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  • 1
    Publication Date: 2024-06-14
    Description: Gas chimneys and gas clouds in the subsurface media are known as one of the indications of possible petroleum reservoirs. Investigations of their properties are mostly initiated by seismic attribute interpretation on reflection seismic data. However, due to the complexity of their behavior and their difficult interpretation of seismic attributes, state-of-the-art methods are mostly required to be applied on the seismic data to prevent any misinterpretation. This is mostly done through attribute integration and multi-attribute analysis. This research presents a study on seismic attributes and integration on several 2D seismic reflection lines from the Gorgan Plain. It is located in Northeast Iran, on the western border of the region’s well-known Kopeh-Dagh fold and thrust belt, and southeastern border of the South Caspian Basin. Hydrocarbon systems of the Gorgan Plain are poorly known and have not been widely studied, but according to preliminary investigations, this region has the potential for hydrocarbon occurrences. The aim of this study is to investigate presence and then delaminate the affected area of possible gas chimneys that are related to possible hydrocarbon reservoirs. Gas chimneys are assumed to be created due to the routes, mostly made by faults, that provoke light hydrocarbons components to migrate toward the surface. Preliminary interpretations of seismic reflection data in this study revealed that at least two gas chimneys occurred within the Gorgan Plain. As it was mentioned, since they are mostly due to the faulting above the hydrocarbon reservoir, gas chimney and heavy faulting might exhibit the same effects on the seismic data and then on its attributes, which are amplitude reduction and high damping on energies, distortion of the waveshape and seismic velocity reduction. Thus, care should be taken in separation of these two different geologic phenomena on seismic attributes. This also was done in this study through utilized integration of the most relevant seismic attributes such as Instantaneous-phase, Chaos, Variance and Remove-bias attributes. Based on the result of interpretations and according to the evolution of the basin and its structural reconstruction on other studies, gas chimneys of the Gorgan Plain, are in relation to the operation of fault zones in Cenozoic erathem in the region. These fault zones which cut the entire Cenozoic erathem, create the pathway for vertical migration of hydrocarbons through Cheleken formation (reservoir rock) and its overburden sedimentary sequences. In other words, operation of fault zones within Cenozoic sedimentary sequence, is the main reason for gas seepage in the Gorgan Plain, which is also shown in seismic data.
    Type: Article , PeerReviewed
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  • 2
    Publication Date: 2024-06-10
    Description: Weather causes extremes in photovoltaic and wind power production. Here we present a comprehensive climatology of anomalies in photovoltaic and wind power production associated with weather patterns in Europe considering the 2019 and potential 2050 installations, and hourly to ten-day events. To that end, we performed kilometer-scale numerical simulations of hourly power production for 23 years and paired the output with a weather classification which allows a detailed assessment of weather-driven spatio-temporal production anomalies. Our results highlight the dependency of low-power production events on the installed capacities and the event duration. South-shifted Westerlies (Anticyclonic South-Easterlies) are associated with the lowest hourly (ten-day) extremes for the 2050 (both) installations. Regional power production anomalies can differ from the ones in the European mean. Our findings suggest that weather patterns can serve as indicators for expected photovoltaic and wind power production anomalies and may be useful for early warnings in the energy sector.
    Type: Article , PeerReviewed
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  • 3
    Publication Date: 2024-06-07
    Description: Marine sponges and other sessile macro-organisms were collected at a shallow water hydrothermal site in Eyjafjörður, Iceland. Bacteria were isolated from the organisms using selective media for actinomycetes, and the isolates were screened for antimicrobial activity. A total of 111 isolates revealed antimicrobial activity displaying different antimicrobial patterns which indicates production of various compounds. Known test strains were grown in the presence of ethyl acetate extracts from one selected isolate, and a clear growth inhibition of Staphylococcus aureus was observed down to 0.1 % extract concentration in the medium. Identification of isolates shows different species of Actinobacteria with Streptomyces sp. playing the largest role, but also members of Bacilli, Alphaproteobacteria and Gammaproteobacteria. Sponges have an excellent record regarding production of bioactive compounds, often involving microbial symbionts. At the hydrothermal vents, however, the majority of active isolates originated from other invertebrates such as sea anemones or algae. The results indicate that antimicrobial assays involving isolates in full growth can detect activity not visible by other methods. The macro-organisms inhabiting the Eyjafjörður hydrothermal vent area host diverse microbial species in the phylum Actinobacteria with antimicrobial activity, and the compounds responsible for the activity will be subject to further research.
    Type: Article , PeerReviewed
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  • 4
    Publication Date: 2024-06-05
    Description: Animals have a deep evolutionary relationship with microbial symbionts, such that individual microbes or an entire microbial community can diverge alongside the host. Here, we explore these host-microbe relationships in Echinometra, a sea urchin genus that speciated with the Isthmus of Panama and throughout the Indo-West Pacific. We find that the eggs from five Echinometra species generally associate with a species-specific bacterial community and that the relatedness of these communities is largely congruent with host phylogeny. Microbiome divergence per million years was higher in more recent speciation events than in older ones. We, however, did not find any bacterial groups that displayed co-phylogeny with Echinometra. Together, these findings suggest that the evolutionary relationship between Echinometra and their microbiota operates at the community level. We find no evidence suggesting that the associated microbiota is the evolutionary driver of Echinometra speciation. Instead, divergence between Echinometra and their microbiota is likely the byproduct of ecological, geographic, and reproductive isolations.
    Type: Article , PeerReviewed
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  • 5
    Publication Date: 2024-05-30
    Description: Past vegetation, fire, and climate dynamics, as well as human impact, have been reconstructed for the first time in the highlands of the Gilan province in the Alborz mountains (above the Hyrcanian forest) for the last 4,300 cal yrs bp. Multi-proxy analysis, including pollen, spores, non-pollen palynomorphs, charcoal, and geochemical analysis, has been applied to investigate the environmental changes at 2,280 m a.s.l., above the Hyrcanian forest. Dominant steppe vegetation occurred in the study area throughout the recorded period. The formation of the studied mire deposits, as well as vegetation composition, suggest a change to wetter climatic conditions after 4,300 until 1,700 cal yrs bp. Fires were frequent, which may imply long-lasting anthropogenic activities in the area. Less vegetation cover with a marked decrease of the Moisture Index (MI) suggests drier conditions between 1,700 and 1,000 cal yrs bp. A high proportion of Cichorioideae and Amaranthaceae, as well as the reduction of trees, in particular Fagus and Quercus, at lower elevations, indicate human activities such as intense livestock grazing and deforestation. Soil erosion as the result of less vegetation due to dry conditions and/or human activities can be reconstructed from a marked increase of Glomus spores and high values of K and Ti. Since 1,000 cal yrs bp, the increasing MI, as well as the rise of Poaceae and Cyperaceae together with forest recovery, suggest a change to wetter conditions. The occurrence of still frequent Cichorioideae and Plantago lanceolata along with Sordaria reflect continued intense grazing of livestock by humans.
    Description: Deutsche Forschungsgemeinschaft (DE)
    Description: Georg-August-Universität Göttingen (1018)
    Keywords: ddc:561 ; Late Holocene ; Northern Iran ; Multi-proxy studies ; Hyrcanian mountain vegetation ; Climate change ; Human impact
    Language: English
    Type: doc-type:article
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  • 6
    Publication Date: 2024-05-28
    Description: Until now, proxy records have been the primary tool for quantitative reconstructions of the physical world of the ancient and late antique Mediterranean. This chapter demonstrates the combined use of proxy datasets and the hitherto underutilized potential of earth system models in the scientific and historical study of past environmental variations and impacts on human societies. Results from model simulations are able to explain hydroclimatic anomalies observed in the proxy records and provide links to relevant mechanisms. The Late Roman Dry Period and the Late Roman Wet Period of the mid-fourth to early eighth centuries AD are each associated with the increase in the frequency of subsistence crises and with the accelerated infrastructural adaptations of communities and agricultural expansion, respectively. The chapter concludes with an examination of the historical and climatic contexts behind one such anomaly, a subsistence crisis in Cappadocia in the late 300s AD.
    Type: Book chapter , NonPeerReviewed
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  • 7
    Publication Date: 2024-05-23
    Description: Es werden mögliche Beiträge geologischer und mariner Kohlenstoffspeicher für die Vermeidung von CO2-Emissionen in die Atmosphäre oder für die Entnahme von bereits emittiertem CO2 aus der Atmosphäre vorgestellt. Neben der Einlagerung von CO2 in geologischen Speichern unter Land und unter dem Meeresboden werden eine forcierte CO2-Entnahme aus der Atmosphäre und Abgabe in den Ozean durch Erhöhung der Alkalinität, durch Ozeandüngung und durch das Management vegetationsreicher Küstenökosysteme untersucht. Alle Optionen können sowohl global als auch aus deutscher Perspektive eine Rolle für das Erreichen der Klimaziele spielen. Umweltverträglichkeit, Permanenz der Speicherung sowie infrastrukturelle und rechtliche Voraussetzungen, gesellschaftliche Akzeptanz und wirtschaftliche Realisierbarkeit bedürfen für alle Ansätze weiterer Klärung, bevor hieraus realisierbare Optionen werden können.
    Type: Book chapter , NonPeerReviewed
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  • 8
    Publication Date: 2024-05-15
    Description: The macrofauna in soft sediments of the deep seafloor is generally diverse and represents a comparatively well-studied faunal group of deep-sea ecosystems. In the abyss of the Clarion Clipperton Fracture Zone (CCFZ) in the NE Pacific, macrofauna are major contributors to benthic biodiversity. Their distribution, composition, and diversity have been frequently investigated to assess the potential impacts of future mining activities on the resident fauna. In this study, patterns of densities and community structure of CCFZ macrobenthic infauna and their relationships with a range of environmental and climatic variables were examined, with a special focus on communities from the eastern German contract area (referred to as BGR CA). However, comparisons were also made with other contractor areas (e.g., IFREMER, IOM, GSR) and one Area of Particular Environmental Interest (APEI3). Material for this study was obtained by means of a box corer during six expeditions to the CCFZ between 2013 and 2018 resulting in 148 samples. Our study uncovered notable spatial and temporal variations in both faunal densities and community composition. While areas within the BGR CA exhibited a similar community composition, slight differences were observed between the various CAs and APEI3. Surprisingly, we found an unexpected negative correlation between food availability and both macrofaunal density and community structure that may be attributed to differences in sampling methodologies and pronounced temporal variation. Furthermore, we explored the impact of climatic fluctuations associated with the El Niño/Southern Oscillation (ENSO) on macrofaunal densities, observing an increase during warm (El Niño) events. Our findings underscore the challenges of accurately assessing spatial and temporal variations in the absence of standardised sampling protocols. Hence, we emphasize the importance of adopting standardised protocols to enhance data comparability, thereby fostering a deeper understanding of the underlying factors influencing spatial and temporal changes in macrofauna community structure within the CCFZ.
    Type: Article , PeerReviewed
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  • 9
    Publication Date: 2024-05-14
    Description: This paper represents a continuation of taxonomic publications on the benthic fauna of polymetallic nodule fields in the eastern Clarion-Clipperton Zone (CCZ) using material collected during baseline environmental survey work targeting two exploration contract areas (“UK-1” and “OMS”) and one Area of Particular Environmental Interest, “APEI-6.” Families Poecilochaetidae Hannerz, 1956 and Spionidae Grube, 1850 of the annelid suborder Spioniformia were studied here. Taxonomic data are presented for 25 species from 98 records as identified by a combination of morphological and genetic approaches. Although sub-optimal morphological condition can prevent new species being formally described, it is essential that morphological, molecular, and voucher data are made available for future surveys. Descriptions of two new species— Poecilochaetus brenkei sp. nov. and Laonice shulseae sp. nov.—increase the number of formally described new annelid species from the areas targeted in this study to 15 and CCZ-wide to 46. We also discuss the commonly reported “cosmopolitan” deep-sea spionid Aurospio dibranchiata Maciolek, 1981, which we show represents several genetically distinct species (three of these from CCZ area alone) but without reliable morphological characters to separate them. Molecular data provide evidence that 15 out of 25 species reported here have a wide distribution within the eastern CCZ and that Aurospio sp. “NHM_2186” and the known species Prionospio amarsupiata Neal & Altamira in Paterson et al. 2016 may be cosmopolitan. Lastly, the molecular data provide insights into relationships within Spioniformia, suggesting that both Poecilochaetidae and Trochochaetidae belong within Spionidae.
    Type: Article , PeerReviewed
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  • 10
    Publication Date: 2024-05-14
    Description: Holothurians are the dominant megabenthic deposit feeders in the Peru Basin (SE Pacific) and feed to various degrees of selectivity on a heterogenous pool of sedimentary detritus, but drivers of feeding selectivity and diet preferences for most holothurian species are unknown. This study reconstructs the diets of 13 holothurian species of the orders Elasipodida, Holothuriida, and Synallactida. Bulk stable isotope analyses (δ13C, δ15N) of holothurian body wall and gut wall tissues, gut contents, and feces were combined with compound-specific stable isotope analyses of amino acids, phospholipid-derived fatty acids, and neutral-lipid-derived fatty acids in the body wall. We further assessed how holothurians in the Peru Basin partition their resources and calculated how much of the daily particulate organic carbon (POC) flux to the area is ingested by them using information about gut contents of nine species. To assess the dependence of holothurians on fresh phytodetritus, we performed in situ pulse-chase experiments using 13C- and 15N-enriched phytodetritus. By measuring the uptake of this phytodetritus in fatty acids and amino acids and by comparing it with the presence of these compounds in the sediment, we calculated net accumulation and net deficiency for specific fatty acids and amino acids and discussed how climate change might affect the dependence on specific compounds. A Sørensen–Dice coefficient-based cluster analysis using data from trophic levels, levels of heterotrophic re-synthesis of amino acids, feeding selectivity, and food sources/diet suggested two major trophic groups with two optional subgroups each. Species-specific traits of locomotion, tentacle morphology, and gut structure likely allow resource partitioning and differences in selectivity among the holothurians, of which a subpopulation of 65% of all specimens can ingest 4 to 27% of the daily POC flux to the Peru Basin. Holothurians are specifically dependent on the uptake of arachidonic acid from phytodetritus, while most essential amino acids are available in the Peru Basin in sufficient concentrations.
    Type: Article , PeerReviewed
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