Stromboli” project. Additional funds for improving our computing hardware were provided by Fondazione Cassa di Risparmio di Torino.

Description: Published

Description: 65-78

Description: 4V. Processi pre-eruttivi

Description: JCR Journal

Description: Volcanic activity exhibits a wide range of eruption styles, from relatively slow effusive eruptions that produce lava flows and lava domes, to explosive eruptions that can inject large volumes of fragmented magma and volcanic gases high into the atmosphere. Although controls on eruption style and scale are not fully understood, previous research suggests that the dynamics of magma ascent in the shallow subsurface (〈 10 km depth) may in part control the transition from effusive to explosive eruption and variations in eruption style and scale. Here we investigate the initial stages of explosive eruptions using a 1D transient model for magma ascent through a conduit based on the theory of the thermodynamically compatible systems. The model is novel in that it implements finite rates of volatile exsolution and velocity and pressure relaxation between the phases. We validate the model against a simple two-phase Riemann problem, the Air-Water Shock Tube problem, which contains strong shock and rarefaction waves. We then use the model to explore the role of the aforementioned finite rates in controlling eruption style and duration, within the context of two types of eruptions at the Soufrière Hills Volcano, Montserrat: Vulcanian and sub-Plinian eruptions. Exsolution, pressure, and velocity relaxation rates all appear to exert important controls on eruption duration. More significantly, however, a single finite exsolution rate characteristic of the Soufrière Hills magma composition is able to produce both end-member eruption durations observed in nature. The duration therefore appears to be largely controlled by the timescales available for exsolution, which depend on dynamic processes such as ascent rate and fragmentation wave speed.

Description: Published

Description: 110-139

Description: 5V. Dinamica dei processi eruttivi e post-eruttivi

Description: JCR Journal

Description: A combined approach merging stable isotopes and fatty acids was applied to study anthropogenic pollution in the Río Negro estuary. Fatty acid markers of vegetal detritus indicated considerable allochthonous inputs at freshwater sites. Correlative evidence of diatom fatty acids, δ13C, chlorophyll and particulate organic matter suggested the importance of diatoms for the autochthonous organic matter production at the river mouth. Low δ15N values (~0�) and high fatty acid 18:1(n-7) concentrations in the suspended particulate matter, in combination with the peaks of coliforms and ammonium, indicated a strong impact of untreated sewage discharge. The 15N depletion was related to oxygen-limited ammonification processes and incorporation of 15N depleted ammonium to microorganisms. This work demonstrates that the combined use of lipid and isotopic markers can greatly increase our understanding of biogeochemical factors and pollutants influencing estuaries, and our findings highlight the urgent need for water management actions to reduce eutrophication.

Description: Among the most derived calanoid copepod superfamily Clausocalanoidea about half of the genera belong to the so-called “Bradfordian” families that are defined by the presence of sensory setae at the maxilla and maxilliped. Many of these “Bradfordian” taxa are insufficiently well described, because their taxonomy is complicated and phylogenetic relationships are not completely resolved. We therefore aimed to unravel their phylogenetic relationships using molecular multi-gene analyses. We conducted molecular multi-gene analysis on 26 species from 15 genera representing all seven “Bradfordian” families using five gene fragments, the nuclear ribosomal 18S, 28S and internal transcribed spacer 2 DNA, and mitochondrial cytochrome c oxidase subunit I and cytochrome b. The monophyly of “Bradfordians” as one lineage in the superfamily Clausocalanoidea was supported by Maximum Likelihood and Bayesian Inference multi-gene analyses. Except for the support of species belonging to the same genus and specimens belonging to the same species, no phylogenetic relationships among genera and families were supported. The impossibility of resolving phylogenetic relationships among “Bradfordian” genera and families may be due to the young age or fast radiation of “Bradfordians” within the mostly derived calanoid superfamily Clausocalanoidea. Therefore, mutation rates might be not sufficient to track phylogenetic relationships. Evidence on phylogenetic relationships between genera and families remain unresolved after implementing integrated morphological and molecular taxonomic approaches.

Description: Life cycle and reproduction of Calanus hyperboreus were studied during a year of record low ice cover in the southeastern Beaufort Sea. Stages CIV, adult females and CV dominated the overwintering population, suggesting a 2- to 3-year life cycle. Within two spring-summer months in the upper water column females filled their energy reserves before initiating their downward seasonal migration. From February to March, vigorous reproduction (20–65 eggs f−1 d−1) delivered numerous eggs (29 000 eggs m−2) at depth and nauplii N1-N3 (17 000 ind. m−2) in the water column. However, CI copepodite recruitment in May, coincident with the phytoplankton bloom, was modest in Amundsen Gulf compared to sites outside the gulf. Consequently, C. hyperboreus abundance and biomass stagnated throughout summer in Amundsen Gulf. As a mismatch between the first-feeding stages and food was unlikely under the favourable feeding conditions of April-May 2008, predation on the egg and larval stages in late winter presumably limited subsequent recruitment and population growth. Particularly abundant in Amundsen Gulf, the copepods Metridia longa and C. glacialis were likely important consumers of C. hyperboreus eggs and nauplii. With the ongoing climate-driven lengthening of the ice-free season, intensification of top-down control of C. hyperboreus recruitment by thriving populations of mesopelagic omnivores and carnivores like M. longa may counteract the potential benefits of increased primary production over the Arctic shelves margins for this key prey of pelagic fish, seabirds and the bowhead whale.

Description: Recent large-scale remote sensing studies have shown that glacier mass loss in south-eastern Tibet, specifically in the eastern Nyainqêntanglha Range exceeds the average in High Asia. However, detailed studies at individual glaciers are scarce and the drivers behind the observed changes are poorly constrained to date. Employing feature tracking techniques on TerraSAR-X data for the periods 2008/2009, 2012/2013 and 2013/2014 we found measurable surface velocities through to the glacier terminus positions of five debris-covered glacier tongues. This is contrary to debris-covered glaciers in other parts of High Asia, where stagnant glacier tongues are common. Our feature tracking results for the 2013/2014 period suggest an average deceleration of 51% when compared with published Landsat velocities for the period 1999/2003. Further, we estimated surface elevation changes for the five glaciers from recently released one arc second resolution elevation data obtained during the Shuttle Radar Topography Mission in 2000 and an interferometrical derived TanDEM-X elevation model for the year 2014. With an average rate of −0.83 ± 0.57 m a^-1 we confirm strong surface lowering in the region, despite the widely discussed insulation effect of debris cover. Beside the influence of thermokarst processes and delayed response times of debris-covered glaciers, we highlight that abundant monsoonal summer rainfall might contribute significantly to the pronounced negative mass balances in the study region.

Description: Solid phase extraction (SPE) has become a widespread method for isolating dissolved organic matter (DOM) of diverse origin such as fresh and marine waters. This study investigated the DOM extraction selectivity of 24 commercially available SPE sorbents under identical conditions (pH = 2, methanol elution) on the example of Suwannee River (SR) water and North Sea (NS) water by using DOC analysis and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). Proton nuclear magnetic resonance (1H NMR) spectroscopy was employed to assess leaching behavior, and HLB sorbent was found to leach substantially, among others. Variable DOC recoveries observed for SR DOM and NS DOM were primarily caused by the respective molecular composition, with subordinated and heterogeneous contributions of relative salinity. Scatter of average H/C and O/C elemental ratios and gross alignment in mass-edited H/C ratios according to five established coarse SPE characteristics was near identical for SR DOM and NS DOM. FTMS-based principal component analysis (PCA) provided essentially analogous alignment of SR DOM and NS DOM molecular compositions according to the five established groups of SPE classification, and corroborated the sorption-mechanism-based selectivity of DOM extraction in both cases. Evaluation of structural blanks and leaching of SPE cartridges requires NMR spectroscopy because FT-ICR mass spectrometry alone will not reveal inconspicuous displacements of continual bulk signatures caused by leaching of SPE resin constituents.

Description: Predicting future thaw slump activity requires a sound understanding of the atmospheric drivers and geomorphic controls on mass wasting across a range of time scales. On sub-seasonal time scales, sparse measurements indicate that mass wasting at active slumps is often limited by the energy available for melting ground ice, but other factors such as rainfall or the formation of an insulating veneer may also be relevant. To study the sub-seasonal drivers, we derive topographic changes from single-pass radar interferometric data acquired by the TanDEM-X satellite (12 m resolution). The high vertical precision (around 30 cm), frequent observations (11 days) and large coverage (5000 km2) allow us to track volume losses as drivers such as the available energy change during summer in two study regions. We find that thaw slumps in the Tuktoyaktuk coastlands, Canada, are not energy limited in June, as they undergo limited mass wasting (height loss of around 0 cm/day) despite the ample available energy, indicating the widespread presence of an insulating snow or debris veneer. Later in summer, height losses generally increase (around 3 cm/day), but they do so in distinct ways. For many slumps, mass wasting tracks the available energy, a temporal pattern that is also observed at coastal yedoma cliffs on the Bykovsky Peninsula, Russia. However, the other two common temporal trajectories are asynchronous with the available energy, as they track strong precipitation events or show a sudden speed-up in late August, respectively. The observed temporal patterns are poorly related to slump characteristics like the slump area. The contrasting temporal behaviour of nearby thaw slumps highlights the importance of complex local and temporally varying controls on mass wasting.

Description: Particulate inorganic matter (PIM) is a key component in estuarine and coastal systems and plays a critical role in trace metal cycling. Better understanding of coastal dynamics and biogeochemistry requires improved quantification of PIM in terms of its concentration, size distribution, and mineral species composition. The angular pattern of light scattering contains detailed information about the size and composition of particles. These volume scattering functions(VSFs) were measured in Mobile Bay, Alabama, USA, a dynamic, PIM dominated coastal environment. From measured VSFs, we determined through inversion the particle size distributions (PSDs) of major components of PIM, amorphous silica and clay minerals. An innovation here is the extension of our reported PSDs significantly into the submicron range. The PSDs of autochthonous amorphous silica exhibit two unique features: a peak centered at about 0.8 μm between 0.2 and 4 μm and a very broad shoulder essentially extending from 4 μm to 〉100 μm. With an active and steady particle source from blooming diatoms, the shapes of amorphous silica PSDs for sizes 〈 10 μm varied little across the study area, but showed more particles of sizes 〉 10 μm inside the bay, likely due to wind-induced resuspension of larger frustules that have settled. Compared to autochthonous amorphous silica, the allochthonous clay minerals are denser and exhibit relatively narrower PSDs with peaks located between 1 and 4 μm. Preferential settling of larger mineral particles as well as the smaller but denser illite component further narrowed the size distributions of clay minerals as they were being transported outside the bay. The derived PSDs also indicated a very dynamic situation in Mobile Bay relative to the cold weather front that passed through during the experiment. With northerly winds of speeds up to 15 m s-1, both amorphous silica and clay minerals showed a dramatic increase in concentration and broadening in size distribution outside the exit of the barrier islands, indicative of wind-induced resuspension and subsequent advection of particles out of Mobile Bay. While collectively recognized as the PIM, amorphous silica and clay minerals, as shown in this study, possess very different size distributions. Considering how differences in PSDs and the associated particle areas will effect differences in sorption/desorption properties of these components, the results also demonstrate the potential of applying VSF-inversion in studying biogeochemistry in the estuarine-coastal ocean system.

Description: A suite of oxygenated volatile organic compounds (OVOCs – acetaldehyde, acetone, propanal, butanal and butanone) were measured concurrently in the surface water and atmosphere of the South China Sea and Sulu Sea in November 2011. A strong correlation was observed between all OVOC concentrations in the surface seawater along the entire cruise track, except for acetaldehyde, suggesting similar sources and sinks in the surface ocean. Additionally, several phytoplankton groups, such as haptophytes or pelagophytes, were also correlated to all OVOCs indicating that phytoplankton may be an important source for marine OVOCs in the South China and Sulu Seas. Humic and protein like fluorescent dissolved organic matter (FDOM) components seemed to be additional precursors for butanone and acetaldehyde. The atmospheric OVOC mixing ratios were relative high compared with literature values, suggesting the coastal region of North Borneo as a local hot spot for atmospheric OVOCs. The flux of atmospheric OVOCs was largely into the ocean for all 5 gases, with a few important exceptions near the coast of Borneo. The calculated amount of OVOCs entrained into the ocean seemed to be an important source of OVOCs to the surface ocean. When the fluxes were out of the ocean, marine OVOCs were found to be enough to control the local measured OVOC distribution in the atmosphere. Based on our model calculations, at least 0.4 ppb of marine derived acetone and butanone can reach the upper troposphere, where they may have an important influence on hydrogen oxide radical formation over the western Pacific Ocean.

Description: The Extrapolar SWIFT model is a fast ozone chemistry scheme for interactive calculation of the extrapolar stratospheric ozone layer in coupled general circulation models (GCMs). In contrast to the widely used prescribed ozone, the SWIFT ozone layer interacts with the model dynamics and can respond to atmospheric variability or climatological trends. The Extrapolar SWIFT model employs a repro-modelling approach, where algebraic functions are used to approximate the numerical output of a full stratospheric chemistry and transport model (ATLAS). The full model solves a coupled chemical differential equations system with 55 initial and boundary conditions (mixing ratio of various chemical species and atmospheric parameters). Hence the rate of change of ozone over 24  h is a function of 55 variables. Using covariances between these variables, we can find linear combinations in order to reduce the parameter space to the following nine basic variables: latitude, pressure altitude, temperature, local ozone column, mixing ratio of ozone and of the ozone depleting families (Cly, Bry, NOy and HOy). We will show that these 9 variables are sufficient to characterize the rate of change of ozone. An automated procedure fits a polynomial function of fourth degree to the rate of change of ozone obtained from several simulations with the ATLAS model. One polynomial function is determined per month which yields the rate of change of ozone over 24 h. A key aspect for the robustness of the Extrapolar SWIFT model is to include a wide range of stratospheric variability in the numerical output of the ATLAS model, also covering atmospheric states that will occur in a future climate (e.g. temperature and meridional circulation changes or reduction of stratospheric chlorine loading). For validation purposes, the Extrapolar SWIFT model has been integrated into the ATLAS model replacing the full stratospheric chemistry scheme. Simulations with SWIFT in ATLAS have proven that the systematic error is small and does not accumulate during the course of a simulation. In the context of a 10 year simulation, the ozone layer, simulated by SWIFT, shows a stable annual cycle, with inter-annual variations comparable to the ATLAS model. The application of Extrapolar SWIFT requires the evaluation of polynomial functions with 30–100 terms. Nowadays, computers can calculate such polynomial functions at thousands of model grid points in seconds. SWIFT provides the desired numerical efficiency and computes the ozone layer 104 times faster than the chemistry scheme in the ATLAS CTM.

Description: n the framework of atmospheric circulation regimes, we study whether the recent Arctic sea ice loss and Arctic Amplification are associated with changes in the frequency of occurrence of preferred atmospheric circulation patterns during the extended winter season from December to March. To determine regimes we applied a cluster analysis to sea-level pressure fields from reanalysis data and output from an atmospheric general circulation model. The specific set up of the two analyzed model simulations for low and high ice conditions allows for attributing differences between the simulations to the prescribed sea ice changes only. The reanalysis data revealed two circulation patterns that occur more frequently for low Arctic sea ice conditions: a Scandinavian blocking in December and January and a negative North Atlantic Oscillation pattern in February and March. An analysis of related patterns of synoptic-scale activity and 2 m temperatures provides a synoptic interpretation of the corresponding large-scale regimes. The regimes that occur more frequently for low sea ice conditions are resembled reasonably well by the model simulations. Based on those results we conclude that the detected changes in the frequency of occurrence of large-scale circulation patterns can be associated with changes in Arctic sea ice conditions.

Description: Ice retreat in the eastern Eurasian Arctic is a consequence of atmospheric and oceanic processes and regional feedback mechanisms acting on the ice cover, both in winter and summer. A correct representation of these processes in numerical models is important, since it will improve predictions of sea ice anomalies along the Northeast Passage and beyond. In this study, we highlight the importance of winter ice dynamics for local summer sea ice anomalies in thickness, volume and extent. By means of airborne sea ice thickness surveys made over pack ice areas in the south-eastern Laptev Sea, we show that years of offshore-directed sea ice transport have a thinning effect on the late-winter sea ice cover. To confirm the preconditioning effect of enhanced offshore advection in late winter on the summer sea ice cover, we perform a sensitivity study using a numerical model. Results verify that the preconditioning effect plays a bigger role for the regional ice extent. Furthermore, they indicate an increase in volume export from the Laptev Sea as a consequence of enhanced offshore advection, which has far-reaching consequences for the entire Arctic sea ice mass balance. Moreover we show that ice dynamics in winter not only preconditions local summer ice extent, but also accelerate fast-ice decay.

Description: eddy located along the Antarctic Polar Front in the Atlantic sector of the Southern Ocean. Mixed layer (ML) waters were characterized by high nitrate (~20 μM), low dissolved iron (DFe ~0.2 nM) and low silicate concentrations (below 1 μM) restricting diatom growth. Upon initial fertilization, chlorophyll-a doubled during the first two weeks and stabilized thereafter, despite a second fertilization on day 21, due to an increase in grazing pressure. Biomass at the different trophic levels was mostly comprised of small autotrophic flagellates, the large copepod Calanus simillimus and the amphipod Themisto gaudichaudii. The downward flux of particulate material comprised mainly copepod fecal pellets that were remineralized in the upper 150 m of the water column with no significant deeper export. showed a greater variability (ranging from 0.3 to 1.3 nM) without a clear vertical pattern. Particulate iron concentrations (measured after 2 months at pH 1.4) decreased with time and showed a vertical pattern that indicated an important non-biogenic component at the bottom of the mixed layer. In order to assess the contribution of copepod grazing to iron cycling we used two different approaches: first, we measured for the first time in a field experiment copepod fecal pellet concentrations in the water column together with the iron content per pellet, and second, we devised a novel analytical scheme based on a two-step leaching protocol to estimate the contribution of copepod fecal pellets to particulate iron in the water column. Analysis of the iron content of isolated fecal pellets from C. simillimus showed that after the second fertilization, the iron content per fecal pellet was ~5 fold higher if the copepod had been captured in fertilized waters. We defined a new fraction termed leachable iron (pH 2.0) in 48 h (LFe48h) that, for the conditions during LOHAFEX, was shown to be an excellent proxy for the concentration of iron contained in copepod fecal pellets. We observed that, as a result of the second fertilization, iron accumulated in copepod fecal pellets and remained high at one third of the total iron stock in the upper 80 m. We hypothesize that our observations are due to a combination of two biological processes. First, phagotrophy of iron colloids freshly formed after the second fertilization by the predominant flagellate community resulted in higher Fe:C ratios per cell that, via grazing, lead to iron enrichment in copepod fecal pellets in fertilized waters. Second, copepod coprophagy could explain the rapid recycling of particulate iron in the upper 100–150 m, the accumulation of LFe48h in the upper 80 m after the second fertilization and provided the iron required for the maintenance of the LOHAFEX bloom for many weeks. Our results provide the first quantitative evidence of the major ecological relevance of copepods and their fecal products in the cycling of iron in silicate depleted areas of the Southern Ocean.

Description: Harde (2017) proposes an alternative accounting scheme for the modern carbon cycle and concludes that only 4.3% of today's atmospheric CO2 is a result of anthropogenic emissions. As we will show, this alternative scheme is too simple, is based on invalid assumptions, and does not address many of the key processes involved in the global carbon cycle that are important on the timescale of interest. Harde (2017) therefore reaches an incorrect conclusion about the role of anthropogenic CO2 emissions. Harde (2017) tries to explain changes in atmospheric CO2 concentration with a single equation, while the most simple model of the carbon cycle must at minimum contain equations of at least two reservoirs (the atmosphere and the surface ocean), which are solved simultaneously. A single equation is fundamentally at odds with basic theory and observations. In the following we will (i) clarify the difference between CO2 atmospheric residence time and adjustment time, (ii) present recently published information about anthropogenic carbon, (iii) present details about the processes that are missing in Harde (2017), (iv) briefly discuss shortcoming in Harde's generalization to paleo timescales, (v) and comment on deficiencies in some of the literature cited in Harde (2017).

Description: We use a comprehensive suite of partially laminated high-resolution sediment cores from the Bering Sea, covering a depth transect from 1100 m to 2700 m to study deglacial surface ocean warming patterns, associated changes in biological productivity, oxygen minimum zone dynamics and continent-ocean links through Yukon river runoff. We apply a combination of planktic and benthic isotopes, x-ray fluorescence (XRF)-derived ele- mental ratios and a multi-proxy assessment of changes in upper ocean temperatures. Severe oxygen depletions occurred during the Bølling/Allerød (B/A) and early Holocene, which is in accordance with other locations in the North Pacific, especially the Alaska margin. Detailed analysis of the timing of lamination occurrence between the different sediment cores revealed that the onset of severe anoxia at the beginning of the B/A and early Holocene is a near-synchronous event, while the disappearance of laminations is a diachronic process. The deglacial Oxygen Minimum Zone(OMZ) strengthening is mainly driven by increased export production, visible in XRF-derived elemental ratios, and corresponding high accumulation rates of biogenic components. The export production in turn is a response to rising sea surface temperatures, decreased sea ice cover and increased thermal stratification, while a major nutrient source was the eastern continental shelf, which was flooded during the deglacial global sea level rise. It is discussed controversially whether oxygenation variations in the deglacial subarctic Pacific were coupled to changes in mid-depth water chemistry, or rather a response to physical processes like deep-intermediate ocean or mixed layer warming, or stratification changes. However, knowledge of the driving forcing mechanism for OMZ strengthening is of particular importance, as these are tightly coupled to the regional marine carbon budget, e.g. via the strength and efficiency of the biological pump. Here, our laminated sediments provided the opportunity to study ocean dynamics in exceptional detail, possible on decadal to annual timescales. Due to the correlation patterns of our records to the NGRIP oxygen isotope record through layer counts we presume that (i) the presence of laminations is tightly coupled to submillennial, short-term warm phases, especially during the Bølling-Allerød (B/A), (ii) that the laminations represent annual layered sediments (varves). The latter point in conjunction with our geochemical proxies strongly supports an atmospheric teleconnection between SE Asia, the North Atlantic and the North Pacific, with observed changes in mid-depth ocean dynamics occurring on fast, nearly decadal timescales. Thus, the Bering Sea OMZ is a highly sensitive system reacting almost instantaneously to small temperature changes and therefore has the potential to influence the global carbon budget on short timescales, in particular during episodes of rapidly warming climate.

Description: The aim of the presented study was to investigate the impact on the radiation budget of a biomass-burning plume, transported from Alaska to the High Arctic region of Ny-Ålesund, Svalbard, in early July 2015. Since the mean aerosol optical depth increased by the factor of 10 above the average summer background values, this large aerosol load event is considered particularly exceptional in the last 25 years. In situ data with hygroscopic growth equations, as well as remote sensing measurements as inputs to radiative transfer models, were used, in order to estimate biases associated with (i) hygroscopicity, (ii) variability of single-scattering albedo profiles, and (iii) plane-parallel closure of the modelled atmosphere. A chemical weather model with satellite-derived biomass-burning emissions was applied to interpret the transport and transformation pathways. The provided MODTRAN radiative transfer model (RTM) simulations for the smoke event (14:00 9 July–11:30 11 July) resulted in a mean aerosol direct radiative forcing at the levels of −78.9 and −47.0 W m ^-2 at the surface and at the top of the atmosphere, respectively, for the mean value of aerosol optical depth equal to 0.64 at 550 nm. This corresponded to the average clear-sky direct radiative forcing of −43.3 W/m ^2, estimated by radiometer and model simulations at the surface. Ultimately, uncertainty associated with the plane-parallel atmosphere approximation altered results by about 2 W m^−2. Furthermore, model-derived aerosol direct radiative forcing efficiency reached on average −126 W m^−2/τ550 and −71 W^m−2/τ550 at the surface and at the top of the atmosphere, respectively. The heating rate, estimated at up to 1.8 K day^−1 inside the biomass-burning plume, implied vertical mixing with turbulent kinetic energy of 0.3 m^2s^−2

Description: In paleoenvironmental studies, the mineralogical composition of sediments is an important indicator. In combination with other indicators, they contribute to the understanding of changes in sediment sourcing as well as in weathering and depositional processes. Fourier transforminfrared spectroscopy (FTIRS) spectra contain information on mineralogical composition because eachmineral has a unique absorption pattern in the mid-IR range. Although easily obtained, FTIR spectra are often too complex to infermineral concentrations directly. In this study, we use a calibration set of ca. 200 sediment samples conventionally measured using X-ray diffraction (XRD) in order to developmultivariate, partial least squares (PLS) regressionmodels relatingmineral contents to sediment spectra. Good correlations were obtained for the most common minerals (e.g. quartz, K-feldspar, illite, plagioclase, smectite, calcite). Correlation coefficients ranged from 0.85 to 0.92, coefficients for the validation varied from 0.64 to 0.80, the number of latent variables (PLS regression components) in the models ranged between 3 and 7 and the range of variation of the RMSEcv gradient was from 15.28 to 5.7.

Description: Time series derived from paleoclimate archives are often irregularly sampled in time and thus not analysable using standard statistical methods such as correlation analyses. Although measures for the similarity between time series have been proposed for irregular time series, they do not account for the time scale dependency of the relationship. Stochastically distributed temporal sampling irregularities act qualitatively as a low-pass filter reducing the influence of fast variations from frequencies higher than about 0.5 (Δtmax) − 1, where Δtmax is the maximum time interval between observations. This may lead to overestimated correlations if the true correlation increases with time scale. Typically, correlations are underestimated due to a non-simultaneous sampling of time series. Here, we investigated different techniques to estimate time scale dependent correlations of weakly irregularly sampled time series, with a particular focus on different resampling methods and filters of varying complexity. The methods were tested on ensembles of synthetic time series that mimic the characteristics of Holocene marine sediment temperature proxy records. We found that a linear interpolation of the irregular time series onto a regular grid, followed by a simple Gaussian filter was the best approach to deal with the irregularity and account for the time scale dependence. This approach had both, minimal filter artefacts, particularly on short time scales, and a minimal loss of information due to filter length.

Description: Rapid declines in Arctic sea ice have captured attention and pose significant challenges to a variety of stakeholders. There is a rising demand for Arctic sea ice prediction at daily to seasonal time scales, which is partly a sea ice initial condition problem. Thus, a multivariate data assimilation that integrates sea ice observations to generate realistic and skillful model initialization is needed to improve predictive skill of Arctic sea ice. Sea ice data assimilation is a relatively new research area. In this review paper, we focus on two challenges for implementing multivariate data assimilation systems for sea ice forecast. First, to address the challenge of limited spatiotemporal coverage and large uncertainties of observations, we discuss sea ice parameters derived from satellite remote sensing that (1) have been utilized for improved model initialization, including concentration, thickness and drift, and (2) are currently under development with the potential for enhancing the predictability of Arctic sea ice, including melt ponds and sea ice leads. Second, to strive to generate the “best” estimate of sea ice initial conditions by combining model simulations/forecasts and observations, we review capabilities and limitations of different data assimilation techniques that have been developed and used to assimilate observed sea ice parameters in dynamical models.

Description: A new 21.3m firn core was drilled in 2015 at a coastal Antarctic high-accumulation site in Adélie Land (66.78◦ S; 139.56◦ E, 602 m a.s.l.), named Terre Adélie 192A (TA192A). The mean isotopic values (−19.3 ‰ ± 3.1 ‰ for δ18O and 5.4 ‰±2.2 ‰ for deuterium excess) are consistent with other coastal Antarctic values. No significant isotope–temperature relationship can be evidenced at any timescale. This rules out a simple interpretation in terms of local temperature. An observed asymmetry in the δ18O seasonal cycle may be explained by the precipitation of air masses coming from the eastern and western sectors in autumn and winter, recorded in the d-excess signal showing outstanding values in austral spring versus autumn. Significant positive trends are observed in the annual d-excess record and local sea ice extent (135–145◦ E) over the period 1998–2014. However, process studies focusing on resulting isotopic compositions and particularly the deuterium excess–δ18O relationship, evidenced as a potential fingerprint of moisture origins, as well as the collection of more isotopic measurements in Adélie Land are needed for an accurate interpretation of our signals.

Description: Hyperiid amphipods are predatory pelagic crustaceans that are particularly prevalent in high-latitude oceans. Many species are likely to have co-evolved with soft-bodied zooplankton groups such as salps and medusae, using them as substrate, for food, shelter or reproduction. Compared to other pelagic groups, such as fish, euphausiids and soft-bodied zooplankton, hyperiid amphipods are poorly studied especially in terms of their distribution and ecology. Hyperiids of the genus Themisto, comprising seven distinct species, are key players in temperate and cold-water pelagic ecosystems where they reach enormous levels of biomass. In these areas, they are important components of marine food webs, and they are major prey for many commercially important fish and squid stocks. In northern parts of the Southern Ocean, Themisto are so prevalent that they are considered to take on the role that Antarctic krill play further south. Nevertheless, although they are around the same size as krill, and may also occur in swarms, their feeding behaviour and mode of reproduction are completely different, hence their respective impacts on ecosystem structure differ. Themisto are major predators of meso- and macrozooplankton in several major oceanic regions covering shelves to open ocean from the polar regions to the subtropics. Based on a combination of published and unpublished occurrence data, we plot out the distributions of the seven species of Themisto. Further, we consider the different predators that rely on Themisto for a large fraction of their diet, demonstrating their major importance for higher trophic levels such as fish, seabirds and mammals. For instance, T. gaudichaudii in the Southern Ocean comprises a major part of the diets of around 80 different species of squid, fish, seabirds and marine mammals, while T. libellula in the Bering Sea and Greenland waters is a main prey item for commercially exploited fish species. We also consider the ongoing and predicted range expansions of Themisto species in light of environmental changes. In northern high latitudes, sub-Arctic Themisto species are replacing truly Arctic, ice-bound, species. In the Southern Ocean, a range expansion of T. gaudichaudii is expected as water masses warm, impacting higher trophic levels and biogeochemical cycles. We identify the many knowlegde gaps that must be filled in order to evaluate, monitor and predict the ecological shifts that will result from the changing patterns of distribution and abundance of this important pelagic group.

Description: Ostracods are small-sized crustaceans, which inhabit all aquatic ecosystems and, because they have a comprehensive fossil record, are important environmental and paleoenvironmental indicators. However several aspects of the ecology of modern species (the basis for the paleontological investigations) are still controversial. Previous authors have raised the hypothesis that benthic ostracods, because of their calcified carapaces, are unable to survive below the Carbonate Compensation Depth (CCD). Herein we test this hypothesis based on (1) ostracods newly collected from the Kuril-Kamchatka Trench at depths far below the CCD during the KuramBio II expedition; and (2) a compilation of all previously published records of (geologically) Recent deep-sea Ostracoda in regions deeper than 3500 m. The KuramBio II expedition provided hundreds of living, hadal ostracods from at least 30 species and 21 genera from thousands of meters deeper than the CCD in the Kuril-Kamchatka Trench region. Additionally, the KuramBio II expedition provided the deepest record (9307 m) of a living ostracod with calcified carapaces: specimens of the genus Krithe. Finally, the compilation of all published information on living ostracods show that a highly diverse assemblage both at high and low taxonomic levels (2 subclasses, 4 suborders, 25 families, 89 genera and at least 206 species) occur below 3500 m. Therefore, we conclude that contrary to previous beliefs, the new data from the Kuril-Kamchatka Trench and the compilation of the literature show that ostracods do live and are even sometimes abundant below the CCD.

Description: Most palaeo-deep-water reconstructions are based on geochemical information stored in the calcareous shells of Cibicidoides species but hardly anything is known about their life cycle, population dynamics or ecology. The number of specimens of a single Cibicidoides species can locally be very limited and species may be lacking completely during certain intervals in the geological past. As a consequence, geochemical analyses are often carried out on lumped Cibicidoides spp. assuming that they share the same epizoic to epifaunal habitat and precipitated their shell in comparable offsets to surrounding bottom water mass properties. However, there is a growing body of evidence that particularly Cibicidoides pachyderma and its morphotypes C. mundulus and C. kullenbergi, may not be reliable bottom water recorders. We have recently developed aquaria that allowed, for the first time, observations of Cibicidoides pachyderma var. C. mundulus under in situ pressure and temperature. Experiments were carried out with and without artificial sediments to simulate soft sediments and rocks, respectively. Seawater was set to pH 8 and pH 7.4 to simulate more or less particulate carbon export or more or less ventilation of bottom water. Our experiments demonstrate that C. mundulus may opt for an epifaunal or an infaunal habitat depending on elapsed time following physical disturbance, pH, current activity, the availability of sediments and growth. The specimen's initial response following transfer from atmospheric pressure into the high-pressure aquaria was to immerse into the sediment or to cover more or less parts of the test with aggregated sediments or algae. However, within 24 h a strong rheotaxis became apparent and most specimens moved to sites of increased current activity under normal pH conditions (pH 8). Only few specimens remained in algae cysts or in the sediment in the pH-8 experiment. On the contrary, all specimens under pH 7.4 agglutinated a firm sediment cyst around their test and remained infaunal throughout the experimental period of three months. Independent of pH, growth was only observed in specimens that lived within an agglutinated cyst or infaunal. A solid thick cyst covered the specimens of the pH 7.4 experiment throughout the experiment and possibly restricted water exchange between the in-cyst water and the surrounding artificial bottom water mass. We suggest that a more fragile and possibly more porous sedimentary envelope may, at least temporally, have covered the infaunal specimens under pH 8 but no evidence for this was found upon termination of the experiment.

Description: The timing and intensity of snowmelt processes on sea ice are key drivers determining the seasonal sea-ice energy and mass budgets. In the Arctic, satellite passive microwave and radar observations have revealed a trend towards an earlier snowmelt onset during the last decades, which is an important aspect of Arctic amplification and sea ice decline. Around Antarctica, snowmelt on perennial ice is weak and very different than in the Arctic, with most snow surviving the summer. Here we compile time series of snowmelt-onset dates on seasonal and perennial Antarctic sea ice from 1992 to 2014/15 using active microwave observations from European Remote Sensing Satellite (ERS-1/2), Quick Scatterometer (QSCAT) and Advanced Scatterometer (ASCAT) radar scatterometers. We define two snowmelt transition stages: A weak backscatter rise indicating the initial warming and destructive metamorphism of the snowpack (pre-melt), followed by a rapid backscatter rise indicating the onset of thaw-freeze cycles (snowmelt). Results show large interannual variability with an average pre-melt onset date of 29 November and melt onset of 10 December, respectively, on perennial ice, without any significant trends over the study period, consistent with the small trends of Antarctic sea ice extent. There was a latitudinal gradient from early snowmelt onsets in mid-November in the northern Weddell Sea to late (end-December) or even absent snowmelt conditions in the southern Weddell Sea. We show that QSCAT Ku-band (13.4 GHz signal frequency) derived pre-melt and snowmelt onset dates are earlier by 20 and 18 days, respectively, than ERS and ASCAT C-band (5.6 GHz) derived dates. This offset has been considered when constructing the time series. Snowmelt onset dates from passive microwave observations (37 GHz) are later by 14 and 6 days than those from the scatterometers, respectively. Based on these characteristic differences between melt onset dates observed by different microwave wavelengths, we developed a conceptual model which illustrates how the seasonal evolution of snow temperature profiles may affect different microwave bands with different penetration depths. These suggest that future multi-frequency active/passive microwave satellite missions could be used to resolve melt processes throughout the vertical snow column of thick snow on perennial Antarctic sea ice.

Description: Recent observations of near-surface soil temperatures over the circumpolar Arctic show accelerated warming of permafrost-affected soils. The availability of a comprehensive near-surface permafrost and active layer dataset is critical to better understanding climate impacts and to constraining permafrost thermal conditions and its spatial distribution in land system models. We compiled a soil temperature dataset from 72 monitoring stations in Alaska using data collected by the US Geological Survey, the National Park Service, and the University of Alaska Fairbanks permafrost monitoring networks. The array of monitoring stations spans a large range of latitudes from 60.9 to 71.3 N and elevations from near sea level to~ 1300 m, comprising tundra and boreal forest regions. This dataset consists of monthly ground temperatures at depths up to 1 m, volumetric soil water content, snow depth, and air temperature during 1997–2016. These data have been quality controlled in collection and processing. Meanwhile, we implemented data harmonization evaluation for the processed dataset. The final product (PF-AK, v0. 1) is available at the Arctic Data Center (https://doi. org/10.18739/A2KG55).

Description: Enrichment of the oceans with CO2 may be beneficial for some marine phytoplankton, including harmful algae. Numerous laboratory experiments provided valuable insights into the effects of elevated pCO2 on the growth and physiology of harmful algal species, including the production of phycotoxins. Experiments close to natural conditions are the next step to improve predictions, as they consider the complex interplay between biotic and abiotic factors that can confound the direct effects of ocean acidification. We therefore investigated the effect of ocean acidification on the occurrence and abundance of phycotoxins in bulk plankton samples during a long-term mesocosm experiment in the Gullmar Fjord, Sweden, an area frequently experiencing harmful algal blooms. During the experimental period, a total of seven phycotoxin-producing harmful algal genera were identified in the fjord, and in accordance, six toxin classes were detected. However, within the mesocosms, only domoic acid and the corresponding producer Pseudo-nitzschia spp. was observed. Despite high variation within treatments, significantly higher particulate domoic acid contents were measured in the mesocosms with elevated pCO2. Higher particulate domoic acid contents were additionally associated with macronutrient limitation. The risks associated with potentially higher phycotoxin levels in the future ocean warrants attention and should be considered in prospective monitoring strategies for coastal marine waters.

Description: Salpa thompsoni is an important grazer in the Southern Ocean. It is found from the Subtropical Convergence southward to the coastal Antarctic Seas but being most abundant in the Antarctic Polar Frontal Zone. Low temperatures appear to negatively affect their development, limiting their ability to occur in the krill dominated high Antarctic ecosystems. Yet reports indicate that with ocean warming S. thompsoni have experienced a southward shift in their distribution. As they are efficient filter feeders, this shift can result in large-scale changes in the Southern Ocean ecosystem by increasing competitive or predatory interactions with Antarctic krill. To explore salp bloom dynamics in the Southern Ocean a size-structured S. thompsoni population model was developed with growth, consumption, reproduction and mortality rates dependent on temperature and chlorophyll a conditions. The largest uncertainties in S. thompsoni population ecology are individual and population growth rates, with a recent study identifying the possibility that the life cycle could be much shorter than previously considered. Here we run a suite of hypothesis scenarios under various environmental conditions to determine the most appropriate growth rate. Temperature and chlorophyll a were sufficient drivers to recreate seasonal and interannual dynamics of salp populations at two locations. The most suitable growth model suggests that mean S. thompsoni growth rates are likely to be ∼1mm body length d−1, 2-fold higher than previous calculations. S. thompsoni biomass was dependent on bud release time, with larger biomass years corresponding to bud release occurring during favorable environmental conditions; increasing the survival and growth of blastozooids and resulting in higher embryo release. This model confirms that it is necessary for growth and reproductive rates to be flexible in order for the salp population to adapt to varying environmental conditions and provides a framework that can examine how future salp populations might respond to climate change.

Description: Although quantitative isotope data from speleothems has been used to evaluate isotope-enabled model simulations, currently no consensus exists regarding the most appropriate methodology through which to achieve this. A number of modelling groups will be running isotope-enabled palaeoclimate simulations in the framework of the Coupled Model Intercomparison Project Phase 6, so it is timely to evaluate different approaches to using the speleothem data for data–model comparisons. Here, we illustrate this using 456 globally distributed speleothem δ18O records from an updated version of the Speleothem Isotopes Synthesis and Analysis (SISAL) database and palaeoclimate simulations generated using the ECHAM5-wiso isotope-enabled atmospheric circulation model. We show that the SISAL records reproduce the first-order spatial patterns of isotopic variability in the modern day, strongly supporting the application of this dataset for evaluating model-derived isotope variability into the past. However, the discontinuous nature of many speleothem records complicates the process of procuring large numbers of records if data–model comparisons are made using the traditional approach of comparing anomalies between a control period and a given palaeoclimate experiment. To circumvent this issue, we illustrate techniques through which the absolute isotope values during any time period could be used for model evaluation. Specifically, we show that speleothem isotope records allow an assessment of a model’s ability to simulate spatial isotopic trends. Our analyses provide a protocol for using speleothem isotope data for model evaluation, including screening the observations to take into account the impact of speleothem mineralogy on δ18O values, the optimum period for the modern observational baseline and the selection of an appropriate time window for creating means of the isotope data for palaeo-time-slices.

Description: Human influence on the climate system, through greenhouse gas emissions, is clear and climate warming unequivocal. Recent climate change has had widespread impacts on natural systems including shifts in the ranges (distributions) of land, freshwater, and marine organisms. Effects of these biogeographical shifts transcend single-species to impact on ecosystem goods and services resulting in significant social and economic costs to human communities. In this article we provide a general overview of these factors by reviewing current evidence from terrestrial, freshwater, and marine ecosystems.

Description: We present here the first results, for the preindustrial and mid-Holocene climatological periods, of the newly developed isotope-enhanced version of the fully coupled Earth system model MPI-ESM, called hereafter MPI-ESM-wiso. The water stable isotopes H16O, H18O and HDO have been implemented into all components of the coupled model setup. The mid-Holocene provides the opportunity to evaluate the model response to changes in the seasonal and latitudinal distribution of insolation induced by different orbital forcing conditions. The results of our equilibrium simulations allow us to evaluate the performance of the isotopic model in simulating the spatial and temporal variations of water isotopes in the different compartments of the hydrological system for warm climates. For the preindustrial climate, MPI-ESM-wiso reproduces very well the observed spatial distribution of the isotopic content in precipitation linked to the spatial variations in temperature and precipitation rate. We also find a good model–data agreement with the observed distribution of isotopic composition in surface seawater but a bias with the presence of surface seawater that is too 18O-depleted in the Arctic Ocean. All these results are improved compared to the previous model version ECHAM5/MPIOM. The spatial relationships of water isotopic composition with temperature, precipitation rate and salinity are consistent with observational data. For the preindustrial climate, the interannual relationships of water isotopes with temperature and salinity are globally lower than the spatial ones, consistent with previous studies. Simulated results under mid-Holocene conditions are in fair agreement with the isotopic measurements from ice cores and continental speleothems. MPI-ESM-wiso simulates a decrease in the isotopic composition of precipitation from North Africa to the Tibetan Plateau via India due to the enhanced monsoons during the mid-Holocene. Over Greenland, our simulation indicates a higher isotopic composition of precipitation linked to higher summer temperature and a reduction in sea ice, shown by positive isotope–temperature gradient. For the Antarctic continent, the model simulates lower isotopic values over the East Antarctic plateau, linked to the lower temperatures during the mid-Holocene period, while similar or higher isotopic values are modeled over the rest of the continent. While variations of isotopic contents in precipitation over West Antarctica between mid-Holocene and preindustrial periods are partly controlled by changes in temperature, the transport of relatively 18O-rich water vapor near the coast to the western ice core sites could play a role in the final isotopic composition. So, more caution has to be taken about the reconstruction of past temperature variations during warm periods over this area. The coupling of such a model with an ice sheet model or the use of a zoomed grid centered on this region could help to better describe the role of the water vapor transport and sea ice around West Antarctica. The reconstruction of past salinity through isotopic content in sea surface waters can be complicated for regions with strong ocean dynamics, variations in sea ice regimes or significant changes in freshwater budget, giving an extremely variable relationship between the isotopic content and salinity of ocean surface waters over small spatial scales. These complicating factors demonstrate the complexity of interpreting water isotopes as past climate signals of warm periods like the mid-Holocene. A systematic isotope model intercomparison study for further insights on the model dependency of these results would be beneficial.

Description: Essential Biodiversity Variables (EBV) are fundamental variables that can be used for assessing biodiversity change over time, for determining adherence to biodiversity policy, for monitoring progress towards sustainable development goals, and for tracking biodiversity responses to disturbances and management interventions. Data from observations or models that provide measured or estimated EBV values, which we refer to as EBV data products, can help to capture the above processes and trends and can serve as a coherent framework for documenting trends in biodiversity. Using primary biodiversity records and other raw data as sources to produce EBV data products depends on cooperation and interoperability among multiple stakeholders, including those collecting and mobilising data for EBVs and those producing, publishing and preserving EBV data products. Here, we encapsulate ten principles for the current best practice in EBV-focused biodiversity informatics as ‘The Bari Manifesto’, serving as implementation guidelines for data and research infrastructure providers to support the emerging EBV operational framework based on trans-national and cross-infrastructure scientific workflows. The principles provide guidance on how to contribute towards the production of EBV data products that are globally oriented, while remaining appropriate to the producer's own mission, vision and goals. These ten principles cover: data management planning; data structure; metadata; services; data quality; workflows; provenance; ontologies/vocabularies; data preservation; and accessibility. For each principle, desired outcomes and goals have been formulated. Some specific actions related to fulfilling the Bari Manifesto principles are highlighted in the context of each of four groups of organizations contributing to enabling data interoperability - data standards bodies, research data infrastructures, the pertinent research communities, and funders. The Bari Manifesto provides a roadmap enabling support for routine generation of EBV data products, and increases the likelihood of success for a global EBV framework.

Description: The hypothesis of this work was that exposure to diverse abiotic factors in two sites with different sediment and iron input (Peñón de Pesca: low impact; Island D: high impact, both areas in Potter Cove, King George Island, Antarctica) affects the physiological and oxidative profile of Gigartina skottsbergii and Himantothallus grandifolius. Daily metabolic carbon balance was significantly lower in both macroalgae from Island D compared to Peñón de Pesca. Lipid radical (LRradical dot) content was significantly higher in G. skottsbergii collected from Island D compared to Peñón de Pesca. In contrast, H. grandifolius showed significantly lower values in Island D compared to Peñón de Pesca. The β-carotene (β-C) content was significantly lower in G. skottsbergii from Island D compared to Peñón de Pesca, and the ratio LRradical dot/β-C showed a 6-fold increase in Island D samples compared to Peñón de Pesca. On the other hand, β-C content in H. grandifolius showed no significant differences between both areas. The LRradical dot/β-C content ratio in this alga was significantly lower (26%) in Island D as compared to Peñón de Pesca. Total iron content was significantly higher in both macroalgae from Island D compared to samples from Peñón de Pesca. Results with G. skottsbergii suggested changes in the oxidative cellular balance, probably related to the higher environmental iron in Island D as compared to Peñón de Pesca. The species H. grandifolius seems to be better adapted to the environmental conditions especially through a higher antioxidant capacity to cope with oxidative stress.

Description: The Himalaya–Tibet orogen contains one of the largest modern topographic and climate gradients on Earth. Proxy data from the region provide a basis for understanding Tibetan Plateau paleo climate and paleo elevation reconstructions. Paleo climate model comparisons to proxy data compliment sparsely located data and can improve climate reconstructions. This study investigates temporal changes in precipitation, temperature and precipitation δ18O(δ18Op) over the Himalaya–Tibet from the Last Glacial Maximum (LGM) to present. We conduct a series of atmospheric General Circulation Model (GCM, ECHAM5-wiso) experiments at discrete time slices including a Pre-industrial (PI, Pre-1850 AD), Mid Holocene (MH, 6 ka BP) and LGM (21 ka BP) simulations. Model predictions are compared with existing proxy records. Model results show muted climate changes across the plateau during the MH and larger changes occurring during the LGM. During the LGM surface temperatures are ∼2.0–4.0◦C lower across the Himalaya and Tibet, and 〉5.0◦C lower at the northwest and northeast edge of the Tibetan Plateau. LGM mean annual precipitation is 200–600 mm/yr lower over on the Tibetan Plateau. Model and proxy data comparison shows a good agreement for the LGM, but large differences for the MH. Large differences are also present between MH proxy studies near each other. The precipitation weighted annual mean δ18Op lapse rate at the Himalaya is about 0.4h/km larger during the MH and 0.2h/km smaller during the LGM than during the PI. Finally, rainfall associated with the continental Indian monsoon (between 70◦E–110◦E and 10◦N–30◦N) is about 44% less in the LGM than during PI times. The LGM monsoon period is about one month shorter than in PI times. Taken together, these results document significant spatial and temporal changes in temperature, precipitation, and δ18Op over the last ∼21 ka. These changes are large enough to impact interpretations of proxy data and the intensity of the Indian monsoon.

Description: Although the Arctic covers 6% of our planet’s surface and plays a key role in the Earth’s climate it remains one of the least explored ecosystems. The global change induced decline of sea ice has led to increasing anthropogenic presence in the Arctic Ocean. Exploitation of its resources is already underway, and Arctic waters are likely important future shipping lanes as indicated by already increasing numbers of fishing vessels, cruise liners and hydrocarbon prospecting in the area over the past decade. Global estimates of plastic entering the oceans currently exceed results based on empirical evidence by up to three orders of magnitude highlighting that we have not yet identified some of the major sinks of plastic in our oceans. Fragmentation into microplastics could explain part of the discrepancy. Indeed, microplastics were identified from numerous marine ecosystems globally, including the Arctic. Here, we analysed horizons of ice cores from the western and eastern Fram Strait by focal plane array based micro-Fourier transform infrared spectroscopy to assess if sea ice is a sink of microplastic. Ice cores were taken from land-locked and drifting sea ice to distinguish between local entrainment of microplastics vs long-distance transport. Mean concentrations of 2 x 106 particles m-3 in pack ice and 6 x 105 particles m-3 in land-locked ice were detected (numbers of fibers will soon be added). Eleven different polymer types were identified; polyethylene (PE) was the most abundant one. Preliminary results from four further ice cores from the central Arctic range in a similar order but the microplastics composition was very different. Calculation of drift trajectories by back-tracking of the ice floes sampled indicates multiple source areas, which explains the differences in the microplastic composition. Preliminary analysis of snow samples taken from ice floes in the Fram Strait showed numerous fibers of yet unknown but most likely anthropogenic origin indicating atmospheric fallout as a possible pathway. Our results exceed concentrations from the North Pacific by several orders of magnitudes. This can be explained partly by the process of ice formation, during which (organic) particles tend to concentrate by 1-2 orders of magnitude compared with ambient seawater. However, the magnitude of the difference indicates that Arctic sea ice is a temporal sink for microplastics. Increasing quantities of small plastic litter items on the seafloor nearby, which is located in the marginal ice zone corroborate the notion that melting sea ice releases entrained plastic particles and that sea ice acts as a vector of transport both horizontally and vertically to underlying ecosystem compartments.

Description: The Mozambique Ridge, a prominent basement high in the southwestern Indian Ocean, consists of four major geomorphological segments associated with numerous phases of volcanic activity in the Lower Cretaceous. The nature and origin of the Mozambique Ridge have been intensely debated with one hypothesis suggesting a Large Igneous Province origin. High-resolution seismic reflection data reveal a large number of extrusion centres with a random distribution throughout the southern Mozambique Ridge and the nearby Transkei Rise. Intra-basement reflections emerge from the extrusion centres and are interpreted to represent massive lava flow sequences. Such lava flow sequences are characteristic of eruptions leading to the formation of continental and oceanic flood basalt provinces, hence supporting a Large Igneous Province origin of the Mozambique Ridge. We observe evidence for widespread post-sedimentary magmatic activity that we correlate with a southward propagation of the East African Rift System. Based on our volumetric analysis of the southern Mozambique Ridge we infer a rapid sequential emplacement between ~131 Ma and ~125 Ma, which is similar to the short formation periods of other Large Igneous Provinces like the Agulhas Plateau.

Description: Vast quantities of plastics are accumulating in the oceans. At sea, plastics interact with marine biota often with deleterious consequences for organisms and habitats. As users of marine food resources and ecosystem services humans are also affected by marine plastic litter. Economic, social and health implications necessitate decisive action to manage this growing environmental problem at a global scale. Accordingly, legislative and technological instruments have been implemented to reduce the amounts of marine plastic debris. Promising strategies to reduce the human plastic footprint in the oceans must involve the minimization of plastic discharges into the marine environment.

Description: For many years, the pollution of the oceans with marine litter received only little attention from the public although the global plastic production has grown steadily. However, since the “discovery” of the oceanic garbage patches and microplastics the littering of the oceans has become a hot topic, which is reflected in strong recent increases in the number of publications. Despite growing research efforts many questions remain unanswered and the new wealth of information does not readily transpire to the general public, which is left unsettled. For example, it is still unclear what the overall extent of ocean pollution is, or how the enormous amounts of oceanic plastics affect marine life and ecosystems. To overcome this uncertainty and make best use of the existing knowledge, we currently develop an online portal for marine litter and microplastic pollution named LITTERBASE. As of early 2017, LITTERBASE will provide access to the current state of understanding of marine litter and microplastics to the general public and stakeholders. Published records of marine litter and microplastics and their impact on marine life will be compiled in a database. The regularly updated information will be displayed in distribution maps and other graphs in an interactive online portal. In the long run, data from citizen scientists may also be integrated into these infographs.

Description: Climate trends in the Antarctic region remain poorly characterized, owing to the brevity and scarcity of direct climate observations and the large magnitude of interannual to decadal-scale climate variability. Here, within the framework of the PAGES Antarctica2k working group, we build an enlarged database of ice core water stable isotope records from Antarctica, consisting of 112 records. We produce both unweighted and weighted isotopic (δ18O) composites and temperature reconstructions since 0 CE, binned at 5- and 10-year resolution, for seven climatically distinct regions covering the Antarctic continent. Following earlier work of the Antarctica2k working group, we also produce composites and reconstructions for the broader regions of East Antarctica, West Antarctica and the whole continent. We use three methods for our temperature reconstructions: (i) a temperature scaling based on the δ18O–temperature relationship output from an ECHAM5-wiso model simulation nudged to ERA-Interim atmospheric reanalyses from 1979 to 2013, and adjusted for the West Antarctic Ice Sheet region to borehole temperature data, (ii) a temperature scaling of the isotopic normalized anomalies to the variance of the regional reanalysis temperature and (iii) a composite-plus-scaling approach used in a previous continent-scale reconstruction of Antarctic temperature since 1 CE but applied to the new Antarctic ice core database. Our new reconstructions confirm a significant cooling trend from 0 to 1900 CE across all Antarctic regions where records extend back into the 1st millennium, with the exception of the Wilkes Land coast and Weddell Sea coast regions. Within this long-term cooling trend from 0 to 1900 CE, we find that the warmest period occurs between 300 and 1000 CE, and the coldest interval occurs from 1200 to 1900 CE. Since 1900 CE, significant warming trends are identified for the West Antarctic Ice Sheet, the Dronning Maud Land coast and the Antarctic Peninsula regions, and these trends are robust across the distribution of records that contribute to the unweighted isotopic composites and also significant in the weighted temperature reconstructions. Only for the Antarctic Peninsula is this most recent century-scale trend unusual in the context of natural variability over the last 2000 years. However, projected warming of the Antarctic continent during the 21st century may soon see significant and unusual warming develop across other parts of the Antarctic continent. The extended Antarctica2k ice core isotope database developed by this working group opens up many avenues for developing a deeper understanding of the response of Antarctic climate to natural and anthropogenic climate forcings. The first long-term quantification of regional climate in Antarctica presented herein is a basis for data–model comparison and assessments of past, present and future driving factors of Antarctic climate.

Description: Arctic sea ice is a critical component of the climate system as it influences the albedo, heat, moisture and gas exchange between ocean and atmosphere as well as the ocean's salinity. An ideal location to study natural sea ice variability during pre-industrial times is the East Greenland Shelf that underlies the East Greenland Current (EGC), the main route of Arctic sea ice and freshwaters from the Arctic Ocean into the northern North Atlantic. Here, we present a new high-resolution biomarker record from the East Greenland Shelf (73°N), which provides new insights into the sea ice variability and accompanying phytoplankton productivity over the past 5.2 kyr. Our IP25 based sea ice reconstructions and the inferred PIP25 index do not reflect the wide-spread late Holocene Neoglacial cooling trend that follows the decreasing solar insolation pattern, which we relate to the strong influence of the polar EGC on the East Greenland Shelf and interactions with the adjacent fjord throughout the studied time interval. However, our reconstructions reveal several oscillations with increasing/decreasing sea ice concentrations that are linked to the known late Holocene climate cold/warm phases, i.e. the Roman Warm Period, Dark Ages Cold Period, Medieval Climate Anomaly and Little Ice Age. The observed changes seem to be connected to general ocean atmosphere circulation changes, possibly related to North Atlantic Oscillation and Atlantic Multidecadal Oscillation regimes. Furthermore, we identify a cyclicity of 73–74 years in sea ice algae and phytoplankton productivity over the last 1.2 kyr, which may indicate a connection to Atlantic Multidecadal Oscillation mechanisms.

Description: The denudation history of active orogens is often interpreted in the context of modern climate gradients. Here we address the validity of this approach and ask what are the spatial and temporal variations in palaeoclimate for a latitudinally diverse range of active orogens? We do this using high-resolution (T159, ca. 80 × 80 km at the Equator) palaeoclimate simulations from the ECHAM5 global atmospheric general circulation model and a statistical cluster analysis of climate over different orogens (Andes, Himalayas, SE Alaska, Pacific NW USA). Time periods and boundary conditions considered include the Pliocene (PLIO, ∼3Ma), the Last Glacial Maximum (LGM, ∼21ka), mid-Holocene (MH, ∼6ka), and pre-industrial (PI, reference year 1850). The regional simulated climates of each orogen are described by means of cluster analyses based on the variability in precipitation, 2 m air temperature, the intra-annual amplitude of these values, and monsoonal wind speeds where appropriate. Results indicate the largest differences in the PI climate existed for the LGM and PLIO climates in the form of widespread cooling and reduced precipitation in the LGM and warming and enhanced precipitation during the PLIO. The LGM climate shows the largest deviation in annual precipitation from the PI climate and shows enhanced precipitation in the temperate Andes and coastal regions for both SE Alaska and the US Pacific Northwest. Furthermore, LGM precipitation is reduced in the western Himalayas and enhanced in the eastern Himalayas, resulting in a shift of the wettest regional climates eastward along the orogen. The cluster-analysis results also suggest more climatic variability across latitudes east of the Andes in the PLIO climate than in other time slice experiments conducted here. Taken together, these results highlight significant changes in late Cenozoic regional climatology over the last ∼3Myr. Comparison of simulated climate with proxy-based reconstructions for the MH and LGM reveal satisfactory to good performance of the model in reproducing precipitation changes, although in some cases discrepancies between neighbouring proxy observations highlight contradictions between proxy observations themselves. Finally, we document regions where the largest magnitudes of late Cenozoic changes in precipitation and temperature occur and offer the highest potential for future observational studies that quantify the impact of climate change on denudation and weathering rates.

Description: The bio-essential trace metal iron (Fe) has poor inorganic solubility in seawater, and therefore dissolution is dependent on organic complexation. The Arctic Ocean is subject to strong terrestrial influences which contribute to organic solubility of Fe, particularly in the surface. These influences are subject to rapid changes in the catchments of the main contributing rivers. Here we report concentrations and binding strengths of Fe-binding organic ligands in relation to spectral properties of Dissolved Organic Matter (DOM) and concentrations of humic substances. Full-depth profiles of Fe and Fe-binding organic ligands were measured for 11 stations, good agreement to previous studies was found with ligand concentrations between 0.9 and 2.2 equivalent nM of Fe (Eq. nM Fe) at depths 〉 200 m. We found nutrient-like profiles of Fe in the Atlantic-influenced Nansen basin, surface enrichment in the surface over the Amundsen and Makarov basins and scavenging effects in the deep Makarov basin. A highly detailed surface transect consisting of two sections crossing the surface flow from the Siberian continental shelf to the Fram Strait, the TransPolar Drift (TPD), clearly indicates the flow path of the riverine contribution to Fe and Fe-binding organic ligands with concentrations of 0.7 to 4.4 nM and 1.6 to 4.1 Eq. nM Fe, respectively. This is on average 4.5 times higher in DFe and 1.7 times higher in Fe-binding organic ligands than outside the TPD flow path. Conditional binding strengths of ligands in the entire dataset were remarkably similar at 11.45 ≤ LogK′ ≤ 12.63. Increased organic Fe-binding organic ligand concentrations were evident in the Arctic Ocean surface. To better identify the organic substances responsible for Fe complexation in the Arctic Ocean, diverse analytical approaches and a standard other than Suwannee River Fulvic Acid are recommended.

Description: Effects of hypoxia on the osmorespiratory functions of the posterior gills of the shore crab Carcinus maenas acclimated to 12 ppt seawater (DSW) were studied. Short-circuit current (Isc) across the hemilamella (one epithelium layer supported by cuticle) was substantially reduced under exposure to 1.6, 2.0, or 2.5 mg O2/L hypoxic saline (both sides of epithelium) and fully recovered after reoxygenation. Isc was reduced equally in the epithelium exposed to 1.6 mg O2/L on both sides and when the apical side was oxygenated and the basolateral side solely exposed to hypoxia. Under 1.6 mg O2/L, at the level of maximum inhibition of Isc, conductance was decreased from 40.0 mS cm−2 to 34.7 mS cm−2 and fully recovered after reoxygenation. Isc inhibition under hypoxia and reduced 86Rb+ (K+) fluxes across apically located K+ channels were caused preferentially by reversible inhibition of basolaterally located and ouabain sensitive Na+,K+-ATPase mediated electrogenic transport. Reversible inhibition of Isc is discussed as decline in active transport energy supply down regulating metabolic processes and saving energy during oxygen deprivation. In response to a 4 day exposure of Carcinus to 2.0 mg O2/L, hemolymph Na+ and Cl− concentration decreased, i.e. hyperosmoregulation was weakened. Variations of the oxygen concentration level and exposure time to hypoxia lead to an increase of the surface of mitochondria per epithelium area and might in part compensate for the decrease in oxygen availability under hypoxic conditions.

Description: Fossil carbonate skeletons of marine organisms are archives for understanding the development and evolution of palaeo-environments. However, the correct assessment of past environment dynamics is only possible when pristine skeletons and their biogenic characteristics are unequivocally distinguishable from diagenetically-alteredskeletal elements and non-biogenic features. In this study, we extend our work on diagenesis of biogenic aragonite (Casella et al. 2017) to the investigation of biogenic low-Mg calcite using brachiopod shells. We examined and compared microstructural characteristics inducedby laboratory-based alteration to structural features derived from diagenetic alteration in natural environments. We used four screening methods: cathodoluminescence (CL), cryogenic and conventional field emission-scanning electronmicroscopy (FE-SEM), atomic force microscopy (AFM) and electron backscatter diffraction (EBSD).We base our assessments of diagenetic alteration and overprint on measurements of, a) images of optical overprint signals, b) changes in calcite crystal orientation patterns, and c) crystal co-orientation statistics. According to the screening process, altered and overprinted samples define two groups. In Group 1 the entire shell is diagenetically overprinted, whereas in Group 2 the shell contains pristine as well as overprinted parts. In the case of Group 2 shells, alteration occurred either along the periphery of the shell including the primary layer or at the interior-facing surface of the fibrous/columnar layer. In addition, we observed an important mode of the overprinting process, namely the migration of diagenetic fluids through the endopunctae corroborated by mineral formation and overprinting in their immediate vicinity, while leaving shell parts between endopunctae in pristine condition. Luminescence (CL) and microstructural imaging (FE-SEM) screening give first-order observations of the degree of overprint as they cover macro-to micron scale alteration features. For a comprehensive assessment of diagenetic overprint these screening methods should be complemented by screening techniques such as EBSD and AFM. They visualise diagenetic changes at submicron and nanoscale levels depicting the replacement of pristine nanocomposite mesocrystal biocarbonate (NMB) by inorganic rhombohedral calcite (IRC). The integration of screening methods allows for the unequivocal identification of highly-detailed alteration features as well as an assessment of the degree of diagenetic alteration.

Description: In austral spring 2016 the Antarctic region experienced anomalous sea ice retreat in all sectors, with sea ice extent in October and November 2016 being the lowest in the Southern Hemisphere over the observational period (1979–present). The extreme sea ice retreat was accompanied by widespread warming along the coastal areas as well as in the interior of the Antarctic continent. This exceptional event occurred along with a strong negative phase of the Southern Annular Mode (SAM) and the moistest and warmest spring on record, over large areas covering the Indian Ocean, the Ross Sea and the Weddell Sea. In October 2016, the positive anomalies of the totally integrated water vapor (IWV) and 2 m air temperature (T2m) over the Indian Ocean, western Pacific, Bellingshausen Sea and southern part of Ross Sea were unprecedented in the last 39 years. In October and November 2016, when the largest magnitude of negative daily sea ice concentration anomalies was observed, repeated episodes of poleward advection of warm and moist air took place. These results suggest the importance of moist and warm air intrusions into the Antarctic region as one of the main contributors to this exceptional sea ice retreat event.

Description: To resolve the mechanisms behind the major climate reorganisation which occurred between 0.9 and 1.2Ma, the recovery of a suitable 1.5 million-year-old ice core is fundamental. The quest for such an Oldest Ice core requires a number of key boundary conditions, of which the poorly known basal geothermal heat flux (GHF) is lacking. We use a transient thermodynamical 1D vertical model that solves for the rate of change of temperature in the vertical, with surface temperature and modelled GHF as boundary conditions. For each point on the ice sheet, the model is forced with variations in atmospheric conditions over the last 2Ma, and modelled ice-thickness variations. The process is repeated for a range of GHF values to determine the value of GHF that marks the limit between frozen and melting conditions over the whole ice sheet, taking into account 2Ma of climate history. These threshold values of GHF are statistically compared to existing GHF data sets. The new probabilistic GHF fields obtained for the ice sheet thus provide the missing boundary conditions in the search for Oldest Ice. High spatial resolution radar data are examined locally in the Dome Fuji and Dome C regions, as these represent the ice core community's primary drilling sites. GHF, bedrock variability, ice thickness and other essential criteria combined highlight a dozen major potential Oldest Ice sites in the vicinity of Dome Fuji and Dome C, where GHF allows for Oldest Ice.

Description: Polar ice core water isotope records are commonly used to infer past changes in Antarctic temperature, motivating an improved understanding and quantification of the temporal relationship between δ18O and temperature. This can be achieved using simulations performed by atmospheric general circulation models equipped with water stable isotopes. Here, we evaluate the skills of the high-resolution water-isotope-enabled atmospheric general circulation model ECHAM5-wiso (the European Centre Hamburg Model) nudged to European Centre for Medium-Range Weather Forecasts (ECMWF) reanalysis using simulations covering the period 1960–2013 over the Antarctic continent. We compare model outputs with field data, first with a focus on regional climate variables and second on water stable isotopes, using our updated dataset of water stable isotope measurements from precipitation, snow, and firn–ice core samples. ECHAM5-wiso simulates a large increase in temperature from 1978 to 1979, possibly caused by a discontinuity in the European Reanalyses (ERA) linked to the assimilation of remote sensing data starting in 1979. Although some model–data mismatches are observed, the (precipitation minus evaporation) outputs are found to be realistic products for surface mass balance. A warm model bias over central East Antarctica and a cold model bias over coastal regions explain first-order δ18O model biases by too strong isotopic depletion on coastal areas and underestimated depletion inland. At the second order, despite these biases, ECHAM5-wiso correctly captures the observed spatial patterns of deuterium excess. The results of model–data comparisons for the inter-annual δ18O standard deviation difer when using precipitation or ice core data. Further studies should explore the importance of deposition and post-deposition processes affecting ice core signals and not resolved in the model. These results build trust in the use of ECHAM5-wiso outputs to investigate the spatial, seasonal, and inter-annual δ18O–temperature relationships. We thus make the first Antarctica-wide synthesis of prior results. First, we show that local spatial or seasonal slopes are not a correct surrogate for inter-annual temporal slopes, leading to the conclusion that the same isotope–temperature slope cannot be applied for the climatic interpretation of Antarctic ice core for all timescales. Finally, we explore the phasing between the seasonal cycles of deuterium excess and δ18O as a source of information on changes in moisture sources affecting the δ18O–temperature relationship. The few available records and ECHAM5-wiso show different phase relationships in coastal, intermediate, and central regions. This work evaluates the use of the ECHAM5-wiso model as a tool for the investigation of water stable isotopes in Antarctic precipitation and calls for extended studies to improve our understanding of such proxies.

Description: The effect of external forcings on atmospheric circulation is debated. Due to the short observational period, the analysis of the role of external forcings is hampered, making it difficult to assess the sensitivity of atmospheric circulation to external forcings, as well as persistence of the effects. In observations, the average response to tropical volcanic eruptions is a positive North Atlantic Oscillation (NAO) during the following winter. However, past major tropical eruptions exceeding the magnitude of eruptions during the instrumental era could have had more lasting effects. Decadal NAO variability has been suggested to follow the 11-year solar cycle, and linkages have been made between grand solar minima and negative NAO. However, the solar link to NAO found by modeling studies is not unequivocally supported by reconstructions, and is not consistently present in observations for the 20th century. Here we present a reconstruction of atmospheric winter circulation for the North Atlantic region covering the period 1241–1970 CE. Based on seasonally resolved Greenland ice core records and a 1200-year-long simulation with an isotope-enabled climate model, we reconstruct sea level pressure and temperature by matching the spatiotemporal variability in the modeled isotopic composition to that of the ice cores. This method allows us to capture the primary (NAO) and secondary mode (Eastern Atlantic Pattern) of atmospheric circulation in the North Atlantic region, while, contrary to previous reconstructions, preserving the amplitude of observed year-to-year atmospheric variability. Our results show five winters of positive NAO on average following major tropical volcanic eruptions, which is more persistent than previously suggested. In response to decadal minima of solar activity we find a high-pressure anomaly over northern Europe, while a reinforced opposite response in pressure emerges with a 5-year time lag. On centennial timescales we observe a similar response of circulation as for the 5-year time-lagged response, with a high-pressure anomaly across North America and south of Greenland. This response to solar forcing is correlated to the second mode of atmospheric circulation, the Eastern Atlantic Pattern. The response could be due to an increase in blocking frequency, possibly linked to a weakening of the subpolar gyre. The long-term anomalies of temperature during solar minima shows cooling across Greenland, Iceland and western Europe, resembling the cooling pattern during the Little Ice Age (1450–1850 CE). While our results show significant correlation between solar forcing and the secondary circulation pattern on decadal (r = 0.29, p 〈 0.01) and centennial timescales (r = 0.6, p 〈 0.01), we find no consistent relationship between solar forcing and NAO. We conclude that solar and volcanic forcing impacts different modes of our reconstructed atmospheric circulation, which can aid in separating the regional effects of forcings and understanding the underlying mechanisms.

Description: Multiple toxic and bioactive compounds produced by Alexandrium spp. cause adverse effects on bivalves, but these effects are frequently difficult to attribute to a single compound class. To disentangle the effect of neurotoxic vs lytic secondary metabolites, we exposed blue mussels to either a paralytic shellfish toxin (PST) producing Alexandrium spp. strain, or to an exclusively lytic compound (LC) producing strain, or a strain containing both compound classes, to evaluate the time dependent effects after 3 and 7 days of feeding. Tested parameters comprised signs of paralysis, feeding activity, and immune cell integrity (hemocyte numbers and viability; lysosomal membrane destabilization) and function (ROS production). Both compound classes caused paralysis and immune impairment. The only effect attributable exclusively to PST was increased phagocytic activity after 3 days and impaired feeding activity after 7 days, which curtailed toxin accumulation in digestive glands. Paralysis signals and lysosomal membrane destabilization were more closely, but not exclusively, matched with LC exposure. Effects on circulating hemocyte integrity and immune related functions were mostly transient or remain stable within 7 days; except for increased lysosomal labialization and decreased extracellular ROS production when mussels were exposed to the toxin combination. M. edulis displays adaptive fitness traits to survive and maintain immune capacity upon prolonged exposure to environmentally relevant concentrations of PST and/or LC producing Alexandrium strains.

Description: As the plastic production has been rising since the last five decades, so does the concern for the occurrence of microplastic particles (〈5 mm)in the marine environment during the past years. But still by now the extent of this microplastic pollution of coastal waters and the open ocean remains unclear. Since monitoring the abundance of microplastics in the marine environment is requested by the Marine Strategy Framework Directive (MSFD) standardized and reliable methods forthe detection of microplastics are urgently needed. Studies differ mainly in their purification methods, aiming to reduce biogenic material in environmental samples without altering the plastic polymers to facilitate a clear assignment of the microplastics. In the present and ongoing study the purification method consists of a treatment with technical enzymes and detergents to reduce the use of oxidants and avoid the use of strong acids as well as the subsequent identification and quantification of microplastics applying Focal Plane Array (FPA)-based μFourier Transform Infrared (μFT-IR) spectroscopy.

Description: We study the basement configuration in the slow-spreading Eurasia Basin, Arctic Ocean. Two multichannel seismic (MCS) profiles, which we acquired during ice-free conditions with a 3600 m long streamer, image the transition from the North Barents Sea Margin into the southern Eurasia Basin. The seismic lines resolve the up to 5000 m thick sedimentary section, as well as the crustal architecture of the southern Eurasia Basin along 120 km and 170 km, respectively. The seismic data show large faulted and rotated basement blocks. Gravity modeling indicates a thin basement with a thickness of 1–3 km and a density of 2.8*103 kg/m3 between the base of the sediments and the top of the mantle, which indicates exhumed and serpentinized mantle. The Gakkel spreading ridge, located in northern prolongation of the seismic lines is characterized by an amagmatic or sparsely magmatic segment. From the structural similarity between the basement close to the ultra-slow spreading ridge and our study area, we conclude that the basement in the Eurasia Basin is predominantly formed by exhumed and serpentinized mantle, with magmatic additions. An initial strike-slip movement of the Lomonosov Ridge along the North Barents Sea Margin and subsequent near-orthogonal opening of the Nansen Basin is supposed to have brought mantle material to the surface, which was serpentinized during this process. Continuous spreading thinned the serpentinized mantle and subsequent normal faulting produced distinct basement blocks. We propose that mantle exhumation has likely been active since the opening of the Eurasia Basin.

Description: North Pacific Intermediate water (NPIW) is a dominant water mass controlling ∼400-1200m depth North Pacific Ocean, meanwhile there is a cessation of North Pacific deep water (NPDW) formation in in modern observations. In contrast, paleoceanographic evidences have recorded NPDW formations during last glacial periods. This sug- gests either a rapid or gradual shutting down process of NPDW formation during the last deglaciation. Here, we use an Earth System Model to diagnose the physical and corresponding biogeochemical evolutions in the North Pacific Ocean before and after the last deglaciation, as well as potential changes during rapid climate shifts of the last deglaciation. Linked to different background climate conditions and varying Atlantic Meridional Over- turning Circulation states, we characterize the modelled NPIW and NPDW changes and builds up linkages to marine records. Our results further develop our understanding about the deglacial switch from NPDW to modern NPIW-only formation process.

Description: The deep basins of the Bransfield Strait (BS) are ventilated by Weddell Sea (WS) waters from different origins. Depending on the source and density, these water masses follow different routes across the complex topography near the tip of the Antarctic Peninsula and thus into the Bransfield Strait abyss. Using a global setup of the Finite Element Sea-ice Ocean Model (FESOM) we show that the WS waters found at the western WS continental shelf break have a higher influence on the short period variability of BS bottom waters than the waters present over the continental shelf. Adding passive tracers to the glacial melt water (GMW) from two different origins, Larsen Ice Shelf (LIS) and Filchner-Ronne Ice Shelf (FRIS), we show that the GMW from FRIS has a larger influence on BS bottom waters than the GMW from LIS. FRIS GMW has a higher concentration in the BS eastern basin, while LIS GMW is more abundant in the BS central basin. This duality mainly leads to the difference between BS central and eastern basins seen on the observations. This is a novel result and we believe is a significant contribution to the understanding of the BS-WS circulation and interactions.

Description: This study analyzed multi-channel seismic reflection data from Lake Van, Eastern Anatolia, to provide key information on the structural elements, deformational patterns and overall tectonic structure of the Lake Van basin. The seismic data reveal three subbasins (the Tatvan, northern and Ahlat subbasins) separated by structural ridges (the northern and Ahlat ridges). The Tatvan basin is a tilted wedge-block in the west, it is a relatively undeformed and flat-lying deep basin, forming a typical example of strike-slip sedimentation. Seismic sections reveal that the deeper sedimentary sections of the Tatvan basin are locally folded, gently in the south and more intensely further north, suggesting a probable gravitational “wedge-block” instability, oblique to the northern margin. The northern subbasin, bounded by normal oblique faults, forms a basin-margin graben structure that is elongated in a northeast-southwest direction. The east-west trending Ahlat ridge forms a fault-wedged sedimentary ridge and appears to offset by reverse oblique faults forming as a push-up rhomb horst structure. The Ahlat subbasin is a fault-wedged trough fill that is elongated in the west-east direction and appears as a horst-foot graben formed by the normal oblique faults. The northeast-southwest directed northern ridge is a faulted crestal terrace of a sublacustrine basement block. Its step-like morphology, in response to the downfaulting of the Tatvan basin, as well as its backthrusted appearance, indicates the normal oblique nature of the bounding faults. The lacustrine shelf and slope show distinctive stratigraphic features; progradational deltas, submerged fluvial channels, distorted and collapsed beddings and soft sediment deformation structures, characterizing a highly unstable nature of shelf caused by strong oblique faulting and related earthquakes. The faulting caused uplift of the Çarpanak spur zone, together with the northeastern Erek delta, deformation of deltaic structures and subsequently exposing the shelf and slope areas. The exposed areas are evident in the angular unconformity surface of the Çarpanak basement block with the northeastern Erek delta and thinned sediments. The uplift resulted in the asymmetric depositional emplacement of the southeastern delta that is controlled by a series of ramp anticlines/low angle reverse faults. The Deveboynu subbasin and Varis spur zone form wide fault-controlled depressions with thick sediments that are elongated in the north-south direction. These subbasins appear as a small pull-apart boundary formed by normal oblique faults at the western end of the southeastern delta.

Description: Which are the trends that are transforming research management and how do research organizations respond to these changes? What are the available services to support research during EC projects’ life-cycles? Are there research information systems in use and to which extent are they integrated? The paper is structured as follows: a survey conducted over a sample of universities and research centers in Italy is presented in section 2. Section 3 describes significant case studies. Section 4 illustrates mobility figures and trends in EU funded projects. Section 5 concludes with considerations about trends and suggestions for improvement.

Description: Published

Description: 309-314

Description: 7TM. Sviluppo e Trasferimento Tecnologico

Description: N/A or not JCR

Description: At Vulcano (Aeolian Islands, Italy), different measurement methods have been developed for more than 30 years and models were formulated to account for the real time evolution of the actual solphataric activity. The results of a long term monitoring of surface temperature and of CO2 flux from soil, reviewed in a multidisciplinary framework, are presented here. These two parameters, monitored at the ground surface, highlighted local variations of the hydrothermal release and the time series of data showed in several instances, different range of values. The background and anomalous ranges defined by this long term monitoring are robust by a statistical point of view. The long term data-series offered a useful tool to verify conceptual framework and to better define the natural hazard evaluation integrating “classical” and “new” investigation techniques. Moreover, La Fossa area lays in a geodynamic context with active seismo- tectonic processes, frequently perturbing the pressure field of the hydrothermal system under investigation. Any perturbation in the pressure state variable (P) of the system, results in an excited state of its components and a relevant transfer of energy and mass towards the surface starts to counterbalance the perturbation. The continuous monitoring of surface temperature reveals the effects of the forces guiding the heat flows whereas the space variation of temperature indicates the rising paths of hydrothermal and magmatic fluids. The occurrence of new fumaroles and mofetes, or even changing emission rates of fluids by these vents, rises questions about the evolution of the equilibrium state of buried hydrothermal system, or about changing physical condition of overburden rocks. The conceptual framework suggesting the potential of our time series of field data is that a rock body, can be seen as a multiphase geochemical system where the fluid phases play a crucial role in defining the physical changes of the body and its response to the different forces acting on it. The changes of pore pressure depend on the balance between gas phases production and gas leaked out from a geochemical system. Analyses of fluxes at the system boundaries can give information on the equilibrium of the interacting geospheres. Even if playing variables are too many, some specific compounds and parameters can be selected as indicators of the state of the system.#

Description: Published

Description: Yokohama, Japan

Description: 4V. Dinamica dei processi pre-eruttivi

Description: Abstract. When combined, the three-dimensional imaging of different physical properties of architectural monumen- tal structures acquired through different methodologies can highlight with efficiency the characteristics of the stone building materials. In this work, we compound high res- olution Digital Color Images (DCI) and Terrestrial Laser Scanner (TLS) data for a dense 3-D reconstruction of an ancient pillar in a nineteenth century building in the town of Cagliari, Italy. The TLS technique was supported by a digital photogrammetry survey in order to obtain a natural color texturized 3-D model of the studied pillar. Geometri- cal anomaly maps showing interesting analogies were com- puted both from the 3-D model derived from the TLS ap- plication and from the high resolution 3-D model detected with the photogrammetry. Starting from the 3-D reconstruc- tion from previous techniques, an acoustic tomography in a sector of prior interest of the investigated architectural ele- ment was planned and carried out. The ultrasonic tomogra- phy proved to be an effective tool for detecting internal decay or defects, locating the position of the anomalies and estimat- ing their sizes, shapes, and characteristics in terms of elastic- mechanical properties. Finally, the combination of geophysi- cal and petrographical data sets represents a powerful method for understanding the quality of the building stone materials in the shallow and inner parts of the investigated architectural structures.

Description: Regione Autonoma della Sardegna (RAS) (Sardinian Autonomous Region), Regional Law 7th August 2007, no. 7, Promotion of scientific research and technological innovation in Sardinia (Italy).

Description: Published

Description: 57-62

Description: 5T. Sismologia, geofisica e geologia per l'ingegneria sismica

Description: JCR Journal

Description: Telica volcano, in north-west Nicaragua, is a young stratovolcano of intermediate magma composition producing frequent Vulcanian to phreatic explosive eruptions. The Telica stratigraphic record also includes examples of (pre)historic sub-Plinian activity. To refine our knowledge of this very active volcano, weanalyzedmajor element composition and volatile content of melt inclusions fromsomestratigraphically significant Telica tephra deposits. These include: (1) the Scoria Telica Superior (STS) deposit (2000 to 200 years Before Present; Volcanic Explosive Index, VEI, of 2–3) and (2) pyroclasts from the post-1970s eruptive cycle (1982; 2011). Based on measurements with nanoscale secondary ion mass spectrometry, olivine-hosted (forsterite [Fo] N 80) glass inclusions fall into 2 distinct clusters: a group of H2O-rich (1.8–5.2 wt%) inclusions, similar to those of nearby Cerro Negro volcano, and a second group of CO2-rich (360–1700 μg/g CO2) inclusions (Nejapa, Granada). Model calculations show that CO2 dominates the equilibrium magmatic vapor phase in the majority of the primitive inclusions (XCO2 N 0.62–0.95). CO2, sulfur (generally b2000 μg/g) and H2O are lost to the vapor phase during deep decompression (P N 400 MPa) and early crystallization of magmas. Chlorine exhibits a wide concentration range (400–2300 μg/g) in primitive olivine-entrapped melts (likely suggesting variable source heterogeneity) and is typically enriched in the most differentiated melts (1000–3000 μg/g). Primitive, volatile-rich olivine-hosted melt inclusions (entrapment pressures, 5–15 km depth) are exclusively found in the largest-scale Telica eruptions (exemplified by STS in our study). These eruptions are thus tentatively explained as due to injection of deep CO2-rich mafic magma into the shallow crustal plumbing system. More recent (post-1970), milder (VEI 1–2) eruptions, instead, do only exhibit evidence for low-pressure (P b 50–60 MPa), volatile-poor (H2O b 0.3–1.7 wt%; CO2 b 23–308 μg/g) magmatic conditions. These are manifested as andesitic magmas, recording multiple magma mixing events, in pyroxene inclusions.Wepropose that post-1970s eruptions are possibly related to the high viscosity of resident magma in shallow plumbing system (b2.4 km), due to crystallization and degassing

Description: Published

Description: 131-148

Description: 1V. Storia eruttiva

Description: JCR Journal

Description: characterization of ultra-calcic arc melts, equilibrium phase relations have been determined experimentally for the La Sommata basalt (Som-1, Vulcano, Aeolian arc). Som-1 (Na2O + K2O = 4.46 wt.%, CaO = 12.97 wt.%, MgO = 8.78 wt.%, CaO/Al2O3 = 1.03) is a reference primitive ne-normative arc basalt with a strong ultra-calcic affinity. The experiments have been performed between 44 and 154 MPa, 1050 and 1150 °C and from NNO + 0.2 to NNO + 1.9. Fluid-present conditions were imposed with H2O–CO2 mixtures yielding melt H2O concentrations from0.7 to 3.5wt.%. Phases encountered include clinopyroxene, olivine, plagioclase and Fe-oxide. Clinopyroxene is slightly earlier than olivine in the crystallization sequence. It is the liquidus phase at 150 MPa, being joined by olivine on the liquidus between 44 and 88MPa. Plagioclase is the third phase to appear in the crystallization sequence and orthopyroxene was not found. Experimental clinopyroxenes (Fs7–16) and olivines (Fo78–92) partially reproduce the natural phenocryst compositions (respectively Fs5–7 and Fo87–91). Upon progressive crystallization, experimental liquids shift towards higher SiO2 (up to ~55 wt.%), Al2O3 (up to ~18 wt.%) and K2O (up to ~5.5wt.%) and lower CaO,MgO and CaO/Al2O3. Experimental glasses and natural whole-rock compositions overlap, indicating that progressive crystallization of Som-1 type melts can generate differentiated compositions such as those encountered at Vulcano. The lowpressure cotectic experimental glasses reproduce glass inclusions in La Sommata clinopyroxene but contrast with glass inclusions in olivine which preserve basaltic melts more primitive than Som-1. Phase relations for the La Sommata basalt are identical in all critical aspects to those obtained previously on a synthetic ultra-calcic arc composition. In particular, clinopyroxene+olivine co-saturation occurs at very low pressures (≤100 MPa). Ultra-calcic arc compositions do not represent primary mantle melts but result from the interaction between a primary mantle melt and clinopyroxene-bearing rocks in the arc crust. At Vulcano, primitive ultra-calcic end-member melts were generated between 250 and 350 MPa in the lower magma accumulation zone by reaction between hot primitive melts and wehrlitic or gabbroic lithologies. At Stromboli, golden pumices and glass inclusions with an ultra-calcic affinity were also generated at shallow pressures, between 150 and 250 MPa, suggesting that the interaction model is of general significance in the Aeolian arc.

Description: Published

Description: 85-101

Description: 2V. Struttura e sistema di alimentazione dei vulcani

Description: JCR Journal

Description: The action of using someone else’s production, ideas, or research without acknowledging the source and then claiming credit for them is known as plagiarism. Plagiarism is in principle a moral offense; it is not always an illegal action but certainly is an ethical complex case. Copying without permission or stealing someone else’s work violates the standard codes of scholarly conduct and ethical behavior in professional scientific research. Science may be somewhat more prone to plagiarism in that scholars exchange ideas and proposals more frequently than artists, for example. Workshops, scientific meetings, and round tables are places where primitive and preliminary researches are presented and discussed before their official presentation. This chapter discusses plagiarism and self plagiarism and tries to point out the role of the scientific community toward this kind of scientific misconduct.

Description: Published

Description: 5TM. Informazione ed editoria

Description: The Istituto Nazionale di Geofisica e Vulcanologia runs the Italian National Seismic Network (about 400 stations, seismometers, accelerometers and GPS antennas) and other networks at national scale for monitoring earthquakes and tsunami as a part of the National Civil Protection System coordinated by the Italian Department of Civil Protection. This work summarises the acquisition and the distribution of the data and the analysis that are carried out for seismic surveillance and tsunami alert.

Description: INGV and DPC

Description: Published

Description: 31-38

Description: 1IT. Reti di monitoraggio

Description: N/A or not JCR

Description: The relationships between trachytes and peralkaline rhyolites (i.e. pantellerites and comendites), which occur in many continental rift systems, oceanic islands and continental intraplate settings, is unclear. To fill this gap, we have performed phase equilibrium experiments on two representative metaluminous trachytes from Pantelleria to determine both their pre-eruptive equilibration conditions (pressure, temperature, H2O content and redox state) and liquid lines of descent. Experiments were performed in the temperature range 750–950 C, pressure 0 5–1 5 kbar and fluid saturation conditions with XH2O [¼H2O/(H2OþCO2)] ranging between zero and unity. Redox conditions were fixed below the nickel–nickel oxide buffer (NNO). The results show that at 950 C and melt water contents (H2Omelt) close to saturation, trachytes are at liquidus conditions at all pressures. Clinopyroxene is the liquidus phase, being followed by iron-rich olivine and alkali feldspar. Comparison of experimental and natural phases (abundances and compositions) yields the following pre-eruptive conditions: P¼160 5 kbar, T¼925625 C, H2Omelt¼261wt %, and fO2 between NNO– 0 5 and NNO– 2. A decrease in temperature from 950 C to 750 C, as well as of H2Omelt, promotes a massive crystallization of alkali feldspar to over 80 wt %. Iron-bearing minerals show gradual iron enrichment when T and fO2 decrease, trending towards the compositions of the phenocrysts of natural pantellerites. Despite the metaluminous character of the bulk-rock compositions, residual glasses obtained after 80 wt % crystallization evolve toward comenditic compositions, owing to profuse alkali feldspar crystallization, which decreases the Al2O3 of the melt, leading to a consequent increase in the peralkalinity index [PI¼molar (Na2OþK2O)/Al2O3]. This is the first experimental demonstration that peralkaline felsic derivatives can be produced by low-pressure fractional crystallization of metaluminous mafic magmas. Our results show that the pantelleritic magmas of basalt–trachyte–rhyolite igneous suites require at least 95 wt % of parental basalt crystallization, consistent with trace element evidence. Redox conditions, through their effect on Fe–Ti oxide stabilities, control the final iron content of the evolving melt.

Description: Published