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  • 1
    Publication Date: 2023-09-21
    Description: The Central and South Atlantic represents a vast ocean area and is home to a diverse range of ecosystems and species. Nevertheless, and similar to the rest of the global south, the area is comparatively understudied yet exposed to increasing levels of multisectoral pressures. To counteract this, the level of scientific exploration in the Central and South Atlantic has increased in recent years and will likely continue to do so within the context of the United Nations (UN) Decade of Ocean Science for Sustainable Development. Here, we compile the literature to investigate the distribution of previous scientific exploration of offshore (30 m+) ecosystems in the Central and South Atlantic, both within and beyond national jurisdiction, allowing us to synthesise overall patterns of biodiversity. Furthermore, through the lens of sustainable management, we have reviewed the existing anthropogenic activities and associated management measures relevant to the region. Through this exercise, we have identified key knowledge gaps and undersampled regions that represent priority areas for future research and commented on how these may be best incorporated into, or enhanced through, future management measures such as those in discussion at the UN Biodiversity Beyond National Jurisdiction negotiations. This review represents a comprehensive summary for scientists and managers alike looking to understand the key topographical, biological, and legislative features of the Central and South Atlantic.
    Type: Book chapter , PeerReviewed
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  • 2
    Publication Date: 2024-02-07
    Description: Coarse woody habitat (CWH) is an important structural habitat in freshwater ecosystems. In natural lakes, CWH accumulates over centuries alongside the succession of littoral tree communities. Newly created gravel pit lakes have difficulties in accumulating CWH due to their young age. Additionally, CWH presence might be negatively affected by shoreline development, where wood is removed to facilitate recreational activities such as angling. We studied 26 gravel pit lakes with an age ≤ 55 yrs in Lower Saxony, Germany, to quantify CWH density and to understand the impact of environmental factors, including lake morphology, lake age, wind direction, abundance of riparian trees, and the presence or absence of fisheries management, on CWH density. We sampled small and large CWH in the littoral zone of the study lakes using a transect-based approach. Density of CWH was lower in German gravel pit lakes than in North American natural lakes. In gravel pit lakes, we detected increasing densities of small CWH with increasing numbers of large trees on the shore and with increasing littoral slopes in lakes managed for recreational fisheries. Large CWH density was positively affected by lake age, by the density of large trees on the shore and with wind from land, and again by steep littoral slopes in lakes managed for recreational fisheries. We recommend that recreational fisheries managers and individual anglers maintain CWH in shallow littoral zones to promote fish habitats in generally low-structured gravel pit lakes.
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  • 3
    Publication Date: 2024-02-07
    Description: Cambrian igneous rocks in the Takaka Terrane of New Zealand provide important constraints for geodynamic reconstructions of the Cambrian SE Gondwana margin. We provide field data and a comprehensive trace element and isotope dataset for such rocks from the upper Baton River area in northwest Nelson, New Zealand, including the first combined Hf-Nd isotope data for Takaka Terrane rocks. These submarine volcanic rocks, known as Mataki and Benson volcanics of the Devil River Volcanics Group, are both interbedded with Haupiri Group sediments, providing a previously not observed direct stratigraphic link between the two volcanic units. Incompatible element abundances of Mataki Volcanics display a full spectrum from subduction-modified back-arc-tholeiites to E-MORB type tholeiites. Initial Hf-Nd isotope compositions are coupled, spanning a range from MORB-like to OIB-like compositions. The MORB-like endmember (initial ϵNd +7 and ϵHf +13), taps moderately depleted asthenospheric mantle. If extrapolated to present-day composition, this depleted mantle endmember does not resemble modern Pacific-type mantle, suggesting formation in a back-arc basin separated from Pacific mantle by a continent-ward, intra-oceanic subduction zone. The enriched asthenospheric mantle endmember in the Mataki Volcanics may be an equivalent to the sources of Neoproterozic or middle Cambrian intra-continental flood basalts in central and SE-Australia.
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  • 4
    Publication Date: 2024-02-07
    Description: Long-term changes in the life history and behaviour of seabirds during the non-breeding season can reflect shifts in environmental conditions. However, long-term marine studies are scarce, particularly on southern hemisphere seabirds. Here, we used moult scores from 86 Brown Skuas (Stercorarius antarcticus lonnbergi), a large predatory seabird breeding on the Chatham Islands, Aotearoa/New Zealand to model both the timing and duration of primary feather moult. In addition, we analysed stable isotope values (δ13C and δ15N) from 62 modern (2014–16) and ten museum tail feathers. These data provide insights into the non-breeding behaviour of Brown Skua. Interestingly, our results show that the primary feather moult occurred prior to birds departing the colony, starting on average on 2 January ± 5 days (SE). The average start of primary feather moult occurred five days prior to the end of breeding (7 January ± 10 days (SD)) and 42 days before the birds departed the colony (13 February ± 11 days (SD)). The average duration of primary feather moult was 189 ± 14 days (SE). Importantly, low δ13C values in four females suggested that tail feather moult might also occur while skuas are at the colony. There was no difference in tail feather δ13C and δ15N values between any pairwise comparison of modern and museum years. However, values of δ15N from tail feathers sampled in 2014 were different from those sampled in 2015 and 2016. This large annual variation in δ15N values from tail feathers over such a short period makes long-term comparisons difficult to interpret, particularly between years with low sample sizes. While the stable isotope analyses of tail feathers are informative, we recommend future studies of skuas sample the primary coverts rather than tail feathers.
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  • 5
    Publication Date: 2022-09-23
    Description: Carbon Dioxide Removal (CDR) will be necessary to fulfil the hundreds of pledges to reach net-zero by 2050. As with any industry, standard methodologies and certification are crucial to guarantee successful and reliable activities. However, buyers and policymakers currently face challenges in evaluating the ecosystem of CDR certification. The issue is not with CDR, nor with individual certifications – some of which may be very robust – but with the lack of transparency in the overall ecosystem. To bring some clarity, we present a snapshot of the CDR certification and standards ecosystem for the year 2021–2022. We find a complex ecosystem with at least 30 standard developing organizations proposing at least 125 standard methodologies for carbon removal from 23 different CDR activities and selling 27 different versions of certification instruments in voluntary and compliance markets. This exercise reveals many more existing standards for nature-based than for engineering-based activities and more diversity from standards serving the voluntary rather than the compliance market. It also highlights a proliferation of standards for the same activity, and a plethora of activities without standards. The process revealed ambiguity on what constitutes carbon removal, with many standards certifying activities that remove CO2 already in the environment as well as activities that avoid or reduce new emissions by sequestering the carbon into reservoirs. This mapping highlights key gaps and potential starting points for reforms to strengthen the CDR certification industry; it also underscores the need for independent oversight.
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  • 6
    Publication Date: 2023-01-04
    Description: The prediction of a spatial variable is of particular importance when analyzing spatial data. The main objective of this study is to evaluate and compare the performance of several prediction-based methods in spatial prediction through a simulation study. The studied methods include ordinary Kriging (OK), along with several neural network methods including Multi-Layer Perceptron network (MLP), Ensemble Neural Networks (ENN), and Radial Basis Function (RBF) network. We simulated several spatial datasets with three different scenarios due to changes in data stationarity and isotropy. The performance of methods was evaluated using the Root Mean Square Error (RMSE), Mean Absolute Error (MAE) and Concordance Correlation Coefficient (CCC) indexes. Although the results of the simulation study revealed that the performance of the neural network in spatial prediction is weaker than the Kriging method, but it can still be a good competitor for Kriging.
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  • 7
    Publication Date: 2024-01-08
    Description: Algae are the oldest representatives of the plant world with reserves exceeding hundreds of millions of tons in the world's oceans. Currently, a growing interest is placed toward the use of algae as feedstocks for obtaining numerous natural products. Algae are a rich source of polyphenols that possess intriguing structural diversity. Among the algal polyphenols, phlorotannins, which are unique to brown seaweeds, and have immense value as potent modulators of biochemical processes linked to chronic diseases. In algae, flavonoids remain under-explored compared to other categories of polyphenols. Both phlorotannins and flavonoids are inclusive of compounds indicating a wide structural diversity. The present paper reviews the literature on the ecological significance, biosynthesis, structural diversity, and bioactivity of seaweed phlorotannins and flavonoids. The potential implementation of these chemical entities in functional foods, cosmeceuticals, medicaments, and as templates in drug design are described in detail, and perspectives are provided to tackle what are perceived to be the most momentous challenges related to the utilization of phlorotannins and flavonoids. Moving beyond: industrial biotechnology applications, metabolic engineering, total synthesis, biomimetic synthesis, and chemical derivatization of phlorotannins and flavonoids could broaden the research perspectives contributing to the health and economic up-gradation.
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  • 8
    Publication Date: 2024-02-07
    Description: Wetlands physical and biological processes are fundamental to the distribution and structuring of organic matter in sediments. This study investigated spatial and temporal changes in organic matter sources in sediments within the Nylsvley Wetland, South Africa across two seasons, five sites and three wetland zones and identified pertinent contributors to sediment organic matter. Results showed distributions were uneven throughout the wetlands, with the seasonal zone having slightly high sediment organic matter in the cool-dry season and the permanent zone had high sediment organic matter in the hot-wet season, whereas the temporary zone had low SOM concentrations. Significant differences in nutrient concentrations were observed across wetland zones and seasons for Phosphorous, Potassium, Calcium and Magnesium, with the seasonal zone tending to be the most nutrient-rich in the cool-dry season, and with permanent zone nutrient levels rising substantially in the hot-wet season. Sediment δ13C differed significantly among wetland zones, whereas δ15N was statistically similar. Autochthonous plants were the main sources of organic matter in sediments overall across sites and zones. This study’s findings help to better understand the distribution of organic matter in wetland ecosystems and the role wetland zones play in the seasonal provisioning of allochthonous inputs.
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  • 9
    Publication Date: 2024-02-14
    Description: Glacio-eustatic cycles lead to changes in sedimentation on all types of continental margins. There is, however, a paucity of sedimentation rate data over eustatic sea-level cycles in active subduction zones. During International Ocean Discovery Program Expedition 375, coring of the upper ∼110 m of the northern Hikurangi Trough Site U1520 recovered a turbidite-dominated succession deposited during the last ∼45 kyrs (Marine Isotope Stages (MIS) 1–3). We present an age model integrating radiocarbon dates, tephrochronology, and δ18O stratigraphy, to evaluate the bed recurrence interval (RI) and sediment accumulation rate (SAR). Our analyses indicate mean bed RI varies from ∼322 yrs in MIS1, ∼49 yrs in MIS2, and ∼231 yrs in MIS3. Large (6-fold) and abrupt variations in SAR are recorded across MIS transitions, with rates of up to ∼10 m/kyr occurring during the Last Glacial Maximum (LGM), and 〈1 m/kyr during MIS1 and 3. The pronounced variability in SAR, with extremely high rates during the LGM, even for a subduction zone, are the result of changes in regional sediment supply associated with climate-driven changes in terrestrial catchment erosion, and critical thresholds of eustatic sea-level change altering the degree of sediment bypassing the continental shelf and slope via submarine canyon systems.
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  • 10
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    Taylor & Francis
    In:  Critical Reviews in Environmental Science and Technology . pp. 1-52.
    Publication Date: 2021-06-25
    Description: Traceability and reliable results are the two pillars of analytical methods; certified reference materials (CRMs) meet this requirement. ISO 17034:2016 credentials provide brief information on general requirements for the competence of Reference Material Producers (RMPs). The different types of CRMs have been produced in recent years for chemical analysis in food, water, soil, and sediment matrices in recent years. This review provides a detailed overview of the development of CRMs in the field of marine environment, as matrix CRMs play an important role in the field of environmental monitoring. COMAR database, EVISA database: materials, LGC standards, and JRC catalogs are very helpful online resources to find various types of CRMs according to the application requirements. Highlights - The classification of certified reference materials (CRMs) in the field of marine environment is presented; - General information about the production and characteristics of CRMs is discussed; - Examples of use of existing marine CRMs are described in detail; - Importance of CRMs for QA/QC and CRMs development for chemical analysis is presented; - The parameters that characterize the CRMs: representativeness, homogeneity, stability, and certified value are provided.
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  • 11
    Publication Date: 2022-01-07
    Description: Sea ice conditions and navigability along four typical routes of the Northeast Passage (NEP) are analysed using remote-sensing data from 1979 to 2019. The influence of air temperature (Tair) and surface wind on the sea ice concentration (SIC) and the navigability of routes is determined. It is found that the annually averaged SICs of the different routes have decreased over the past 41 years. The fastest rate of decrease occurred in the Kara Sea (∼−1% per year), while the slowest rates of decrease occurred in the Laptev/East Siberian Sea (∼−0.42% per year). The number of navigable days for the Kara Sea has become ∼1–2 months longer than the Laptev/East Siberian Sea route as a result. The effect of Tair on SIC, quantified by ΔSIC/ΔTair in the routes through the eastern Kara Sea and Laptev/East Siberian Sea in 2010s was ∼−0.04/°C, two to three times that seen during the 1980s. Air temperature is becoming a significant driving force of melting ice in these routes. Surface winds are also a crucial factor for the navigability of the Vilkitsky Strait and Long Strait, as they drive ice drift, and affect the navigability of the Kara Strait by introducing warm air.
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  • 12
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    Taylor & Francis
    In:  Climate Policy . pp. 1-19.
    Publication Date: 2022-01-07
    Description: Negative emissions technologies (NETs) are an essential part of most scenarios for achieving the Paris Agreement goal of limiting warming to below 2°C and for all scenarios that limit warming to 1.5 °C. The deployment of these technologies requires carbon accounting methods for a range of different purposes, such as determining the effectiveness of specific technologies or incentivising NETs. Although the need for carbon accounting methods is discussed within the literature on NETs, there does not appear to be a clear understanding of the range of different accounting challenges. Based on a systematic literature review this study identifies five distinct accounting issues related to NETs: 1. estimating total system-wide change in emissions/removals; 2. non-permanence; 3. non-equivalence of ‘no overshoot’ and ‘overshoot and removal’; 4. accounting for incentives for NETs; and 5. the temporal distribution of emissions/removals. Solutions to these accounting challenges are proposed, or alternatively, areas for further research and the development of solutions are highlighted. One key recommendation is that carbon accounting methods should follow a ‘reality principle’ to report emissions and removals when and where they actually occur, and an important overall conclusion is that it is essential to use the correct accounting method for its appropriate purpose. For example, consequential methods that take account of total system-wide changes in emissions/removals should be used if the purpose is to inform decisions on the deployment or incentivisation of NETs. Attributional methods, however, should be used if the purpose is to construct static descriptions of possible net zero worlds.
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  • 13
    Publication Date: 2022-02-23
    Description: Touch interaction has established a dominating role in the realisation of Human–Machine Interfaces. However, to be able to use touch effectively and efficiently, users have to comply with particular prerequisites. Due to age-related changes, such as the decline of tactile accuracy and speed, especially elderly users often struggle with the touch modality. Interfaces that adapt to specific user characteristics could be a promising solution to overcome this problem. Notwithstanding the advantages of adaptive systems, perceived changes in the user interface can reduce the system's predictability and transparency. The present study compares three approaches concerning the adaptation of touch button sizes: no adaptation and adaptation with visible and invisible feedback. Results show that especially elderly users substantially benefit from an adaptive approach. Furthermore, data shows that the type of adaptation supports different usage goals. While adaption with visual feedback enables a higher interaction speed, invisible adaptation leads to a higher degree of accuracy.
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  • 14
    Publication Date: 2022-02-25
    Description: Pyroxene crystals from recent Central Plateau tephras are used to deduce their formation conditions through two-pyroxene thermobarometry. Crystals return pseudo-pressures and pseudo-temperatures that are artefacts of uptake of antecrysts formed at a range of crustal levels by isobaric cooling of previously intruded magmas. MELTS modelling of tephra glass compositions shows that pseudo-PT conditions are reproduced at oxygen fugacities above the nickel-nickel oxide buffer (NNO+1, NNO+2), mid- to upper crustal pressures (100–400 MPa), and temperatures between c. 900°C and 〉1100°C. Modelled crystals from the deep crust (800 MPa) are restricted to clinopyroxenes. However, these display chemical equilibrium with shallow orthopyroxenes at higher pseudo-PT conditions than observed in Central Plateau pyroxenes. The data indicate uptake of high-temperature pyroxenes at mid- to shallow crustal levels into ascending andesitic melts and thus preclude the presence of long-lived crustal mush zones (〈1000°C) as a source for the crystal cargo of the Central Plateau tephras studied here. Further, the apparent absence of deep crustal pyroxene antecrysts does not preclude models of arc andesite genesis without a ‘deep crustal hot zone’ beneath the Central Plateau. Generation and ascent of primary andesites from a heterogeneous mantle wedge is therefore a possible scenario at the southern Hikurangi margin.
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  • 15
    Publication Date: 2023-01-04
    Description: Whakaari/White Island is a partially submerged, offshore andesite island volcano, located at the northern end of the Taupō Volcanic Zone. Since the late 1960s, volcanic activity has alternated between quiescence, unrest, and eruption on short timescales. For this review we compiled extensive observational records, examined the rich scientific literature, and use newly acquired data, to understand the broad volcanic history and system dynamics. Based on recent bathymetry data, we propose a distinction exists between the Whakaari edifice and Te Paepae o Aotea/Volkner Rocks, which were previously considered to be part of the same edifice. Geochemical analyses of scoria samples from the island have been used to build a magma system model where dominantly andesitic-dacitic magma is periodically intruded by basalt. More dynamic processes are recorded in the hydrothermal system, where the location and activity of fumarolic features have been ephemeral and the crater lake has varied in scale over short time intervals. Eruptions of the dominantly andesitic magma have historically been small and range from phreatomagmatic through to magmatic, largely depositing ash and scoria to a restricted distance that is confined to the main crater floor. Phreatic eruptions are the most common eruption style, based on recently observed and monitored activity.
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  • 16
    Publication Date: 2023-01-04
    Description: Recently, the aeromagnetic survey with Unmanned Aerial Vehicle (UAV) for mineral exploration has become ubiquitous. They can fly at a lower speed, lower altitude, need fewer crew members, and are cost-effective compared to traditional manned aeromagnetic. With the development of drones, magnetometers were also developed, which reduced the cost, weight, size, and energy consumption of these sensors. One of these sensors is the magneto-inductive magnetometer. This study investigates the integration of the UAV with a magneto-inductive sensor. We have performed an aeromagnetic survey along with six profiles and compared them with the terrestrial magnetic survey using a proton precision magnetometer. We show that the magneto-inductive sensor can sense Earth’s magnetic field’s change up to less than 60 nT. These results show the promising potential of using the UAV equipped with the magneto-inductive sensor to prospect the magnetic ore deposits.
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  • 17
    Publication Date: 2023-01-04
    Description: Tephra deposits in Aotearoa New Zealand (ANZ) have been studied for 〉180 years. The now-global discipline of tephrochronology, which has some developmental roots in ANZ, forms the basis of a powerful chronostratigraphic correlational tool and age-equivalent dating method for geological, volcanological, palaeoenvironmental, and archaeological research in ANZ. Its utility is founded on the key principle that tephras or cryptotephras provide widespread isochrons in many different environments. In the first part of this article, we summarise the history of tephra studies in ANZ and then describe how tephras have been mapped, characterised, and correlated using field and laboratory-based methods. We document advances in geochemical fingerprinting of glass; tephra/cryptotephra detection and correlation by sediment-core scanning methods (e.g. X-radiography, CT imaging, XRF elemental analysis, magnetic susceptibility); statistical correlation methods; and dating of tephras/cryptotephras. We discuss the advent of ANZ cryptotephra studies (from mid-1970s) and their more-recent growth. The second part comprises examples of applications of tephrochronology in ANZ: climate-event stratigraphy (NZ-INTIMATE project); eruptive-event stratigraphy in the Auckland Volcanic Field; developments in the marine tephra record; advances in identifying, correlating, and dating old (pre-50 ka) tephras and weathered-tephra deposits; forming soils/paleosols on tephras; tephras and archaeology; Kopouatai bog tephrostratigraphy and palaeoenvironments; and volcanic-hazard assessments.
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  • 18
    Publication Date: 2023-01-24
    Description: There is a significant interest in the usage of algae in everyday diet because of their positive influence on the gastrointestinal system due to the presence of high amounts of dietary fibres, while the presence of ω-3 fatty acids contributes to the protection of cardiovascular system. Algal derived polysaccharides are found in the food products as stabilisers, thickening agents and emulsifiers. In the cosmetic industry, algae are used in sunscreen, anti-age, anti-cellulite, moisturising and skin whitening products. These products can be used for the development of cosmeceuticals which contain algal derived bioactive compounds and they can exert a pharmaceutical therapeutic benefit. However, these compounds also have potential for being isolated and used for development of novel drugs against diseases, such as cancer, neurodegenerative disorders, and diabetes. Present review provides information about algal compounds incorporated into various food, cosmetic or medicinal products, as well as their potential for health improvement was evaluated.
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  • 19
    Publication Date: 2023-05-24
    Description: During World War I, an enormous amount of chemical and conventional munitions was fired. Many of these munitions did not explode and are still recovered in the soil of the regions where the war raged for several years. After the war, many of the remaining munitions were dumped in the sea as an easy way of removal. These unexploded and dumped munitions are still present so many years after the end of the war. The explosive material inside the munitions is more than 100 years old now. Samples were collected from some of these old munitions. These samples have been analyzed to determine their composition. The explosives typically used in World War I (TNT, DNT, DNB and picric acid) have been identified. It has been shown that the aged samples still contain their energy. They have not become more sensitive to friction or impact. For one the samples, it has been shown that it is still cap-sensitive and detonates normally. These results are important for any risk assessment involving old munitions.
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  • 20
    Publication Date: 2024-02-07
    Description: A recent analysis of observed oxygen changes shows a 2% decline in marine oxygen during the 50 years since 1960. However, these oxygen changes vary on time scales related to climate modes and by regions, including areas of increasing oxygen. Hence, any local oxygen change is related to various subsets of these drivers for the different regions and time scales. Here we provide an overview of drivers presently known for the different regions in the upper and deep ocean and the regional influence of climate modes, focussing on decadal and longer time scales for open ocean regions. We identify and compile regions where changes in solubility, stratification, decadal to multidecadal variability, source waters (either increases or decreases), overturning circulation or circulation-driven changes, and biological or nutrient stimulation have been shown to play a role in oxygen changes. The superposition and interaction of drivers and processes makes the decomposition of the impact on oxygen distribution difficult. Nevertheless, the description of the different drivers identified will help in better understanding the oxygen changes observed and lead to better verification of numerical models of future ocean oxygen levels.
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  • 21
    Publication Date: 2024-02-07
    Description: Despite the diversity and oftentimes large biomass of jellyfish in marine systems, their ecological role remains poorly understood. We here provide the first systematic review of studies on jellyfish trophic ecology in the Baltic Sea (a regional marine system under strong multiple global and regional anthropogenic pressures). In total, we identified 57 peer-reviewed publications, with notable taxonomic bias towards two species (Aurelia aurita; non-indigenous Mnemiopsis leidyi) and spatial bias towards five areas (Bornholm Basin, Kiel Bight, Kertinge Nor, Lim- and Gullmarsfjord). The studies provide evidence for diverse trophic roles of jellyfish as predators and as competitors of other jellyfish, zooplankton and fish species. In combination, the studies also highlight potentially large impacts via top-down (grazing) and bottom-up (nutrient excretion) effects, but also, strong spatio-temporal variability in the magnitude of these effects, depending on the occurrence of jellyfish blooms. Studies on the role of jellyfish as prey for fish, seabirds or marine mammals, and for benthic systems via food-falls, were limited or lacking for the Baltic Sea, despite increasing focus on these topics globally. Improved understanding of the temporal (seasonal, inter-annual, long-term) and spatial variability of blooms and corresponding trophic effects, would provide more systematic understanding of the ecological role of jellyfish in the spatio-temporally variable Baltic Sea. A broader spatial coverage, inclusion of more jellyfish taxa and under-studied early life history stages, as well as the implementation and continuation of long-term data series would represent important steps towards this goal.
    Type: Article , PeerReviewed , info:eu-repo/semantics/article
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  • 22
    Publication Date: 2024-02-07
    Description: This article presents the results of a marine geophysical and sedimentological study carried out around Lesvos Island (NE Aegean) to investigate the potential of exploitable marine aggregate (MA) deposits that could be used for beach replenishment purposes. Sub-bottom profiler data showed a good prospect for potential coarse-grained deposits in two of the three surveyed areas around Lesvos. Grain size and mineralogical analysis of the surficial sediments revealed sands that could properly feed nourishment schemes for eroded beaches or artificial beach development. Observed MA volumes are considered adequate for renourishment operations, when the threat of projected sea-level rise is introduced. Environmental constraints, as well as human activities, are considered for the suggestion and prioritization of specific areas for detailed surveying before future exploitation.
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  • 23
    Publication Date: 2024-02-07
    Description: Modelling the drift of marine debris in quasi-real time can be of societal relevance. One pertinent example is Malaysia Airlines flight MH370. The aircraft is assumed to have crashed in the Indian Ocean, leaving floating wreckage to drift on the surface. Some of these items were recovered around the western Indian Ocean. We use ocean currents simulated by an operational ocean model in conjunction with surface Stokes drift to determine the possible paths taken by the debris. We consider: (1) How important is the influence of surface waves on the drift? (2) What are the relative benefits of forward- and backward-tracking in time? (3) Does including information from more items refine the most probable crash-site region? Our results highlight a critical contribution of Stokes drift and emphasise the need to know precisely the buoyancy characteristics of the items. The differences between the tracking approaches provide a measure of uncertainty which can be minimised by simulating a sufficiently large number of virtual debris. Given the uncertainties associated with the timings of the debris sightings, we show that at least 5 items are required to achieve an optimal most probable crash-site region. The results have implications for other drift simulation applications.
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  • 24
    Publication Date: 2024-02-07
    Description: Chirp sub-bottom profilers (SBP) provide centi-to-decimetre resolution, seismic data with applications for various geophysical and geological purposes. To verify the field application of imaging of a buried target with a cost-effective and easy-to-apply pseudo-3D Chirp SBP survey, we explored the buried site of an ancient wooden shipwreck off the west coast of Korea before underwater excavations. The survey was conducted using a commercial 2D Chirp SBP system with a newly devised recording system that preserved the true polarity of the chirp signal. To produce high-resolution 3D Chirp SBP data from 2D Chirp SBP datasets recorded by the novel system, an optimal data processing sequence, consisting of a first phase of 2D data processing and a second phase of 3D data processing was designed. The first, 2D phase, included the estimation of a source sweep signature, cross-correlation, and deconvolution using an inverse filter. The resulting resolution of the 2D Chirp SBP data was better than that of the enveloped data provided by the commercial acquisition system. The second phase of 3D data processing included gathering 3D datasets, redistributing of ping positions, and static correction. To improve the consistency of the seismic events and reduce the repetitive corrections (swell, tidal, tie, and residual corrections), a static correction was based on multi-beam echo sounder data. The amplitude variation near the shipwreck was clearly apparent in the time slice from the final pseudo-3D Chirp SBP dataset with a bin size of 2.0 m (crossline) × 0.6 m (inline). Through 3D rendering, the buried ancient shipwreck with dimensions of 5 m (width) × 12 m (length) × 2 m (depth) was imaged successfully.
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  • 25
    Publication Date: 2024-02-07
    Description: Riparian zones are important for the maintenance of aquatic ecosystem functional integrity, yet are considered to be particularly vulnerable to plant invasions. The role of terrestrial riparian plant invasions in compromising aquatic ecosystem processes is, however, still poorly understood. This issue is particularly relevant for temporary rivers, which are understudied compared to permanent river systems, despite their ubiquity and largescale contributions to biogeochemical processes. Here we experimentally assessed leaf litter breakdown dynamics in situ in a temporary river in arid southeastern Botswana, Southern Africa. We contrasted aquatic leaching and microbial and invertebrate litter breakdown contributions to the native leadwood Combretum imberbe and invasive river red gum Eucalyptus camaldulensis in the Lotsane River. Fine-mesh (detritivore exclusion) and coarse-mesh (detritivore inclusion) bags were separately filled with leaf litter from each species and deployed in the river during a hydroperiod (wet phase), with decomposition measured over a 6-week period. E. camaldulensis shed significantly more leachate than the native C. imberbe. Significantly more microbial and detritivore breakdown was, however, observed in native than in invasive leaf litter. Overall, invertebrates contributed little to biological leaf litter breakdown processes compared to microbial breakdown contributions. Although significantly higher in native leaves, low invertebrate numbers were found in leaf litter in the study. This study highlights the role of microbial contributions to detrital decay in temporary arid zone rivers, whereas invertebrate contributions were relatively minor. The study further contributes to our understanding of how invasive riparian plant species alter aquatic detrital pool dynamics in invaded temporary wetland ecosystems.
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  • 26
    Publication Date: 2024-02-07
    Description: Gonatus fabricii (Lichtenstein, 1818) is an ecologically important squid that spends its entire life cycle within the Arctic where it is the most abundant cephalopod. Due to the rarity of mature and reproducing females, it is unknown how many eggs females spawn (actual fecundity). Among 47,000 specimens studied between 2005 and 2019 one spent, degenerated and gelatinous female with a mantle length of 230 mm was caught in West Greenland in 2019. Examination allowed the first detailed description of fecundity and spawning pattern in the species. Oocyte development shows that the most considerable maturation of mid-vitellogenic oocytes to late vitellogenic and then to ripe stages occurs immediately after the first ripe oocytes appear in the ovary. There were no ripe oocytes in the ovary or oviducts. The ovary contained an estimated 6561 oocytes and 2551 post-ovulatory follicles and hence the total fecundity was 9112. This specimen of G. fabricii realised 28.0% of its potential fecundity which is comparable to Berryteuthis magister, which also belongs to Gonatidae, and lower than in the majority of studied deep-sea squids (including other gonatids). Spent females may provide clues as to where the major spawning areas of this abundant but poorly known squid are located.
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  • 27
    Publication Date: 2024-02-07
    Description: Accurate and repeatable population estimates are key to establishing population trends and conservation status. Rako, or Buller’s Shearwater (Ardenna bulleri) is a seabird endemic to New Zealand that breeds only on the Poor Knights Islands, but forages throughout wider areas of the Pacific Ocean during the non-breeding season. The lack of threats on the breeding grounds and the wide foraging range of Buller’s Shearwaters makes them ideal sentinels of ocean health. Although they are commonly seen at sea and the population in the 1980s was thought to be around 2.5 million birds, other rapid land-based surveys suggested a much lower figure (~100,000 pairs on Aorangi), and no thorough population estimate has been undertaken to date. We calculated a population estimate for Buller’s Shearwater based on burrow counts and state of occupancy conducted at the Poor Knights during either the 2016–2017 or the 2017–2018 breeding seasons. We incorporated information on habitat availability and preference in population models. Our estimate of 78,645 (95% confidence interval 67,176–89,178) active burrows, broadly representing breeding pairs, is lower than some previously published assessments. This is a repeatable quantitative study of the Buller’s Shearwater breeding population, including breeding activity, and provides critical baseline data to determine population trends for this potentially important marine indicator species. © 2021 BirdLife Australia.
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  • 28
    Publication Date: 2024-02-07
    Description: Anthropogenic pressures on standing waterbody systems potentially result in changes to sediment and water qualities, and thus ecological community characteristics. We tested effects of drawdown on physical, water and sediment variables, as well as their effects on littoral macroinvertebrate community composition in two subtropical reservoirs. Water levels differed significantly between reservoirs and over time, with significant effects on several water chemistry parameters (e.g., pH, conductivity, Mg, Fe), whilst sediment properties were less affected. Significant effects of water level, site and macrophyte cover on macroinvertebrate community structures were not detected, however macroinvertebrate community structuring differed significantly over time. Redundancy analysis (RDA) highlighted that the first and second axes accounted for 45.6% of the total macroinvertebrate community and environmental variables relationship variance. Most of the sediment variables, such as Cu, Mg, Na and Pb and water chemistry (i.e., HCO3-), were positively associated with the first axis, while water temperature and pH were negatively associated with the first axis. The RDA variation partitioning showed that water and sediment chemistry variables accounted for 40.3% and 30.3%, respectively, of the total macroinvertebrate variation. The present study contributes to understandings of the interplays between water level, physico-chemical properties and community compositions in human-altered aquatic ecosystems.
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  • 29
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    Taylor & Francis
    In:  Critical Reviews in Biotechnology . pp. 1-14.
    Publication Date: 2021-01-08
    Description: The marine environment encompasses a huge biological diversity and can be considered as an underexplored location for prospecting bioactive molecules. In this review, the current state of art about antimicrobial molecules from marine bacteria has been summarized considering the main phylum and sources evolved in a marine environment. Considering the last two decades, we have found as most studied group of bacteria producers of substances with antimicrobial activity is the Firmicutes phylum, in particular strains of the Bacillus genus. The reason for that can be attributed to the difficult cultivation of typical Actinobacteria from a marine sediment, whose members are the major producers of antimicrobial substances in land environments. However, a reversed trend has been observed in recent years with an increasing number of reports settling on Actinobacteria. Great diversity of chemical structures have been identified, such as fijimicyns and lynamicyns from Actinomycetes and macrolactins produced by Bacillus.
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  • 30
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    In:  Expert Opinion on Drug Discovery, 15 (4). pp. 499-522.
    Publication Date: 2021-01-08
    Description: Introduction: The marine environment is a very promising resource for natural product research, with many of these reaching the market as new drugs, especially in the field of cancer therapy as well as the drug discovery pipeline for new antimicrobials. Exploitation for bioactive marine compounds with unique structures and novel bioactivity such as the isoquinoline alkaloid; trabectedin, the polyether macrolide; halichondrin B, and the peptide; dolastatin 10, requires the use of analytical techniques, which can generate unbiased, quantitative, and qualitative data to benefit the biodiscovery process. Metabolomics has shown to bridge this understanding and facilitate the development of new potential drugs from marine sources and particularly their microbial symbionts. Areas covered: In this review, articles on applied secondary metabolomics ranging from 1990–2018 as well as to the last quarter of 2019 were probed to investigate the impact of metabolomics on drug discovery for new antibiotics and cancer treatment. Expert opinion: The current literature review highlighted the effectiveness of metabolomics in the study of targeting biologically active secondary metabolites from marine sources for optimized discovery of potential new natural products to be made accessible to a R&D pipeline.
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  • 31
    Publication Date: 2021-01-08
    Description: Freshwater sponges can be considered a promising new source of bioactive compounds for the pharmaceutical industry; however, the research on their chemical composition is still in the incipient stage. We evaluated the most endemic Amazonian freshwater sponge species from the Drulia and Metania genera by untargeted metabolomic approaches, based on UHPCL-HRMS, in order to identify chemical markers and explore the diversity of specialized metabolites. The use of untargeted approaches allowed us to observe subsets of metabolites that enabled the characterization of, not only each genus, but also, of each species. Freshwater sponge species presented themselves as rich sources of fatty acids and sterols, which were putatively identified. These metabolites were suggested as chemical markers for further targeted metabolomic studies.
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  • 32
    Publication Date: 2023-02-08
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  • 33
    Publication Date: 2023-02-08
    Description: Understanding the physical and biogeochemical interactions and feedbacks between the ocean and atmosphere is a vital component of environmental and Earth system research. The ability to predict and respond to future environmental change relies on a detailed understanding of these processes. The Surface Ocean-Lower Atmosphere Study (SOLAS) is an international research platform that focuses on the study of ocean-atmosphere interactions, for which Future Earth is a sponsor. SOLAS instigated a collaborative initiative process to connect efforts in the natural and social sciences related to these processes, as a contribution to the emerging Future Earth Ocean Knowledge-Action Network (Ocean KAN). This is imperative because many of the recent changes in the Earth system are anthropogenic. An understanding of adaptation and counteracting measures requires an alliance of scientists from both domains to bridge the gap between science and policy. To this end, three SOLAS research areas were targeted for a case study to determine a more effective method of interdisciplinary research: valuing carbon and the ocean’s role; air-sea interactions, policy and stewardship; and, air-sea interactions and the shipping industry.
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  • 34
    Publication Date: 2023-02-08
    Description: Monowai is an active submarine volcanic centre in the Kermadec Arc, Southwest Pacific Ocean. Multi-beam data acquired during expedition SO225 aboard R/V SONNE in December 2012 indicates that the topography of the main stratocone has evolved significantly since the last survey in June 2011. Bathymetric measurements of the edifice reveal differences of up to 42 m in seafloor depth and indicate a net volume increase of ∼0.037 km3 across the summit area. Explosive volcanism observed onsite during the SO225 mapping campaign could be linked to a 20h-long swarm of unusually coherent T phase arrivals, suggesting that Monowai is a prime source of broadband seismic noise in the Southwest Pacific region during times of activity. Our findings further document the dynamic nature of volcanic processes at Monowai and have implications for future expedition planning.
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  • 35
    Publication Date: 2023-02-08
    Description: This study examined the residential perceptions of industrial activities in Ilupeju, Lagos, Nigeria. The relevance of distance decay theory, which postulates that the magnitude of effects of the outputs from an industrial establishment would decrease with increasing distance from the point of origin, was tested in the study. Global Positioning System was used to capture the coordinates of the identified firms in Ilupeju. Additionally, two different sets of structured questionnaire were designed; the first set, which was distributed among the industrialists, sought information on the types of waste generated among others while the second set was randomly distributed among the residents and was used to elicit information on the types of pollution emanating from the industries, socioeconomic benefits, among others. The result shows that there is a significant variation in the perceived effects as people living within 0.5 km to the industrial sites claimed to suffer more pollution than those living 1.5 km away from the industrial sites, which is consistent with the distance decay theory. On the other hand, the distance decay theory cannot explain socioeconomic impacts such as increase in living costs, among others as they are felt around the study area irrespective of distance away from the industrial sites.
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  • 36
    Publication Date: 2023-02-08
    Description: Dissimilatory iron reduction and sulfate reduction are the most important processes for anaerobic mineralization of organic carbon in marine sediments. The thermodynamics and kinetics of microbial Fe(III) reduction depend on the characteristics of the Fe(III) minerals, which influence the potential of Fe(III)-reducers to compete with sulfate-reducers for common organic substrates. In the present study, we tested different methods to quantify and characterize microbially reducible Fe(III) in sediments from a transect in Kongsfjorden, Svalbard, using different standard sequential endpoint extractions and time-course extractions with either ascorbate or a Fe(III)-reducing microbial culture. Similar trends of increasing ‘reactive Fe’ content of the sediment along the fjord transect were found using the different extraction methods. However, the total amount of ‘reactive Fe’ extracted differed between the methods, due to different Fe dissolution mechanisms and different targeted Fe fractions. Time-course extractions additionally provided information on the reactivity and heterogeneity of the extracted Fe(III) minerals, which also impact the favorability for microbial reduction. Our results show which fractions of the existing Fe extraction protocols should be considered ‘reactive’ in the sense of being favorable for microbial Fe(III) reduction, which is important in studies on early diagenesis in marine sediments.
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  • 37
    Publication Date: 2023-02-08
    Description: Microbial metabolisms in sediments play a pivotal role in marine element cycling. In hydrothermal sediments chemosynthetic microorganisms likely prevail, while in non-hydrothermally impacted sediment regimes microorganisms associated with organic matter decomposition are primarily recognized. To test how these microorganisms are distributed along the hitherto neglected transition zone influenced to different degrees by hydrothermal input we sampled four sediment sites: these were (i) near an active vent, (ii) the outer rim, and (iii) the inactive area of the Kairei hydrothermal field as well as (iv) sediments roughly 200 km south-east of the Kairei field. Chemistry and microbial community compositions were different at all sampling sites. Against expectations, the sediments near the active vent did not host typical chemosynthetic microorganisms and chemistry did not indicate current, extensive hydrothermal venting. Data from the outer rim area of the active Kairei field suggested microbially mediated saponite production and diffuse hydrothermal flow from below accompanied by increased metal concentrations. A steep redox gradient in the inactive Kairei field points towards significant redox driven processes resulting in dissolution of hydrothermal precipitates and intense metal mobilization. Local microorganisms were primarily Chloroflexi, Bacillales, Thermoplasmata, and Thaumarchaeota.
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  • 38
    Publication Date: 2023-12-12
    Description: Versatile peroxidase, a new family of ligninolytic peroxidases have catalytic properties of both lignin peroxidase and manganese peroxidase and has been isolated from citrus sinensis leaf extract which contains manganese peroxidase activity of 2.2 IU/ml and lignin peroxidase activity of 0.44 IU/ml. The overall recovery yield was 11 % with specific activity 1.0 IU/mg. Its molecular wt was found to be 24.60KDa. Km and Kcat value using veratryl alcohol and manganese sulphate as a substrate is 20 μM, 7.87sec and 12.5 μM, 13.84sec-1. The calculated pH optimum was 2.4 ± 0.1 for lignin peroxidase activity and 4.5 ± 0.1 for manganese peroxidase activity. The temperature optimum of the enzyme was 18°C for LiP and 25°C for MnP. Degradation of polyaromatic hydrocarbons like α-naphthol, β-naphthol, and 1,10-phenanthroline has been studied using UV/VIS spectrophotometer and cyclovoltameter at room temperature. Enzyme activity was inhibited by sodium azide and EDTA effectively.
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  • 39
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    In:  Environmental Politics, 28 (3). pp. 460-479.
    Publication Date: 2020-02-05
    Description: Geoengineering is regarded by advocates as a creative and responsible technological option in the face of a climate emergency. Critics often see it as a hubristic attempt to play God, with disastrous consequences for the planet and humanity. These antipodal perspectives are represented by the ideal types of Prometheans and Gaians. Prometheans and Gaians typically talk past each other. The geoengineering debate can be made more fruitful by well articulating their respective positions and subsequently situating them in the discourse of sustainability. A sustainability orientation does not answer the troubling question whether geoengineering should be developed and deployed. But it can foster a ‘fusion of horizons’ between Prometheans and Gaians, providing common ground in an otherwise polarized debate and making a more productive dialogue possible.
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  • 40
    Publication Date: 2020-01-02
    Description: Hydroacoustic and optical remote sensing have been commonly used to map shallow nearshore benthic features. However, the number, type, scale, and accuracy of the mapping products that can be obtained from the two sensors differ; as such, there can be limited agreement between their mapping products. These differences can be further accentuated if the hydroacoustic data are interpolated to produce a map. Interpolation introduces spatial uncertainty and reduces map accuracy. Consequently, maps generated from the two sensors may provide dissimilar spatial and temporal representations of the same benthic features. We therefore compared the performance of a random forest regression (RFr) and a universal kriging (UK) interpolation method and a post-classification enhancement that can be used to increase the accuracy and complementarity of benthic habitat maps derived from hydroacoustic data. First, we used single beam echosounder (SBES) survey bathymetry data from the Bluefields Bay marine protected area (MPA) in western Jamaica (13.82 km2 in size), to create a bathymetric surface model (BSM), from which rugosity and bathymetric position index (BPI) maps were generated. Next, the RFr was used to create submerged aquatic vegetation (SAV) percentage cover maps from the SBES SAV cover data by predicting cover at un-sampled locations. Predictors included auxiliary data such as depth, BPI, survey points coordinates and radiometrically corrected, deglinted and water column corrected image reflectance index values from each of the following: WorldView-2, Geoeye-1 and Landsat 8. Additionally, a SAV map was created using the UK. The most accurate SAV cover thresholds were identified and were used to create binary maps from the RFr and UK maps. A rugosity derived coral reef map was then added to the binary maps. The resulting benthic habitat maps had comparable accuracies and class coverage to benthic maps classified from GeoEye-1 and WorldView-2 images using pixel and object-based classifiers. However, map accuracies were calculated using a suboptimal number of reference points (〈50) for two of the benthic map classes (SAV absent and coral reef). This was not considered to be problematic as the addition of the coral reef class to the binary maps resulted in a significant decrease in uncertainty (standard error and confidence interval width of the overall accuracy) and a significant increase in the user’s accuracy of the SAV absent map class. Also, the difference in uncertainty and accuracy between the map classes did not change. The methods used in this study can therefore be used to increase the accuracy (and to decrease the uncertainty) and the complementarity of maps derived from hydroacoustic data.
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  • 41
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    In:  European Journal of Environmental and Civil Engineering . pp. 1-25.
    Publication Date: 2021-01-08
    Description: A series of triaxial compression tests of frozen sandy soil are carried out under five confining pressures (1 MPa, 4 MPa, 6 MPa, 8 MPa and 10 MPa) at –6 °C. By comparing the grain size distribution curves of frozen sandy soil before and after shearing, it is found that significant particle breakage can occur during triaxial shearing. Particle breakage changes internal structure of geomaterials and has a significant effect on their stress–strain relationships. In order to accurately describe the effect of particle breakage of frozen sandy soil on the stress–strain relationships, an elastoplastic constitutive model for frozen sandy soil considering particle breakage is proposed. Based on the energy balance equation established by Indraratna and Salim, the constant critical state stress ratio (Mcr) in the energy balance equation is modified to the stress ratio (M) which changed with shear strain during the shearing process. A yield function, considering particle breakage, is proposed using the modified energy balance equation. The hardening law is determined based on the rebound test results of frozen sandy soil, and the associated flow rule is adopted in the model. Compared with experimental data, the model can well simulate the stress–strain relationships under different confining pressures for frozen sandy soil. • Highlights • The particle breakage characteristics of frozen sandy soil are studied. • The energy balance equation considering particle breakage is modified to calculate the energy dissipation of frozen sandy soil. • An elastoplastic constitutive model for frozen sandy soil considering particle breakage is proposed.
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  • 42
    Publication Date: 2021-01-08
    Description: Surfactant-mediated extraction (SME), pressurized liquid extraction (PLE), and enzyme-assisted extraction (EAE) have been compared to improve the isolation of phlorotannins from the brown algae Lobophora variegata. Enzymatic treatment with Alcalase 2.4 L FG, Carezyme 4500 L, protease from Streptomyces griseus, pectinase from Aspergillus niger, Celluclast 1.5 L, protease from Bacillus licheniformis; surfactant extraction with triacetin and guaiacol and PLE with ethanol:water as extracting solvent, have been studied in terms of total phenolic content by the Folin–Ciocalteu method and total phlorotannin content using the DMBA assay. The results showed that SME yields the highest amount of phenols and phlorotannins by using food grade guaiacol as the surfactant. An extraction protocol was developed to maximize the amount of extract obtained from L. variegata. The effects of various parameters such as the type of surfactant, efficacy of surfactant, and optimum pH, on the extraction efficiency of polyphenols were examined. The simultaneous use of the enzyme and surfactant was also investigated. However, a synergistic effect between the enzymes and the surfactant for the extraction of polyphenols has not been observed. Considering total phenols and total phlorotannins in the extract, the extraction yield were obtained for total phenols as SME 〉 EAE 〉 PLE and for total phlorotannins as SME 〉 PLE 〉 EAE.
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  • 43
    Publication Date: 2021-01-08
    Description: The Ponto-Caspian round goby (Neogobius melanostomus Pallas, 1814) is a prominent invasive species in many European waters. Eggs of the Western Baltic Spring Spawning Atlantic herring might be attractive prey for the invasive round goby during the spawning season. However, investigations of the small fish fauna in an important spawning area of herring, which was characterized by high densities of macrophytes, indicated a spatio-temporal mismatch of round goby and herring spawn in spring, at least on some of the known important spawning beds situated on vegetated sandy bottoms. In contrast, a spatio-temporal overlap between round gobies and herring spawn was observed in a more structured area, characterized with stones, where round gobies’ stomachs were sampled. Further field study results suggest that large round gobies (〉 10 cm) do not feed on herring eggs, while smaller round gobies (〈 10 cm) do so. To support these results, we conducted laboratory feeding experiments with round gobies. When C. crangon, M. edulis and herring eggs were offered simultaneously, round gobies preferred C. crangon. M. edulis was preferred over herring eggs when C. crangon was absent. The predatory impact of the round goby on herring eggs seems to be of minor importance compared to other species, such as three-spined stickleback or perch. Applying the same data, different food ‘preference indices’ revealed a discrepancy in preference between indices. Therefore, we propose a modified food preference index (mE), taking into account four important parameters and combining benefits of two commonly applied indices.
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  • 44
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    Taylor & Francis
    In:  Molecular Physics, 117 (23-24). pp. 3556-3568.
    Publication Date: 2021-01-08
    Description: Gas hydrates continue to attract enormous attention throughout the energy industry, as both a hindrance in conventional production and a substantial unconventional resource. Scientists continue to be fascinated by the hydrates’ ability of sequestering large amounts of hydrophobic gases, unusual thermal transport properties and unique molecular structures. Technologically, clathrate hydrates promise advantages in applications as diverse as carbon sequestration and water desalination. The communities interested in hydrates span traditional academic disciplines, including earth science, physical chemistry and petroleum engineering. The studies on this field are equally diverse, including field expeditions to attempt the production of natural gas from hydrate deposits accumulated naturally on the seafloor, to lab-scale studies to exchange CO2 for CH4 in hydrates; from theoretical studies to understand the stability of hydrates depending on the guest molecules, to molecular simulations probing nucleation mechanisms. This review highlights a few fundamental questions, with focus on knowledge gaps representing some of the barriers that must be addressed to enable growth in the practical applications of hydrate technology, including natural gas storage, water desalination, CO2 – CH4 exchange in hydrate deposits and prevention of hydrate plugs in conventional energy transportation.
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  • 45
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    In:  Geomicrobiology Journal, 36 (6). pp. 492-505.
    Publication Date: 2021-01-08
    Description: Fermentation plays a fundamental role in organic carbon degradation on a global scale. However, little is known about how environmental variables influence this process. In a step towards quantifying how temperature and composition influence fermentation, we have calculated the Gibbs energies of 47 fermentation reaction, ΔGr, from 0–150 °C for a broad range of compositions representing microbial habitats as variable as sediments, estuaries, soils, and crustal rocks. The organic compounds in these reactions include amino acids, nucleic acid bases, monosaccharides, carboxylates, methanogenic compounds and more. The amount of energy available varies considerably, from +54 kJ (mol C)−1 for palmitate fermentation, to −184 kJ (mol C)−1 for methylamine disproportionation. For some reactions, there is little difference in ΔGr between low and high energy systems (e.g., the monosaccharide reactions) while others span a much broader range (e.g., the nucleic acid bases). There is no clear-cut trend between exergonicity and temperature, and the values of standard state Gibbs energies of reactions, ΔG0r, for nearly half of the reactions lie outside the range of ΔGr values. To carry out some of these calculations, the thermodynamic properties for six organic compounds were estimated: dimethylamine, trimethylamine, resorcinol, phloroglucinol and cyclohexane carboxylate and its conjugate acid.
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  • 46
    Publication Date: 2021-01-08
    Description: As an emerging technology, hyperspectral imaging (HSI), which combines both advanced spectroscopy and imaging techniques, provides sufficient information for spectral and spatial analysis and is thus suitable for distribution and property investigation of nanoscale materials. Considering the applications of HSI have spread from remote sensing to quality control of macro products such as food and milk, this article reviews recent research of HSI in a new field of nanoscale materials. On the basis of fundamental parts of a HSI system, new techniques fitting specifically for nanoscale materials imaging such as dark field and Raman spectroscopy are introduced. Nanoscale materials, including metal nanoparticles, carbon nanotubes and graphene, biological components in cells and tissues, as well as multi-layer nanoscale materials, are the research hotspots utilizing HSI technology. Related research reports of the above materials are reviewed based on the physical distinction of these nanoscale materials. It is believed that HSI technology is a strongly potential technique for property investigation and manipulation of nanomaterial for various applications.
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  • 47
    Publication Date: 2022-01-31
    Description: DNA barcoding analysis, using tufA, revealed considerable differences between the expected and observed species inventory of Ulva sensu lato in the Baltic and North Sea areas of the German state of Schleswig-Holstein. Of 20 observed genetic entities, at least four (U. australis, U. californica, U. gigantea and Umbraulva dangeardii) had been introduced recently, whereas three others (one Ulva sp. and two Blidingia spp.) could not be identified at the species level and could also represent recently introduced species. In addition, the observed distributions of Kornmannia leptoderma and U. rigida were much more extensive than indicated by historical records, whereas Blidingia minima and Gayralia oxysperma were absent or much less common than expected. Barcoding analysis also revealed that both U. tenera (type material) and U. pseudocurvata (historical vouchers) from Helgoland, an off-shore island in the North Sea, actually belong to U. lactuca, a species that appears to be restricted to this island. Furthermore, past morphological descriptions of U. intestinalis and U. compressa have apparently been too restrictive and have been responsible for numerous misidentifications. The same is true for U. linza, which, in northern Germany, clusters into two genetically closely related but morphologically indistinguishable entities. One of these entities is present on Helgoland, while the second is present on North Sea and Baltic Sea mainland coasts.
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  • 48
    Publication Date: 2022-01-31
    Description: To resolve historical misinterpretations of species descriptions and to comprehend the morphological diversity together with the distribution of Ulva compressa Linnaeus in northern Germany, a morphological and molecular study was undertaken of recently collected specimens and herbarium vouchers. Phylogenetic analyses from sequences of the plastid encoded tufA gene confirmed that U. compressa is abundant along the German Baltic Sea and North Sea coasts. We were able to genetically confirm the presence of U. compressa in the Baltic Sea below salinities of 15 PSU. However, we detected morphologies agreeing with the attached and branched tubular type material only in the North Sea, while U. compressa on Baltic Sea coasts indiscriminately exhibited a very distinct morphology of sheet-like thalli that were always unattached, with the exception of one collection site. Drifting forms were also frequently detected in the Wadden Sea, but not on the island of Helgoland. The tufA sequences of attached and tubular forms of U. compressa from the German Wadden Sea were identical to the drifting sheets found in the Wadden and Baltic Seas and the sequence divergence was extremely small at ≤0.9%. The proliferating, blade-like thalli of U. compressa appear as a nuisance ecotype that is able to form massive accumulations associated with oxygen depletion. Mass accumulations were observed to cause severe damage and increased mortality of habitat forming Zostera and Ruppia populations.
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  • 49
    Publication Date: 2022-01-31
    Description: Cytospora is a genus including important phytopathogens causing severe dieback and canker diseases distributed worldwide with a wide host range. However, identification of Cytospora species is difficult since the currently available DNA sequence data are insufficient. Aside the limited availability of ex-type sequence data, most of the genetic work is only based on the ITS region DNA marker which lacks the resolution to delineate to the species level in Cytospora. In this study, three fresh strains were isolated from the symptomatic branches of Elaeagnus angustifolia in Xinjiang Uygur Autonomous Region, China. Morphological observation and multi-locus phylogenetic analyses (ITS, LSU, ACT and RPB2) support these specimens are best accommodated as a distinct novel species of Cytospora. Cytospora elaeagnicola sp. nov. is introduced, having discoid, nearly flat, pycnidial conidiomata with hyaline, allantoid conidia, and differs from its relatives genetically and by host association.
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  • 50
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    Taylor & Francis
    In:  Atmospheric and Oceanic Science Letters, 12 (2). pp. 131-139.
    Publication Date: 2022-01-31
    Description: The long-term trend of diurnal temperature range (DTR) over Nigeria was examined using daily station-based datasets for the period 1971–2013. The results show that the regionally averaged DTR has decreased significantly (−0.34°C per decade) over the Nigerian Sahel (north of 10°N), but there has been a slight increasing trend (0.01°C per decade) over the Nigerian Guinea Coast. The annual decreasing trend of DTR in the Nigerian Sahel is mainly attributable to the significant increasing trend in daily minimum temperature (Tmin, 0.51°C per decade), which far outstrips the rate of increase in the daily maximum (Tmax, 0.17°C per decade). In contrast, the comparable trends in Tmin (0.19°C per decade) and Tmax (0.20°C per decade) may explain the non-significant trend of the DTR averaged over the Guinea Coast region. It is observed that the DTR has decreased more in boreal summer (June–July–August) than in boreal winter (December–January–February) for the regions. Furthermore, it is found that the significant DTR declining trend over the Nigerian Sahel is closely associated with an increasing trend of annual and summer precipitation in the region, but the increasing DTR trend in the Nigerian Guinea Coast region can be attributed to the decreasing trend of cloud cover over the region.
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  • 51
    Publication Date: 2021-02-08
    Description: New biostratigraphical, geochemical, and magnetic evidence is synthesized with IODP Expedition 352 shipboard results to understand the sedimentary and tectono-magmatic development of the Izu–Bonin outer forearc region. The oceanic basement of the Izu–Bonin forearc was created by supra-subduction zone seafloor spreading during early Eocene (c. 50–51 Ma). Seafloor spreading created an irregular seafloor topography on which talus locally accumulated. Oxide-rich sediments accumulated above the igneous basement by mixing of hydrothermal and pelagic sediment. Basaltic volcanism was followed by a hiatus of up to 15 million years as a result of topographic isolation or sediment bypassing. Variably tuffaceous deep-sea sediments were deposited during Oligocene to early Miocene and from mid-Miocene to Pleistocene. The sediments ponded into extensional fault-controlled basins, whereas condensed sediments accumulated on a local basement high. Oligocene nannofossil ooze accumulated together with felsic tuff that was mainly derived from the nearby Izu–Bonin arc. Accumulation of radiolarian-bearing mud, silty clay, and hydrogenous metal oxides beneath the carbonate compensation depth (CCD) characterized the early Miocene, followed by middle Miocene–Pleistocene increased carbonate preservation, deepened CCD and tephra input from both the oceanic Izu–Bonin arc and the continental margin Honshu arc. The Izu–Bonin forearc basement formed in a near-equatorial setting, with late Mesozoic arc remnants to the west. Subduction-initiation magmatism is likely to have taken place near a pre-existing continent–oceanic crust boundary. The Izu–Bonin arc migrated northward and clockwise to collide with Honshu by early Miocene, strongly influencing regional sedimentation.
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  • 52
    Publication Date: 2021-02-08
    Description: The fluttering shearwater (Puffinus gavia) is an abundant seabird endemic to breeding colonies in northern and central New Zealand. The species remains poorly studied, and here we present the first study to examine its breeding biology in detail. Fluttering shearwater nests were monitored daily from laying in September 2015 to fledging in January 2016 on Burgess Island (Mokohinau Islands group) in the outer Hauraki Gulf, northern New Zealand. Burrows were generally simple and non-branched. Eggs were laid over a period of 39 days with laying peaking 12th September. Incubation was 50 ± 3.7 days and chicks fledged after an average of 74 ± 4.3 days, from late December to the end of January. Chick development corresponds to the pattern observed for other Procellariiformes, gaining body mass rapidly to a maximum of 115% of adult mass, and then losing weight until fledging. Chicks were fed most nights throughout chick-rearing, indicating adult birds have access to a stable food supply close to the colony. Breeding success was 63.8% and similar to other Puffinus species. This study provides baseline biological data for a poorly studied, yet common, New Zealand endemics seabird. The obtained new information will allow for further ecological investigations and improved conservation management for the species
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  • 53
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    In:  Journal of Biomolecular Structure and Dynamics, 36 (10). pp. 2699-2712.
    Publication Date: 2020-01-02
    Description: Glyoxalase is one of two enzymes of the glyoxalase detoxification system against methylglyoxal and other aldehydes, the metabolites derived from glycolysis. The glyoxalase system is found almost in all living organisms: bacteria, protozoa, plants, and animals, including humans, and is related to the class of ‘life essential proteins’. The enzyme belongs to the expanded Glyoxalase/Bleomycin resistance protein/Dioxygenase superfamily. At present the GenBank contains about 700 of amino acid sequences of this enzyme type, and the Protein Data Bank includes dozens of spatial structures. We have offered a novel approach for structural identification of glyoxalase I protein family, which is based on the selecting of basic representative proteins with known structures. On this basis, six new subfamilies of these enzymes have been derived. Most populated subfamilies A1 and A2 were based on representative human Homo sapiens and bacterial Escherichia coli enzymes. We have found that the principle feature, which defines the subfamilies’ structural differences, is conditioned by arrangement of N- and C-domains inside the protein monomer. Finely, we have deduced the structural classification for the glyoxalase I and assigned about 460 protein sequences distributed among six new subfamilies. Structural similarities and specific differences of all the subfamilies have been presented. This approach can be used for structural identification of thousands of the so-called hypothetical proteins with the known PDB structures allowing to identify many of already existing atomic coordinate entrees.
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  • 54
    Publication Date: 2020-01-02
    Description: Morphological variability in gorgonians is frequent and commonly associated with habitat variability, often resulting in segregated morphotypes. Paramuricea macrospina is an endemic Mediterranean gorgonian species found on rocky bottoms between 40 and 160 m depth and has recently been reported as one of the most abundant species in continental shelf and shelf edge environments. Three different chromatic forms of P. macrospina were observed in the Menorca Channel: a yellow form and a light purple form occurring on maërl beds of the continental shelf, and a dark purple form occurring on rocky substrates of the shelf edge. The objective of the present work is to verify if these P. macrospina forms may represent distinct taxonomic units by analysing differences in colony morphology and sclerite size and shape of the three chromatic forms. No significant differences were found in colony shape, suggesting that environmental variability between the continental shelf and the shelf edge is not influential enough to significantly alter colony morphology. Significant differences in sclerite size and shape were found amongst all forms, suggesting that sclerites may be influenced by environmental conditions. However, the co-occurrence of the yellow and light purple forms side by side on the continental shelf may indicate a certain degree of genetic differentiation.
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  • 55
    Publication Date: 2018-12-17
    Description: The feeding habits of two sympatric squid species, Uroteuthis (Photololigo) chinensis and Uroteuthis (Photololigo) duvaucelii from the southwestern Gulf of Thailand were studied. They fed on low numbers of food types (AF) and had a low diet breadth; 1.18 and 0.01 for U. (P.) chinensis and 1.49 and 0.05 for U. (P.) duvaucelii, respectively. Three major prey types (fishes, crustaceans and molluscs) were always detected and cannibalism was observed. Fish was the greatest contributor to the diet of both species, contributing 89.5% for U. (P.) chinensis and 69.9% for U. (P.) duvaucelii. Fish size significantly affected fullness index (FL) and AF for U. (P.) chinensis (P 〈 0.001) and U. (P.) duvaucelii (P 〈 0.001). Depth affected the FL of U. (P.) chinensis (P 〈 0.001) but not of U. (P.) duvaucelii (P 〉 0.05). Maturity stages of both male and female U. (P.) chinensis influenced FL (male: P 〈 0.001; female: P 〈 0.05) and AF (male: P 〈 0.05; female: P 〈 0.01). The FL of squid from cast nets was higher than those from trawls. The multivariate results showed dietary grouping between size classes of both species.
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  • 56
    Publication Date: 2020-01-02
    Description: Indian squid, Uroteuthis (Photololigo) duvaucelii (Loliginidae) constitute an important component of the inshore cephalopod fisheries along the eastern Arabian Sea. Local environmental variation plays an important role in species–environment interactions in neritic squids, which inhabit nearshore/coastal waters. Such ‘active’ and ‘passive’ responses of squids to environmental changes is crucial in understanding their relationships and influence on the biological processes, distribution and abundance of the fast-growing short-lived coastal loliginids. The empirical relationship between squid abundance and the variability in rainfall and sea surface temperature (SST) were explored in a tropical monsoon fishery. Monthly catch rates (catch per fishing hour) of squids in commercial trawl during 1987–2009 were used as the abundance index. Linear regression models with ARIMA errors were fitted with catch per unit hour time series as dependent variable and rainfall and SST as exogenous variables. While rainfall was observed to have a negative effect on squid abundance, the SST recorded a positive impact. ARIMA models provided satisfactory fit to observed data and forecast of 22 months. Given that the squid life-cycle is a function of their environment, this result is relevant in forecasting squid biomass for the management of tropical monsoon fisheries.
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  • 57
    Publication Date: 2020-01-02
    Description: The distribution pattern of purpleback flying squid and the relationship between its abundance and environmental variables in the south-eastern Arabian Sea were analysed using a geographical information system (GIS) and a generalised additive model (GAM). Highest abundances were observed during December and January within 10 and 13°N and 71 and 72°E around the Lakshadweep Islands. The mean abundance in the area was 4.21 tonnes/km2 and the maximum sustainable yield (MSY) was estimated as 0.63 million tonnes. GAM indicated that very high squid abundance was associated with low values of dissolved oxygen (6.01–6.27 mg/L), sea surface temperature (28.03–28.62°C), pH (7.75–8.56), salinity (30.42–34.48 psu), chlorophyll-a (0.4–0.6 mg/m3), zooplankton biomass (0.23–0.64 mL/m3), and shallow 20°C isotherm (101.2–134.7 m) and mixed layer depth (17.8–29.8 m). As a carnivore from paralarval stages, S. oualaniensis depends on secondary and tertiary production to sustain its population for which primary production is used up. In the tropical Arabian Sea where temperature differences are not so pronounced, S. oualaniensis distribution was found to be related to a low but very narrow sea surface temperature (SST) band. There is sufficient fishable biomass in the area to possibly launch a new targeted oceanic squid fishery from the western seaboard of India.
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  • 58
    Publication Date: 2021-02-08
    Description: The environmental system of the northern Nordic Seas is very sensitive to oceanographic and climatic changes at the contact of cold Arctic and warmer North Atlantic waters. These contrasts are reflected in the associations of marine microorganisms and archived in the bottom sediments. A microfossil study (diatoms, coccoliths) of late Holocene sediments in core MSM5/5-712-1 from the eastern Fram Strait provides a better understanding of marine ecosystems and palaeoenvironments during Arctic warming events of the last two millennia. Indicative diatom species and groups of species revealed a high variability of sea-surface conditions. Based on the diatom distribution, three warming periods could be detected, corresponding to the time intervals of 0 to 440 CE (the later part of the Roman Warm Period), 1200 to1420 CE (the final part of the Medieval Climate Anomaly) and 1730 CE to present (including the Recent Warming). The various micropalaeontological proxies used in this study and other publications describe the Roman Warm Period and, especially, the Recent Warming as the most pronounced warm events in the area during the last 2000 years. A comparison of data from the different microfossil groups, indicators of sea-surface and subsurface conditions, reveals variable, complicated and non-simultaneous palaeoenvironmental signals within the warm periods. This can potentially be explained by changes in the surface/subsurface water structure during the events (variations in the cold/warm water advection, stratification, availability of nutrients, seasonal succession of bioproductivity, etc.), which are reflected by changes in the microplankton communities.
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  • 59
    Publication Date: 2019-01-02
    Description: Microplastic contamination of aquatic environments has become an increasingly alarming problem. These, defined as particles 〈5 mm, are mostly formed due to the cracking and embrittlement of larger plastic particles. Recent reports show that the increasing presence of microplastics in the environment could have significant deleterious consequences over the health of marine organisms, but also across the food chain. Herein, we have studied the effects of artificial seawater on polyethylene (PE)-based beads by exposing them up to eight weeks to saltwater in stirred batch reactors in the dark and examined the structural and morphological changes these endured. Electron microscopy observations showed that artificial seawater induces severe microcracking of the pellets' surfaces. Additionally, Fourier transform infrared spectroscopy (FTIR) analyses evidenced the formation of oxidized groups whenever these particles were exposed to water and an increase in organic matter content of the waters in which the pellets were kept was evidenced by Raman spectroscopy. There were also noticeable consequences in the thermal stability of the polyethylene pellets, as determined by thermogravimetric studies (TGA). Furthermore, the parallel exposure of polyethylene pellets to UV radiation yielded less pronounced effects, thus underscoring its lower preponderance in the degradation of this material. These results highlight the importance of determining the mechanisms of degradation of microplastics in marine settings and what the implications may be for the environment. Overall, the herein presented results show that a relatively short period of time of accelerated exposure can yield quantifiable chemical and physical impacts on the structural and morphological characteristics of PE pellets.
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  • 60
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    In:  Journal of Asian Natural Products Research . pp. 1-22.
    Publication Date: 2018-12-17
    Description: A large number of remarkable studies on the secondary metabolites of fungi have been conducted in recent years. This review gives an overview of one hundred and sixty-seven molecules with novel skeletons and their bioactivities that have been reported in seventy-nine articles published from 2013 to 2017. Our statistical data showed that endophytic fungi and marine-derived fungi are the major sources of novel bioactive secondary metabolites.
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  • 61
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    Taylor & Francis
    In:  Botany Letters . pp. 1-5.
    Publication Date: 2018-12-17
    Description: As an important DNA source, herbarium specimens have been widely used in plant phylogenetics due to their easy accessibility and richness. However, contamination is a constant risk owing to low quality and/or quantity of DNA extracted from old samples. The inclusion of contaminant sequences can mislead phylogenetic reconstruction, and thereby affect subsequent analyses, such as divergence time estimates and biogeographic inferences. To employ appropriately herbarium specimens in plant phylogenetics, we outline here several suggestions regarding DNA extraction, PCR amplification and sequencing. We hope that these suggestions will serve as a guide for researchers using herbarium specimens in plant phylogenetics and help them identify from the early steps potential contaminant sequences from other plants or other organisms.
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  • 62
    Publication Date: 2018-12-17
    Description: The feeding habits of two sympatric squid species, Uroteuthis (Photololigo) chinensis and Uroteuthis (Photololigo) duvaucelii from the southwestern Gulf of Thailand were studied. They fed on low numbers of food types (AF) and had a low diet breadth; 1.18 and 0.01 for U. (P.) chinensis and 1.49 and 0.05 for U. (P.) duvaucelii, respectively. Three major prey types (fishes, crustaceans and molluscs) were always detected and cannibalism was observed. Fish was the greatest contributor to the diet of both species, contributing 89.5% for U. (P.) chinensis and 69.9% for U. (P.) duvaucelii. Fish size significantly affected fullness index (FL) and AF for U. (P.) chinensis (P 〈 0.001) and U. (P.) duvaucelii (P 〈 0.001). Depth affected the FL of U. (P.) chinensis (P 〈 0.001) but not of U. (P.) duvaucelii (P 〉 0.05). Maturity stages of both male and female U. (P.) chinensis influenced FL (male: P 〈 0.001; female: P 〈 0.05) and AF (male: P 〈 0.05; female: P 〈 0.01). The FL of squid from cast nets was higher than those from trawls. The multivariate results showed dietary grouping between size classes of both species.
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  • 63
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    In:  Critical Reviews in Biochemistry and Molecular Biology, 53 (4). pp. 356-381.
    Publication Date: 2018-12-17
    Description: Iron is required for microbial growth and proliferation. To survive in low-iron environments, some microorganisms secrete ferric iron chelators called siderophores. Siderophore biosynthesis occurs via two pathways: the non-ribosomal peptide synthetase (NRPS) pathway and the NRPS-independent siderophore (NIS) synthetase pathway. NIS enzymes function by adenylating a carboxylic acid substrate, typically citrate, or a derivative, followed by nucleophilic capture of an amine or alcohol and displacement of a citryl intermediate. In this review, we summarize recent advances in NIS biochemistry with a particular focus on structural biology and confirm the classification of NIS enzymes into Types A, A', B, and C based on substrate specificity. Based on a phylogenetic analysis, we also propose a new subclass of NIS enzymes, Type C', responsible for dimerization and macrocyclization of complex and substituted amine or amide intermediates. Finally, we describe the role of NIS enzymes in virulence of pathogenic microbes and discuss NIS inhibitors as potential anti-microbial agents.
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  • 64
    Publication Date: 2018-12-17
    Description: Hydrothermal precipitates and hydrothermal alteration products could record important information about temporal variations of seafloor hydrothermal systems. Geochemistry, mineralogy, and microscopic features of three pumice samples (T3-1, T3-2, and T3-3) near the Iheya North hydrothermal field were analyzed in this article. The results show that T3-3 sample has undergone at least two-stage influences by hydrothermal fluids. In the first stage, pure amorphous silica from hydrothermal fluid precipitated in the vesicles of all three T3 samples as a result of conductive cooling and fluid–seawater mixing. The precipitation temperatures according to oxygen isotope thermometer are approximately 13–21°C. In the second stage, T3-3 pumice underwent low-temperature hydrothermal alteration, during which the amorphous silica precipitates were redissolved, together resulting in losses of FeO and SiO2 and gains of MgO, Pb, Zn, and Cu. Furthermore, ferruginous filamentous silica, which might be related to activities of Fe-oxidizing bacteria, was formed in the altered pumice. The transformation from pure amorphous silica precipitation to redissolution of the silica in T3-3 pumice might indicate a rise of temperature and/or decrease in silica concentrations in hydrothermal fluids, implying a changing hydrothermal environment.
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  • 65
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    In:  Marine Georesources & Geotechnology, 36 (7). pp. 768-780.
    Publication Date: 2018-12-17
    Description: We propose a geochemical parameter, “metal flux” in evaluating hydrogenetic Co-rich ferromanganese crust deposits in the Pacific seamount area, that is based on physical, chemical, and geological characterization of the integrated growth piles of crusts. We calculated the metal flux for fifteen sites from different depths ranging between 900-6000m from different seamounts. The secular and areal variations of metal flux indicate a strong geological controls, and also can be a reliable tool for estimating an economic potential of the crusts. The Co flux decreases with increasing water depth, followed by almost constant flux of Ni and Mn. The Al and Fe fluxes vary with regions, indicating higher values in the western regions near the island arc probably related to a supply from the Asian continents. The results imply that Co, a redox sensitive metal element, is controlled by redox conditions of seawater, while Fe and Al are by terrigenous input. The metal flux reflects global and regional conditions and controls the compositional diversity of metals, thus consequently, the parameter can be a reliable powerful tool to estimate or single out more potential areas.
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  • 66
    Publication Date: 2020-01-02
    Description: Different studies on the position of the non-indigenous species Neogobius melanostomus within the coastal food web of the Pomeranian Bay (western Baltic) were performed, resulting in a quantitative and qualitative species list of prey organisms found in the stomachs of the invader and an estimation concerning the importance of round goby as prey for different resident predators. It seems that the colonization process is not fully completed yet, but the results reveal that the species is already established in the food web 16 years after the first observation within the study area. The results show that N. melanostomus feed upon a wide range of different resident organisms. While a direct predation effect on native fish species appears rather unlikely, indirect effects such as competition cannot yet be excluded. In addition, our results reveal an ontogenetic diet shift and that the round goby itself already serves as an important prey for piscivorous fish and seabirds. Finally, we formulate different hypotheses based on our results which will require further research.
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  • 67
    Publication Date: 2020-02-06
    Description: International Ocean Discovery Program (IODP) Expedition 352 recovered a high-fidelity record of volcanism related to subduction initiation in the Bonin fore-arc. Two sites (U1440 and U1441) located in deep water nearer to the trench recovered basalts and related rocks; two sites (U1439 and U1442) located in shallower water further from the trench recovered boninites and related rocks. Drilling in both areas ended in dolerites inferred to be sheeted intrusive rocks. The basalts apparently erupted immediately after subduction initiation and have compositions similar to those of the most depleted basalts generated by rapid sea-floor spreading at mid-ocean ridges, with little or no slab input. Subsequent melting to generate boninites involved more depleted mantle and hotter and deeper subducted components as subduction progressed and volcanism migrated away from the trench. This volcanic sequence is akin to that recorded by many ophiolites, supporting a direct link between subduction initiation, fore-arc spreading, and ophiolite genesis.
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  • 68
    Publication Date: 2020-02-06
    Description: The production of shiga toxin (Stx) is a critical step in the establishment and progress of enterohemorrhagic Escherichia coli (EHEC) infections. The possible release of Stx from dead and dying bacteria, and the risk of resistance development have restricted the usage of antibiotics against EHEC. The chlorinated quaternary ammonium compound, strepthonium A, was isolated from the culture of Streptomyces sp. SBT345 that was cultivated from the Mediterranean sponge Agelas oroides. The structure was elucidated and confirmed by spectroscopic analyses including 1D and 2D NMR, ESI-HRMS, as well as ESI-HRMS2. Strepthonium A follows Lipinski's rule of five with respect to its molecular weight, CLogP values and the number of hydrogen acceptors and donors. Verotoxin ELISA assay demonstrated that Strepthonium A reduced the Stx production in EHEC strain EDL933 at 80 μM concentration without growth inhibition. This study demonstrates the potential of strepthonium A in restraining the production of Stx in EHEC infections.
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  • 69
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    In:  Journal of Maps, 13 (1). pp. 24-30.
    Publication Date: 2020-02-06
    Description: Land-use dynamic is a major challenge for town and country planners especially in developing countries such as Iran. Iran has been under rapid urban expansion and population growth for past three decades which led to lack of resources, environmental deterioration and haphazard landscape development. In this paper, an attempt has been made to map the urbanization dynamics of Tehran in 40 years based on remote sensing imagery and by means of artificial neural networks. The presented scheme could be taken into consideration when planning initiatives aimed at surveying, monitoring, managing and sustainable development of the territory. Moreover, it can serve the experts in the fields of geography, urban studies and planning as a background for number of geographical analyses.
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  • 70
    Publication Date: 2020-02-06
    Description: Current antifouling (AF) technologies are based on the continuous release of biocides into the water, and consequently discharge into the environment. Major efforts to develop more environmentally friendly coatings require efficient testing in laboratory assays, followed by field studies. Barnacles are important fouling organisms worldwide, increasing hydrodynamic drag on ships and damaging coatings on underwater surfaces, and thus are extensively used as models in AF research, mostly in static, laboratory-based systems. Reliable flow-through test assays for the screening of biocide-containing AF paints, however, are rare. Herein, a flow-through bioassay was developed to screen for diverse low-release biocide paints, and to evaluate their effects on pre- and post-settlement traits in barnacles. The assay distinguishes between the effects from direct surface contact and bulk-water effects, which are crucial when developing low-emission AF coatings. This flow-through bioassay adds a new tool for rapid laboratory-based first-stage screening of candidate compounds and novel AF formulations.
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  • 71
    Publication Date: 2020-02-06
    Description: IODP Expedition 350 was the first to be drilled in the rear part of the Izu-Bonin, although several sites had been drilled in the arc axis to fore-arc region; the scientific objective was to understand the evolution of the Izu rear arc, by drilling a deep-water volcaniclastic section with a long temporal record (Site U1437). The Izu rear arc is dominated by a series of basaltic to dacitic seamount chains up to ~100-km long roughly perpendicular to the arc front. Dredge samples from these are geochemically distinct from arc front rocks, and drilling was undertaken to understand this arc asymmetry. Site U1437 lies in an ~20-km-wide basin between two rear arc seamount chains, ~90-km west of the arc front, and was drilled to 1804 m below the sea floor (mbsf) with excellent recovery. We expected to drill a volcaniclastic apron, but the section is much more mud-rich than expected (~60%), and the remaining fraction of the section is much finer-grained than predicted from its position within the Izu arc, composed half of ashes/tuffs, and half of lapilli tuffs of fine grain size (clasts 〈3 cm). Volcanic blocks (〉6.4 cm) are only sparsely scattered through the lowermost 25% of the section, and only one igneous unit was encountered, a rhyolite peperite intrusion at ~1390 mbsf. The lowest biostratigaphic datum is at 867 mbsf (~6.5 Ma), the lowest palaeomagnetic datum is at ~1300 mbsf (~9 Ma), and the rhyolite peperite at ~1390 mbsf has yielded a U–Pb zircon concordia intercept age of (13.6 + 1.6/−1.7) Ma. Both arc front and rear arc sources contributed to the fine-grained (distal) tephras of the upper 1320 m, but the coarse-grained (proximal) volcaniclastics in the lowest 25% of the section are geochemically similar to the arc front, suggesting arc asymmetry is not recorded in rocks older than ~13 Ma.
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  • 72
    Publication Date: 2020-02-06
    Description: In this opinion paper, we, a group of scientists from environmental-, geo-, ocean- and information science, argue visual data exploration should become a common analytics approach in Earth system science due to its potential for analysis and interpretation of large and complex spatio-temporal data. We discuss the challenges that appear such as synthesis of heterogeneous data from various sources, reducing the amount of information and facilitating multidisciplinary, collaborative research. We argue that to fully exploit the potential of visual data exploration, several bottlenecks and challenges have to be addressed: providing an efficient data management and an integrated modular workflow, developing and applying suitable visual exploration concepts and methods with the help of effective and tailored tools as well as generating and raising the awareness of visual data exploration and education. We are convinced visual data exploration is worth the effort since it significantly facilitates insight into environmental data and derivation of knowledge from it.
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  • 73
    Publication Date: 2020-02-06
    Description: A bioassay-guided approach was used to identify defense compounds that are present on the surface of Zostera marina and which inhibit settlement of microfoulers at natural concentrations. Moderately polar eelgrass surface extracts inhibited the settlement of seven marine bacteria and one yeast that originated from non-living substrata. In contrast, five other bacterial strains that had been directly isolated from eelgrass surfaces were all insensitive, which suggested a selective effect of surface metabolites on the microbial communities present on eelgrass. Bioassay-guided isolation of active compounds from the extracts in combination with UPLC-MS and 1H-NMR spectroscopy resulted in the identification of rosmarinic acid, luteolin-7-sulfate and diosmetin-7-sulfate or its isomer chrysoeriol-7-sulfate. All three compounds are nontoxic repellents, as they did not inhibit bacterial growth, but prevented bacterial settlement in a dose-dependent manner. Between 15.6 and 106.8 μg ml−1 of rosmarinic acid were present on the eelgrass surface, enough for half maximal settlement inhibition of bacteria.
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  • 74
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    In:  Geomechanics and Geoengineering, 12 (4). pp. 221-233.
    Publication Date: 2018-12-17
    Description: The progressive bond breakage of artificially cemented sands induced by shear straining was investigated through conventional isotropically consolidated drained triaxial compression tests. Sand specimens were prepared with a low degree of cementation by adopting a chemical grout. Test results were interpreted in terms of two stress–dilatancy theories for cohesive-frictional materials proposed in literature. The influence of debonding on the stress–dilatancy behaviour of cemented sands was analysed with particular emphasis on the ‘delayed dilatancy’ phenomenon. A bonding degradation curve was determined for each test relating the interparticle cohesion (c) to the magnitude of the total plastic strain vector (εd) and a bond degradation rate factor (Dc) was assessed from each curve. The maximum value of interparticle cohesion (c0) before the onset of bond degradation under shearing was found to correspond with a sharp decrease in the soil stiffness of the specimens. The influence of the effective confining stress (p′c)on both c0 and Dc parameters gathered from each test was also ascertained.
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  • 75
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    In:  Isotopes in Environmental and Health Studies, 53 (6). pp. 563-579.
    Publication Date: 2020-01-02
    Description: The spatial variations in the elemental and stable carbon, nitrogen, and sulphur isotope composition of bladder wrack (Fucus vesiculosus) growing along the shore line of the semi-enclosed urbanized Kiel Fjord (western Baltic Sea) was investigated at more than 60 sites. The analyses of the carbon-nitrogen-sulphur (CNS) stoichiometry and C and N stable isotope signature of F. vesiculosus displayed substantial differences between the north-western and the south-eastern parts of the Kiel Fjord. Different size classes displayed in part differences in C:N and C:S ratios, and the carbon isotope composition, reflecting the impact of the boundary conditions during growth. Whereas the sulphur isotope composition was controlled by the assimilation of seawater sulphate, the carbon isotope composition reflected the difference in the composition of surface waters. The δ15N values of the organic tissue tend to be an integrated monitor of anthropogenic impacts on the fjord. Results are compared to the composition of surface waters.
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  • 76
    Publication Date: 2020-02-06
    Description: This study aimed to differentiate local and migratory spawning groups of the shortfin squid Illex argentinus caught in Brazilian waters using geometric and traditional morphometric methods and size-selective processes. The back-calculated length distributions reconstructed from daily growth increments deposited in the gladius allowed the identification of size-selective processes that may be related to different life history strategies. Landmark analysis on body shape (geometric morphometric) revealed that spawning groups presented significant ontogenetic variations in terms of body outline. In addition, traditional morphometric methods, based on multivariate analysis, associated juveniles of the expected migratory group (large size) and differentiated them from the local group individuals (small size). The changes in form, probably linked to the environmental gradients experienced by individuals throughout ontogeny, were interpreted as adaptations to improve swimming capacity. Migrant individuals have being differentiated from the smaller sizes group by body characteristics (broad fins, elongated and thicker mantle), which may increase the ability to perform long migrations.
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  • 77
    Publication Date: 2020-07-30
    Description: We investigated the biogeochemical constituents, microbial communities and functional genes (mcr and dsr) associated with anaerobic methane oxidation and sulfate reduction, and metabolic activities by sulfate reduction in the sulfate–methane transition zone (SMTZ) of gas-hydrate-bearing sediment of the Ulleung Basin in the East Sea. Maxima in the sulfate reduction rate (12.6 nmol cm¡3 d¡1), CO concentration (83 mM), and gene abundances of dsrA (9.1 £ 106 copies cm¡3) and mcrA (11.6 £ 106 copies cm¡3) occurred in the SMTZ. The peaks of CO consistently found in the SMTZ suggested that CO is an intermediate metabolic product related to methane oxidation. Candidate division JS1, the predominant bacterial group that comprised 59.0–63.7% of the 16S rRNA gene sequences, was recognized as an important organic carbon oxidizer. Both Marine Benthic Group D (MBGD) and Marine Benthic Group B (MBGB), which constituted 40.8–52.9 and 10.3–43.9% of the 16S rRNA gene sequences, respectively, were the dominant archaeal groups. Analysis of functional gene diversity revealed that anaerobic methanotroph-1-related phylotypes appeared to be the major CH4 oxidizer, whereas Firmicutes-like group was a predominant sulfate reducer in the 0.8 mbsf in SMTZ with low SO42¡ concentration. Overall results indicated that JS1 and two archaeal groups (MBGB and MBGD) seem to play a significant role in carbon and elements cycles in the gas-hydrate-bearing subsurface sediment of the Ulleung Basin.
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  • 78
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    In:  Expert Review of Anti-infective Therapy, 15 (5). pp. 425-433.
    Publication Date: 2018-12-17
    Description: Introduction: The combination of growing antimicrobial resistance with a dry pipeline has resulted in infections that can no longer be treated. Specific reasons have led to companies’ exit from the antibacterial space, however recent incentives are spurring interest to reinvigorate the pipeline. Areas covered: This article summarizes the available information on the discovery, developmental, and regulatory challenges in antibacterial development that have led to disinterest in the space, as well as ongoing incentives such as public-private partnerships and streamlined pathways to mend these challenges and bring new antibiotics to patients in need. Expert commentary: Clinicians should not only understand the reasons for the decline in antibiotic development that have resulted in the dry pipeline, but also the ongoing initiatives in place to build an appropriate supply. Doing so will result in greater appreciation and prudent use of these life-saving drugs when they become available.
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  • 79
    Publication Date: 2020-02-06
    Description: The Red Sea has been recognized as a unique region to study the effects of ecohydrographic gradients at a basin-wide scale. Its gradient of temperature and salinity relates to the Indian Ocean monsoon and associated wind-driven transport of fertile and plankton-rich water in winter from the Gulf of Aden into the Red Sea. Subsequent evaporation and thermohaline circulation increase the salinity and decrease water temperatures toward the North. Compared with other ocean systems, however, relatively little is known about the zooplankton biodiversity of the Red Sea and how this relates to Red Sea latitudinal gradients. Among the most abundant zooplankton taxa are Chaetognatha, which play an important role as secondary consumers in most marine food webs. Since Chaetognatha are sensitive to changes in temperature and salinity, we surmised latitudinal changes in their biodiversity, community structure and diel variability along the coast of Saudi Arabia. Samples were collected at nine coral reefs spanning approximately 1500 km, from the Gulf of Aqaba in the northern Red Sea to the Farasan Archipelago in the southern Red Sea. Thirteen Chaetognatha species belonging to two families (Sagittidae and Krohnittidae) were identified. Latitudinal environmental changes and availability of prey (i.e. Copepoda, Crustacea) altered Chaetognatha density and distribution. The cosmopolitan epiplanktonic Flaccisagitta enflata (38.1%) dominated the Chaetognatha community, and its abundance gradually decreased from South to North. Notable were two mesopelagic species (Decipisagitta decipiens and Caecosagitta macrocephala) in the near-reef surface mixed layers at some sites. This was related to wind-induced upwelling of deep water into the coral reefs providing evidence of trophic oceanic subsidies. Most Sagittidae occurred in higher abundances at night, whereas Krohnittidae were more present during the day. Chaetognatha with developing (stage II) or mature ovaries (stage III) were more active at night, demonstrating stage-specific diel vertical migration as a potential predator avoidance strategy.
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  • 80
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    In:  Atmospheric and Oceanic Science Letters, 10 (4). pp. 325-328.
    Publication Date: 2020-01-02
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  • 81
    Publication Date: 2020-02-06
    Description: Many studies have shown that natural marine compounds can prevent biofouling by a broad spectrum of organisms without toxic effects, encouraging their use in antifouling (AF) coatings. Studies over the past 25 years of the natural product zosteric acid (ZA) are systematically organized in this review. ZA is a sulfated phenolic acid produced by the seagrass Zostera marina that has very promising AF potential against several micro- and macrofouling organisms. ZA was shown to have appropriate environmental fate parameters such as high water solubility, a low log P, low bioaccumulation, and no ecotoxicity, which demonstrated the potential of ZA as a safe AF agent. This review also highlights that ZA has been successfully incorporated into several types of coatings. The synthesis of analogs is also considered in this review, and it has allowed a better understanding of ZA structure–AF activity relationships and clarified the mechanism of action of ZA.
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  • 82
    Publication Date: 2020-07-14
    Description: Microbial production routes, notably whole-cell lipase-mediated biotransformation and fatty-acids-derived biosynthesis, offer new opportunities for synthesizing biodiesel. They compare favorably to immobilized lipase and chemically catalyzed processes. Genetically modified whole-cell lipase-mediated in vitro route, together with in vivo and ex vivo microbial biosynthesis routes, constitutes emerging and rapidly developing research areas for effective production of biodiesel. This review presents recent advances in customizing microorganisms for producing biodiesel, via genetic engineering of lipases and metabolic engineering (including system regulation) of fatty-acids-derived pathways. Microbial hosts used include Escherichia coli, Saccharomyces cerevisiae, Pichia pastoris and Aspergillus oryzae. These microbial cells can be genetically modified to produce lipases under different forms: intracellularly expressed, secreted or surface-displayed. They can be metabolically redesigned and systematically regulated to obtain balanced biodiesel-producing cells, as highlighted in this study. Such genetically or metabolically modified microbial cells can support not only in vitro biotransformation of various common oil feedstocks to biodiesel, but also de novo biosynthesis of biodiesel from glucose, glycerol or even cellulosic biomass. We believe that the genetically tractable oleaginous yeast Yarrowia lipolytica could be developed to an effective biodiesel-producing microbial cell factory. For this purpose, we propose several engineered pathways, based on lipase and wax ester synthase, in this promising oleaginous host.
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  • 83
    Publication Date: 2020-07-09
    Description: Species richness and species abundance (colonization pressure and propagule pressure, respectively) are commonly used to characterize invasion risk for ballast-water-mediated introductions, which can be high if either parameter is high. For practical reasons, the adopted IMO-D2 standard for organisms in discharged ballast water only considers total abundance of biological indicators, without consideration of species richness or source community. Here we explore the effect of ballast-water source, ballast water exchange, chlorination, or a combination of both (hybrid treatment) on both colonization pressure and propagule pressure for one IMO-D2 size class (≥10 µm and 〈50 µm; phytoplankton). A strong reduction of propagule pressure was observed in all experimental trials and taxonomic groups, probably owing to environment conditions inside ballast tanks and treatment effects. However, only the hybrid treatment met the IMO-D2 standard for propagule pressure, while also significantly reducing colonization pressure, from 25 initial groups to 16 final groups. In this treatment, dinoflagellates and diatoms dominated final composition. The impact of different treatments on colonization pressure and propagule pressure was always lower when the vessel was ballasted in a brackish than freshwater port. Our study demonstrates that even treated ballast water compliant with the IMO-D2 standard may still harbor a diverse phytoplankton community, albeit with low individual species abundances. These results might be similar even using a type approved ballast water management systems which usually includes a filter for 〉50 µm organisms as a pre-treatment.
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  • 84
    Publication Date: 2020-08-03
    Description: Four quinolinones (1–4; 1 is a new compound) were isolated from the static fermentation culture of a shark gill-derived fungus Penicillium crustosum AP2T1. In addition, five new quinolinone derivatives (5–9) and also 1 were obtained in a trimethylsilyldiazomethane-induced methylation reaction of 4. Their structures were elucidated by spectroscopic analyses. In bioassays, compounds 7 and 5 with lactim structures moderately inhibited the proliferation of human cancer cell line HCT116 (wild-type) with IC50-24 h of 8.4 μg/mL and 30.7 μg/mL, respectively; the other compounds displayed weaker inhibition. The p53 gene may play some role in their action as suggested by their much weakened activity towards p53-knockout HCT116 cell line. Besides, 6 and 8 exhibited moderate or weak toxicity to brine shrimp larvae, and 3, 4, 8 and 9 showed weak inhibition against Staphylococcus aureus. It is the first report on elucidation of new compounds with origin of shark-derived fungi.
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  • 85
    Publication Date: 2021-04-23
    Description: Climate change has significant implications for biodiversity and ecosystems. With slow progress towards reducing greenhouse gas emissions, climate engineering (or ‘geoengineering’) is receiving increasing attention for its potential to limit anthropogenic climate change and its damaging effects. Proposed techniques, such as ocean fertilization for carbon dioxide removal or stratospheric sulfate injections to reduce incoming solar radiation, would significantly alter atmospheric, terrestrial and marine environments, yet potential side-effects of their implementation for ecosystems and biodiversity have received little attention. A literature review was carried out to identify details of the potential ecological effects of climate engineering techniques. A group of biodiversity and environmental change researchers then employed a modified Delphi expert consultation technique to evaluate this evidence and prioritize the effects based on the relative importance of, and scientific understanding about, their biodiversity and ecosystem consequences. The key issues and knowledge gaps are used to shape a discussion of the biodiversity and ecosystem implications of climate engineering, including novel climatic conditions, alterations to marine systems and substantial terrestrial habitat change. This review highlights several current research priorities in which the climate engineering context is crucial to consider, as well as identifying some novel topics for ecological investigation.
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  • 86
    Publication Date: 2019-02-01
    Description: The surface chemistry of aquatic organisms determines their biotic interactions. Metabolites in the spatially limited laminar boundary layer mediate processes, such as antifouling, allelopathy and chemical defense against herbivores. However, very few methods are available for the investigation of such surface metabolites. An approach is described in which surfaces are extracted by means of C18 solid phase material. By powdering wet algal surfaces with this material, organic compounds are adsorbed and can be easily recovered for subsequent liquid chromatography/mass spectrometry (LC/MS) and gas chromatography/mass spectrometry (GC/MS) investigations. The method is robust, picks up metabolites of a broad polarity range and is easy to handle. It is more universal compared to established solvent dipping protocols and it does not cause damage to the test organisms. A protocol is introduced for the macroalgae Fucus vesiculosus, Caulerpa taxifolia and Gracilaria vermiculophylla, but it can be easily transferred to other aquatic organisms.
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  • 87
    Publication Date: 2019-02-01
    Description: One new diterpene, trichocitrin (1), and four known secondary metabolites, nafuredin (2), 5-hydroxy-2,3-dimethyl-7-methoxychromone (3), 24-methylenecycloartanol (4) and citrostadienol (5), were isolated from the culture of marine brown alga-endophytic Trichoderma citrinoviride cf-27. Trichocitrin (1) represents the first Trichoderma-derived and furan-bearing fusicoccane diterpene, and its structure and relative configuration were identified by analysis of 1D/2D NMR and mass spectroscopic data. Compounds 1 and 2 exhibited 8.0- and 9.5-mm inhibition zones, respectively, against Escherichia coli at 20 μg/disc and 54.1 and 36.7% growth inhibition, respectively, of Prorocentrum donghaiense at 80 μg/mL.
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  • 88
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    In:  Biodiversity, 17 (1-2). pp. 5-11.
    Publication Date: 2017-03-31
    Description: Antarctica is a still unexplored area in many respects, among which biological diversity and, even more so, chemical diversity are important challenges. Over recent years, our research group has been studying marine benthic ecosystems in different Antarctic areas. These studies yielded several interesting discoveries, including species new to science, as well as new natural products never seen before. Overall, we have been trying to unravel the complex network of interactions that exist between marine benthic organisms in these cold and hardly accessible ecosystems. We present here an overview of our recent results regarding the biological and the chemical diversity of these organisms. In fact, these ecosystems are as complex as many other marine environments on the planet, and indeed, many questions remain yet to be answered.
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  • 89
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    In:  Marine Georesources & Geotechnology, 34 (5). pp. 465-473.
    Publication Date: 2019-02-01
    Description: In this study, Lade's double-surface work-hardening constitutive model was adopted which uses the elasto-plasticity model as a basic conceptual framework. The model can analyze work hardening and work softening of nonlinear stress-strain behavior, and is regarded as superior to other elasto-plasticity constitutive models in terms of estimation. In the double-surface work-hardening constitutive model, 14 soil parameters are needed to estimate soil behaviors. To determine them, laboratory tests—isotropical consolidation test and conventional compression test—were conducted. Determining of soil parameters is highly complicated and time-consuming; randomness cannot be ruled out in determining parameters that are sensitive to stress-strain estimation, and error may occur. For this reason, a linear and nonlinear regression analysis was used to determine soil parameters. In estimation of undrained behavior, the estimated stress-strain behavior based on the two constitutive models largely overlapped with the test results. However, in estimating drained behavior, the outcome of the two models and the test results were mostly the same, but between the two models, the double-surface work-hardening constitutive model had a sharper slope in initial stress state, and a smaller maximum deviatoric stress.
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  • 90
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    In:  Plant Biosystems - An International Journal Dealing with all Aspects of Plant Biology, 150 (1). pp. 152-160.
    Publication Date: 2019-02-01
    Description: The aim of this study was to test the effects of temperature on phenolic content of the brown seaweed Cystoseira amentacea. Phenolic compounds are secondary metabolites involved in different protection mechanisms as, for example, against grazers, epiphytes and UV radiation. Seasonal variations of phenolic content in C. amentacea were analysed and laboratory experiments, in which C. amentacea was exposed to an increase of temperature (25°C and 30°C), were performed. Total phenolic content (TPC) was determined colorimetrically with the Folin–Ciocalteu reagent. In C. amentacea, a seasonal pattern in TPC was observed, with a maximum value in winter-spring. C. amentacea responded significantly to the temperature treatments with a consistent decrease in TPC after 48 h.
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  • 91
    Publication Date: 2019-02-01
    Description: Fluorescent-amplified fragment length polymorphism (FAFLP) fingerprinting assay was used to compare the genetic diversity within and between tadpole shrimps (Notostraca) populations of Lepidurus apus (n=7) and Triops cancriformis (n=2) from rain pools in Israel. Each ephemeral water body has revealed a unique fingerprint pattern with an entailed genetic drift between nearby ponds. High similarity of genotypic diversity within each geographic area led to three clusters of water bodies, north, south and center of Israel. FAFLP assays on several newly hatched individuals of T. cancriformis revealed high identity amongst kin, as compared to L. apus where newly hatched from the same maternal source showed high diversity. Results indicate that T. cancriformis populations from Israel are probably parthenogenetic as indicated by clonal structures. The higher genetic variability in the L. apus populations and in laboratory-hatched specimens indicates the existence of sexual reproduction.
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  • 92
    Publication Date: 2020-07-09
    Description: Gammarids from the Caspian complex have invaded many European waters along the rivers and canals of the inland migration corridors. The species examined in this work are well known as invaders of European freshwater environments, so the colonization of brackish habitats is a phenomenon inviting more detailed investigation. The aim of this study was to determine the condition of the Ponto-Caspian gammarids Pontogammarus robustoides (G.O. Sars, 1894), Obesogammarus crassus (G.O. Sars, 1894), Dikerogammarus haemobaphes (Eichwald, 1841) and Dikerogammarus villosus (Sowinsky, 1894) as expressed by the relationship between total length and the wet weight of specimens in the brackish waters of the Gulf of Gdansk (Poland). The relationships can be regarded as responses to a newly expanded habitat after they overcome the salinity barrier of the southern Baltic Sea coastal waters. All these Ponto-Caspian gammarids demonstrated an increase in weight with increasing total length: P. robustoides (b = 2.852), O. crassus (b = 3.3477), D. haemobaphes (b = 3.7855) and D. villosus (b = 2.6917). The results are an indicator of the relatively good condition of the organisms and indicate that the brackish environment of the Gulf of Gdansk affords them excellent possibilities for growth.
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  • 93
    Publication Date: 2019-02-01
    Description: For the environmental monitoring of coral, mucus appears to be an appropriate biological matrix due to its array of functions in coral biology and the non-intrusive manner in which it can be collected. The aim of the present study was to evaluate the feasibility of using mucus of the stony coral Lophelia pertusa (L. pertusa) as an analytical matrix for discovery of biomarkers used for environmental monitoring. More specifically, to assess whether a mass-spectrometry-based proteomic approach can be applied to characterize the protein composition of coral mucus and changes related to petroleum discharges at the seafloor. Surface-enhanced laser desorption/ionization–time of flight mass spectrometry (SELDI-TOF MS) screening analyses of orange and white L. pertusa showed that the mucosal protein composition varies significantly with color phenotype, a pattern not reported prior to this study. Hence, to reduce variability from phenotype difference, L. pertusa white individuals only were selected to characterize in more detail the basal protein composition in mucus using liquid chromatography, mass spectrometry, mass spectrometry (LC-MS/MS). In total, 297 proteins were identified in L. pertusa mucus of unexposed coral individuals. Individuals exposed to drill cuttings in the range 2 to 12 mg/L showed modifications in coral mucus protein composition compared to unexposed corals. Although the results were somewhat inconsistent between individuals and require further validation in both the lab and the field, this study demonstrated preliminary encouraging results for discovery of protein markers in coral mucus that might provide more comprehensive insight into potential consequences attributed to anthropogenic stressors and may be used in future monitoring of coral health.
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  • 94
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    In:  In: Energy Geotechnics. , ed. by Wuttke, F., Bauer, S. and Sanchez, M. Taylor & Francis, London, pp. 437-443. ISBN 978-1-138-03299-6
    Publication Date: 2020-07-27
    Description: Results from two recent field trials, onshore in the Alaska permafrost and in the Nankai Trough offshore Japan, suggest that natural gas could be produced from marine gas hydrate reservoirs at compatible yields and rates. However, both field trials were accompanied by different technical issues, the most striking problems resulting from un-predicted geomechanical behaviour, sediment destabilization and catastrophic sand production. So far, there is a lack of experimental data which could help to understand relevant mechanisms and triggers for potential soil failure in gas hydrate production, to guide model development for simulation of soil behaviour in large-scale production, and to identify processes which drive or, further, mitigate sand production. We use high-pressure flow-through systems in combination with different online and in situ monitoring tools (e.g. Raman microscopy, MRI) to simulate relevant gas hydrate production scenarios. Key components for soil mechanical studies are triaxial systems with ERT (Electric resistivity tomography) and high-resolution localstrain analysis. Sand production control and management is studied in a novel hollow-cylinder-type triaxial setup with a miniaturized borehole which allows fluid and particle transport at different fluid injection and flow conditions. We further apply a novel large-scale high-pressure flow-through triaxial test system equipped with μ-CT to evaluate soil failure modes and triggers relevant to gas hydrate production and slope stability. The presentation will emphasize an in-depth evaluation of our experimental approach, and it is our concern to discuss important issues of translating laboratory results to gas hydrate reservoirs in nature. We will present results from high-pressure flow-through experiments which are designed to systematically compare soil mechanical behaviour of gas hydrate-bearing sediments in relevant production scenarios focusing on depressurization and CO2 injection. Experimental datasets are analyzed based on numerical models which are able to simulate coupled process dynamics during gas hydrate formation and gas production.
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  • 95
    Publication Date: 2019-02-01
    Description: Suspended particulate matter (SPM) causes most of the scattering in natural waters and thus has a strong influence on the underwater light field, and consequently on the whole ecosystem. Turbidity is related to the concentration of SPM which usually is measured gravimetrically, a rather time-consuming method. Measuring turbidity is quick and easy, and therefore also more cost-effective. When derived from remote sensing data the method becomes even more cost-effective because of the good spatial resolution of satellite data and the synoptic capability of the method. Turbidity is also listed in the European Union’s Marine Strategy Framework Directive as a supporting monitoring parameter, especially in the coastal zone. In this study, we aim to provide a new Baltic Sea algorithm to retrieve SPM concentration from in situ turbidity and investigate how this can be applied to satellite data. An in situ dataset was collected in Swedish coastal waters to develop a new SPM model. The model was then tested against independent datasets from both Swedish and Lithuanian coastal waters. Despite the optical variability in the datasets, SPM and turbidity were strongly correlated (r = 0.97). The developed model predicts SPM reliably from in situ turbidity (R2 = 0.93) with a mean normalized bias (MNB) of 2.4% for the Swedish and 14.0% for the Lithuanian datasets, and a relative error (RMS) of 25.3% and 37.3%, respectively. In the validation dataset, turbidity ranged from 0.3 to 49.8 FNU (Formazin Nephelometric Unit) and correspondingly, SPM concentration ranged from 0.3 to 34.0 g m–3 which covers the ranges typical for Baltic Sea waters. Next, the medium-resolution imaging spectrometer (MERIS) standard SPM product MERIS Ground Segment (MEGS) was tested on all available match-up data (n = 67). The correlation between SPM retrieved from MERIS and in situ SPM was strong for the Swedish dataset with r = 0.74 (RMS = 47.4 and MNB = 11.3%; n = 32) and very strong for the Lithuanian dataset with r = 0.94 (RMS = 29.5% and MNB = −1.5%; n = 35). Then, the turbidity was derived from the MERIS standard SPM product using the new in situ SPM model, but retrieving turbidity from SPM instead. The derived image was then compared to existing in situ data and showed to be in the right range of values for each sub-area. The new SPM model provides a robust and cost-efficient method to determine SPM from in situ turbidity measurements (or vice versa). The developed SPM model predicts SPM concentration with high quality despite the high coloured dissolved organic matter (CDOM) range in the Baltic Sea. By applying the developed SPM model to already existing remote sensing data (MERIS/Envisat) and most importantly to a new generation of satellite sensors (in particular OLCI on board the Sentinel-3), it is possible to derive turbidity for the Baltic Sea.
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  • 96
    Publication Date: 2019-02-01
    Description: Abstract: Context: Some Ajuga L. (Lamiaceae) species are traditionally used for the treatment of malaria, as well as fever, which is a common symptom of many parasitic diseases. Objective: In the continuation of our studies on the identification of antiprotozoal secondary metabolites of Turkish Lamiaceae species, we have investigated the aerial parts of Ajuga laxmannii. Materials and methods: The aerial parts of A. laxmannii were extracted with MeOH. The H2O subextract was subjected to polyamide, C18-MPLC and SiO2 CCs to yield eight metabolites. The structures of the isolates were elucidated by NMR spectroscopy and MS analyses. The extract, subextracts as well as the isolates were tested for their in vitro antiprotozoal activities against Plasmodium falciparum, Trypanasoma brucei rhodesiense, T. cruzi and Leishmania donovani at concentrations of 90–0.123 μg/mL. Results: Two iridoid glycosides harpagide (1) and 8-O-acetylharpagide (2), three o-coumaric acid derivatives cis-melilotoside (3), trans-melilotoside (4) and dihydromelilotoside (5), two phenylethanoid glycosides verbascoside (6) and galactosylmartynoside (7) and a flavone-C-glycoside, isoorientin (8) were isolated. Many compounds showed moderate to good antiparasitic activity, with isoorientin (8) displaying the most significant antimalarial potential (an IC50 value of 9.7 μg/mL). Discussion and conclusion: This is the first report on the antiprotozoal evaluation of A. laxmannii extracts and isolates. Furthermore, isoorientin and dihydromelilotoside are being reported for the first time from the genus Ajuga.
    Type: Article , PeerReviewed
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  • 97
    Publication Date: 2020-06-19
    Description: This study aimed to improve understanding of the strategies developed by the Mediterranean seaweed Taonia atomaria to chemically control bacterial epibiosis. An experimental protocol was optimized to specifically extract algal surface-associated metabolites by a technique involving dipping in organic solvents whilst the integrity of algal cell membranes was assessed by fluorescent microscopy. This methodology was validated using mass spectrometry-based profiles of algal extracts and analysis of their principal components, which led to the selection of methanol as the extraction solvent with a maximum exposure time of 15 s. Six compounds (A–F) were identified in the resulting surface extracts. Two of these surface-associated compounds (B and C) showed selective anti-adhesion properties against reference bacterial strains isolated from artificial surfaces while remaining inactive against epibiotic bacteria of T. atomaria. Such specificity was not observed for commercial antifouling biocides and other molecules identified in the surface or whole-cell extracts of T. atomaria.
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  • 98
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    Taylor & Francis
    In:  Atmospheric and Oceanic Science Letters, 9 (6). pp. 428-435.
    Publication Date: 2019-10-08
    Description: Recent SST and atmospheric circulation anomaly data suggest that the 2015/16 El Niño event is quickly decaying. Some researchers have predicted a forthcoming La Niña event in late summer or early fall 2016. From the perspective of the modulation of tropical SST by solar activity, the authors studied the evolution of the 2015/16 El Niño event, which occurred right after the 2014 solar peak year. Based on statistical and composite analysis, a significant positive correlation was found between sunspot number index and El Niño Modoki index, with a lag of two years. A clear evolution of El Niño Modoki events was found within 1–3 years following each solar peak year during the past 126 years, suggesting that anomalously strong solar activity during solar peak periods favors the triggering of an El Niño Modoki event. The patterns of seasonal mean SST and wind anomalies since 2014 are more like a mixture of two types of El Niño (i.e. eastern Pacific El Niño and El Niño Modoki), which is similar to the pattern modulated by solar activity during the years following a solar peak. Therefore, the El Niño Modoki component in the 2015/16 El Niño event may be a consequence of solar activity, which probably will not decay as quickly as the eastern Pacific El Niño component. The positive SST anomaly will probably sustain in the central equatorial Pacific (around the dateline) and the northeastern Pacific along the coast of North America, with a low-intensity level, during the second half of 2016.
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  • 99
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    Taylor & Francis
    In:  Current Eye Research, 41 (10). pp. 1316-1325.
    Publication Date: 2019-08-30
    Description: Purpose: To compare keratocyte activation, cellular morphologic changes and wound healing after SMILE and PRK procedures using transmission electron microscope (TEM).Methods: In this study, 22 New Zealand white rabbits (10- to 15-week old) were used. The right eyes of all animals underwent SMILE procedure and the left eyes underwent PRK procedure. Cornea samples taken 1 day and 1 week postoperatively were examined using TEM.Results: Using TEM 1 day after SMILE procedure, the organization of collagen fibers seemed to have been preserved without thermal alterations. Keratocyte activation was observed in the anterior stroma. Disrupted collagen arrangement and debris of cells are visible in the area of damage, and some phagocytic cells and a large number of secondary lysosomes are visible in those cells. At the perimeter zone of the interface, many coenocytes and collagen fragments could be found within the phagocytic cell. One week after SMILE procedure, potential lacuna could be discerned. A large part of the interface of the lenticule extracted had an appearance of clearly being adhered to some mucus secretions. One day after PRK procedure, an irregular epithelial surface was visible using TEM. Keratocytes had been activated and the rough endoplasmic reticulum in those cells had expanded. One week after PRK procedure, the epithelial surface still was irregular and keratinization of the epithelium was still visible in some areas. Corneal endothelium cells were mildly damaged and some vacuoles within the cytoplasm could be discerned. In the anterior stroma, some unhealthy activated keratocytes could still be observed. New collagen fibrils were found present near the activated keratocytes.Conclusion: Using TEM, keratocyte activation could still be observed after SMILE compared to after PRK procedure. Fewer cellular ultrastructural changes were seen after SMILE procedure. Unlike in PRK procedure, no damaged epithelium and endothelium were found after SMILE.
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  • 100
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    Taylor & Francis
    In:  Atmospheric and Oceanic Science Letters, 10 (1). pp. 1-8.
    Publication Date: 2019-10-08
    Description: Solar radiation is a forcing of the climate system with a quasi-11-year period. As a quasi-period forcing, the influence of the phase of the solar cycle on the ocean system is an interesting topic of study. In this paper, the authors investigate a particular feature, the ocean heat content (OHC) anomaly, in different phases of the total solar irradiance (TSI) cycle. The results show that almostopposite spatial patterns appear in the tropical Pacific during the ascending and declining phases of the TSI cycle. Further analysis reveals the presence of the quasi-decadal (~11-year) solar signal in the SST, OHC and surface zonal wind anomaly field over the tropical Pacific with a high level of statistical confidence (〉95%). It is noted that the maximum centers of the ocean temperature anomaly are trapped in the upper ocean above the main pycnocline, in which the variations of OHC are related closely with zonal wind and ocean currents.
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