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  • Wiley-Blackwell
  • 2015-2019  (71)
  • 2010-2014  (141)
  • 1980-1984  (43,083)
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  • 1
    Publication Date: 2020-05-14
    Description: Mud diapirism has recently been recognized in several modern accretionary wedges. It provides an important means of dewatering accretionary wedges and should be regarded as an important process for producing the melanges found in both modern and ancient accretionary terranes. Mud diapirism affects a large area of the Barbados Ridge Accretionary Complex. The distribution of the mud diapirs appears to be primarily controlled by the presence of underconsolidated terrigenous submarine fan deposits that are being accreted to the complex. The frequency of diapir occurrence decreases northward as the fan becomes thinner. Mud diapirs are absent from the very eastern most part of the complex formed from sediments accreted at its toe, with the exception of a few mud volcanoes on the ocean floor in front of the complex. The initiation of diapirism appears to be spatially coincident with the onset of subcretion, or underplating, of sediment to the base of the complex at a ramp between two levels of decollement. It is proposed that the release of mud and pore water from the subcreted sediments is a direct or indirect cause of most of the mud diapirism in the accretionary complex. There is a range of diapiric form dependent on the viscosity of the mud, from mud volcanoes fed by low viscosity mud, to higher viscosity mud ridges. The diapirs in the eastern areas of the complex are generally mud volcanoes with narrow conduits feeding a surface mound. Mud ridges are prominent in the western parts of the complex. This is interpreted as reflecting a general westward decrease in the fluid content of the accretionary complex. Bottom-simulating seismic reflectors formed by gas hydrate are commonly developed in the areas of mud volcano occurrences. The presence of the hydrate indicates that large volumes of methane are being generated at depth in these regions. The generation of methane may be contributing to zones of overpressuring in the wedge. Methane may also be partly responsible for driving the diapiric material to the surface to form mud volcanoes. Ridges in the subducting oceanic crust beneath the accretionary complex locally enhance diapirism above their crests and southern flanks. Faults formed later in the development of the complex are more commonly associated with diapirism than those resulting from accretion at the toe of the wedge. These later faults play an important role in controlling the sites of individual mud volcanoes, chains of mud volcanoes, and mud ridges.
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  • 2
    Publication Date: 2021-02-08
    Description: To enable quality control of measurement procedures for determinations of Mg isotope amount ratios, expressed as δ26Mg and δ25Mg values, in Earth-surface studies, the δ26Mg and δ25Mg values of eight reference materials (RMs) were determined by inter-laboratory comparison between five laboratories and considering published data, if available. These matrix RMs, including river water SLRS-5, spring water NIST SRM 1640a, Dead Sea brine DSW-1, dolomites JDo-1 and CRM 512, limestone CRM 513, soil NIST SRM 2709a and vegetation NIST SRM 1515 apple leaves, are representative for a wide range of Earth-surface materials from low-temperature environments. The inter-laboratory variability, 2s (twice the standard deviation), of all eight RMs ranges from 0.05 to 0.17‰ in δ26Mg. Thus, it is suggested that all these materials are suitable for validation of δ26Mg and δ25Mg determinations of Earth-surface geochemical studies.
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  • 3
    Publication Date: 2018-03-28
    Description: The relationship between the biomass of reproductively mature individuals (spawning stock) and the resulting offspring added to the population (recruitment), the stock–recruitment relationship, is a fundamental and challenging problem in all of population biology. The steepness of this relationship is commonly defined as the fraction of recruitment from an unfished population obtained when the spawning stock biomass is 20% of its unfished level. Since its introduction about 20 years ago, steepness has become widely used in fishery management, where it is usually treated as a statistical quantity. Here, we investigate the reproductive ecology of steepness, using both unstructured and age‐structured models. We show that if one has sufficient information to construct a density‐independent population model (maximum per capita productivity and natural mortality for the unstructured case or maximum per capita productivity, natural mortality and schedules of size and maturity at age for the structured model) then one can construct a point estimate for steepness. Thus, steepness cannot be chosen arbitrarily. If one assumes that the survival of recruited individuals fluctuates within populations, it is possible, by considering the early life history, to construct a prior distribution for steepness from this same demographic information. We develop the ideas for both compensatory (Beverton–Holt) and over‐compensatory (Ricker) stock–recruitment relationships. We illustrate our ideas with an example concerning bluefin tuna (Thunnus thynnus/orientalis, Scombridae). We show that assuming that steepness is unity when recruitment is considered to be environmentally driven is not biologically consistent, is inconsistent with a precautionary approach, and leads to the wrong scientific inference (which also applies for assigning steepness any other single value).
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  • 4
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    Wiley-Blackwell
    In:  Journal of Zoology, 163 (3). pp. 277-284.
    Publication Date: 2020-07-17
    Description: The total length, the dorsal mantle length and the weight of the lens of Octopus vulgaris Lamarck have been related to the live body weight. The effect of fixation on the body weight and dorsal mantle length has been tested on six small octopuses.
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  • 5
    Publication Date: 2017-11-03
    Description: Two discontinuous tephra layers were discovered at Burney Spring Mountain, northern California. Stratigraphic relationships suggest that they are two distinct primary fall tephras. The geochemistries of these tephras from electron probe microanalysis were compared with those of known layers found in the area to test for potential correlations, using clustering analysis on geochemistry. In most cases, geochemical data from a tephra layer can be assigned to a single cluster, but in some cases the analyses are spread over several clusters. This spreading is a direct result of mixing and reworking of several tephra layers. The mixing, in turn, appears to be related to the influence of wind in a marshy environment.
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  • 6
    Publication Date: 2017-11-16
    Description: Four primary glass populations, well defined by their Sr, Ba and Y concentrations, occur in the Youngest Toba Tuff (YTT), which was deposited during a Supereruption of the Toba caldera complex in northern Sumatra 75 ka. Average concentrations of major and trace elements indicate a coherent, systematic Variation of glass composition across populations. No clear pattern in the areal distribution of these four glass groups can be discerned. The multiple glass populations of the YTT easily distinguish it from the single homogeneous glass population of the Middle Toba Tuff (~500 ka), as represented by its basal vitrophyre, and that of the Oldest Toba Tuff (~800 ka), as represented by ash Layer D at the Ocean Drilling Program site 758 in the Indian Ocean.
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  • 7
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    Wiley-Blackwell
    In:  Fish and Fisheries, 18 (4). pp. 656-667.
    Publication Date: 2019-02-01
    Description: Fisheries advice is based on demographic calculations, which assume that density-dependent processes regulating recruitment occur only in early life. This assumption is challenged by laboratory and lake studies and some recent indications from marine systems that demonstrate density-dependent regulation late in life. By accounting for spatial dynamics of a population, something that has previously been ignored in models of fish, we show that density-dependent regulation is determined by the size of the habitat: in small habitats, for example small lakes, regulation occurs late in life, while it can occur early in large habitats. When regulation happens late in life, fisheries yield is maximized by exploitation of mainly juvenile fish, while exploiting mature fish maximizes yield if regulation happens early. We review and interpret observations of density dependence in the light of the theory. Our results challenge the current assumption that density dependence always occurs early in life and highlights the need for an increased understanding of density-dependent processes. This can only come about by a change of focus from determining stock-recruitment relationships towards understanding when and how density-dependent regulation occurs in nature.
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  • 8
    Publication Date: 2018-03-22
    Description: The relationship between the biomass of reproductively mature individuals (spawning stock) and the resulting offspring added to the population (recruitment), the stock–recruitment relationship, is a fundamental and challenging problem in all of population biology. The steepness of this relationship is commonly defined as the fraction of recruitment from an unfished population obtained when the spawning stock biomass is 20% of its unfished level. Since its introduction about 20 years ago, steepness has become widely used in fishery management, where it is usually treated as a statistical quantity. Here, we investigate the reproductive ecology of steepness, using both unstructured and age‐structured models. We show that if one has sufficient information to construct a density‐independent population model (maximum per capita productivity and natural mortality for the unstructured case or maximum per capita productivity, natural mortality and schedules of size and maturity at age for the structured model) then one can construct a point estimate for steepness. Thus, steepness cannot be chosen arbitrarily. If one assumes that the survival of recruited individuals fluctuates within populations, it is possible, by considering the early life history, to construct a prior distribution for steepness from this same demographic information. We develop the ideas for both compensatory (Beverton–Holt) and over‐compensatory (Ricker) stock–recruitment relationships. We illustrate our ideas with an example concerning bluefin tuna (Thunnus thynnus/orientalis, Scombridae). We show that assuming that steepness is unity when recruitment is considered to be environmentally driven is not biologically consistent, is inconsistent with a precautionary approach, and leads to the wrong scientific inference (which also applies for assigning steepness any other single value).
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  • 9
    Publication Date: 2018-03-21
    Description: Stock‐based and ecosystem‐based indicators are used to provide a new diagnosis of the fishing impact and environmental status of European seas. In the seven European marine ecosystems covering the Baltic and the North‐east Atlantic, (i) trends in landings since 1950 were examined; (ii) syntheses of the status and trends in fish stocks were consolidated at the ecosystem level; and (iii) trends in ecosystem indicators based on landings and surveys were analysed. We show that yields began to decrease everywhere (except in the Baltic) from the mid‐1970s, as a result of the over‐exploitation of some major stocks. Fishermen adapted by increasing fishing effort and exploiting a wider part of the ecosystems. This was insufficient to compensate for the decrease in abundance of many stocks, and total landings have halved over the last 30 years. The highest fishing impact took place in the late 1990s, with a clear decrease in stock‐based and ecosystem indicators. In particular, trophic‐based indicators exhibited a continuous decreasing trend in almost all ecosystems. Over the past decade, a decrease in fishing pressure has been observed, the mean fishing mortality rate of assessed stocks being almost halved in all the considered ecosystems, but no clear recovery in the biomass and ecosystem indicators is yet apparent. In addition, the mean recruitment index was shown to decrease by around 50% in all ecosystems (except the Baltic). We conclude that building this kind of diagnosis is a key step on the path to implementing an ecosystem approach to fisheries management.
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  • 10
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    Wiley-Blackwell
    In:  The Journal of Comparative Neurology, 520 (1). pp. 142-153.
    Publication Date: 2018-04-11
    Description: Teleost fish grow continuously throughout their lifespan, and this growth includes visual system components: eyes, optic nerves, and brain. As fish grow, the optic nerve lengthens and neural signals must travel increasing distances from the eye to the optic tectum along thousands of retinal ganglion cell (RGC) axons. Larger fish have better vision that enhances their ability to capture prey, but they are faced with the potential computational problem of changes in the relative timing of visual information arriving at the brain. Optic nerve conduction delays depend on RGC axon conduction velocities, and velocity is primarily determined by axon diameters. If axon diameters do not increase in proportion to body length, then absolute and relative conduction delays will vary with fish size. We have measured optic nerve lengths and axon diameter distributions in different sized zebrafish (Danio rerio) and goldfish (Carassius auratus) and find that, as both species of fish grow, axon diameters increase to reduce average conduction delays by about half and to keep relative delays constant. This invariance of relative conduction delays simplifies computational problems faced by the optic tectum.
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  • 11
    Publication Date: 2019-02-01
    Description: The spatial structure of species is important for their dynamics and evolution, but also for management and conservation. There are numerous ways of inferring spatial structures, and information from multiple methods is becoming more common to examine how different processes shape the spatial structures of species to improve fish management. Here, we investigate the spatial structure of a suite of Baltic Sea fish species based on the following: (i) spatial (presumably neutral) genetic differentiation, reviewed from the literature, and (ii) spatial synchrony in abundance changes from time series of fishery‐independent surveys, which we currently find to be underused given the amount of data available. For each of these two methods, species were classified as having a distinct, continuous or no/weak spatial structure. In addition, based on each source of information, we estimated the spatial scale of management units for species. The results show that only among species confined to the coastal zone the two sources of information yielded a congruence of the spatial structure (displaying a continuous spatial structure). In contrast, offshore species show weak spatial genetic structure but stronger spatial structure of synchrony in abundance. Based on this, we suggest that population genetic structure and synchrony in abundance should be used as complementary information as they reflect different spatial processes and suggest that management actions should differ with respect to scale depending on the management targets applied. We propose similar analysis should be applied to areas outside the Baltic Sea, and other stock identification methods, to improve management of fish resources.
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  • 12
    Publication Date: 2018-06-14
    Description: As sessile filter feeders, sponges rely on a highly efficient fluid transport system. Their physiology depends on efficient water exchange, which is performed by the aquiferous system. This prominent poriferan anatomical character represents a dense network of incurrent and excurrent canals on which we lack detailed 3D models. To overcome this, we investigated the complex leucon‐type architecture in the demosponge Tethya wilhelma using corrosion casting, microtomography, and 3D reconstructions. Our integrative qualitative and quantitative approach allowed us to create, for the first time, high‐resolution 3D representations of entire canal systems which were used for detailed geometric and morphometric measurements. Canal diameters lack distinct size classes, and bifurcations are non‐uniformly ramified. A relatively high number of bifurcations show previously unknown and atypical cross‐sectional area ratios. Scaling properties and topological patterns of the canals indicate a more complex overall architecture than previously assumed. As a consequence, it might be more convenient to group canals into functional units rather than hierarchical clusters. Our data qualify the leucon canal system architecture of T. wilhelma as a highly efficient fluid transport system adapted toward minimal flow resistance. Our results and approach are relevant for a better understanding of sponge biology and cultivation techniques.
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  • 13
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    Wiley-Blackwell
    In:  Journal of Metamorphic Geology .
    Publication Date: 2020-07-23
    Description: We report U–Pb zircon ages of c. 700–550 Ma, 262–220 Ma, 47–38 Ma and 15–14 Ma from amphibolites on Naxos Island in the Aegean extensional province of Greece. The zircon has complex internal structures. Based on cathodoluminescence response, zoning and crosscutting relationships a minimum of four zircon growth stages are identified: inherited core, magmatic core, inner metamorphic (?) rim and an outer metamorphic rim. Trace element compositions of the amphibolites suggest igneous differentiation and crustal assimilation. Zircon solubility as a function of saturation temperatures, Zr content and melt composition indicates that the zircon did not originally crystallize in the mafic bodies but was inherited from felsic precursor rocks, and subsequently assimilated into the mafic intrusives during emplacement. Zircon inheritance is corroborated by the complex, xenocrystic nature of the zircon in one sample. Ages of c. 700–550 Ma and 262–220 Ma are assigned to inherited zircon. Available geochemical data suggest that the 15–14 Ma metamorphic rims grew in situ in the amphibolites, corresponding to a high-grade metamorphic event at this time. However, the geochemical data cannot conclusively establish if the c. 40 Ma zircon rims also grew in situ, or whether they were inherited along with the xenocrystic cores. Two scenarios for emplacement of the mafic intrusives are discussed: (i) Intrusion during late-Triassic to Jurassic ocean basin development of the Aegean realm, in which case the 40 Ma zircon rims would have grown in situ, and (ii) emplacement in the Miocene as a result mafic underplating during large-scale extension. In this case, only the 15–14 Ma metamorphic outer rims would have formed in situ in the amphibolitic host rocks.
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  • 14
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    Wiley-Blackwell
    In:  Journal of Quaternary Science, 27 (2). pp. 141-149.
    Publication Date: 2017-05-10
    Description: The tephrostratigraphy of lake sediments in the Endinger Bruch provides the first robust age model for the Lateglacial palynological records of Vorpommern (north-east Germany). Cryptotephra investigations revealed six tephra layers within sediments spanning from Open vegetation phase I (∼Bølling, ∼15 ka) to the Early Holocene Betula/Pinus forest phase (∼Pre-boreal, ∼10.5 ka). Four of these layers have been correlated with previously described tephra layers found in sites across Europe. The Laacher See Tephra (Eifel Volcanic Field) is present in very high concentrations within sediments of the Lateglacial Betula (/Pinus) forest phase (∼Allerød). The Vedde Ash (Iceland) lies midway through Open vegetation phase III (∼Younger Dryas). The Hässeldalen and the Askja tephras (Iceland) lie in the Early Holocene Betula/Pinus forest phase (∼Preboreal). These tephra layers have independently derived age estimates, which have been imported into the Endinger Bruch record. Furthermore, the layers facilitate direct correlation of the regional vegetation record with other palaeoenvironmental archives, which contain one or more of the same tephra layers, from Greenland to Southern Europe. In doing this, localized variations are confirmed in some aspects of the pollen stratigraphy; however, transitions between the main vegetation phases appear to occur synchronously (within centennial errors) with the equivalent environmental transitions observed in sites across the European continent.
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  • 15
    Publication Date: 2017-12-19
    Description: Here we present a tephrostratigraphic record (core Co1202) recovered from the northeastern part of Lake Ohrid (Republics of Macedonia and Albania) reaching back to Marine Isotope Stage (MIS) 6. Overall ten horizons (OT0702-1 to OT0702-10) containing volcanic tephra have been recognised throughout the 14.94m long sediment succession. Four tephra layers were visible at macroscopic inspection (OT0702-4, OT0702-6, OT0702-8 and OT0702-9), while the remaining six are cryptotephras (OT0702-1, OT0702-2, OT0702-3, OT0702-5, OT0702-7 and OT0702-10) identified from peaks in K, Zr and Sr intensities, magnetic susceptibility measurements, and washing and sieving of the sediments. Glass shards of tephra layers and cryptotephras were analysed with respect to their major element composition, and correlated to explosive eruptions of Italian volcanoes. The stratigraphy and the major element composition of tephra layers and cryptotephras allowed the correlation of OT0702-1 to AD 472 or AD 512 eruptions of Somma-Vesuvius, OT0702-2 to the FL eruption of Mount Etna, OT0702-3 to the Mercato from Somma-Vesuvius, OT0702-4 to SMP1-e/Y-3 eruption from the Campi Flegrei caldera, OT0702-5 to the Codola eruption (Somma-Vesuvius or Campi Flegrei), OT0702-6 to the Campanian Ignimbrite/Y-5 from the Campi Flegrei caldera, OT0702-7 to the Green Tuff/Y-6 eruption from Pantelleria Island, OT0702-8 to the X-5 eruption probably originating from the Campi Flegrei caldera, OT0702-9 to the X-6 eruption of generic Campanian origin, and OT0702-10 to the P-11 eruption from Pantelleria Island. The fairly well-known ages of these tephra layers and parent eruptions provide new data on the dispersal and deposition of these tephras and, furthermore, allow the establishment of a chronological framework for core Co1202 for a first interpretation of major sedimentological changes.
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  • 16
    Publication Date: 2021-02-08
    Description: Populations of fishes provide valuable services for billions of people, but face diverse and interacting threats that jeopardize their sustainability. Human population growth and intensifying resource use for food, water, energy and goods are compromising fish populations through a variety of mechanisms, including overfishing, habitat degradation and declines in water quality. The important challenges raised by these issues have been recognized and have led to considerable advances over past decades in managing and mitigating threats to fishes worldwide. In this review, we identify the major threats faced by fish populations alongside recent advances that are helping to address these issues. There are very significant efforts worldwide directed towards ensuring a sustainable future for the world's fishes and fisheries and those who rely on them. Although considerable challenges remain, by drawing attention to successful mitigation of threats to fish and fisheries we hope to provide the encouragement and direction that will allow these challenges to be overcome in the future.
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  • 17
    Publication Date: 2020-07-17
    Description: Hundreds of Sepia officinalis were hatched and cultured through the life cycle in each of 13 populations. Two genetic lines were maintained: one for an unprecedented seven generations and another presently in its fourth. All generations—save one—produced animals in excess of 1·0 kg body weight. Seven of eight generations with adequate data records had mean weights of 1–2 kg, and the largest cuttlefish reared were a male 2·6 kg and a female 2·9 kg. Fecundity levels were high, but there was a trend towards decreased fertility in later generations, with fertilization rates dropping below 10%. In the 7th generation, most mature animals failed to engage in agonistic courtship and mating behaviour. Almost no normal eggs were laid and none was fertile, thus ending the lineage. Most culture took place at 20–24°C and temperature generally explained variations in life span duration: being of shorter length at higher temperatures. Life spans were consistently longer at 20°C and sizes were greater than predicted from previously published literature. In both lines there was a trend towards larger individuals and longer life spans in subsequent generations. Survival of hatchlings typically exceeded 90% for two months post-hatching, and survival averaged 50% or higher to sexual maturity when corrected for animals removed from the populations for experimental use.
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  • 18
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    Wiley-Blackwell
    In:  Journal of the World Aquaculture Society, 48 (2). pp. 353-359.
    Publication Date: 2020-07-16
    Description: Japanese flounder, Paralichthys olivaceus, is an economically important marine fish species in Asia. A suite of 18 microsatellite markers chosen from published genetic linkage maps was used to carry out parentage assignments of 188 hatchery-reared juveniles from a small number of breeders. The probabilities of exclusion for the 18 microsatellite markers were 0.604–0.913, and the effectiveness of combined probability of exclusion reached 100% when using the eight microsatellite markers with higher Excl 1 probabilities. The cultured and wild stocks (WSs) were differentiated in a release-recapture population based on these markers. Of the 321 recaptured offspring, 28.34% were assigned to their parental pairs in our broodstock, whereas the remaining offspring could not be traced back to a possible sire or dam. Significant reduction in genetic diversity of the cultured stock (CS) had not been found compared with that of the WS. The results suggest that CSs released into the wild will not adversely affect the genetic structure of natural populations. Our results demonstrate that these markers provide an efficient tool for parentage assignments and genetic analysis of Japanese flounder.
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  • 19
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    Wiley-Blackwell
    In:  Fish and Fisheries, 18 (2). pp. 199-211.
    Publication Date: 2019-02-01
    Description: Managing fisheries presents trade-offs between objectives, for example yields, profits, minimizing ecosystem impact, that have to be weighed against one another. These trade-offs are compounded by interacting species and fisheries at the ecosystem level. Weighing objectives becomes increasingly challenging when managers have to consider opposing objectives from different stakeholders. An alternative to weighing incomparable and conflicting objectives is to focus on win–wins until Pareto efficiency is achieved: a state from which it is impossible to improve with respect to any objective without regressing at least one other. We investigate the ecosystem-level efficiency of fisheries in five large marine ecosystems (LMEs) with respect to yield and an aggregate measure of ecosystem impact using a novel calibration of size-based ecosystem models. We estimate that fishing patterns in three LMEs (North Sea, Barents Sea and Benguela Current) are nearly efficient with respect to long-term yield and ecosystem impact and that efficiency has improved over the last 30 years. In two LMEs (Baltic Sea and North East US Continental Shelf), fishing is inefficient and win–wins remain available. We additionally examine the efficiency of North Sea and Baltic Sea fisheries with respect to economic rent and ecosystem impact, finding both to be inefficient but steadily improving. Our results suggest the following: (i) a broad and encouraging trend towards ecosystem-level efficiency of fisheries; (ii) that ecosystem-scale win–wins, especially with respect to conservation and profits, may still be common; and (iii) single-species assessment approaches may overestimate the availability of win–wins by failing to account for trade-offs across interacting species.
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  • 20
    Publication Date: 2021-02-08
    Description: Mass fractions of Sn and In were determined in sixteen geological reference materials including basaltic/mafic (BCR‐2, BE‐N, BHVO‐1, BHVO‐2, BIR‐1, OKUM, W‐2, WS‐E), ultramafic (DTS‐2b, MUH‐1, PCC‐1, UB‐N) and felsic/sedimentary reference materials (AGV‐2, JA‐1, SdAR‐M2, SdAR‐H1). Extensive digestion and ion exchange separation tests were carried out in order to provide high yields (〉 90% for Sn, 〉 85% for In), low total procedural blanks (~ 1 ng for Sn, 〈 3 pg for In) and low analytical uncertainties for the elements of interest in a variety of silicate sample matrices. Replicate analyses (n = 2–13) of Sn‐In mass fractions give a combined measurement uncertainty of 2u that are generally 〈 3% and in agreement with literature data, where available. We present the first high precision In data for reference materials OKUM (32.1 ± 1.5 ng g−1), DTS‐2b (2.03 ± 0.25 ng g−1), MUH‐1 (6.44 ± 0.30 ng g−1), and PCC‐1 (3.55 ± 0.35 ng g−1) as well as the first Sn data for MUH‐1 (0.057 ± 0.010 μg g−1) and DTS‐2b (0.623 ± 0.018 μg g−1).
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  • 21
    Publication Date: 2019-09-24
    Description: Conceptual models predict a unimodal effect of consumer abundance on prey diversity with the highest diversity at intermediate consumer abundance (intermediate disturbance hypothesis). Consumer selectivity and prey productivity are assumed to be further important determinants. Preferential grazing on dominant prey species favoured by high nutrient supply is supposed to increase prey diversity, whereas the effect of consumers on prey diversity may be negative under low nutrient conditions (grazer reversal hypothesis). We tested the effect of four common consumers the isopod Idotea baltica, the amphipod Gammarus oceanicus, and the gastropods Littorina littorea and Rissoa membranacea on diversity and composition of epiphytes growing on eelgrass Zostera marina. Consumer density was manipulated (four levels: grazer free control, low, medium, high) based on abundances observed in eelgrass systems. Additionally, we manipulated nutrient supply (three levels) and the presence of Idotea in a factorial experiment. The impact of consumer abundance on epiphyte diversity varied depending on consumer identity and epiphyte evenness was affected rather than species number in this short-term experiment. Idotea reduced epiphyte diversity (Shannon-Wiener index H') and Gammarus increased epiphyte diversity. Littorina had no effect at low and medium abundance, but a negative effect in the high density treatment. Only Rissoa supported the conceptual models as it caused the proposed unimodal pattern in epiphyte diversity. The varying species-specific selectivity of the studied consumers is likely to explain their diverse impact on epiphyte diversity. Nutrients enhanced epiphyte diversity at medium enrichment, whereas higher nutrient supply reduced epiphyte diversity. The effect of Idotea changed from negative at low nutrient concentration to positive at higher nutrient supply, supporting the grazer reversal hypothesis. This study implies that consumer species identity and nutrient concentrations are important in controlling prey diversity and composition. Different consumer selectivity and changes in selectivity with growing consumer abundance and nutrient concentration are the causal factors for this effect.
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  • 22
    Publication Date: 2020-10-26
    Description: Ecological studies based on time-series often investigate community changes centered on species abundance or biomass but rarely expose the consequential functional aspects underlying such changes. Functional diversity measures have proven to be more accurate predictors for ecosystem functioning than traditional taxonomic approaches and hence gained much attention. There are only limited studies available that analyse the functional implications behind decadal changes of entire communities. We studied zoobenthic communities of two habitats, sheltered and exposed, of a coastal system subject to contrasting changes in community composition over the past four decades. Besides eutrophication and climate-related impacts, the system has been invaded by a non-native polycheate Marenzelleria spp., adding altered functional properties to the communities. The functional dispersion (FDis) metric was used as a measure for comparing the functional diversity of the contrasting habitats, with special focus on the role of Marenzelleria for the entire communities. We highlight changes in the functional identity of the communities, expressed as community-weighted means of trait expression (CWM), using multivariate techniques, and investigate the relationship between taxonomic and functional changes. Despite contrasting community developments in the two habitats, with characteristics traditionally suggesting different environmental quality, we found that the FDis in both habitats remained similar and increased with the introduction of Marenzelleria. Although showing maintained functional diversity across time and space, the functional identity (CWM) of communities changed irrespective of taxonomical differences. Examples include inter alia alterations in palatability proxies, feeding position and sediment transportation types, indicating changed functionality of zoobenthos in coastal systems. We show, when focussing on qualitative functional changes of communities, it is important to evaluate the underlying functional identity, and not only rely on measures of the diversity of functions per se, as the quality indication of expressed functional traits can be concealed when using multi-functionality approaches.
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  • 23
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    Wiley-Blackwell
    In:  Functional Ecology, 27 (6). pp. 1415-1423.
    Publication Date: 2020-07-31
    Description: Climate change will increase both average temperatures and extreme summer temperatures. Analyses of the fitness consequences of climate change have generally omitted negative fitness and population declines associated with heat stress. Here, we examine how seasonal and interannual temperature variability will impact fitness shifts of ectotherms from the past (1961–1990) to future (2071–2100), by modelling thermal performance curves (TPCs) for insect species across latitudes. In temperate regions, climate change increased the length of the growing season (increasing fitness) and increased the frequency of heat stress (decreasing fitness). Consequently, species at mid-latitudes (20–40°) showed pronounced but heterogeneous responses to climate change. Fitness decreases for these species were accompanied by greater interannual variation in fitness. An alternative TPC model and a larger data set gave qualitatively similar results. How close maximum summer temperatures are to the critical thermal maximum of a species – the thermal buffer – is a good predictor of the change in mean fitness expected under climate change. Thermal buffers will decrease to near or below zero by 2100 for many tropical and mid-latitude species. Our forecasts suggest that mid-latitude species will be particularly susceptible to heat stress associated with climate change due to temperature variation
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  • 24
    Publication Date: 2015-10-06
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  • 25
    Publication Date: 2020-07-30
    Description: The advent of genomic-, transcriptomic- and proteomic-based approaches has revolutionized our ability to describe marine microbial communities, including biogeography, metabolic potential and diversity, mechanisms of adaptation, and phylogeny and evolutionary history. New interdisciplinary approaches are needed to move from this descriptive level to improved quantitative, process-level understanding of the roles of marine microbes in biogeochemical cycles and of the impact of environmental change on the marine microbial ecosystem. Linking studies at levels from the genome to the organism, to ecological strategies and organism and ecosystem response, requires new modelling approaches. Key to this will be a fundamental shift in modelling scale that represents micro-organisms from the level of their macromolecular components. This will enable contact with omics data sets and allow acclimation and adaptive response at the phenotype level (i.e. traits) to be simulated as a combination of fitness maximization and evolutionary constraints. This way forward will build on ecological approaches that identify key organism traits and systems biology approaches that integrate traditional physiological measurements with new insights from omics. It will rely on developing an improved understanding of ecophysiology to understand quantitatively environmental controls on microbial growth strategies. It will also incorporate results from experimental evolution studies in the representation of adaptation. The resulting ecosystem-level models can then evaluate our level of understanding of controls on ecosystem structure and function, highlight major gaps in understanding and help prioritize areas for future research programs. Ultimately, this grand synthesis should improve predictive capability of the ecosystem response to multiple environmental drivers.
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  • 26
    Publication Date: 2020-07-27
    Description: Abstract Aims Bacterially induced calcium carbonate precipitation from various isolates was investigated aiming at developing an environmentally friendly technique for ornamental stone protection and restoration. Methods and Results Microorganisms isolated from stone samples and identified using 16S rDNA and biochemical tests promoted calcium carbonate precipitation in solid and novel liquid growth media. Biomineral morphology was studied on marble samples with scanning electron microscopy. Most isolates demonstrated specimen weight increase, covering partially or even completely the marble surfaces mainly with vaterite. The conditions under which vaterite precipitated and its stability throughout the experimental runs are presented. Conclusions A growth medium that facilitated bacterial growth of different species and promoted biomineralization was formulated. Most isolates induced biomineralization of CaCO3. Microorganisms may actually be a milestone in the investigation of vaterite formation facilitating our understanding of geomicrobiological interactions. Pseudomonas, Pantoea and Cupriavidus strains could be candidates for bio‐consolidation of ornamental stone protection. Significance and Impact of the Study Characterization of biomineralization capacity of different bacterial species improves understanding of the bacterially induced mineralization processes and enriches the list of candidates for bio‐restoration applications. Knowledge of biomineral morphology assists in differentiating mineral from biologically induced precipitates.
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  • 27
    Publication Date: 2015-12-16
    Description: The round goby Neogobius melanostomus is one of the most wide-ranging invasive fish on earth, with substantial introduced populations within the Laurentian Great Lakes watershed, the Baltic Sea and several major European rivers. Rapid expansion and deleterious ecosystem effects have motivated extensive research on this species; here this research is synthesized. Maps of the global distribution are provided and the invasion history of N. melanostomus, which spread more rapidly at first in North America, but has undergone substantial expansion over the past decade in the Baltic Sea, is summarized. Meta-analyses comparing their size at age, diet, competitors and predators in North American and European ecosystems are provided. Size at age is region specific, with saline habitats typically supporting larger and faster growing individuals than fresh water. Neogobius melanostomus prey differs substantially between regions, demonstrating a capacity to adapt to locally abundant food sources. Neogobius melanostomus comprise at least 50% of the diet of eight taxa in at least one site or life stage; in total, 16 predator taxa are documented from the Laurentian Great Lakes v. five from Eurasia. Invasive N. melanostomus are the only common forage fish to heavily exploit mussels in the Laurentian Great Lakes and the Baltic Sea, facilitating the transfer of energy from mussels to higher trophic levels in both systems. Neogobius melanostomus morphology, life history, reproduction, habitat preferences, environmental tolerances, parasites, environmental effects, sampling strategies and management are also discussed. Neogobius melanostomus inhabit a wide range of temperate freshwater and brackish-water ecosystems and will probably continue to spread via ballast water, accidental bait release and natural dispersal worldwide. Climate change will probably enhance N. melanostomus expansion by elevating water temperatures closer to its energetic optimum of 26° C. Future research needs are presented; most pressing are evaluating the economic effects of N. melanostomus invasion, determining long-term population level effects of egg predation on game-fish recruitment and comparing several variables (density, ecological effects morphology and life history) among invaded ecosystems. This review provides a central reference as researchers continue studying N. melanostomus, often as examples for advancing basic ecology and invasion biology.
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  • 28
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    Wiley-Blackwell
    In:  Geografiska Annaler: Series A, Physical Geography, 92 (2). pp. 155-176.
    Publication Date: 2020-07-31
    Description: Fluvial processes dominate sediment flux from most cold environments and as such are particularly sensitive to environmental change. However, these systems demonstrate high variability in flow and sediment transfer rates in both the short and long-term which presents specific problems for establishing integrated sediment flux studies. The objective of this paper is to briefly review the nature of fluvial and floodplain sediment sources in cold environments and to make recommendations on the measurement of fluvial sediment fluxes from these sources to sinks. The paper outlines a framework for examining fluvial sediment fluxes in cold environments including: sources of sediment in glacial and periglacial environments; techniques for measuring fluvial sediment transfers; and methods for measuring contemporary deposition in lacustrine sediment sinks. Within this framework, we stress that it is particularly important to provide consistency in methods for monitoring sediment flux and to adopt appropriate sampling frequencies. We recommend that the most appropriate methods for establishing integrated sediment flux studies in these cold environments are: repeat surveys and terrestrial laser scanning of valley and slope sediment stores on a monthly – daily frequency; weekly-daily sediment budgeting of bedload transfer using rapid resurvey methods; hourly or better time series of suspended and solute transport using data logger acquisition systems; and monitoring of lacustrine sedimentation using sediment accumulation sensors and/or weekly-daily estimates from passive sediment traps. Application of the proposed integrated framework will improve our understanding of sediment flux in cold environments and allow us to better assess the sensitivity of cold environments to environmental change within the context of contemporary and past sediment flux.
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  • 29
    Publication Date: 2020-07-16
    Description: Mussel aquaculture is a growing industry in Scotland, dominated by the production of Mytilus edulis. However, Mytilus trossulus, Mytilus galloprovincialis, and their hybrids with M. edulis have recently been detected in Scotland. At some farms, M. trossulus have been associated with significant losses in production because of presenting low meat yields and fragile shells. In the present study, M. edulis, M. trossulus, and their hybrids were examined from three cultivation areas in order to investigate shell and meat characteristics and advise on future management of mixed-species areas in Scotland. Results suggest that M. edulis is likely to consistently outperform M. trossulus and hybrids in mixed-species areas, but that M. trossulus meat yields from different areas can vary considerably. The ability to classify mussels into two (M. edulis and non-edulis) groups suggests that separation of M. trossulus genotypes could potentially be achieved by grading the harvested mussels. In the most affected areas, however, the fallowing of cultivation sites and importation of unispecific M. edulis spat appear as an alternative. Management of this problem in Scotland is likely to involve the implementation of area-specific measures, and the establishment of clear guidance on good practice aiming at preventing further distribution of M. trossulus.
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  • 30
    Publication Date: 2019-02-01
    Description: Despite considerable progress in the production of alternative diets, small concentrations of antinutrients remain common in aquaculture nutrition, resulting in a perpetual limitation with regard to the inclusion of plant ingredients in aquafeeds. These compounds are known to impair the general performance of fish when fed for a prolonged period of time, potentially affecting the animal's susceptibility to stress, too. Therefore, a 12-week feeding trial was conducted to examine the chronic effects of purified rapeseed protein concentrate (RPC), containing low concentrations of glucosinolates and phytic acid, on the relative expression of multiple target genes in the liver of juvenile turbot (Psetta maxima, L.). Our results revealed divergent patterns of gene expression, suggesting different coping strategies dependent on the grade of RPC substitution. Data implies increased metabolic rate of turbot fed a 33% RPC-substituted diet due to an upregulation of cytochrome c oxidase mRNA, accompanied by minor adjustments in metabolic pathways. While no signs of reduced welfare were found, data adumbrate a beneficial hormetic reaction. In the highest treatment level (66% RPC), diminished fish condition and reduced growth performance coincided with a downregulation of insulin-like growth factor I, further indicating a potential impaired resistance to stress. An additional downregulation of transferrin hints towards an increased liability to bacterial infections.
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  • 31
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    Wiley-Blackwell
    In:  (In Press / Accepted) Zoological Journal of the Linnean Society .
    Publication Date: 2020-04-21
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  • 32
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    Wiley-Blackwell
    In:  Journal of Quaternary Science, 29 (7). pp. 627-640.
    Publication Date: 2015-09-01
    Description: Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is used widely to analyse single volcanic glass shards from Quaternary tephra deposits for stratigraphic correlation. As yet, no generally accepted protocol for these analyses exists and published methods report significant differences in crater size and calibration strategies. Using Ca as the ‘internal standard’ (CaI.S.), and not SiI.S., for the analysis of rhyolitic glass can cause significant problems, because of ablation of (i) Ca-rich phenocrysts, notably ‘ubiquitous’ plagioclase, but also calcic-amphibole, apatite and allanite or (ii) mounting epoxy resin which can contribute to the Ca internal standard signal. Using CaI.S. can cause underreporting of many elements which concentrate in Ca-rich phenocrysts, making their ablation difficult to recognize, but when using SiI.S., no such underreporting occurs. Additionally, larger ablation craters (50mm diameter) potentially incorporate even small volumes of phenocryst material, whereas smaller craters (〈20mm diameter) more frequently miss phenocrysts. Thus, for the LA-ICP-MS analysis of rhyolitic glass shards, smaller ablation craters should be employed and calibrated using SiI.S., allowing recognition and removal of analyses incorporating Ca-rich phenocrysts and avoiding issues related to the ablation of the mounting resin.
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  • 33
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    Wiley-Blackwell
    In:  Geology Today, 31 (4). pp. 153-159.
    Publication Date: 2020-07-30
    Description: The geological development of the Fogo island volcano commenced in the early Quaternary, and much later during the Last Glacial stage this involved a mega-scale lateral collapse of the former edifice. This later event created a large caldera-like landform open to the east, the floor of which is known as the Chã, and subsequently within this a strato-volcanic cone has grown. The last phase of volcanic activity started in late 2014 and persisted for 77 days. It had a devastating impact on the lives of the 1000 plus people who were living within the ‘caldera’, since two large villages and a smaller one were each totally destroyed in a matter of days by the advancing lavas. In addition, large areas of cultivated land, upon which the inhabitants were dependent for their livelihood, were enveloped by lava. The eruption proved to be of a greater magnitude than the immediately preceding one of 1995, when a mass evacuation was necessary but as only a few buildings were affected, resettlement followed. Unfortunately the much greater devastation to the human environment makes it doubtful whether any significant resettlement will be possible after the 2014–2015 event.
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  • 34
    Publication Date: 2019-09-23
    Description: We analyse the fluid flow regime within sediments on the Eastern levee of the modern Mississippi Canyon using 3D seismic data and downhole logging data acquired at Sites U1322 and U1324 during the 2005 Integrated Ocean Drilling Program (IODP) Expedition 308 in the Gulf of Mexico. Sulphate and methane concentrations in pore water show that sulphate–methane transition zone, at 74 and 94 m below seafloor, are amongst the deepest ever found in a sedimentary basin. This is in part due to a basinward fluid flow in a buried turbiditic channel (Blue Unit, 1000 mbsf), which separates sedimentary compartments located below and above this unit, preventing normal upward methane flux to the seafloor. Overpressure in the lower compartment leads to episodic and focused fluid migration through deep conduits that bypass the upper compartment, forming mud volcanoes at the seabed. This may also favour seawater circulation and we interpret the deep sulphate–methane transition zones as a result of high downward sulphate fluxes coming from seawater that are about 5–10 times above those measured in other basins. The results show that geochemical reactions within shallow sediments are dominated by seawater downwelling in the Mars-Ursa basin, compared to other basins in which the upward fluid flux is controlling methane-related reactions. This has implications for the occurrence of gas hydrates in the subsurface and is evidence of the active connection between buried sediments and the water column.
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  • 35
    Publication Date: 2017-07-21
    Description: This paper contains the results of an extensive isotopic study of United States Geological Survey GSD-1G and MPI-DING reference glasses. Thirteen different laboratories were involved using high-precision bulk (TIMS, MC-ICP-MS) and microanalytical (LA-MC-ICP-MS, LA-ICP-MS) techniques. Detailed studies were performed to demonstrate the large-scale and small-scale homogeneity of the reference glasses. Together with previously published isotopic data from ten other laboratories, preliminary reference and information values as well as their uncertainties at the 95% confidence level were determined for H, O, Li, B, Si, Ca, Sr, Nd, Hf, Pb, Th and U isotopes using the recommendations of the International Association of Geoanalysts for certification of reference materials. Our results indicate that GSD-1G and the MPI-DING glasses are suitable reference materials for microanalytical and bulk analytical purposes.
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  • 36
    Publication Date: 2017-09-14
    Description: Transverse sections of otoliths from Atlantic cod Gadus morhua from the Baltic Sea revealed narrow growth increments. The widths of these increments corresponded to daily increments from fish with known otolith growth rates and were therefore assumed to be daily increments. They exhibited a distinct pattern with increasing distance from the primary primordium. A series of zones with clearly distinguishable increments, first with increasing then with decreasing widths in a dome-shaped pattern, were separated by zones where no regular increment structure was visible. Increment width seemed to be tightly coupled to the annual cycle in environmental temperature at a depth of 30–60 m, where G. morhua predominantly reside. Between 135 and 200 increments occurred within the different zones, with a non-significant trend towards lower increment numbers and widths with distance from the primary primordium of the otolith. Increment formation apparently ceased at temperatures 〈 5–6° C, but growth during the cold months corresponded closely with estimated growth rates. The increment patterns seemed to reflect annual cycles in environmental temperature, and the count of the increment cycles may thus be a promising tool for the determination of the true age of Baltic G. morhua.
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  • 37
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    Wiley-Blackwell
    In:  In: Life in the World's Oceans: Diversity, Distribution, and Abundance. Wiley-Blackwell, Chichester, UK, pp. 103-121. ISBN 978-1-4051-9297-2
    Publication Date: 2016-10-17
    Type: Book chapter , NonPeerReviewed
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  • 38
    Publication Date: 2017-09-14
    Description: The relative roles of temperature and food availability on the seasonal and daily growth of whitefish Coregonus lavaretus larvae were investigated in the oligotrophic peri-alpine Lake Annecy, France. During the spring from 2004 to 2007, surface water temperature and density of potential zooplankton prey were monitored, and 2688 larvae were caught and measured. In addition, the daily growth of 130 larvae was estimated retrospectively by investigating the microstructure of their otoliths. Temperature played the predominant role in controlling both seasonal and daily growth of early larvae. In contrast, the abundance of Mesocyclops leuckarti and larval density was only slightly correlated to larval growth, suggesting no food limitation nor strong interindividual competition over the study period. Overall, these findings run counter to concerns about potential food limitation, but sound a warning about the potential impact of climate change on fish ecology and fisheries management.
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  • 39
    Publication Date: 2019-09-23
    Description: Understanding the ecological mechanisms that underlie species diversity decline in response to environmental change has become an urgent objective in current ecological research. Not only direct (lethal) effects on single species but also indirect effects altering biotic interactions between species within and across trophic levels comprise the driving force of ecosystem change. In an experimental marine benthic microalgae–grazer system we tested for indirect effects of moderate temperature change on algal diversity by manipulation of temperature, nutrient supply and grazer density. In our model system warming did not exert indirect effects on microalgal diversity via effects on resource competition. However, moderate warming strengthened consumer control and thereby indirectly affected algal community structure which ultimately resulted in decreased diversity. Only in low temperature and low nutrient regimes did the antagonizing mechanisms of bottom–up and top–down regulation establish a balancing effect on algal diversity within 29 days (corresponding to 15–29 algae generations). Effects of thermal habitat change did not appear before 9–18 algae generations, which points to the relevance of longer-term experiments and ecological monitoring in order to separate transient biotic responses and subtle changes of community dynamics in consequence to global change.
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  • 40
    Publication Date: 2017-07-21
    Description: Molybdenum concentration and δ98/95Mo values for NIST SRM 610 and 612 (solid glass), NIST SRM 3134 (lot 891307; liquid) and IAPSO seawater reference material are presented based on comparative measurements by MC-ICP-MS performed in laboratories at the Universities of Bern and Oxford. NIST SRM 3134 and NIST SRM 610 and 612 were found to have identical and homogeneous 98Mo/95Mo ratios at a test portion mass of 0.02 g. We suggest, therefore, that NIST SRM 3134 should be used as reference for the δ–Mo notation and to employ NIST SRM 610 or 612 as solid silicate secondary measurement standards, in the absence of an isotopically homogeneous solid geological reference material for Mo. The δ98/95MoJMC Bern composition (Johnson Matthey ICP standard solution, lot 602332B as reference) of NIST SRM 3134 was 0.25 ± 0.09‰ (2s). Based on five new values, we determined more precisely the mean open ocean δ98/95MoSRM 3134 value of 2.09 ± 0.07‰, which equals the value of δ98/95MoJMC Bern of 2.34 ± 0.07‰. We also refined the Mo concentration data for NIST SRM 610 to 412 ± 9 μg g−1 (2s) and NIST SRM 612 to 6.4 ± 0.7 μg g−1 by isotope dilution. We propose these concentration data as new working values, which allow for more accurate in situ Mo determination using laser ablation ICP-MS or SIMS.
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  • 41
    Publication Date: 2019-09-23
    Description: Individual migration behaviour during the juvenile and adult life phase of the anadromous twaite shad Alosa fallax in the Elbe estuary was examined using otolith Sr:Ca and Ba:Ca profiles. Between hatching and the end of the first year of life, juveniles showed two migration patterns. Pattern one exhibited a single downstream migration from fresh water to the sea with no return into fresh water. In contrast, pattern two showed a first migration into the sea, then a return into fresh water and, finally, a second downstream migration into marine water. This first report of migration plasticity for A. fallax points to different exposure times to estuarine threats depending on the migration strategy. In adults, high Sr:Ca and low Ba:Ca in the majority of individuals confirmed prior reports of a primarily marine habitat use. Patterns reflecting spawning migrations were rarely observed on otoliths, possibly due to the short duration of visits to fresh water.
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  • 42
    Publication Date: 2017-11-14
    Description: Process length variation of cysts of the dinoflagellate Protoceratium reticulatum (Claparède et Lachmann) Bütschli in surface sediments from the North Pacific was investigated. The average process length showed a significant inverse relation to annual seawater density: σt annual = −0.8674 × average process length + 1029.3 (R2 = 0.84), with a standard error of 0.78 kg m−3. A sediment trap study from Effingham Inlet in British Columbia revealed the same relationship between average process length and local seawater density variations. In the Baltic–Skagerrak region, the average process length variation was related significantly to annual seawater density: σt annual = 3.5457 × average process length − 993.28 (R2 = 0.86), with a standard error of 3.09 kg m−3. These calibrations cannot be reconciled, which accentuates the regional character of the calibrations. This can be related to variations in molecular data (small subunit, long subunit and internal transcribed spacer sequences), which show the presence of several genotypes and the occurrence of pseudo-cryptic speciation within this species.
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  • 43
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    Wiley-Blackwell
    In:  Perspektiven der Wirtschaftspolitik, 11 (S1). pp. 4-12.
    Publication Date: 2019-09-23
    Description: At least half of the global warming observed during the 20th century of about 0.8°C is of anthropogenic origin and mostly due to enhanced atmospheric carbon dioxide levels in response to the burning of fossil fuels. The climate problem is therefore closely linked to the way we produce energy. Climate models predict a massive warming by the end of the century should global greenhouse gas emissions not be strongly reduced. The Intergovernmental Panel on Climate Change (IPCC) reports that the warming can amount to up to 4°C in a worst case scenario, which would be unprecedented in speed and extent in man's history. This can lead to an increase of extreme weather events and a rise of global sea level by up to 1m. A less known impact of increasing atmospheric carbon dioxide is ocean acidification, as the oceans take up large amounts of carbon dioxide. Ocean acidification potentially threatens marine life and global food production.
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  • 44
    Publication Date: 2020-07-15
    Description: The herbal remedy, milk thistle (Silybum marianum), has been used in traditional medicine for various liver, kidney, and gall bladder ailments. For over a decade, our research group has been investigating the flavonolignans obtained from this medicinal herb for cancer chemoprevention and hepatoprotection.[1–6] Recently, we extended our studies toward examining the diversity as well as distribution patterns of fungal endophytes in leaves, stem, and roots of milk thistle.[7] These fungi inhabit the internal living tissues of the host plants asymptomatically, though they may also cause disease over time.[8] In addition to the phylogenetic profiling of these endophytes, a series of fungal extracts were also examined for chemical composition. Although the plant–endophyte relationship may ormay not be mutualistic, the compounds produced by some endophytes could play a role in the growth and survival of the host. In a previous study, Penicillium restrictum, isolated from milk thistle, yielded promising secondary metabolites.[9] Hence, in pursuit of interesting chemistry, a related monoverticillate endophytic Penicillium sp. was explored.
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  • 45
    Publication Date: 2019-09-23
    Description: Landscape connectivity can increase the capacity of communities to maintain their function when environments change by promoting the immigration of species or populations with adapted traits. However, high immigration may also restrict fine tuning of species compositions to local environmental conditions by homogenizing the community. Here we demonstrate that dispersal generates such a tradeoff between maximizing local biomass and the capacity of model periphyton metacommunities to recover after a simulated heat wave. In non-disturbed metacommunities, dispersal decreased the total biomass by preventing differentiation in species composition between the local patches making up the metacommunity. On the contrary, in metacommunities exposed to a realistic summer heat wave, dispersal promoted recovery by increasing the biomass of heat tolerant species in all local patches. Thus, the heat wave reorganized the species composition of the metacommunities and after an initial decrease in total biomass by 38.7%, dispersal fueled a full recovery of biomass in the restructured metacommunities. Although dispersal may decrease equilibrium biomass, our results highlight that connectivity is a key requirement for the response diversity that allows ecological communities to adapt to climate change through species sorting.
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  • 46
    Publication Date: 2016-09-06
    Description: This paper focuses on the marine foundation eelgrass species, Zostera marina, along a gradient from the northern Baltic Sea to the north-east Atlantic. This vast region supports a minimum of 1480 km2 eelgrass (maximum 〉2100 km2), which corresponds to more than four times the previously quantified area of eelgrass in Western Europe. Eelgrass meadows in the low salinity Baltic Sea support the highest diversity (4–6 spp.) of angiosperms overall, but eelgrass productivity is low (〈2 g dw m-2 d-1) and meadows are isolated and genetically impoverished. Higher salinity areas support monospecific meadows, with higher productivity (3–10 g dw m-2 d-1) and greater genetic connectivity. The salinity gradient further imposes functional differences in biodiversity and food webs, in particular a decline in number, but increase in biomass of mesograzers in the Baltic. Significant declines in eelgrass depth limits and areal cover are documented, particularly in regions experiencing high human pressure. The failure of eelgrass to re-establish itself in affected areas, despite nutrient reductions and improved water quality, signals complex recovery trajectories and calls for much greater conservation effort to protect existing meadows. The knowledge base for Nordic eelgrass meadows is broad and sufficient to establish monitoring objectives across nine national borders. Nevertheless, ensuring awareness of their vulnerability remains challenging. Given the areal extent of Nordic eelgrass systems and the ecosystem services they provide, it is crucial to further develop incentives for protecting them.
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  • 47
    Publication Date: 2017-07-21
    Description: Molybdenum isotopes are increasingly widely applied in Earth Sciences. They are primarily used to investigate the oxygenation of Earth's ocean and atmosphere. However, more and more fields of application are being developed, such as magmatic and hydrothermal processes, planetary sciences or the tracking of environmental pollution. Here, we present a proposal for a unifying presentation of Mo isotope ratios in the studies of mass-dependent isotope fractionation. We suggest that the Mo-98/95 of the NIST SRM 3134 be defined as +0.25. The rationale is that the vast majority of published data are presented relative to reference materials that are similar, but not identical, and that are all slightly lighter than NIST SRM 3134. Our proposed data presentation allows a direct first-order comparison of almost all old data with future work while referring to an international measurement standard. In particular, canonical Mo-98/95 values such as +2.3 parts per thousand for seawater and -0.7 parts per thousand for marine Fe-Mn precipitates can be kept for discussion. As recent publications show that the ocean molybdenum isotope signature is homogeneous, the IAPSO ocean water standard or any other open ocean water sample is suggested as a secondary measurement standard, with a defined Mo-98/95 value of +2.34 +/- 0.10 parts per thousand (2s).
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  • 48
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    Wiley-Blackwell
    In:  Journal of Fish Biology, 84 (6). pp. 1740-1747.
    Publication Date: 2017-09-14
    Description: This study investigated growth, condition and development of American eels Anguilla rostrata that were introduced into a European river to estimate their competitive potential in a non-native habitat. Results demonstrate that A. rostrata develops normally in European waters and successfully competes with the native European eel Anguilla anguilla. In addition, A. rostrata appears to be more susceptible to the Asian swimbladder nematode Anguillicola crassus than A. anguilla and could support the further propagation of this parasite. Detected differences in fat content and gonad mass between Anguilla species are assumed to reflect species-specific adaptations to spawning migration distances. This study indicates that A. rostrata is a potential competitor for the native fauna in European fresh waters and suggests strict import regulations to prevent additional pressure on A. anguilla and a potential further deterioration of its stock situation.
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  • 49
    Publication Date: 2017-01-31
    Description: Ecosystem functioning is affected by horizontal (within trophic groups) and vertical (across trophic levels) biodiversity. Theory predicts that the effects of vertical biodiversity depend on consumer specialization. In a microcosm experiment, we investigated ciliate consumer diversity and specialization effects on algal prey biovolume, evenness and composition, and on ciliate biovolume production. The experimental data was complemented by a process-based model further analyzing the ecological mechanisms behind the observed diversity effects. Overall, increasing consumer diversity had no significant effect on prey biovolume or evenness. However, consumer specialization affected the prey community. Specialist consumers showed a stronger negative impact on prey biovolume and evenness than generalists. The model confirmed that this pattern was mainly driven by a single specialist with a high per capita grazing rate, consuming the two most productive prey species. When these were suppressed, the prey assemblage became dominated by a less productive species, consequently decreasing prey biovolume and evenness. Consumer diversity increased consumer biovolume, which was stronger for generalists than for specialists and highest in mixed combinations, indicating that consumer functional diversity, i.e. more diverse feeding strategies, increased resource use efficiency. Overall, our results indicate that consumer diversity effects on prey and consumers strongly depend on species-specific growth and grazing rates, which may be at least equally important as consumer specialization in driving consumer diversity effects across trophic levels.
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  • 50
    Publication Date: 2019-09-23
    Description: We compared the development and fatty acid content of the harpacticoid copepods Tachidius discipes and Tisbe sp. fed with different microalgal species (Dunaliella tertiolecta, Rhodomonas sp., Phaeodactylum tricornutum, Isochrysis galbana and a concentrate of Pavlova sp.), which differed in cell size and fatty acid composition. Tisbe could develop in 11 days with every alga to the same average stage, whereas Tachidius developed poorly when fed with Isochrysis and Dunaliella. Feeding with Phaeodactylum resulted in a fast development of both copepods at low algal concentrations. However, reproduction was higher with Rhodomonas as food than with the other algae. Fatty acid compositions of copepods were influenced by their food source, but both were able to convert docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) from precursors. Tachidius fed with Rhodomonas or Phaeodactylum was closest to the DHA/EPA/arachidonic acid (ARA) ratio of 10 : 5 : 1 considered optimal for some marine fish larvae. Tachidius showed similar development and reproduction capacity as Tisbe, but requested higher absolute fatty acid contents in the diet. Tisbe was superior in the utilization of bacteria as additional food source and the bioconversion of precursor fatty acids. Phaeodactylum and Rhodomonas are recommendable food sources for both copepod species, but Phaeodactylum is more easily cultured.
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  • 51
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    In:  In: Methods for the Study of Marine Benthos. , ed. by Eleftheriou, A. Wiley-Blackwell, Chichester, UK, pp. 97-124. 4. ed. ISBN 978-0-470-67086-6
    Publication Date: 2013-06-25
    Type: Book chapter , NonPeerReviewed
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  • 52
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    In:  Journal of Fish Biology, 83 (6). pp. 1528-1550.
    Publication Date: 2017-09-14
    Description: Analysis of maximum depth of occurrence of 11 952 marine fish species shows a global decrease in species number (N) with depth (x; m): log10 N = -0·000422x + 3·610000 (r(2)  = 0·948). The rate of decrease is close to global estimates for change in pelagic and benthic biomass with depth (-0·000430), indicating that species richness of fishes may be limited by food energy availability in the deep sea. The slopes for the Classes Myxini (-0·000488) and Actinopterygii (-0·000413) follow this trend but Chondrichthyes decrease more rapidly (-0·000731) implying deficiency in ability to colonize the deep sea. Maximum depths attained are 2743, 4156 and 8370 m for Myxini, Chondrichthyes and Actinopterygii, respectively. Endemic species occur in abundance at 7-7800 m depth in hadal trenches but appear to be absent from the deepest parts of the oceans, 〉9000 m deep. There have been six global oceanic anoxic events (OAE) since the origin of the major fish taxa in the Devonian c. 400 million years ago (mya). Colonization of the deep sea has taken place largely since the most recent OAE in the Cretaceous 94 mya when the Atlantic Ocean opened up. Patterns of global oceanic circulation oxygenating the deep ocean basins became established coinciding with a period of teleost diversification and appearance of the Acanthopterygii. Within the Actinopterygii, there is a trend for greater invasion of the deep sea by the lower taxa in accordance with the Andriashev paradigm. Here, 31 deep-sea families of Actinopterygii were identified with mean maximum depth 〉1000 m and with 〉10 species. Those with most of their constituent species living shallower than 1000 m are proposed as invasive, with extinctions in the deep being continuously balanced by export of species from shallow seas. Specialized families with most species deeper than 1000 m are termed deep-sea endemics in this study; these appear to persist in the deep by virtue of global distribution enabling recovery from regional extinctions. Deep-sea invasive families such as Ophidiidae and Liparidae make the greatest contribution to fish fauna at depths 〉6000 m.
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  • 53
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    Wiley-Blackwell
    In:  Wiley Interdisciplinary Reviews: Climate Change, 8 (1). e441.
    Publication Date: 2019-02-01
    Description: To estimate the anthropogenic contribution to climate signals in the recent past and future decades implies a certain degree of confidence in both understanding and simulating natural internal variability at interdecadal time scales. If we are to embark on the challenge of decadal prediction, we must be able to mechanistically attribute events to known processes and phenomena, and reproduce their features and statistics within our models. To date, models have succeeded in reproducing only partially spatial patterns, statistics and climatic impacts of interdecadal modes of variability. Reasons for the partial success and agreement among models are to be attributed to the short observational record, the different and complex flavours of coupling between the many subcomponents of the climate system, and the present inability to resolve all climate processes. At an even more fundamental level, this difficulty is aggravated by the limited understanding of the physical mechanisms involved. Here, we review the proposed mechanisms giving rise to interdecadal climate variability, we discuss the hypotheses explaining the main interdecadal modes of variability, and present an overview on the ability and level of agreement in their simulation by the latest generation of coupled climate models. To achieve any progress, the modeling community should focus on both improving the representation and parameterization of key ocean physical processes and obtaining a firmer grasp on the physical mechanisms generating the variability. Both goals can benefit from process studies, intercomparisons with perturbation experiments to study model's sensitivities, and the use of a hierarchy of climate models.
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  • 54
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    In:  Journal of Zoology, 190 (2). pp. 211-215.
    Publication Date: 2020-07-17
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  • 55
    Publication Date: 2020-02-06
    Description: The spatial structure of species is important for their dynamics and evolution, but also for management and conservation. There are numerous ways of inferring spatial structures, and information from multiple methods is becoming more common to examine how different processes shape the spatial structures of species to improve fish management. Here, we investigate the spatial structure of a suite of Baltic Sea fish species based on the following: (i) spatial (presumably neutral) genetic differentiation, reviewed from the literature, and (ii) spatial synchrony in abundance changes from time series of fishery-independent surveys, which we currently find to be underused given the amount of data available. For each of these two methods, species were classified as having a distinct, continuous or no/weak spatial structure. In addition, based on each source of information, we estimated the spatial scale of management units for species. The results show that only among species confined to the coastal zone the two sources of information yielded a congruence of the spatial structure (displaying a continuous spatial structure). In contrast, offshore species show weak spatial genetic structure but stronger spatial structure of synchrony in abundance. Based on this, we suggest that population genetic structure and synchrony in abundance should be used as complementary information as they reflect different spatial processes and suggest that management actions should differ with respect to scale depending on the management targets applied. We propose similar analysis should be applied to areas outside the Baltic Sea, and other stock identification methods, to improve management of fish resources.
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  • 56
    Publication Date: 2020-10-26
    Description: Climatic warming is a primary driver of change in ecosystems worldwide. Here, we synthesize responses of species richness and evenness from 187 experimental warming studies in a quantitative meta-analysis. We asked 1) whether effects of warming on diversity were detectable and consistent across terrestrial, freshwater and marine ecosystems, 2) if effects on diversity correlated with intensity, duration, and experimental unit size of temperature change manipulations, and 3) whether these experimental effects on diversity interacted with ecosystem types. Using multilevel mixed linear models and model averaging, we also tested the relative importance of variables that described uncontrolled environmental variation and attributes of experimental units. Overall, experimental warming reduced richness across ecosystems (mean log-response ratio = –0.091, 95% bootstrapped CI: –0.13, –0.05) representing an 8.9% decline relative to ambient temperature treatments. Richness did not change in response to warming in freshwater systems, but was more strongly negative in terrestrial (–11.8%) and marine (–10.5%) experiments. In contrast, warming impacts on evenness were neutral overall and in aquatic systems, but weakly negative on land (7.6%). Intensity and duration of experimental warming did not explain variation in diversity responses, but negative effects on richness were stronger in smaller experimental units, particularly in marine systems. Model-averaged parameter estimation confirmed these main effects while accounting for variation in latitude, ambient temperature at the sites of manipulations, venue (field versus lab), community trophic type, and whether experiments were open or closed to colonization. These analyses synthesize extensive experimental evidence showing declines in local richness with increased temperature, particularly in terrestrial and marine communities. However, the more variable effects of warming on evenness were better explained by the random effect of site identity, suggesting that effects on species’ relative abundances were contingent on local species composition.
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  • 57
    Publication Date: 2021-02-08
    Description: Sediment core PS1904 reveals continuous records of planktic and benthic foraminiferal stable isotopes (δ18O/δ13C) from the north-eastern Greenland continental margin. The data show good comparability with other records from the Nordic Seas, allowing the stratigraphic range of PS1904 to be dated to Marine Isotope Stage (MIS) 6. Focusing on MIS 5 reveals light δ18O values during MIS 5a compared to the last interglacial peak (MIS 5e) which indicates that surface and bottom water layers were strongly affected by freshwater during the former event. We present two possible scenarios explaining the origin and routing of the freshwater: (i) drainage of a Eurasian proglacial lake coupled with the collapse of the Kara Sea Ice Sheet at the MIS 5b/a boundary, and (ii) destabilization and melting of the nearby Greenland Ice Sheet. Although both scenarios could have acted simultaneously, sediment records from the Eurasian sector of the Arctic Ocean hint at the proglacial lake system in north-western Siberia as the largest freshwater source. Regardless of the actual source, the freshwater lowered the surface ocean salinity causing water column stratification and sea ice expansion. Increased sea-ice abundance led to a higher albedo and probably contributed to the cooling and global ice sheet growth that occurred subsequently during MIS 4.
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  • 58
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    In:  Journal of Quaternary Science, 28 (8). pp. 803-811.
    Publication Date: 2018-09-05
    Description: A number of rapid climate oscillations occur during the Lateglacial–Early Holocene, 15–8 ka BP period and a well-developed tephrostratigraphy in association with these oscillations increases the possibilities to correlate climate archives around the North Atlantic. This paper presents a tephrostratigraphy for Fosen peninsula, Central Norway. Both the Vedde Ash ca.12.1 ka BP and the Saksunarvatn Ash ~10.3 ka BP are important isochrones for correlations of Late Quaternary palaeoenvironmental records in the North Atlantic region and have been assigned ages in GICC05. Beside these tephras we have also identified a new tephra, the Fosen Tephra, with a Borrobol-type geochemistry that occurs above both the Vedde Ash and the Saksunarvatn Ash with an age ~10.2 ka BP. Several tephras with Borrobol-type geochemistry have been identified around the North Atlantic. One group is the Borrobol/Penifiler tephras dated to Greenland Interstadial-1 and another group is dated to the Early Holocene. We suggest that some of the Early Holocene Borrobol-type tephras and the Fosen Tephra may actually be the same layer. If so, the Fosen Tephra is spread over a large area of the North Atlantic and has the potential to become an important marker for short-term climate variability in Scandinavia and in the northern hemisphere.
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  • 59
    Publication Date: 2019-01-23
    Description: In experimental metacommunities with marine benthic microalgae, we tested whether heat stress changes effects of connectivity and habitat heterogeneity on metacommunity structure and functioning, by manipulating a simulated heat wave, dispersal frequency and a light intensity gradient. We found that all measures of mean local and regional diversity and community biomass significantly declined after the heat wave and showed no sign of recovery. Additionally, dispersal decreased diversity and increased dominance in both the heat stressed and control communities. Together the heat wave and high dispersal frequency induced a dominance shift by spreading a temperature tolerant but low yielding species from its source patches with low light intensity across the metacommunity, an effect that increased with time. Although different species became dominant at high dispersal frequency with and without the heat wave, the shift towards a temperature tolerant species was not sufficient to maintain total community biomass. Thus, short-term disturbance may cause longer-term loss of ecosystem function due to dominance shifts in the composition of communities. This study illustrates the importance of employing multispecies approaches when attempting to predict responses of communities to environmental changes.
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  • 60
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    In:  Journal of Food Science, 77 (7). M359-M363.
    Publication Date: 2018-09-26
    Description: The microbial communities were analyzed from commercially available dried dairy nutraceutical products, including 4 brands of dried colostrum, 2 brands of dried whey, and 1 brand of nonfat dry milk. A culture‐dependent 16S rRNA sequencing approach was utilized to elucidate the identity of individual isolates recovered from each dried dairy product. Approximately 69% of all bacterial isolates were members the genus of Bacillus, while approximately 14% of all bacterial isolates were identified as members of the genus Pseudomonas. Members of the Kocuria, Microbacterium, and Enterococcus genera were identified as well.
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  • 61
    Publication Date: 2022-01-31
    Description: A new olivine reference material – MongOL Sh11‐2 – for in situ analysis has been prepared from a central portion of a large (20 cm × 20 cm × 10 cm) mantle peridotite xenolith from a ~ 0.5 Ma old basaltic breccia at Shavaryn‐Tsaram, Tariat region, central Mongolia. The xenolith is a fertile mantle lherzolite with minimal signs of alteration. Approximately 10 g of 0.5 to 2 mm gem quality olivine fragments were separated under binocular microscope and analysed by EPMA, LA‐ICP‐MS, SIMS and bulk analytical methods (ID ICP‐MS for Mg and Fe, XRF, ICP‐MS) for major, minor and trace elements at six institutions worldwide. The results show that the olivine fragments are sufficiently homogeneous with respect to major (Mg, Fe, Si) and minor and trace elements. Significant inhomogeneity was revealed only for phosphorus (homogeneity index of 12.4), whereas Li, Na, Al, Sc, Ti and Cr show minor inhomogeneity (homogeneity index of 1–2). The presence of some mineral and fluid‐melt micro‐inclusions may be responsible for the inconsistency in mass fractions obtained by in situ and bulk analytical methods for Al, Cu, Sr, Zr, Ga, Dy and Ho. Here we report reference and information values for twenty‐seven major, minor and trace elements.
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  • 62
    Publication Date: 2022-01-31
    Description: Aim: The interdependencies between trophic interactions, environmental factors and anthropogenic forcing determine how species distributions change over time. Large changes in species distributions have occurred as a result of climate change. The objective of this study was to analyse how the spatial distribution of cod and flounder has changed in the Baltic Sea during the past four decades characterized by large hydrological changes. Location: Baltic Sea. Taxon: Cod (Gadus morhua) and flounder (Platichthys flesus). Methods: Catch per unit of effort (CPUE) data for adult and juvenile cod and for adult flounder were modelled using Delta-Generalized additive models including environmental and geographical variables between 1979 and 2016. From the annual CPUE predictions for each species, yearly distribution maps and depth distribution curves were obtained. Mean depth and the depth range were estimated to provide an indication on preferred depth and habitat occupancy. Results: Adult and juvenile cod showed a contraction in their distribution in the southern areas of the Baltic Sea. Flounder, instead, showed an expansion in its distribution with an increase in abundance in the northern areas. The depth distributions showed a progressive shift of the mean depth of occurrence towards shallower waters for adult cod and flounder and towards deeper waters for juvenile cod, as well as a contraction of the species depth ranges, evident mainly from the late 1980s. Main conclusions: Our study illustrates large changes in the spatial distribution of cod and flounder in the Baltic Sea. The changes in depth distribution occurred from the late 1980s are probably due to a combination of expanded areas of hypoxia in deep waters and an increase in predation risk in shallow waters. The net effect of these changes is an increased spatial overlap between life stages and species, which may amplify cod cannibalism and the interaction strength between cod and flounder
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  • 63
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    Publication Date: 2022-03-21
    Type: info:eu-repo/semantics/other
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  • 64
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    In:  Crop Adaptation to Climate Change
    Publication Date: 2022-03-21
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  • 65
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    Wiley-Blackwell
    In:  Crop Adaptation to Climate Change
    Publication Date: 2022-03-21
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  • 66
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    Wiley-Blackwell
    In:  Improving Water and Nutrient-Use Efficiency in Food Production Systems
    Publication Date: 2022-03-21
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  • 67
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    Wiley-Blackwell
    In:  Climate Change Adaptation in Practice
    Publication Date: 2022-03-21
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  • 68
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    In:  Climate Change Adaptation in Practice
    Publication Date: 2022-03-21
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  • 69
    Publication Date: 2024-03-21
    Description: The continental expression of global cooling during the Miocene Climate Transition in Central Asia is poorly documented, as the tectonically active setting complicates the correlation of Neogene regional and global climatic developments. This study presents new geochemical data (CaSO 4 content, carbonate δ 13 C and δ 18 O) from the endorheic alluvial‐lacustrine Aktau succession (Ili Basin, south‐east Kazakhstan) combined with findings from the previously published facies evolution. Time series analysis revealed long‐eccentricity forcing of the paleohydrology throughout the entire succession, split into several facies‐dependent segments. Orbital tuning, constrained by new laser ablation U‐Pb dates and a preexisting magnetostratigraphy, places the succession in a 5.0 Ma long interval in the middle to late Miocene (15.6 to 10.6 Ma). The long‐term water accumulation in the Ili Basin followed the timing of the Miocene Climate Transition, suggesting increased precipitation in the catchment area in response to climate cooling and stronger westerly winds. This was paced by minima of the 2.4 Ma eccentricity cycle, which favored the establishment of a discharge playa (~14.3 Ma) and a perennial lake (12.6 to 11.8 Ma). Furthermore, low obliquity amplitudes (nodes) caused a transient weakening of the westerlies at ~13.7 to 13.5 Ma and at ~12.7 Ma, resulting in negative hydrological budgets and salinization. Flooding of the windward Ili Basin coeval with aridification in the leeward basins suggests that the Tian Shan was a climate boundary already in the middle Miocene. Our results emphasize the impact of climate fluctuations on the westerlies' strength and thus on Central Asian hydrology.
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  • 70
    Publication Date: 2021-01-07
    Description: The elemental fluxes and heat flow associated with large aquifer systems can be significant both at local and at regional scales. In fact, large amounts of heat transported by regional groundwater flow can affect the subsurface thermal regime, and the amount of matter discharged towards the surface by large spring systems can be significant relative to the elemental fluxes of surface waters. The Narni-Amelia regional aquifer system (Central Italy) discharges more than 13 m3 sec)1 of groundwater characterised by a slight thermal anomaly, high salinity and high pCO2. During circulation in the regional aquifer, groundwater reacts with the host rocks (dolostones, limestones and evaporites) and mixes with deep CO2-rich fluids of mantle origin. These processes transfer large amounts of dissolved substances, in particular carbon dioxide, and a considerable amount of heat towards the surface. Because practically all the water circulating in the Narni-Amelia system is discharged by few large springs (Stifone-Montoro), the mass and energy balance of these springs can give a good estimation of the mass and heat transported from the entire system towards the surface. By means of a detailed mass and balance of the aquifer and considering the soil CO2 fluxes measured from the main gas emission of the region, we computed a total CO2 discharge of about 7.8 · 109 mol a)1 for the whole Narni-Amelia system. Finally, considering the enthalpy difference between infiltrating water and water discharged by the springs, we computed an advective heat transfer related to groundwater flow of 410 ± 50 MW.
    Description: Published
    Description: 182-196
    Description: 2.4. TTC - Laboratori di geochimica dei fluidi
    Description: 4.5. Studi sul degassamento naturale e sui gas petroliferi
    Description: JCR Journal
    Description: reserved
    Keywords: carbon dioxide degassing ; heat flow ; regional aquifer ; 04. Solid Earth::04.02. Exploration geophysics::04.02.01. Geochemical exploration ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 71
    Publication Date: 2021-06-16
    Description: In this study, Mg/Ca, Sr/Ca and Ba/Ca ratios in a Lateglacial to Holocene stalagmite (CC26) from Corchia Cave (central Italy) are compared with stable isotope data to define palaeohydrological changes. For most of the record, the trace element ratios show small absolute variability but similar patterns, which are also consistent with stable isotope variations. Higher trace element-to-calcium values are interpreted as responses to decreasing moisture, inducing changes in the residence time of percolation, producing prior calcite precipitation and/or variations in the hydrological routing. Statistically meaningful levels of covariability were determined using anomalies of Mg/Ca, d18O and d13C. Combining these three time series into a single ‘palaeomoisture-trend’ parameter, we highlight several events of reduced moisture (ca. 8.9–8.4, 6.2, 4.2, 3.1 and 2.0 ka), a humid period between ca. 7.9 and 8.3 ka and other shorter-term wet events at ca. 5.8, 5.3 and 3.7 ka. Most of these events can be correlated with climate changes inferred from other regional studies. For both extremities of the record (i.e. before ca. 12.4 ka and after ca. 0.5 ka) Mg/Ca and Sr/Ca are anti-correlated and show the greatest amplitude of values, a likely explanation for which involves aragonite and/or gypsum precipitation (the latter derived from pyrite oxidation) above the CC26 drip point.
    Description: Published
    Description: 381–392
    Description: 4A. Clima e Oceani
    Description: JCR Journal
    Description: restricted
    Keywords: central Italy; Corchia Cave; Holocene; speleothems; trace elements ; 01. Atmosphere::01.01. Atmosphere::01.01.02. Climate
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 72
    Publication Date: 2021-06-14
    Description: This study is focused on the (micro)biogeochemical features of two close geothermal sites (FAV1 and FAV2), both selected at the main exhalative area of Pantelleria Island, Italy. A previous biogeochemical survey revealed high CH4 consumption and the presence of a diverse community of methanotrophs at FAV2 site, whereas the close site FAV1 was apparently devoid of methanotrophs and recorded no CH4 consumption. Next-Generation Sequencing (NGS) techniques were applied to describe the bacterial and archaeal communities which have been linked to the physicochemical conditions and the geothermal sources of energy available at the two sites. Both sites are dominated by Bacteria and host a negligible component of ammonia-oxidizing Archaea (phylum Thaumarchaeota). The FAV2 bacterial community is characterized by an extraordinary diversity of methanotrophs, with 40% of the sequences assigned to Methylocaldum, Methylobacter (Gammaproteobacteria) and Bejerickia (Alphaproteobacteria); conversely, a community of thermo-acidophilic chemolithotrophs (Acidithiobacillus, Nitrosococcus) or putative chemolithotrophs (Ktedonobacter) dominates the FAV1 community, in the absence of methanotrophs. Since physical andchemical factors of FAV1, such as temperature and pH, cannot be considered limiting for methanotrophy, it is hypothesized that the main limiting factor for methanotrophs could be high NH4+ concentration. At the same time, abundant availability of NH4+ and other high energy electron donors and acceptors determined by the hydrothermal flux in this site create more energetically favourable conditions for chemolithotrophs that outcompete methanotrophs in non-nitrogen-limited soils.
    Description: Published
    Description: 150–162
    Description: 4V. Vulcani e ambiente
    Description: JCR Journal
    Description: restricted
    Keywords: geothermal soils ; geomicrobiology ; chemolithotrophs ; methanotrophs ; Pantelleria ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 73
    Publication Date: 2020-12-21
    Description: We detail the Kamil crater (Egypt) structure and refine the impact scenario, based on the geological and geophysical data collected during our first expedition in February 2010. Kamil Crater is a model for terrestrial small-scale hypervelocity impact craters. It is an exceptionally well-preserved, simple crater with a diameter of 45 m, depth of 10 m, and rayed pattern of bright ejecta. It occurs in a simple geological context: flat, rocky desert surface, and target rocks comprising subhorizontally layered sandstones. The high depth-to-diameter ratio of the transient crater, its concave, yet asymmetric, bottom, and the fact that Kamil Crater is not part of a crater field confirm that it formed by the impact of a single iron mass (or a tight cluster of fragments) that fragmented upon hypervelocity impact with the ground. The circular crater shape and asymmetries in ejecta and shrapnel distributions coherently indicate a direction of incidence from the NW and an impact angle of approximately 30 to 45 . Newly identified asymmetries, including the off-center bottom of the transient crater floor downrange, maximum overturning of target rocks along the impact direction, and lower crater rim elevation downrange, may be diagnostic of oblique impacts in well-preserved craters. Geomagnetic data reveal no buried individual impactor masses 〉100 kg and suggest that the total mass of the buried shrapnel 〉100 g is approximately 1050–1700 kg. Based on this mass value plus that of shrapnel 〉10 g identified earlier on the surface during systematic search, the new estimate of the minimum projectile mass is approximately 5 t.
    Description: Published
    Description: 1842–1868
    Description: 3.8. Geofisica per l'ambiente
    Description: JCR Journal
    Description: restricted
    Keywords: Impact craters ; geophysical survey ; iron meteorite ; impact scenario ; 04. Solid Earth::04.02. Exploration geophysics::04.02.99. General or miscellaneous ; 04. Solid Earth::04.02. Exploration geophysics::04.02.07. Instruments and techniques ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 74
    Publication Date: 2020-12-07
    Description: We present new stratigraphic, palaeomagnetic, 87Sr/86Sr and 40Ar/39Ar data from a lacustrine succession of the Sulmona basin, central Italy, which, according to an early study, included six unconformitybounded lacustrine units (from SUL6, oldest, to SUL1, youngest) spanning the interval 〉600 to 2 ka. The results of the present study, on the one hand confirm some of the previous conclusions, but by contrast reveal that units SUL2 and SUL1, previously attributed to the Holocene, are actually equivalent to the older SUL6 and SUL5 units – here dated to 814–〉530 ka and 530–〈457 ka, respectively – and that the U-series dates previously published for both former SUL2 and SUL1 units yielded abnormally young ages. In light of the present results, a reassessment of the chronology of the Sulmona basin succession and a revision of the tephrostratigraphy of the SUL2/SUL6 and SUL1/SUL5 units is in order.
    Description: Published
    Description: 545–551
    Description: 2.2. Laboratorio di paleomagnetismo
    Description: JCR Journal
    Description: restricted
    Keywords: 40Ar/39Ar dating; central Italy ; Sr isotope composition ; Sulmona lacustrine succession ; Brunhes–Matuyama geomagnetic reversal ; tephrostratigraphy ; U-series dating ; 04. Solid Earth::04.04. Geology::04.04.08. Sediments: dating, processes, transport ; 04. Solid Earth::04.04. Geology::04.04.10. Stratigraphy ; 04. Solid Earth::04.05. Geomagnetism::04.05.06. Paleomagnetism
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 75
    Publication Date: 2020-12-14
    Description: We study the implications of a recently published mass balance of the Greenland ice sheet (GrIS), derived from repeated surface elevation measurements from NASA’s ice cloud and land elevation satellite (ICESat) for the time period between 2003 and 2008. To characterize the effects of this new, high-resolution GrIS mass balance, we study the time-variations of various geophysical quantities in response to the current mass loss. They include vertical uplift and subsidence, geoid height variations, global patterns of sea level change (or fingerprints), and regional sea level variations along the coasts of Greenland. Long-wavelength uplifts and gravity variations in response to current or past ice thickness variations are obtained solving the sea level equation, which accounts for both the elastic and the viscoelastic components of deformation. To capture the short-wavelength components of vertical uplift in response to current ice mass loss, which is not resolved by satellite gravity observations, we have specifically developed a high-resolution regional elastic rebound (ER) model. The elastic component of vertical uplift is combined with estimates of the viscoelastic displacement fields associated with the process of glacial-isostatic adjustment (GIA), according to a set of published ice chronologies and associated mantle rheological profiles. We compare the sensitivity of global positioning system (GPS) observations along the coasts of Greenland to the ongoing ER and GIA. In notable contrast with past reports, we show that vertical velocities obtained by GPS data from five stations with sufficiently long records and from one tide gauge at the GrIS margins can be reconciled with model predictions based on the ICE-5G deglaciation model and the ER associated with the new ICESat-derived mass balance.
    Description: Published
    Description: 1457-1474
    Description: 3.3. Geodinamica e struttura dell'interno della Terra
    Description: JCR Journal
    Description: restricted
    Keywords: Sea level change ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 76
    Publication Date: 2020-12-15
    Description: We present a time-independent gridded earthquake rate forecast for the European region including Turkey. The spatial component of our model is based on kernel density estimation techniques, which we applied to both past earthquake locations and fault moment release on mapped crustal faults and subduction zone interfaces with assigned slip rates. Our forecast relies on the assumption that the locations of past seismicity is a good guide to future seismicity, and that future large-magnitude events occur more likely in the vicinity of known faults. We show that the optimal weighted sum of the corresponding two spatial densities depends on the magnitude range considered. The kernel bandwidths and density weighting function are optimized using retrospective likelihood-based forecast experiments. We computed earthquake activity rates (a- and b-value) of the truncated Gutenberg–Richter distribution separately for crustal and subduction seismicity based on a maximum likelihood approach that considers the spatial and temporal completeness history of the catalogue. The final annual rate of our forecast is purely driven by the maximum likelihood fit of activity rates to the catalogue data, whereas its spatial component incorporates contributions from both earthquake and fault moment-rate densities. Our model constitutes one branch of the earthquake source model logic tree of the 2013 European seismic hazard model released by the EU-FP7 project ‘Seismic HAzard haRmonization in Europe’ (SHARE) and contributes to the assessment of epistemic uncertainties in earthquake activity rates. We performed retrospective and pseudo-prospective likelihood consistency tests to underline the reliability of our model and SHARE’s area source model (ASM) using the testing algorithms applied in the collaboratory for the study of earthquake predictability (CSEP). We comparatively tested our model’s forecasting skill against the ASM and find a statistically significant better performance for testing periods of 10–20 yr. The testing results suggest that our model is a viable candidate model to serve for long-term forecasting on timescales of years to decades for the European region.
    Description: EC-Research FP7-projects, SHARE, under grant agreement No. 226967 and NERA, under grant agreement No. 262330
    Description: Published
    Description: 1159-1172
    Description: 2T. Tettonica attiva
    Description: 3T. Pericolosità sismica e contributo alla definizione del rischio
    Description: JCR Journal
    Description: restricted
    Keywords: Probabilistic forecasting ; Statistical seismology ; Europe ; 04. Solid Earth::04.06. Seismology::04.06.02. Earthquake interactions and probability ; 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 77
    Publication Date: 2021-03-18
    Description: This article presents an integrated approach for the probabilistic systemic risk analysis of a road network considering spatial seismic hazard with correlation of ground motion intensities, vulnerability of the network components, and the effect of interactions within the network, as well as, between roadway components and built environment to the network functionality. The system performance is evaluated at the system level through a global connectivity performance indicator, which depends on both physical damages to its components and induced functionality losses due to interactions with other systems. An object-oriented modeling paradigm is used, where the complex problem of several interacting systems is decomposed in a number of interacting objects, accounting for intra- and interdependencies between and within systems. Each system is specified with its components, solving algorithms, performance indicators and interactions with other systems. The proposed approach is implemented for the analysis of the road network in the city of Thessaloniki (Greece) to demonstrate its applicability. In particular, the risk for the road network in the area is calculated, specifically focusing on the short-term impact of seismic events (just after the earthquake). The potential of road blockages due to collapses of adjacent buildings and overpass bridges is analyzed, trying to individuate possible criticalities related to specific components/subsystems. The application can be extended based on the proposed approach, to account for other interactions such as failure of pipelines beneath the road segments, collapse of adjacent electric poles, or malfunction of lighting and signaling systems due to damage in the electric power network.
    Description: Published
    Description: 524–540
    Description: 3T. Pericolosità sismica e contributo alla definizione del rischio
    Description: JCR Journal
    Description: restricted
    Keywords: Systemic vulnerability ; 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 78
    Publication Date: 2021-06-08
    Description: We investigated the high frequency attenuation of S-waves in Southeastern Alps and Northern External Dinarides using waveforms from 331 earthquakes (3.0〈 Mw〈 6.5). The spectral decay parameter, k, was computed using 1345 three component high quality records, collected by the Italian Strong Motion Network (RAN) and by the Short-Period Seismometric Network of North-Eastern Italy (NEI) in the period 1976-2007. Weak motion data from 11 stations of the NEI network and strong motion data collected by 5 accelerometers of the RAN were analyzed. The k parameter was estimated in the 0-250 Km distance range, in a frequency band extending from the corner frequency of the event up to 25 or 45 Hz, using the amplitude acceleration Fourier spectra of S-waves. The observed record-to-record variability of k was modeled by applying a generalized inversion procedure, using both parametric and non-parametric approaches. Our results evidence that k is independent on earthquake size, while it shows both site and distance dependence. Stations of the NEI network present the same increase of k with epicentral distance, Re, and show values of the zero-distance k parameter, k0(S), between 0.017 and 0.053 s. For the whole region, the k increase with distance can be described through a linear model with slope dk/dRe = (1.4±0.1)x10^(-4) s/Km. Assuming an average S-wave velocity, 〈Vs〉=3.34 Km/s between 5 and 15 Km depth, we estimate an average frequency independent quality factor, 〈Qi〉=2140, for the corresponding crustal layer. The non-parametric approach evidences a weak positive concavity of the curve that describes the k increase with Re at about 90 Km distance. This result can be approximated through a piecewise linear function with slopes of 1.0x10^(-4) s/Km and 1.7x10^(-4) s/Km, in accordance with a three layers model where moving from the intermediate to the bottom layer both 〈Qi〉 and 〈Vs〉 decrease. Two regional dependences were found: data from earthquakes located westward to the NEI network evidence weaker attenuation properties, probably because of S-wave reflections from different part of the Moho discontinuity under the eastern Po Plain, at about 25-30 Km depth, while earthquakes located eastward (in western Slovenia), where the Moho deepens up to 45-50 Km, evidence a higher attenuation. Moreover, the k estimates obtained with data from earthquakes located in the area of the 1998 (Mw=5.7) and 2004 (Mw=5.2) Kobarid events are 0.017 s higher than the values predicted for the whole region, probably because of the high level of fracturing that characterizes fault zones. The comparison between measured and theoretical values of k, computed at a few stations with available S-wave velocity profiles, reveals that the major contribution to the total k0(S) is due to the sedimentary column (from surface to 800 m depth). The hard rock section contribution is limited to 0.005 s, in accordance with a maximum contribution of 0.010 s predicted by the non-parametric inversion.
    Description: Published
    Description: 1393-1416
    Description: 3.3. Geodinamica e struttura dell'interno della Terra
    Description: JCR Journal
    Description: open
    Keywords: Earthquake source observations ; Body waves ; Seismic attenuation ; Site effects ; Wave propagation ; 04. Solid Earth::04.06. Seismology::04.06.04. Ground motion
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 79
    Publication Date: 2021-06-22
    Description: The building materials of the Theatre of Marcellus, 44–11 BCE, reflect Roman builders’ careful selections of tuff and travertine for dimension stone and volcanic aggregates for pozzolanic concretes. The vitric–lithic–crystal Tufo Lionato tuff dimension stone contains a high proportion of lava lithic fragments, which increase its compressive strength and decrease water sorption, enhancing durability. Sophisticated installations of travertine dimension stone reinforce the tuff masonry, which is integrated with durable concrete walls and barrel vaults. The pozzolanic mortars of the concretes contain harenae fossiciae mainly from the intermediate alteration facies of the mid-Pleistocene, scoriaceous Pozzolane Rosse pyroclastic flow. They have pervasive interpenetrating pozzolanic cements, including strätlingite, similar to highquality, imperial era mortars. Concrete walls are faced with refined Tufo Lionato opus reticulatum and tufelli, and opus testaceum of fired, greyish-yellow brick. The exploratory concrete masonry, which includes some of the earliest examples of brick facings and strätlingite cements in Rome, and the integration of these materials in complex architectural elements and internal spaces, reflect the highly skilled workmanship, rigorous work-site management and technical supervision of Roman builders trained in republican era methods and materials.
    Description: Published
    Description: 728–742
    Description: JCR Journal
    Description: restricted
    Keywords: VOLCANIC TUFF MASONRY ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 80
    Publication Date: 2021-06-07
    Description: We present a high-resolution palaeomagnetic and rock magnetic study of two cores, MS06 and MS06-SW (6.7 and 1.1 m long, respectively), collected at 72 m below sea level in the Augusta Bay shelf (Eastern Sicily, Ionian Sea, Italy) about 2.3 kmfrom the coastline. Geophysical surveying carried out in the sampling area highlighted the presence of a homogeneous sedimentary sequence that most likely was deposited after the Last Glacial Maximum and was not affected by anthropogenic disturbances. The two cores penetrated a monotonous mud sedimentary sequence, interrupted at ∼3 m depth by a 3–4-cm-thick volcanic sandy layer that is correlated with the tephra fallout deposit produced by the 122 BC plinian eruption of Mt Etna. This tephra, along with radiocarbon dating of nine marine shells and with radioactive tracers for the uppermost 0.3 m (210Pb and 137Cs), provide the chronological constraints for the stratigraphic sequence that resulted younger than 4500 yr BP. Palaeomagnetic and rock magnetic data show that the sample sequence is magnetically homogeneous. A single peak of high magnetic mineral concentration is present and corresponds to the volcanic sandy layer. Palaeomagnetic data allowed the identification of a well-defined characteristic remanent magnetization that provides a high-resolution record of palaeosecular variation (PSV) at the sampling site. The reconstructed PSV curve is in good agreement with the available regional reference PSV curves and with the prediction from recent PSV modelling for Europe. The palaeomagnetic data obtained in this study on the one hand support and refine the age model for the cores, derived from other independent constraints, and on the other hand provide an original high-resolution PSV curve that can serve as a reference for the central Mediterranean over the last 4 ka.
    Description: Published
    Description: 191 - 202
    Description: 2.2. Laboratorio di paleomagnetismo
    Description: JCR Journal
    Description: restricted
    Keywords: Palaeointensity ; Palaeomagnetic secular variation ; Marine magnetics and palaeomagnetics ; Europe ; 04. Solid Earth::04.05. Geomagnetism::04.05.02. Geomagnetic field variations and reversals ; 04. Solid Earth::04.05. Geomagnetism::04.05.06. Paleomagnetism
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 81
    Publication Date: 2020-12-14
    Description: The knowledge of the local soil structure is important for the assessment of seismic hazards. A widespread, but time-consuming technique to retrieve the parameters of the local underground is the drilling of boreholes. Another way to obtain the shear wave velocity profile at a given location is the inversion of surface wave dispersion curves. To ensure a good resolution for both superficial and deeper layers, the used dispersion curves need to cover a wide frequency range. This wide frequency range can be obtained using several arrays of seismic sensors or a single array comprising a large number of sensors. Consequently, these measurements are time-consuming. A simpler alternative is provided by the use of the ellipticity of Rayleigh waves. The frequency dependence of the ellipticity is tightly linked to the shear wave velocity profile. Furthermore, it can be measured using a single seismic sensor. As soil structures obtained by scaling of a given model exhibit the same ellipticity curve, any inversion of the ellipticity curve alone will be ambiguous. Therefore, additional measurements which fix the absolute value of the shear wave velocity profile at some points have to be included in the inversion process. Small-scale spatial autocorrelation measurements or MASW measurements can provide the needed data. Using a theoretical soil structure, we show which parts of the ellipticity curve have to be included in the inversion process to get a reliable result and which parts can be omitted. Furthermore, the use of autocorrelation or high-frequency dispersion curves will be highlighted. The resulting guidelines for inversions including ellipticity data are then applied to real data measurements collected at 14 different sites during the European NERIES project. It is found that the results are in good agreement with dispersion curve measurements. Furthermore, the method can help in identifying the mode of Rayleigh waves in dispersion curve measurements.
    Description: Published
    Description: 207-229
    Description: 3T. Pericolosità sismica e contributo alla definizione del rischio
    Description: JCR Journal
    Description: restricted
    Keywords: Inverse theory Surface waves and free oscillations Site effects Computational seismology Wave propagation ; 04. Solid Earth::04.02. Exploration geophysics::04.02.06. Seismic methods
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 82
    Publication Date: 2020-12-15
    Description: Seismogram envelopes recorded at Campi Flegrei caldera show diffusive characteristics as well as steep amplitude increases in the intermediate and late coda, which can be related to the presence of a non-uniformly scattering medium. In this paper, we first show the results of a simulation with a statistical model considering anisotropic scattering interactions, in order to match coda-envelope duration and shape.We consider as realistic parameters for a volcanic caldera the presence of large square root velocity fluctuations (10 per cent) and two typical correlation lengths for such an heterogeneous crust, a = 0.1 and 1 km. Then, we propose the inclusion of a diffusive boundary condition in the stochastic description of multiple scattering, in order to model intermediate and late coda intensities, and particularly the sharp intensity peaks at some stations in the caldera. Finally, we show that a reliable 2-D synthetic model of the envelopes produced by earthquakes vertically sampling a small region can be obtained including a single drastic change of the scattering properties of the volcano, that is, a caldera rim of radius 3 km, and sections varying between 2 and 3 km. These boundary conditions are diffusive, which signifies that the rim must have more scattering potential than the rest of the medium, with its diffusivity 2–3 orders of magnitude lower than the one of the background medium, so that the secondary sources on its interface(s) could enhance coda intensities. We achieve a good first-order model of high-frequency (18 Hz) envelope broadening adding to the Monte Carlo solution for the incident flux the secondary source effects produced by a closed annular boundary, designed on the caldera rim signature at 1.5 km depth. At lower frequencies (3 Hz) the annular boundary controls the intermediate and late coda envelope behaviour, in a way similar to an extended diffusive source. In our interpretation, the anomalous intensities observed at several stations and predicted by the final Monte Carlo solutions are mainly due to the diffusive transmission reflection from a scattering object of increased scattering power, and are controlled by its varying thickness.
    Description: This work was carried out under the HPC-Europa2 project (project number: 228398) with the support of the European Commission Capacities Area-Research Infrastructures Initiative. We thank the whole staff at EPCC (Edinburgh Parallel Computing Centre) in Edinburgh and particularly Dr. Adam Carter for their help in both developing and parallelizing the code. The challenging comments and suggestions of the editor and two anonymous reviewers helped both in focusing the aim and in overcoming the strong limits of a previous version of the paper.
    Description: Published
    Description: 1102–1119
    Description: 3.1. Fisica dei terremoti
    Description: JCR Journal
    Description: restricted
    Keywords: Numerical solutions; ; Seismic anisotropy; ; Seismic attenuation ; Seismic tomography ; Wave scattering and diffraction ; Calderas ; 04. Solid Earth::04.06. Seismology::04.06.09. Waves and wave analysis
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 83
    Publication Date: 2021-04-07
    Description: Stable isotopes were measured in the carbonate and organic matter of palaeosols in the Somma–Vesuvius area, southern Italy in order to test whether they are suitable proxy records for climatic and ecological changes in this area during the past 18000 yr. The ages of the soils span from ca. 18 to ca. 3 kyr BP. Surprisingly, the Last Glacial to Holocene climate transition was not accompanied by significant change in d18O of pedogenic carbonate. This could be explained by changes in evaporation rate and in isotope fractionation between water and precipitated carbonate with temperature, which counterbalanced the expected change in isotope composition of meteoric water. Because of the rise in temperature and humidity and the progressive increase in tree cover during the Holocene, the Holocene soil carbonates closely reflect the isotopic composition of meteoric water. A cooling of about 2°C after the Avellino eruption (3.8 ka) accounts for a sudden decrease of about 1‰ in d18O of pedogenic carbonate recorded after this eruption. The d13C values of organic matter and pedogenic carbonate covary, indicating an effective isotope equilibrium between the organic matter, as the source of CO2, and the pedogenic carbonate. Carbon isotopes suggest prevailing C3 vegetation and negligible mixing with volcanogenic or atmospheric CO2.
    Description: Published
    Description: 813-824
    Description: 1V. Storia e struttura dei sistemi vulcanici
    Description: JCR Journal
    Description: restricted
    Keywords: stable isotope ; palaeosols ; Somma–Vesuvius ; palaeoclimate ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 84
    Publication Date: 2021-06-22
    Description: Operative seismic aftershock risk forecasting can be particularly useful for rapid decision-making in the presence of an ongoing sequence. In such a context, limit state first-excursion probabilities (risk) for the forecasting interval (a day) can represent the potential for progressive state of damage in a structure. This work lays out a performance-based framework for adaptive aftershock risk assessment in the immediate post-mainshock environment. A time-dependent structural performance variable is adopted in order to measure the cumulative damage in a structure. A set of event-dependent fragility curves as a function of the first-mode spectral acceleration for a prescribed limit state is calculated by employing back-to-back non- linear dynamic analyses. An epidemic-type aftershock sequence model is employed for estimating the spatio-temporal evolution of aftershocks. The event-dependent fragility curves for a given limit state are then integrated together with the probability distribution of aftershock spectral acceleration based on the epidemic-type aftershock sequence aftershock hazard. The daily probability of limit state first-excursion is finally calculated as a weighted combination of the sequence of limit state probabilities conditioned on the num- ber of aftershocks. As a numerical example, daily aftershock risk is calculated for the L’Aquila 2009 aftershock sequence (central Italy). A representative three-story reinforced concrete frame with infill panels, which has cyclic strength and stiffness degradation, is used in order to evaluate the progressive damage. It is observed that the proposed framework leads to a sound forecasting of limit state first-excursion in the structure for two limit states of significant damage and near collapse. Copyright © 2014 John Wiley & Sons, Ltd.
    Description: Published
    Description: 2179–2197
    Description: 3T. Pericolosità sismica e contributo alla definizione del rischio
    Description: JCR Journal
    Description: reserved
    Keywords: aftershock ; time-dependent reliability ; seismic risk ; etas modeling ; 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 85
    facet.materialart.
    Unknown
    Wiley-Blackwell
    In:  EPIC3Harmful Algal Blooms: A Compendium Desk Reference, Wiley-Blackwell, 12 p., pp. 563-574, ISBN: 978-1-118-99465-8
    Publication Date: 2018-06-28
    Description: The genus Alexandrium (Halim) is perhaps the most intensively studied among toxic marine dinoflagellates. This is largely attributable to the devastating consequences of toxigenic blooms of this genus, with human poisonings from contaminated seafood, primarily from shellfish and more rarely from finfish; socio–economic losses to the aquaculture and fisheries industries; marine faunal mortalities; and food web disruptions common in coastal waters throughout the world. Members of this genus are globally distributed from the Arctic to the tropics, and in both hemispheres from sub–polar through temperate to sub–tropical to tropicalwaters. At least four distinct groups of marine phycotoxins are associated with various Alexandrium species, along with poorly characterized bioactive compounds (allelochemicals) that may affect species interactions among the plankton. According to the most recent iteration of the IOC–UNESCO reference list of toxic microalgae, there are now more than 30 recognized morphological species of Alexandrium, posing a daunting challenge for risk assessment and accurate identification in toxic phytoplankton monitoring programs.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Inbook , peerRev
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  • 86
    facet.materialart.
    Unknown
    Wiley-Blackwell
    In:  EPIC3Climate Change Impacts on Fisheries and Aquaculture: A Global Analysis, Climate Change Impacts on Fisheries and Aquaculture: A Global Analysis, Wiley-Blackwell, pp. 663-701, ISBN: 978-1-119-15404-4
    Publication Date: 2017-10-09
    Description: Exploitation of Southern Ocean marine resources began more than 200 years ago with the massive hunt for seals and whales. In the 1960s/70s, fisheries for finfish and krill entered Southern Ocean waters. Within a few years many fish populations were heavily overfished and dramatically depleted, and some of these stocks still did not recover. Today, fish stocks and fisheries activities are managed and monitored by the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) which was established in 1982 to ensure sustainable exploitation and protection of the delicate marine ecosystem. Current target species include Mackerel icefish (Champsocephalus gunnari), Patagonian as well as Antarctic toothfish (Dissostichus eleginoides and D. mawsoni) and Antarctic krill (Euphausia superba). Most of these species are vulnerable to overfishing due to slow growth, late age at maturity, and rather low fecundity. This vulnerability might increase, as Southern Ocean living communities are currently also faced with alterations of their environment due to climate change, such as increasing water temperatures and decreasing sea ice. Species, including the ones targetted by fisheries, are well-adapted to their particular environmental conditions and are believed to be highly sensitive to changes because of their cold-adapted physiology, their life history traits, and their direct or indirect dependence on sea ice. The species will be exposed to several stressors at the same time, and fishing pressure, direct abiotic forcing and changes mediated via the food web might act synergistically and result in significant population declines. In particular the strongly sea ice-dependent Antarctic krill, a key species in the food web, might be adversely affected. Fish species seems to have low tolerance towards higher water temperatures and may thus, in the long run, be replaced by lower latitude species.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Inbook , peerRev
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  • 87
    facet.materialart.
    Unknown
    Wiley-Blackwell
    In:  EPIC3Harmful Algal Blooms: A Compendium Desk Reference, Wiley-Blackwell, 8 p., pp. 605-612, ISBN: 978-1-118-99465-8
    Publication Date: 2018-06-28
    Repository Name: EPIC Alfred Wegener Institut
    Type: Inbook , peerRev
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  • 88
    Publication Date: 2017-04-04
    Description: Prominent arrivals in the coda of seismograms from the wider Alpine area can be associated with lateral reflections of Love waves at the northern Apennines mountain chain (Italy), where structural heterogeneity causes an abrupt contrast in phase velocity. We discuss an approach to image lateral heterogeneity from reflected surface waves using intermediate-period, three- component coda waveforms as sources for an adjoint wavefield that propagates the reflections backward in time. We numerically compute three-dimensional sensitivity kernels for the dependence of coda waveforms on P velocity, S velocity and density, based upon correlations between the adjoint and the regular forward wavefields. We consider synthetic coda waveforms for a simplified model of the northern Apennines, as well as real coda observations from five moderate magnitude earthquakes (M W 4.6–5.6) in the southern Alps. Wave propagation is simulated using the spectral-element method, for which a 3-D regional earth model is used in the case of real data. Single and combined event sensitivity kernels provide clear images of the reflectivity associated with the northern Apennines in kernels for density and S-wave speed. The kernels show that surface wave reflections occur near the axial zone of the mountain chain. Apart from the Apennines, the approach is able to image other smaller reflectivity patches from the coda waveforms, like the Ivrea zone in the southern Alps. Our coda misfit kernels can be integrated in a gradient-based waveform tomography, where they could enhance the shar pness of the model at lateral discontinuities.
    Description: Published
    Description: 543–554
    Description: 3.3. Geodinamica e struttura dell'interno della Terra
    Description: JCR Journal
    Description: reserved
    Keywords: Tomography; ; Computational seismology ; Wave scattering and diffraction ; Crustal structure ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 89
    Publication Date: 2017-04-04
    Description: Stick-slip dynamic instability is a key mechanism governing frictional processes from microscale physics to earthquake faults and landslides; yet challenging questions are stil open about its nucleation and propagation dynamics. We present novel observations on laboratory experimental faults where spontaneously nucleating fractures are produced, describing (1) an initial quasistatic, stable rupture front accelerating to subshear and then intersonic velocity; 2) the arisal of a higher degree of complexity when the friction to prestress ratio is increased on the sliding surface. The complex behaviour includes stop and go sequences, irregular proportion and rerupturing episodes within short-time intervals, implying rapid restrengthening of the surface and the formation of self-healing pulses, reproducing experimentally for the first time a behaviour observed on seismic faults.
    Description: Published
    Description: 697-702
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: 3.1. Fisica dei terremoti
    Description: JCR Journal
    Description: reserved
    Keywords: Fractures and flow; friction; earthquake dynamics; Dynamics and mechanics of faulting ; 04. Solid Earth::04.04. Geology::04.04.06. Rheology, friction, and structure of fault zones
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 90
    Publication Date: 2017-04-04
    Description: The Montalbano Jonico (MJ) section, cropping out in Southern Italy, represents a potential candidate to define the Lower/Middle Pleistocene boundary and it has been proposed as a suitable Global Stratotype Section and Point (GSSP) of the Ionian Stage (Middle Pleistocene). The MJ section is the only continuous benthic and planktonic δ18O on-land reference in the Mediterranean area for the Mid-Pleistocene transition, spanning an interval between about 1240 and 645 ka. Combined biostratigraphy and sapropel chronology, tephra stratigraphy and complete high-resolution benthic and planktonic foraminiferal stable oxygen isotope records already provide a firm chronostratigraphic framework for the MJ section. However, magnetostratigraphy was still required to precisely locate the Brunhes-Matuyama transition and to mark the GSSP for the Ionian stage. We carried out a palaeomagnetic study of a subsection (Ideale section) of the MJ composite section, sampling 61 oriented cores from 56 stratigraphic levels spread over a ca. 80-m-thick stratigraphic interval that correlates to the oxygen isotopic stage 19 and should therefore include the Brunhes-Matuyama reversal. The palaeomagnetic data indicate a stable and almost single-component natural remanent magnetization (NRM). A characteristic remanent magnetization (ChRM) was clearly identified by stepwise demagnetization of the NRM. The ChRM declination values vary around 0◦ and the ChRM inclination around the expected value (59◦) for a geocentric axial dipole field at the sampling locality. This result indicates that the section has been remagnetized during the Brunhes Chron. A preliminary study of 27 additional not azimuthally oriented hand samples, collected at various levels from other parts of the MJ composite section, indicates that all the samples are of normal polarity and demonstrates that the remagnetization is widespread across the whole exposed stratigraphic sequence. A series of specific rock magnetic techniques were then applied to investigate the nature of the main magnetic carrier in the study sediments, and they suggest that the main magnetic mineral in the MJ section is the iron sulphide greigite (Fe3S4). Scanning electron microscope observations and elemental microanalysis reveal that greigite occurs both as individual euhedral crystals and in iron sulphides aggregates filling voids in the clay matrix. Therefore, we infer that the remagnetization of the section is due to the late-diagenetic growth of greigite under reducing conditions, most likely resulting in the almost complete dissolution of the original magnetic minerals. Iron sulphide formation in the MJ section can be linked to migration of mineralized fluids. Our inferred timing of the remagnetization associated with greigite growth represents the longest remanence acquisition delay documented in greigite-bearing clays of the Italian peninsula so far.
    Description: In press
    Description: 2.2. Laboratorio di paleomagnetismo
    Description: JCR Journal
    Description: open
    Keywords: Remagnetization ; 04. Solid Earth::04.05. Geomagnetism::04.05.06. Paleomagnetism ; 04. Solid Earth::04.05. Geomagnetism::04.05.07. Rock magnetism
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 91
    Publication Date: 2017-04-04
    Description: We present a high-resolution palaeomagnetic and rock magnetic study of two cores, MS06 and MS06-SW (6.7 and 1.1 m long, respectively), collected at 72 m below sea level in the Augusta Bay shelf (Eastern Sicily, Ionian Sea, Italy) about 2.3 kmfrom the coastline. Geophysical surveying carried out in the sampling area highlighted the presence of a homogeneous sedimentary sequence that most likely was deposited after the Last Glacial Maximum and was not affected by anthropogenic disturbances. The two cores penetrated a monotonous mud sedimentary sequence, interrupted at ∼3 m depth by a 3–4-cm-thick volcanic sandy layer that is correlated with the tephra fallout deposit produced by the 122 BC plinian eruption of Mt Etna. This tephra, along with radiocarbon dating of nine marine shells and with radioactive tracers for the uppermost 0.3 m (210Pb and 137Cs), provide the chronological constraints for the stratigraphic sequence that resulted younger than 4500 yr BP. Palaeomagnetic and rock magnetic data show that the sample sequence is magnetically homogeneous. A single peak of high magnetic mineral concentration is present and corresponds to the volcanic sandy layer. Palaeomagnetic data allowed the identification of a well-defined characteristic remanent magnetization that provides a high-resolution record of palaeosecular variation (PSV) at the sampling site. The reconstructed PSV curve is in good agreement with the available regional reference PSV curves and with the prediction from recent PSV modelling for Europe. The palaeomagnetic data obtained in this study on the one hand support and refine the age model for the cores, derived from other independent constraints, and on the other hand provide an original high-resolution PSV curve that can serve as a reference for the central Mediterranean over the last 4 ka.
    Description: In press
    Description: 2.2. Laboratorio di paleomagnetismo
    Description: JCR Journal
    Description: restricted
    Keywords: Palaeomagnetic secular variation ; Palaeointensity ; Marine magnetics and palaeomagnetics ; Europe ; 04. Solid Earth::04.05. Geomagnetism::04.05.02. Geomagnetic field variations and reversals ; 04. Solid Earth::04.05. Geomagnetism::04.05.06. Paleomagnetism
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 92
    Publication Date: 2017-04-04
    Description: The connection between Tropical Pacific and North Pacific variability is investigated in a state-of-the art coupled ocean-atmosphere model, comparing two 20th century simulations at T30 and T106 atmospheric horizontal resolutions. Despite a better simulation of the frequency and the spatial distribution of the Tropical Pacific anomalies associated with the El Nino Southern Oscillation (ENSO) in the high-resolution experiment, the response in the North Pacific is scarcely different from the low-resolution experiment where the ENSO variability is weaker and at higher than observed frequency. In the North Pacific, the response of surface atmospheric fields to the variability in the Tropical Pacific appears to be affected by local coupling processes significantly different in the two experiments. The coupling between sea level pressure (SLP) and sea surface temperature (SST) in the North Pacific as well as the influence of the Tropical Pacific SST has been measured here by means of the ‘coupled manifold’ technique. In the low-resolution case the SLP variances linked to the fraction of North Pacific SST not influenced by the Tropical Pacific are weak suggesting that the remote influence is strong, consistently with the observations. On the contrary, in the high-resolution experiment the fractions and the patterns of the SLP variances due to the Tropical Pacific SST and those linked to the North Pacific SST are comparable. In the latter case, model systematic errors in the northwestern Pacific influences the local coupling processes thus triggering the remote response. We conclude that an increased atmospheric horizontal resolution does not reduce the coupled model systematic errors in the representation of the teleconnection between the North and the Tropical Pacific and that the validation of coupled models has to consider both remote and local processes.
    Description: Published
    Description: 1640-1653
    Description: 3.7. Dinamica del clima e dell'oceano
    Description: JCR Journal
    Description: open
    Keywords: Tropical Pacific-North Pacific teleconnection ; ENSO ; coupled GCMs ; 01. Atmosphere::01.01. Atmosphere::01.01.02. Climate ; 01. Atmosphere::01.01. Atmosphere::01.01.04. Processes and Dynamics ; 03. Hydrosphere::03.01. General::03.01.03. Global climate models
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 93
    Publication Date: 2017-04-04
    Description: Edifice instability, that can result in catastrophic flank collapse, is a fundamental volcanic hazard. The subvolcanic basement can encourage such instability, especially if it is susceptible to mechanical weakening by devolatilization reactions near magmatic temperatures. For this reason, understanding how the physical and chemical properties of representative lithologies deteriorate at high temperatures is potentially highly relevant for volcanic hazard mitigation. This is particularly true for sedimentary rock, commonly found underlying volcanic edifices worldwide, that undergo rapid deterioration even under modest temperatures. Therefore, here we present the first experimental study of devolatilization reactions, induced by magmatic temperatures, on sedimentary rock comprising a subvolcanic basement. Our results show that, for a marly limestone representative of the basement at Mt Etna, devolatilization reactions, namely the dehydroxylation of clay minerals and the decarbonation of calcium carbonate, result in a dramatic reduction of mechanical strength and seismic velocities. These temperature-driven reactions can promote volcanic instability at stresses much lower than previously estimated.
    Description: Published
    Description: 1073–1077
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: JCR Journal
    Description: reserved
    Keywords: Phase transitions ; Experimental volcanism ; 04. Solid Earth::04.01. Earth Interior::04.01.04. Mineral physics and properties of rocks
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 94
    Publication Date: 2017-04-03
    Description: With the continued growth in availability of DInSAR and GPS data, space based geodesy has been widely applied to image the coseismic displacement field and to retrieve the static dislocation over the fault plane for almost all the significant earthquakes of the past two decades. This is performed by linear data inversion over a set of subfaults, generally characterized by a constant and predefined or manually adjusted dimensions. In this paper we propose a new algorithm to automatically retrieve an optimized fault subdivision in the linear inversion of coseismic geodetic data. The code iteratively keeps the parameter resolution close to a predefined high value. We first discuss the rationale supporting our algorithm and, after a detailed description of its implementation, we analyze the advantages of its introduction in the data inversion. The algorithm was tested against an exhaustive range of synthetic and real datasets and fault mechanisms. Among them, we present the results for the Mw 6.2, 2009 L’Aquila (Central Italy) earthquake and compare the new and previously published slip distributions showing the disappearance of misleading slip pattern and the increased resolution for shallower zones.
    Description: Published
    Description: 529-538
    Description: 1.10. TTC - Telerilevamento
    Description: JCR Journal
    Description: open
    Keywords: fault modelling ; geodetic data inversion ; 04. Solid Earth::04.03. Geodesy::04.03.07. Satellite geodesy
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 95
    Publication Date: 2017-04-04
    Description: The 2009 April 6, Mw= 6.3 L’Aquila earthquake occurred within a complex system of NW–SE trending normal faults in the Abruzzi Central Apennines (Italy). We analyse the coseismic deformation as measured by 〉70 global positioning system (GPS) stations, both from continuous and survey-mode networks, providing unprecedented details for a moderate normal faulting earthquake in Italy from GPS measurements. We use rectangular, uniform-slip, dislocations embedded in an elastic, homogeneous and isotropic half-space and a constrained, non-linear optimization algorithm, to solve for the best-fitting rectangular dislocation geometry and coseismic-slip distribution. We use a bootstrap approach to investigate uncertainties in the model parameters and define confidence bounds for all the inverted parameters. The rupture occurred on a N129°E striking and 50° southwestward dipping normal fault, in agreement with geological observations of surface breaks along the Paganica fault. Our distributed slip model exhibits a zone of relatively higher slip (〉60 cm) between ∼1.5 and ∼11 km depth, along a roughly downdip, NW–SE elongated patch, confined within the fault plane inverted assuming uniform-slip. The highest slip, of the order of ∼1 m, occurred on a ∼16 km2 area located at ∼5 km depth, SE of the mainshock epicentre. The analysis of model resolution suggests that slip at depth below ∼5 km can be resolved only at a spatial scale larger than 2 km, so a finer discretization of different asperities within the main patch of coseismic-slip is not allowed by GPS data. We compute the coseismic Coulomb stress changes in the crustal volume affected by the major aftershocks, and compare the results obtained from the uniform-slip and the heterogeneous-slip models. We find that most of the large aftershocks occurred in areas of Coulomb stress increase of 0.2–13 bar and that a deepening of the slip distribution down to a depth greater than 6 km in the SE part of the fault plane, in agreement with the inverted slip model, can explain the deepest, April 7, Mw 5.3 aftershock.
    Description: Published
    Description: 473-489
    Description: 1.9. Rete GPS nazionale
    Description: 3.2. Tettonica attiva
    Description: JCR Journal
    Description: reserved
    Keywords: Satellite geodesy ; Space geodetic surveys ; Earthquake ground motions ; Earthquake source observations ; Earthquake interaction, forecasting, and prediction ; 04. Solid Earth::04.03. Geodesy::04.03.01. Crustal deformations ; 04. Solid Earth::04.03. Geodesy::04.03.07. Satellite geodesy ; 04. Solid Earth::04.06. Seismology::04.06.01. Earthquake faults: properties and evolution ; 04. Solid Earth::04.06. Seismology::04.06.02. Earthquake interactions and probability ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 96
    Publication Date: 2017-04-04
    Description: We propose a method to introduce a refined representation of the ground motion in the framework of the Probabilistic Seismic Hazard Analysis (PSHA). This study is especially oriented to the incorporation of a priori information about source parameters, by focusing on the directivity effect and its influence on seismic hazard maps. Two strategies have been followed. One considers the seismic source as an extended source, and it is valid when the PSHA seismogenetic sources are represented as fault segments. We show that the incorporation of variables related to the directivity effect can lead to variations up to 30% of the hazard level, in terms of spectral acceleration response at 5 sec., exceeding probability of 10% in 50 years. The second one concerns the more general problem of the seismogenetic areas, where each point is a seismogenetic source having the same chance of enucleate a seismic event. In our proposition the point source is associated to the rupture-related parameters, defined using a statistical description. As an example, we consider a source point of an area characterized by strike slip faulting style. With the introduction of the directivity correction the modulation of the hazard map reaches values up to 100%. The introduction of directivity does not increase uniformly the hazard level, but acts more like a redistribution of the estimation that is consistent with the fault orientation. A general increase appears only when no a-priori information is available. However, nowadays good a-priori knowledge exists on style of faulting, dip and orientation of faults associated to the majority of the seismogenetic zones of the present seismic hazard maps. Following this method, all the information collected may be easily converted to obtain a more comprehensive and meaningful probabilistic Seismic Hazard formulation.
    Description: Published
    Description: 616-626
    Description: 4.1. Metodologie sismologiche per l'ingegneria sismica
    Description: JCR Journal
    Description: reserved
    Keywords: Earthquake ground motion ; Earthquake source observation ; Probabilistic Seismic Hazard ; 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 97
    Publication Date: 2017-04-04
    Description: The occurrence of crystallized and glassy melt inclusions (MI) in high-grade, partially melted metapelites and metagraywackes has opened up new possibilities to investigate anatectic processes. The present study focuses on three case studies: khondalites from the Kerala Khondalite Belt (India), the Ronda migmatites (Spain), and the Barun Gneiss (Nepal Himalaya). The results of a detailed microstructural investigation are reported, along with some new microchemical data on the bulk composition of MI. These inclusions were trapped within peritectic garnet and ilmenite during crystal growth and are therefore primary inclusions. They are generally isometric and very small in size, mostly £15 lm, and only rarely reaching 30 lm; they occur in clusters. In most cases inclusions are crystallized ( nanogranites ) and contain a granitic phase assemblage with quartz, feldspar and one or two mica depending on the particular case study, commonly with accessory phases (mainly zircon, apatite, rutile). In many cases the polycrystalline aggregates that make up the nanogranites show igneous microstructures, e.g. granophyric intergrowths, micrographic quartz in K-feldspar and cuneiform rods of quartz in plagioclase. Further evidence for the former presence of melt within the investigated inclusions consists of melt pseudomorphs, similar to those recognized at larger scale in the host migmatites. Moreover, partially crystallized inclusions are locally abundant and together with very small (£8 lm) glassy inclusions may occur in the same clusters. Both crystallized and partially crystallized inclusions often display a diffuse nanoporosity, which may contain fluids, depending on the case study. After entrapment, inclusions underwent limited microstructural modifications, such as shape maturation, local necking down processes, and decrepitation (mainly in the Barun Gneiss), which did not influence their bulk composition. Re-homogenized nanogranites and glassy inclusions show a leucogranitic and peraluminous composition, consistent with the results of partial melting experiments on metapelites and metagraywackes. Anatectic MI should therefore be considered as a new and important opportunity to understand the partial melting processes.
    Description: Published
    Description: 303-322
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: JCR Journal
    Description: restricted
    Keywords: garnet ; melt inclusions ; melt microstructures ; migmatites ; nanogranite ; 04. Solid Earth::04.04. Geology::04.04.05. Mineralogy and petrology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 98
    Publication Date: 2017-04-03
    Description: Campi Flegrei collapse caldera (Italy) is a high-risk volcanic area located close to Naples and includes part of the densely populated city. This area is characterised by large up and down ground displacements. The last large uplift episode caused 3.5 m of cumulative vertical displacement at the centre of the town of Pozzuoli, during the period 1969–1984. Up and down ground movements in this area often occur without intercurring eruptions and are similar to what is observed at other calderas worldwide. Here, however, they appear more evident and amplified. Understanding the mechanism of such movements is crucial for hazard assessment and eruption forecast, mainly due to this densely populated area. This paper presents a detailed model for ground displacements due to deep fluid injection in shallower layers. Such a model explains in a natural way the occurrence of uplift and subsidence without eruptions. We show that it is possible to fit observed ground deformation in this area with a thermofluid dynamical model. The model obtained is also consistent with other observations like microgravity changes, changes in CO2 flux, etc. Here, we suggest that significant uplift and subsidence at calderas can be due to effects of deep fluid injections other than magma. At Campi Flegrei, however, a partial magmatic contribution at the origin of the observed episodes cannot be excluded.
    Description: Published
    Description: 833–847
    Description: JCR Journal
    Description: restricted
    Keywords: Numerical approximations and analysis; Hydrothermal systems; Explosive volcanism; Calderas ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 99
    Publication Date: 2017-04-04
    Description: Two direct search methods, simulated annealing and neighbourhood algorithm, are applied to the inversion of the viscosity profile of the mantle using relative sea level time-histories for the Hudson Bay region. In problems characterized by a low-dimensional model space (Nd = 2 in this study), the two inversion methods show comparable performances. When a larger number of dimensions is involved (specifically Nd = 6), we directly show that simulated annealing is less effective than neighbourhood algorithm in overcoming the obstacles that are found in the model space when our specific data set is employed. This study confirms that modifications of the conventional Monte Carlo inversion method, such as simulated annealing and neighbourhood algorithm, are viable tools to determine the viscosity profile of the mantle, which, until recently, has been mainly tackled by means of linearized techniques.
    Description: Published
    Description: 890-900
    Description: 3.3. Geodinamica e struttura dell'interno della Terra
    Description: JCR Journal
    Description: restricted
    Keywords: mantle viscosity ; simulated annealing ; neighbourhood algorithm ; postglacial rebound ; 04. Solid Earth::04.01. Earth Interior::04.01.03. Mantle and Core dynamics
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 100
    Publication Date: 2017-04-03
    Description: In the first part of this work, we make use of two non-parametric statistical pattern recognition algorithms and a multiple regression analysis to analyse seismic clusters occur ring around Mount Etna, Italy. The aim is to determine if the onset of flank eruptions at Mount Etna is linked to variations in the regional seismicity at a timescale of few weeks. From the analysis, we find that the discrimination between clusters preceding flank eruptions and clusters not related in time to flank activity is mainly linked to the volume output of the previous flank eruption, in some cases together with the time elapsed from its end. Instead, we do not find any difference in the seismicity features characterizing different types of clusters, except for a very small contribution of the number of seismic events in the clusters. This result does not confirm the existence, suggested in the past, of a direct link between the regional state of stress at a timescale of few weeks and the occurrence of flank eruptions on Mount Etna volcano. On the contrary, the result suggests that a prominent role in the flank eruption occur rence is played by the re-charging of the feeding system. In the second part of this study we analyse the relationship between the magma volume erupted in an eruption and the interevent time following it, finding that a ‘time-predictable model’ satisfactorily describes the occurrence of eruptions at Mount Etna in the last decades. The latter analysis is car ried out both on the flank eruption catalogue only, and on the complete catalogue of flank and summit eruptions, with comparable results.
    Description: Published
    Description: 1203–1218
    Description: JCR Journal
    Description: restricted
    Keywords: flank eruptions ; Mount Etna volcano ; regional tectonic stress ; statistical pattern recognition ; time predictability ; 05. General::05.01. Computational geophysics::05.01.04. Statistical analysis
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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