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  • Other Sources  (206)
  • Taylor & Francis  (107)
  • MDPI  (62)
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  • 2015-2019  (177)
  • 1980-1984  (29)
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  • 1
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    Cambridge University Press
    In:  Cambridge, 342 pp., Cambridge University Press, vol. 13, no. XVI:, pp. 227-235, (ISBN 3-540-43528-X)
    Publication Date: 1983
    Keywords: Textbook of geophysics ; Seismology ; Seismics (controlled source seismology) ; Waves
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  • 2
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    Cambridge University Press
    In:  Boston, 227 pp., Cambridge University Press, vol. Developments in Petroleum Science vol. 15B, no. Publ. No. 12, pp. 9, (ISBN 0-521-66023-8 hc (0-521-66953-7 pb))
    Publication Date: 1982
    Keywords: Textbook of geophysics ; Seismics (controlled source seismology)
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  • 3
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    Cambridge University Press
    In:  Boston, 227 pp., Cambridge University Press, vol. Developments in Petroleum Science vol. 15B, no. Publ. No. 12, pp. 9, (ISBN 0-521-66023-8 hc (0-521-66953-7 pb))
    Publication Date: 1983
    Keywords: Textbook of geophysics ; Seismics (controlled source seismology)
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  • 4
    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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  • 5
    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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  • 6
    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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  • 7
    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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  • 8
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    Cambridge University Press
    In:  Journal of the Marine Biological Association of the United Kingdom, 64 . pp. 573-579.
    Publication Date: 2020-07-16
    Description: Males of Eledone cirrhosa grow to a size little over 600 g and normally have well-developed, and presumably active, reproductive organs from about 200 g upwards. Total weight of the genital bag is well correlated with total body weight (r= 0·906). Growth of the testis precedes that of the spermatophoric sac, and the size of neither of these reproductive components is predictable from body weight. The sizes of these organs and the estimated number and length of stored spermatophores are given for 100 g intervals of total body weight. No evidence was obtained for a seasonal trend in male maturity.
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  • 9
    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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  • 10
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    Taylor & Francis
    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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  • 11
    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.
    Type: Article , PeerReviewed , info:eu-repo/semantics/article
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  • 12
    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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  • 13
    Publication Date: 2020-02-06
    Description: Linear diterpenes that are commonly found in brown algae are of high chemotaxonomic and ecological importance. This study reports bifurcatriol (1), a new linear diterpene featuring two stereogenic centers isolated from the Irish brown alga Bifurcariabifurcata. The gross structure of this new natural product was elucidated based on its spectroscopic data (IR, 1D and 2D-NMR, HRMS). Its absolute configuration was identified by experimental and computational vibrational circular dichroism (VCD) spectroscopy, combined with the calculation of 13C-NMR chemical shielding constants. Bifurcatriol (1) was tested for in vitro antiprotozoal activity towards a small panel of parasites (Plasmodium falciparum, Trypanosoma brucei rhodesiense, T. cruzi, and Leishmania donovani) and cytotoxicity against mammalian primary cells. The highest activity was exerted against the malaria parasite P. falciparum (IC50 value 0.65 μg/mL) with low cytotoxicity (IC50 value 56.6 μg/mL). To our knowledge, this is the first successful application of VCD and DP4 probability analysis of the calculated 13C-NMR chemical shifts for the simultaneous assignment of the absolute configuration of multiple stereogenic centers in a long-chain acyclic natural product.
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  • 14
    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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  • 15
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    Taylor & Francis
    In:  Marine Behaviour and Physiology, 7 (1). pp. 15-24.
    Publication Date: 2018-04-18
    Description: Foraging rate was highly variable among shore crabs of the same size category and for individual crabs from day to day. Possible physiological reasons for this variability are discussed. Shore crab foraging rate, both in terms of mussels eaten per day and energy intake per day, was estimated to be higher at 17°C than at 10°C. The shape of diet curves and their mode for male shore crabs at 17°C closely resembled those for 10°C, indicating that the temperature increase had no effect on their previously demonstrated optimal foraging strategy. Female and certain male shore crabs showed a preference for prey smaller than for other equivalent sized males. These suboptimally feeding male and female crabs attained a relatively higher prédation rate (mussels day‐1), although their energy intake (KJ day‐1) remained lower than that of optimally feeding males. Preferred mussel size, number of mussels eaten per day and energy intake were strongly related to master chela height. The diet curves for female and suboptimally feeding male shore crabs could be explained by these crabs’ proportionately smaller master chelae.
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  • 16
    Publication Date: 2021-02-08
    Description: The structural repertoire of bioactive naphthacene quinones is expanded by engineering Streptomyces albus to express the lysolipin minimal polyketide synthase II (PKS II) genes from Streptomyces tendae Tü 4042 (llpD-F) with the corresponding cyclase genes llpCI-CIII. Fermentation of the recombinant strain revealed the two new polyaromatic tridecaketides lysoquinone-TH1 (7, identified) and TH2 (8, postulated structure) as engineered congeners of the dodecaketide lysolipin (1). The chemical structure of 7, a benzo[a]naphthacene-8,13-dione, was elucidated by NMR and HR-MS and confirmed by feeding experiments with [1,2-13C2]-labeled acetate. Lysoquinone-TH1 (7) is a pentangular polyphenol and one example of such rare extended polyaromatic systems of the benz[a]napthacene quinone type produced by the expression of a minimal PKS II in combination with cyclases in an artificial system. While the natural product lysolipin (1) has antimicrobial activity in nM-range, lysoquinone-TH1 (7) showed only minor potency as inhibitor of Gram-positive microorganisms. The bioactivity profiling of lysoquinone-TH1 (7) revealed inhibitory activity towards phosphodiesterase 4 (PDE4), an important target for the treatment in human health like asthma or chronic obstructive pulmonary disease (COPD). These results underline the availability of pentangular polyphenolic structural skeletons from biosynthetic engineering in the search of new chemical entities in drug discovery
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  • 17
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    Cambridge University Press
    In:  Geological Magazine, 121 (6). pp. 563-575.
    Publication Date: 2020-07-31
    Description: We present chemical data on magmatically heterogeneous pyroclastic deposits of late Quaternary age erupted from zoned magma systems underlying Tenerife (Canary Islands), Sao Miguel and Faial (Azores), and Vesuvius. The most fractionated magmas present at each centre are respectively Na-rich phonolite, trachyte, and K-rich phonolite. Within any one deposit, chemical variation is either accompanied by changes in the phenocryst assemblage (petrographic zonation) or is largely manifested in trace element abundances, unaccompanied by any petrographic change (occult zonation). Zoning is analogous to that in calc-alkaline systems where the most fractionated products are high-silica rhyolites. When a range of magma types are considered, a correlation emerges between roofward depletion of trace elements (especially REE) in the zoned system and compatability of those same trace elements in the accessory phenocryst phases present. Thus, allanite- or chevkinite-bearing rhyolitic systems are light-REE depleted roofwards, the sphene-bearing Tenerife system is middle-REE depleted roofwards, the melanite-bearing Vesuvius system is heavy-REE depleted roofwards, while the Azores systems, which lack these phases, display roofward REE enrichment. Therefore, the behaviour of trace elements may in each case be explained by fractionation of observed phenocryst assemblages. The resemblance between features of zoned magma systems and published work on the dynamic consequences of cooling saturated aqueous solutions prompts us to suggest that sidewall crystallization and consequent boundary-layer uprise to form a capping layer at top of the system may be a plausible mechanism for the generation of both petrographic and occult zonation. Reverse zoning occurs among the first-erupted tephra of some deposits, demonstrating that the most highly differentiated magma available is not always the first to be tapped during an eruption from a zoned system.
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  • 18
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    Cambridge University Press
    In:  Journal of the Marine Biological Association of the United Kingdom, 63 . pp. 71-83.
    Publication Date: 2020-07-16
    Description: Changes in the relative size of the ovary, oviducal glands and eggs are described for Eledone cirrhosa captured from the North Sea off Aberdeen over a 3 year period (N = 488). The analysis is based only on freshly caught animals, excluding those held in aquarium conditions (〉 5 days). Ovary enlargement and egg size estimates are used as indices of sexual maturity. Between 0–15% and 18–95% of total body weight is contributed by the ovary. Maximum egg length in the ovary ranges up to 7 mm. On these criteria, sexual maturation typically occurs at body sizes between 400–1000 g although some animals of 1000–1200 g are found showing no evidence of ovary enlargement. The majority of the monthly sample is always immature but maturation can apparently occur at almost any time of the year. Increase in mean ovary index and mean values for egg size are strongly seasonal and indicate a peak incidence of sexual maturity over 2–3 months in the July-September period. Spawning is presumed to follow within 1 month. Estimates of the fecundity of the females, based on the egg sample from the ovary, range from 2·2 × 103 to 55 × 10 3 eggs with a mean of 11 × 10 3 and a mode of 7·5 × 10 3 eggs.
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  • 19
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    Cambridge University Press
    In:  Journal of the Marine Biological Association of the United Kingdom, 64 . pp. 581-585.
    Publication Date: 2020-07-16
    Description: Female Eledone cirrhosa held in aquarium conditions for periods of time of five daysand over show relatively enlarged ovary sizes. Values for ovary index considerably exceed thoseof freshly caught animals and the incidence of the final stage of maturity, in which eggs pack the oviducts, is greater. A comparison of maturity indices for fresh and aquarium males was inconclusive. The range of factors associated with aquarium conditions is briefly reviewed and it is concluded that studies of cephalopod reproductive maturation must distinguish fresh and aquarium animals. Introduction External factors effective in inducing sexual maturation in cephalopods have been suggested several times. The influence of the absence of light has been implicated since the experiments of Wells & Wells (1959) showed that blinded Octopus vulgar is matured precociously. An effect of short day length in stimulating the optic glands of Sepia has been found by Defretin & Richard (1967) and Richard (1967) but this is not clearly the case for Octopus (Buckley, 1977). Octopuses kept in aquarium conditions for lengthy periods are said to have larger relative gonad sizes than those fresh from the sea (Wells & Wells, 1975). One of the factors associated with aquarium conditions is often a degree of starvation, and this circumstance alone is held to be a factor in inducing precocious sexual maturation in Eledone (Mangold & Boucher-Rodoni, 1973). In the course of recent studies on the growth and reproduction of Eledone cirrhosa from the North Sea (Boyle & Knobloch, 1982,1983,1984) animals which had remained in aquarium conditions for 5 days or over were separated from the analysis.
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  • 20
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    Taylor & Francis
    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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  • 21
    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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  • 22
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    Cambridge University Press
    In:  Journal of the Marine Biological Association of the United Kingdom, 64 (02). pp. 285-302.
    Publication Date: 2020-07-16
    Description: A new species of a monogenean Isancistrum subulatae (Gyrodactylidae) has been discovered on the arms and tentacles of the cephalopod mollusc Alloteuthis subulata at Plymouth and I. loliginis, on the gills of the same host, has been re-discovered for the first time since its original description in 1912. I. subulatae, like other gyrodactylids, is viviparous, and has been shown by experiments to transfer to new hosts by contagion. In nature such transfers probably take place during copulation of the hosts and since the parasite may occur in numbers of several thousands per host, it may thereby constitute a venereal disease.
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  • 23
    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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  • 24
    Publication Date: 2020-02-06
    Description: The knowledge of the phase behavior of carbon dioxide (CO2)-rich mixtures is a key factor to understand the chemistry and migration of natural volcanic CO2 seeps in the marine environment, as well as to develop engineering processes for CO2 sequestration coupled to methane (CH4) production from gas hydrate deposits. In both cases, it is important to gain insights into the interactions of the CO2-rich phase—liquid or gas—with the aqueous medium (H2O) in the pore space below the seafloor or in the ocean. Thus, the CH4-CO2 binary and CH4-CO2-H2O ternary mixtures were investigated at relevant pressure and temperature conditions. The solubility of CH4 in liquid CO2 (vapor-liquid equilibrium) was determined in laboratory experiments and then modelled with the Soave–Redlich–Kwong equation of state (EoS) consisting of an optimized binary interaction parameter kij(CH4-CO2) = 1.32 × 10−3 × T − 0.251 describing the non-ideality of the mixture. The hydrate-liquid-liquid equilibrium (HLLE) was measured in addition to the composition of the CO2-rich fluid phase in the presence of H2O. In contrast to the behavior in the presence of vapor, gas hydrates become more stable when increasing the CH4 content, and the relative proportion of CH4 to CO2 decreases in the CO2-rich phase after gas hydrate formation.
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  • 25
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    Taylor & Francis
    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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  • 26
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    Taylor & Francis
    In:  Marine Behaviour and Physiology, 9 (2). pp. 139-170.
    Publication Date: 2018-05-22
    Description: The behaviour of Chelophyes has been analysed from the point of view of coordination between stem and nectophores, and an electron microscope study of the effectors and conducting elements has been carried out. Coordination between the stem and anterior nectophore involves two pathways, one epithelial and the other nervous. The nervous link consists of a bundle of small neurites and a single giant axon. There is some evidence that this mediates rapid escape behaviour. After the nerves have been cut, coordination is maintained via the epithelial route. Impulses can jump from epithelial cells into nerves but the transmission process is unclear. Neuro‐epithelial transmission involves conventional synapses. As in physonectid siphonophores, the stem has two nervous systems each with its own giant fibre, and a slow system, the endodermal epithelium. In the nectophore, marginal nerve centres generate a swimming rhythm. Conduction in the subumbrellar muscle is myoid. The exumbrellar epithelium and the subumbrellar endoderm are conducting tissues. Histological study reveals synapses in the predicted locations and gives details of myo‐epithelial organization and nervous layout. Novel histological features include elements resembling steroid‐secreting cells, which ensheath nerves and are innervated by them, and innervated giant non‐nervous cells lying between the nerve ring and the hydroecium. The subumbrellar muscle cells are shown to have sarcolemmal invaginations reminiscent of the f‐tubule system of vertebrate muscle.
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  • 27
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    Taylor & Francis
    In:  Marine Behaviour and Physiology, 8 (2). pp. 135-148.
    Publication Date: 2020-07-14
    Description: The major light and dark components of body displays are described and classified for the octopus Eledone cirrhosa (Lamarck) under aquarium conditions. Comparisons are made with Octopus vulgaris and Eledone moschata. Upon the basic similarity of white display components in the three species is superimposed a trend of modification. Dark components are less various in Eledone cirrhosa and although the chromatophores are organised with leucophores into chromatic units these are not clearly limited morphologically by “grooves”. The mottle patterns of Eledone seem to be arranged along the longitudinal and latitudinal (radial) axes of the animal, the grade of mottle does not respond to grade of background contrast.
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  • 28
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    Taylor & Francis
    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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  • 29
    Publication Date: 2018-02-05
    Description: We have developed a transportable spectroscopic nitrogen isotopic analyzer. The spectrometer is based on dual-modulation Faraday rotation spectroscopy of nitric oxide isotopologues with near shot-noise limited performance and baseline-free operation. Noise analysis indicates minor isotope (15NO) detection sensitivity of 0.36 ppbv·Hz−1/2, corresponding to noise-equivalent Faraday rotation angle (NEA) of 1.31 × 10−8 rad·Hz−1/2 and noise-equivalent absorbance (αL)min of 6.27 × 10−8 Hz−1/2. White-noise limited performance at 2.8× the shot-noise limit is observed up to ~1000 s, allowing reliable calibration and sample measurement within the drift-free interval of the spectrometer. Integration with wet-chemistry based on acidic vanadium(III) enables conversion of aqueous nitrate/nitrite samples to gaseous NO for total nitrogen isotope analysis. Isotopic ratiometry is accomplished via time-multiplexed measurements of two NO isotope transitions. For 5 μmol potassium nitrate samples, the instrument consistently yields ratiometric precision below 0.3‰, thus demonstrating potential as an in situ diagnostic tool for environmental nitrogen cycle studies.
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  • 30
    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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  • 31
    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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  • 32
    Publication Date: 2020-02-06
    Description: In the frame of studies on secondary metabolites produced by fungi from deep-sea environments we have investigated inhibitors of enzymes playing key roles in signaling cascades of biochemical pathways relevant for the treatment of diseases. Here we report on a new inhibitor of the human protein tyrosine phosphatase 1B (PTP1B), a target in the signaling pathway of insulin. A new asperentin analog is produced by an Aspergillus sydowii strain isolated from the sediment of the deep Mediterranean Sea. Asperentin B (1) contains an additional phenolic hydroxy function at C-6 and exhibits an IC50 value against PTP1B of 2 μM in vitro, which is six times stronger than the positive control, suramin. Interestingly, asperentin (2) did not show any inhibition of this enzymatic activity. Asperentin B (1) is discussed as possible therapeutic agents for type 2 diabetes and sleeping sickness.
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  • 33
    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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  • 34
    Publication Date: 2020-02-06
    Description: A new cyclic dipeptide, petrocidin A (1), along with three known compounds—2,3dihydroxybenzoic acid (2), 2,3-dihydroxybenzamide (3), and maltol (4)—were isolated from the solid culture of Streptomyces sp. SBT348. The strain Streptomyces sp. SBT348 had been prioritized in a strain collection of 64 sponge-associated actinomycetes based on its distinct metabolomic profile using liquid chromatography/high-resolution mass spectrometry (LC-HRMS) and nuclear magnetic resonance (NMR). The absolute configuration of all α-amino acids was determined by HPLC analysis after derivatization with Marfey’s reagent and comparison with commercially available reference amino acids. Structure elucidation was pursued in the presented study by mass spectrometry and NMR spectral data. Petrocidin A (1) and 2,3-dihydroxybenzamide (3) exhibited significant cytotoxicity towards the human promyelocytic HL-60 and the human colon adenocarcinoma HT-29 cell lines. These results demonstrated the potential of sponge-associated actinomycetes for the discovery of novel and pharmacologically active natural products.
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  • 35
    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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  • 36
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    Taylor & Francis
    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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  • 37
    Publication Date: 2021-03-19
    Description: The combination of LC-MS/MS based metabolomics approach and anti-MRSA activity-guided fractionation scheme was applied on the Gram-negative bacterium Aequorivita sp. isolated from shallow Antarctic sea sediment using a miniaturized culture chip technique. This methodology afforded the isolation of three new (1–3) and four known (4–7) N-terminal glycine- or serine-bearing iso-fatty acid amides esterified with another iso-fatty acid through their C-3 hydroxy groups. The chemical structures of the new compounds were elucidated using a set of spectroscopic (NMR, [α]D and FT-IR) and spectrometric (HRMS, HRMS/MS) methods. The aminolipids possessing an N-terminal glycine unit (1, 2, 4, 5) showed moderate in vitro antimicrobial activity against MRSA (IC50 values 22–145 µg/mL). This is the first in-depth chemistry and biological activity study performed on the microbial genus Aequorivita.
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  • 38
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    American Association for the Advancement of Science (AAAS)
    In:  Science, 224 (4652). pp. 990-992.
    Publication Date: 2019-03-19
    Description: Study of Nautilus belauensis i its natural habitat in Palau, West Caroline Islands, shows that growth is slow (0.1 millimeter of shell per day on the average) and decreases as maturity is approached and that individuals may live at least 4 years beyond maturity. Age estimates for seven animals marked and recaptured between 45 and 355 days after release range from 14.5 to 17.2 years. These data indicate that the life-span of Nautilus may exceed 20 years and that its life strategy is very different from that of other living cephalopods.
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  • 39
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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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  • 40
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    Cambridge University Press
    In:  In: Climate Change Geoengineering Philosophical Perspectives, Legal Issues. Cambridge University Press, Cambridge, UK, pp. 242-262. ISBN 9781107502635
    Publication Date: 2019-09-23
    Description: Introduction. Today, most countries have accepted a 2 degrees Celsius temperature increase above preindustrial levels as the maximum tolerable limit for global warming. An exceedance probability of below 20 percent for this limit implies an emission budget of less than 250 GtC from 2000 until 2049, however, extrapolating from current global CO2 emissions, this budget will only last until 2024. This sobering math should wake us up to the reality that all options, including climate engineering, need to be considered to address climate change. Climate engineering options can be classified broadly into two categories: solar radiation management and carbon dioxide removal measures. Solar radiation management schemes seek to decrease the incoming solar radiation or to increase the reflection of incoming solar radiation. These approaches can generate fast climate responses, but do not immediately address the cause of the problem. Carbon dioxide removal measures seek to decrease atmospheric carbon concentrations by enhancing or substituting natural carbon sinks. The terrestrial carbon sink can be enhanced by means of forestation; the oceanic sink may, in some regions, be enhanced by means of fertilization, for example by artificially enhanced upwelling of macronutrients or by purposeful addition of the micronutrient iron; the mineral carbon sink can be enhanced by means of chemically accelerated weathering. Some analysts have expressed doubts about the potential of mitigating climate change by sink enhancement, because of concerns about whether carbon can be stored permanently. Nevertheless, terrestrial vegetation sinks have entered the Kyoto Protocol (KP) as offsets for anthropogenic greenhouse gas emissions, but ocean sinks have not.
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  • 41
    Publication Date: 2017-01-19
    Description: Manganese nodule coverage is estimated based on multi-beam and deep-towed video nodule survey profiles of about 1,700 km in the China Pioneer Area of Eastern Pacific. Two statistical equations for estimating nodule coverage are derived separately from the multi-beam normal incidence amplitude data and angular amplitude data based on theoretical analysis of influence factors on multi-beam amplitude data. Predictions generated by the normal incidence amplitude model fall within 5% of real nodule coverage, and theoretically calculated angular amplitude data fits well with the original multi-beam amplitudes at incident angles larger than 20° according to nodule coverage estimated from the deep-towed video data.
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  • 42
    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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  • 43
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    Cambridge University Press
    In:  Journal of the Marine Biological Association of the United Kingdom, 62 (2). pp. 277-296.
    Publication Date: 2020-07-16
    Description: The growth of the octopus Eledone cirrhosa has been studied in a population from the North Sea off Aberdeen. Data are presented for the growth of individuals isolated in aquarium conditions; the growth of size classes in thefieldpopulation; and preliminary information on the growth relationships of gonad, somatic, cardiac and brain components of the body. At 15 °C Eledone cirrhosa is capable of growing from 10 to 1000 g in 270 days. From octopuses which feed readily in captivity, weight specific growth rates of up to about 3–5 % day-1 for animals of 100 g body weight are recorded, falling to a maximum of about 1–5 % day-1 at body sizes above 500 g. Females stop growing when sexually mature, but in the sample captured they were consistently larger than males, a feature which may account for the 7:1 bias towards the incidence of females. On a wet-weight basis, the mean food incorporation into growth is 37 % of the food ingested, which is 49% of the gross weight of crabs killed. Field data for 1978/79 suggest that animals recruited to the population at the beginning of the year grew steadily until December, overwintered without growing, then grew rapidly for several months in the subsequent year before disappearing from the samples. The estimated average age of those animals and by implication, the life span, is 20 months.
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  • 44
    Publication Date: 2020-02-06
    Description: As part of an international research project, the marine fungal strain collection of the Helmholtz Centre for Ocean Research (GEOMAR) research centre was analysed for secondary metabolite profiles associated with anticancer activity. Strain MF458 was identified as Tolypocladium geodes, by internal transcribed spacer region (ITS) sequence similarity and its natural product production profile. By using five different media in two conditions and two time points, we were able to identify eight natural products produced by MF458. As well as cyclosporin A (1), efrapeptin D (2), pyridoxatin (3), terricolin A (4), malettinins B and E (5 and 6), and tolypocladenols A1/A2 (8), we identified a new secondary metabolite which we termed tolypocladenol C (7). All compounds were analysed for their anticancer potential using a selection of the NCI60 cancer cell line panel, with malettinins B and E (5 and 6) being the most promising candidates. In order to obtain sufficient quantities of these compounds to start preclinical development, their production was transferred from a static flask culture to a stirred tank reactor, and fermentation medium development resulted in a nearly eight-fold increase in compound production. The strain MF458 is therefore a producer of a number of interesting and new secondary metabolites and their production levels can be readily improved to achieve higher yields
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  • 45
    Publication Date: 2020-02-06
    Description: Plate-boundary fault rupture during the 2004 Sumatra-Andaman subduction earthquake extended closer to the trench than expected, increasing earthquake and tsunami size. International Ocean Discovery Program Expedition 362 sampled incoming sediments offshore northern Sumatra, revealing recent release of fresh water within the deep sediments. Thermal modeling links this freshening to amorphous silica dehydration driven by rapid burial-induced temperature increases in the past 9 million years. Complete dehydration of silicates is expected before plate subduction, contrasting with prevailing models for subduction seismogenesis calling for fluid production during subduction. Shallow slip offshore Sumatra appears driven by diagenetic strengthening of deeply buried fault-forming sediments, contrasting with weakening proposed for the shallow Tohoku-Oki 2011 rupture, but our results are applicable to other thickly sedimented subduction zones including those with limited earthquake records.
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  • 46
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    Taylor & Francis
    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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  • 47
    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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  • 48
    Publication Date: 2020-02-06
    Description: This study explores non-metric multidimensional scaling (nMDS) as a tool for investigating parasites as indicators of the elasmobranch biology. An attractive feature of nMDS is its ability to allow assemblage-level parasite data to be simultaneously applied to questions of host biology. This method was examined using the tapeworm order Trypanorhyncha Diesing, 1863, which is known to be transmitted among their hosts through the marine food web (via predation), can unambiguously be identified in the intermediate and final hosts, and has the potential as an indicator of the host feeding biology. Our analyses focused on trypanorhynch assemblages in elasmobranchs as definitive hosts. The relationships between trypanorhynch assemblages and the depth, feeding ecology, habitat, and phylogeny for all sharks were complex, but we found that depth distribution, diet composition and habitat type were the major influencing factors. Several species of sharks showed different characters than known from their descriptions that could be attributed to the change of shark behavior or the trypanorhynch host path. The relationship between the trypanorhynch assemblage and factors for carcharhiniform species alone was more robust than for all sharks. In the carcharhiniform analysis, the relationship between habitat type and trypanorhynch assemblage was most remarkable. Overlapping host ecology was evident even in phylogenetically-distant related hosts.
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  • 49
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    Taylor & Francis
    In:  Journal of Asian Natural Products Research, 17 (5). pp. 468-474.
    Publication Date: 2017-10-04
    Description: Chemical examination of the fermentation broth of a sponge-associated fungus Trichoderma harzinum HMS-15-3 led to the isolation of four pairs of new C13 lipid enantiomers namely harzianumols A–H (1a–4b). Their structures were elucidated on the basis of extensive spectroscopic (IR, MS, 1D, and 2D NMR) data analysis, including the modified Mosher's method for the assignment of their absolute configurations. The new compounds were evaluated for antihyperlipidemic effects in HepG2 cells.
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  • 50
    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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  • 51
    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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  • 52
    Publication Date: 2020-02-06
    Description: Arctic sea-ice loss is a leading indicator of climate change and can be attributed, in large part, to atmospheric forcing. Here, we show that recent ice reductions, weakening of the halocline, and shoaling of intermediate-depth Atlantic Water layer in the eastern Eurasian Basin have increased winter ventilation in the ocean interior, making this region structurally similar to that of the western Eurasian Basin. The associated enhanced release of oceanic heat has reduced winter sea-ice formation at a rate now comparable to losses from atmospheric thermodynamic forcing, thus explaining the recent reduction in sea-ice cover in the eastern Eurasian Basin. This encroaching “atlantification” of the Eurasian Basin represents an essential step toward a new Arctic climate state, with a substantially greater role for Atlantic inflows.
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  • 53
    Publication Date: 2021-02-08
    Description: As plastic waste pollutes the oceans and fish stocks decline, unseen below the surface another problem grows: deoxygenation. Breitburg et al. review the evidence for the downward trajectory of oxygen levels in increasing areas of the open ocean and coastal waters. Rising nutrient loads coupled with climate change—each resulting from human activities—are changing ocean biogeochemistry and increasing oxygen consumption. This results in destabilization of sediments and fundamental shifts in the availability of key nutrients. In the short term, some compensatory effects may result in improvements in local fisheries, such as in cases where stocks are squeezed between the surface and elevated oxygen minimum zones. In the longer term, these conditions are unsustainable and may result in ecosystem collapses, which ultimately will cause societal and economic harm.
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  • 54
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    Taylor & Francis
    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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  • 55
    Publication Date: 2021-02-08
    Description: Stratification of the deep Southern Ocean during the Last Glacial Maximum is thought to have facilitated carbon storage and subsequent release during the deglaciation as stratification broke down, contributing to atmospheric CO2 rise. Here, we present neodymium isotope evidence from deep to abyssal waters in the South Pacific that confirms stratification of the deepwater column during the Last Glacial Maximum. The results indicate a glacial northward expansion of Ross Sea Bottom Water and a Southern Hemisphere climate trigger for the deglacial breakup of deep stratification. It highlights the important role of abyssal waters in sustaining a deep glacial carbon reservoir and Southern Hemisphere climate change as a prerequisite for the destabilization of the water column and hence the deglacial release of sequestered CO2 through upwelling.
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  • 56
    Publication Date: 2019-02-01
    Description: The presence of sea-ice leads represents a key feature of the Arctic sea ice cover. Leads promote the flux of sensible and latent heat from the ocean to the cold winter atmosphere and are thereby crucial for air-sea-ice-ocean interactions. We here apply a binary segmentation procedure to identify leads from MODIS thermal infrared imagery on a daily time scale. The method separates identified leads into two uncertainty categories, with the high uncertainty being attributed to artifacts that arise from warm signatures of unrecognized clouds. Based on the obtained lead detections, we compute quasi-daily pan-Arctic lead maps for the months of January to April, 2003–2015. Our results highlight the marginal ice zone in the Fram Strait and Barents Sea as the primary region for lead activity. The spatial distribution of the average pan-Arctic lead frequencies reveals, moreover, distinct patterns of predominant fracture zones in the Beaufort Sea and along the shelf-breaks, mainly in the Siberian sector of the Arctic Ocean as well as the well-known polynya and fast-ice locations. Additionally, a substantial inter-annual variability of lead occurrences in the Arctic is indicated.
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  • 57
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    Taylor & Francis
    In:  Journal of Natural History, 49 (45-48). pp. 2891-2903.
    Publication Date: 2016-02-23
    Description: This paper reviews aspects of the biology of copepods infecting marine fish commercially cultured at fish farms or held as broodstock at governmental hatcheries in Japan. In total, 20 species of parasitic copepods have been reported from these fish: they are mostly caligids (12 spp.), followed by lernaeopodids (4 spp.), pennellid (1 sp.), chondracanthid (1 sp.), taeniacanthid (1 sp.), and unidentified species (1 sp.). The identified copepods are: Caligus fugu, C. lagocephalus, C. lalandei, C. latigenitalis, C. longipedis, C. macarovi, C. orientalis, C. sclerotinosus, C. spinosus, Lepeophtheirus longiventralis, L. paralichthydis, L. salmonis (Caligidae); Alella macrotrachelus, Clavella parva, Parabrachiella hugu, P. seriolae (Lernaeopodidae); Peniculus minuticaudae (Pennellidae); Acanthochondria priacanthi (Chondracanthidae); and Biacanthus pleuronichthydis (Taeniacanthidae). The fish recorded as hosts include carangids (4 spp.), sparids (2 spp.), monacanthids (2 spp.), salmonids (2 spp.), scombrid (1 sp.), tetraodontid (1 sp.), pleuronectid (1 sp.), paralichthyid (1 sp.), and trichodontid (1 sp.). Only five species (C. orientalis, L. longiventralis, L. salmonis, C. parva and A. priacanthi) parasitize farmed fish in subarctic waters, while all other species (15 spp.) infect farmed fish in temperate waters. No information is yet available on copepods from fish farmed in subtropical waters. Three species of Caligus (C. fugu, C. sclerotinosus and C. longipedis) are serious pests in aquaculture of Japanese pufferfish (Takifugu rubripes), red seabream (Pagrus major), and striped jaw (Pseudocaranx dentex), respectively. Due to its one-host life cycle that is unique among pennellids, P. minuticaudae is considered as a potentially serious pest with further development of aquaculture of its filefish hosts, threadsail filefish (Stephanolepis cirrhifer) and black scraper (Thamnaconus modestus). Infection of farmed salmonids by L. salmonis is not a serious problem in Japan
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  • 58
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    American Association for the Advancement of Science (AAAS)
    In:  Science, 216 (4550). pp. 1128-1131.
    Publication Date: 2018-03-08
    Description: Large euhedral crystals of calcium carbonate hexahydrate were recovered from a shelf basin of the Bransfield Strait, Antarctic Peninsula, at a water depth of 1950 meters and sub-zero bottom water temperatures. The chemistry, mineralogy, and stable isotope composition of this hydrated calcium carbonate phase, its environment of formation, and its mode of precipitation confirm the properties variously attributed to hypothetical precursors of the glendonites and thereby greatly expand their use in paleoceanographic interpretation.
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  • 59
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    MDPI
    In:  ISPRS International Journal of Geo-Information, 5 (4). p. 40.
    Publication Date: 2019-02-01
    Description: Sharing and secondary analysis of data have become increasingly important for research. Especially in geography, the collection of digital data has grown due to technological changes. Responsible handling and proper documentation of research data have therefore become essential for funders, publishers and higher education institutions. To achieve this goal, universities offer support and training in research data management. This article presents the experiences of a pilot workshop in research data management, especially for geographers. A discipline-specific approach to research data management training is recommended. The focus of this approach increases researchers’ interest and allows for more specific guidance. The instructors identified problems and challenges of research data management for geographers. In regards to training, the communication of benefits and reaching the target groups seem to be the biggest challenges. Consequently, better incentive structures as well as communication channels have to be established.
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  • 60
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    Cambridge University Press
    In:  Journal of the Marine Biological Association of the United Kingdom UK, 62 . pp. 435-451.
    Publication Date: 2020-07-27
    Description: The planktonic foraminifer Globigerinoides sacculifer (Brady) was cultured under two different light intensities and in continuous darkness. High light intensity (HLI = 4oo-soo einsteins/m2/s) resulted in a longer lifespan, a greater number of chambers formed, and a larger final shell size compared with individuals cultured under low light intensity (LLI = 20-50 einsteins/m2/s) or in continuous darkness. Shell growth rates were unaffected by increasing light intensity, but gametogenesis was delayed. Continuous darkness induced a rapid onset of gametogenesis in organisms with shell lengths larger than 250 m. Feeding frequency had a greater effect on growth and reproduction than light intensity under conditions of LLI and HLI, but continuous darkness had an overriding effect on growth and reproduction owing to the rapid onset of gametogenesis which terminated the life of the mother cell. Our previous data indicated that the longevity of G. sacculifer was dependent on feeding frequency, and that G. sacculifer cultured under LLI had a lifespan of approximately 2-4 weeks. Present results suggest that the lifespan can vary from a minimum of 8 days for organisms fed daily in continuous darkness to a maximum of 54 days for organisms fed once every 7 days and maintained in HLI. It is concluded that individual G. sacculifer attain a shell size greater than 6oo ,urn only if they maintain their position in the euphotic zone. Prolonged existence below the euphotic zone would result in premature death or gametogenesis following stunted shell growth.
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  • 61
    Publication Date: 2015-08-03
    Description: The Soil Moisture and Ocean Salinity (SMOS) mission observes brightness temperatures at a low microwave frequency of 1.4 GHz (L-band) with a daily coverage of the polar regions. L-band radiometry has been shown to provide information on the thickness of thin sea ice. Here, we apply a new emission model that has previously been used to investigate the impact of snow on thick Arctic sea ice. The model has not yet been used to retrieve ice thickness. In contrast to previous SMOS ice thickness retrievals, the new model allows us to include a snow layer in the brightness temperature simulations. Using ice thickness estimations from satellite thermal imagery, we simulate brightness temperatures during the ice growth season 2011 in the northern Baltic Sea. In both the simulations and the SMOS observations, brightness temperatures increase by more than 20 K, most likely due to an increase of ice thickness. Only if we include the snow in the model, the absolute values of the simulations and the observations agree well (mean deviations below 3.5 K). In a second comparison, we use high-resolution measurements of total ice thickness (sum of ice and snow thickness) from an electromagnetic (EM) sounding system to simulate brightness temperatures for 12 circular areas. While the SMOS observations and the simulations that use the EM modal ice thickness are highly correlated (r2=0.95), the simulated brightness temperatures are on average 12 K higher than observed by SMOS. This would correspond to an 8-cm overestimation of the modal ice thickness by the SMOS retrieval. In contrast, if the simulations take into account the shape of the EM ice thickness distributions (r2=0.87), the mean deviation between simulated and observed brightness temperatures is below 0.1 K.
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  • 62
    Publication Date: 2019-08-19
    Description: Marine calcifiers as a plankton functional type (PFT) are a crucial part of the global carbon cycle, being responsible for much of the carbon export to the deep ocean entering via biological pathways. Deep ocean carbon export through calcifiers is controlled by physiological, ecological, and biogeochemical factors. This paper describes the implementation of a calcifying phytoplankton PFT in the University of Victoria Earth System Climate Model, version 2.9 (UVic ESCM), and mechanistic improvements to the representation of model carbon export (a full calcite tracer, carbonate chemistry dependent calcite dissolution rates, and a ballasting scheme). An iterative method for stabilizing and tuning the biogeochemistry is furthermore described. The UVic ESCM now fills a niche in Earth system modelling that was previously unoccupied in that it is relatively inexpensive to run, yet resolves the complete Earth system carbon cycle including prognostic calcium carbonate and a separate phytoplankton calcifier PFT. The model is now well suited to testing feedbacks between the carbonate and carbon cycles and the climate system as transient simulations. The modifications described improve the UVic ESCM's mechanistic realism without compromising performance with respect to observed carbon and nutrient fluxes. Primary production, export production, particulate organic carbon, and calcite fluxes all fall within independently observed estimates.
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  • 63
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    Taylor & Francis
    In:  Journal of Natural History, 49 (45-48). pp. 2727-2741.
    Publication Date: 2017-04-11
    Description: The current state of development of an interactive electronic identification key for females of the marine pelagic microcopepod family Oncaeidae is presented. To date, 112 species have been described, allocated to seven genera (Archioncaea, Conaea, Epicalymma, Monothula, Oncaea s.str., Spinoncaea, and Triconia) and 16 species groups within the speciose paraphyletic taxon Oncaea s.l. Only two species of Oncaea s.l. show an uncertain group status. Of all described oncaeids, seven species are not yet included in the key due to inadequacies in morphological description and/or lack of type material for re-examination. In addition, seven morphologically distinct species and two new species groups are considered that have not yet been formally described. The key uses easily distinguishable morphological characters as far as possible (e.g. body size, proportional lengths of urosomites, length of P5 exopod) and includes more difficult characters (e.g. spine counts on swimming legs, proportional spine lengths) where required for unequivocal identification. The characters used in the key allow the identification of genera and species groups by investigators with limited taxonomic experience; species separation in most cases requires some advanced dissection skills. Potential identification problems caused by difficulties discerning minute morphological features or intraspecific morphometric variability are discussed. The present version of the identification key still requires complementary illustrations of character states and inclusion of fact sheets summarizing the characteristics of each species with notes on taxonomic uncertainties and links to databases providing zoogeographical and genetic information.
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  • 64
    Publication Date: 2021-03-04
    Description: An unusual polyketide with a new carbon skeleton, lindgomycin (1), and the recently described ascosetin (2) were extracted from mycelia and culture broth of different Lindgomycetaceae strains, which were isolated from a sponge of the Kiel Fjord in the Baltic Sea (Germany) and from the Antarctic. Their structures were established by spectroscopic means. In the new polyketide, two distinct domains, a bicyclic hydrocarbon and a tetramic acid, are connected by a bridging carbonyl. The tetramic acid substructure of compound 1 was proved to possess a unique 5-benzylpyrrolidine-2,4-dione unit. The combination of 5-benzylpyrrolidine-2,4-dione of compound 1 in its tetramic acid half and 3-methylbut-3-enoic acid pendant in its decalin half allow the assignment of a new carbon skeleton. The new compound 1 and ascosetin showed antibiotic activities with IC50 value of 5.1 (±0.2) µM and 3.2 (±0.4) μM, respectively, against methicillin-resistant Staphylococcus aureus.
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  • 65
    Publication Date: 2019-01-23
    Description: Some 290 species of squids comprise the order Teuthida that belongs to the molluscan Class Cephalopoda. Of these, about 30-40 squid species have substantial commercial importance around the world. Squid fisheries make a rather small contribution to world landings from capture fisheries relative to that of fish, but the proportion has increased steadily over the last decade, with some signs of recent leveling off. The present overview describes all substantial squid fisheries around the globe. The main ecological and biological features of exploited stocks, and key aspects of fisheries management are presented for each commercial species of squid worldwide. The history and fishing methods used in squid fisheries are also described. Special attention has been paid to interactions between squid fisheries and marine ecosystems including the effects of fishing gear, the role of squid in ecosystem change induced by overfishing on groundfish, and ecosystem-based fishery management.
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  • 66
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    Taylor & Francis
    In:  Geomicrobiology Journal, 3 (2). pp. 151-163.
    Publication Date: 2015-07-08
    Description: We studied the formation of exocellular precipitates of struvite (Mg NH4PO4.6H2O) by 96 kinds of calcite‐pro‐ducing bacterial strains isolated from soil. We also studied the influence of calcium ions on struvite precipitation. The number of strains producing struvite was 20. Only four consistently formed large amounts. These results seem to indicate that the bacterial precipitation of struvite is not a general phenomenon. The strains studied were taxonomically identified, and no relationship was found between the production of struvite and the taxonomic identity of such strains. Calcium, supplied as Ca acetate in the culture medium, appeared to inhibit the biological precipitation of struvite.
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  • 67
    Publication Date: 2015-09-04
    Description: Changes in the formation of dense water in the Arctic Ocean and Nordic Seas [the “Arctic Mediterranean” (AM)] probably contributed to the altered climate of the last glacial period. We examined past changes in AM circulation by reconstructing radiocarbon ventilation ages of the deep Nordic Seas over the past 30,000 years. Our results show that the glacial deep AM was extremely poorly ventilated (ventilation ages of up to 10,000 years). Subsequent episodic overflow of aged water into the mid-depth North Atlantic occurred during deglaciation. Proxy data also suggest that the deep glacial AM was ~2° to 3°C warmer than modern temperatures; deglacial mixing of the deep AM with the upper ocean thus potentially contributed to the melting of sea ice, icebergs, and terminal ice-sheet margins.
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  • 68
    Publication Date: 2016-02-23
    Description: Sea ice leads play an essential role in ocean-ice-atmosphere exchange, in ocean circulation, geochemistry and in ice dynamics. Their precise detection is crucial for altimetric estimations of sea ice thickness and volume. This study evaluates the performance of the SARAL/AltiKa altimeter to detect leads and to monitor their spatio-temporal dynamics. We show that a pulse peakiness parameter (PP) used to detect leads by Envisat RA-2 and ERS-1,-2 altimeters is not suitable because of saturation of AltiKa return echoes over the leads. The signal saturation results in loss of 6–10% of PP data over sea ice. We propose a different parameter: maximal power of waveform, and define the threshold to discriminate the leads. Our algorithm can be applied from December until May. It detects well the leads of small and medium size: from 200 m to 3–4 km. So, the combination of the high-resolution altimetric estimates with low-resolution thermal infra-red or radiometric lead fraction products could enhance the capability of remote sensing to monitor sea ice fracturing.
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  • 69
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    Taylor & Francis
    In:  Hydrological Sciences Journal - Journal Des Sciences Hydrologiques, 60 (7-8). pp. 1225-1241.
    Publication Date: 2017-01-24
    Description: The impact of fire on daily discharges from two mountainous basins located in the permafrost region of Eastern Siberia; the Vitimkan (969 km2) and Vitim rivers (18 200 km2), affected by fire over 78% and 49% of their areas, respectively, in 2003 was investigated. The results of hydrological and meteorological data analysis suggested that the Vitimkan River basin had a rapid and profound hydrological response to wildfire in 2003 expressed through an increased summer flow of 41% (133 mm). Conversely, the larger Vitim River basin showed no significant changes in discharges after the fire. The parameters of the process-based hydrological model Hydrograph were estimated for pre-fire conditions. The results of runoff simulations conducted for continuous pre-fire periods of 1966–2002 and 1970–2002 for the Vitimkan and Vitim River basins respectively on a daily time step showed satisfactory agreement with the observed flow series of both basins. Significant underestimation of precipitation and its poor representativeness for mountainous watersheds was revealed as the main cause of observed and simulated flow discrepancies, especially for high flood events. The set of dynamic parameters was developed based on data analysis and post-fire landscape changes as derived from a literature review. The model was applied to investigate the processes in the soil column and their effect on runoff formation during the post-fire period. The new set of model parameters implied intensification of soil thaw, reduction of infiltration rate and evapotranspiration, and increase of upper subsurface flow fraction in summer flood events following the fire. According to modelling results, the post-fire thaw depth exceeded the pre-fire thaw depth by 0.4–0.7 m. Total evapotranspiration reduced by 40% in summer months, while surface flow increased almost 2.5 times during maximum flood events.
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  • 70
    Publication Date: 2019-09-23
    Description: Macroalgae, especially perennial species, are exposed to a seasonally variable fouling pressure. It was hypothesized that macroalgae regulate their antifouling defense to fouling pressure. Over one year, the macrofouling pressure and the chemical anti-macrofouling defense strength of the brown algae Fucus vesiculosus and Fucus serratus were assessed with monthly evaluation. The anti-macrofouling defense was assessed by means of surface-extracted Fucus metabolites tested at near-natural concentrations in a novel in situ bioassay. Additionally, the mannitol content of both Fucus species was determined to assess resource availability for defense production. The surface chemistry of both Fucus species exhibited seasonal variability in attractiveness to Amphibalanus improvisus and Mytilus edulis. Of this variability, 50–60% is explained by a sinusoidal model. Only F. vesiculosus extracts originating from the spring and summer significantly deterred settlement of A. improvisus. The strength of macroalgal antifouling defense did not correlate either with in situ macrofouling pressure or with measured mannitol content, which, however, were never depleted.
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  • 71
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    American Association for the Advancement of Science (AAAS)
    In:  Science, 349 (6243). pp. 24-27.
    Publication Date: 2016-09-08
    Type: Article , NonPeerReviewed
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  • 72
    Publication Date: 2019-01-21
    Description: We used our novel and programmable Porpoise Alarm (PAL, patd.) to synthesize life-like, electronic harbour porpoise communication signals based on those described for captive animals. In the Little Belt, Denmark, we employed PAL (source level 158 ± 1 dB p–p re 1 μPa@1 m; centroid frequency 133 ± 8.5 kHz) to synthesize three aggressive click train types termed “A”, “F3” and “M1” to naive, free-living harbour porpoises. Via theodolite tracking (372 h of total visual effort spread over 10 expeditions) we found that, depending on signal type, porpoises either avoid or become attracted to PAL: Signal types “A” and “F3” are slight deterrents, porpoises increasing minimum range (+23 to 32 m, respectively), whereas “M1” attracts porpoises, reducing range (by − 29 m). As determined via archival acoustic detectors (AADs), both signals “F3” and “M1” led the animals to significantly intensify their click rate (by +10% and 68%, respectively) while signal “A” led to a significant reduction ( − 59%). We propose that equipping fishing gear with PAL emitting signal “F3” could potentially reduce porpoise by-catch by increasing (1) awareness through enhanced echolocation and (2) distance to the nets. Detection probability and radius of PAL/AAD tandems could be improved by emitting signal “M1” to focus porpoise echolocation signals on the AAD. The signal may also be useful in luring animals away from hazards, which may be helpful for conservation measures prior to the onset of harmful acoustic activities such as pile-driving, seismic exploration or ammunition clearance.
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  • 73
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    Taylor & Francis
    In:  Israel Journal of Ecology & Evolution, 61 (2). pp. 77-89.
    Publication Date: 2017-04-13
    Description: Rarity of species is often considered to set priorities for biodiversity conservation. Less abundant species are expected to be at higher risk of extinction and make significant contribution to food web functioning. However, the relationship between species abundance and position in food webs is still unclear. Here we tested possible correlations between species abundance and structural position in Prince William Sound food web. Species abundance was inferred from biomass data and structural position was characterized by 13 centrality indices. We found that less abundant species have higher trophic positions and display more generalist feeding strategies. However, positive correlations link most of the centrality indices to population size. Thus, being locally rare translates into more peripheral food web positions and implies marginal roles in the spread of indirect effects. Species characterized by largest population size are responsible for the transfer of largest amounts of biomass and regulate the transmission of indirect effects. Less abundant species are of marginal structural importance and are exposed to impacts mediated by larger populations. In Prince William Sound ecosystem, rarity is associated with critical food web positions and does not simply reflect a marginal contribution to biodiversity. We suggest that knowing the food web position of rare species might help to formulate more effective, system-level solutions for their conservation, rather than simply focusing on the direct treatment of symptoms.
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  • 74
    Publication Date: 2019-09-23
    Description: Several acoustic and optical techniques have been used for characterizing natural and anthropogenic gas leaks (carbon dioxide, methane) from the ocean floor. Here, single-camera based methods for bubble stream observation have become an important tool, as they help estimating flux and bubble sizes under certain assumptions. However, they record only a projection of a bubble into the camera and therefore cannot capture the full 3D shape, which is particularly important for larger, non-spherical bubbles. The unknown distance of the bubble to the camera (making it appear larger or smaller than expected) as well as refraction at the camera interface introduce extra uncertainties. In this article, we introduce our wide baseline stereo-camera deep-sea sensor bubble box that overcomes these limitations, as it observes bubbles from two orthogonal directions using calibrated cameras. Besides the setup and the hardware of the system, we discuss appropriate calibration and the different automated processing steps deblurring, detection, tracking, and 3D fitting that are crucial to arrive at a 3D ellipsoidal shape and rise speed of each bubble. The obtained values for single bubbles can be aggregated into statistical bubble size distributions or fluxes for extrapolation based on diffusion and dissolution models and large scale acoustic surveys. We demonstrate and evaluate the wide baseline stereo measurement model using a controlled test setup with ground truth information.
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  • 75
    Publication Date: 2017-04-13
    Description: Antifungal bioactivity-guided fractionation of the organic extract of the sponge Polymastia boletiformis, collected from the west coast of Ireland, led to the isolation of two new sulfated steroid-amino acid conjugates (1 and 2). Extensive 1D and 2D NMR analyses in combination with quantum mechanical calculations of the electronic circular dichroism (ECD) spectra, optical rotation, and 13C chemical shifts were used to establish the chemical structures of 1 and 2. Both compounds exhibited moderate antifungal activity against Cladosporium cucumerinum, while compound 2 was also active against Candida albicans. Marine natural products containing steroidal and amino acid constituents are extremely rare in nature.
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  • 76
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    Cambridge University Press
    In:  Journal of The Marine Biological Association of The United Kingdom, 95 (08). pp. 1613-1620.
    Publication Date: 2020-07-17
    Description: Density distribution of the common infaunal bivalves, Macoma balthica and Cerastoderma edule, was studied along the Murman Coast of the Barents Sea during 2002–2010. In both species, abundance was generally higher in West Murman in contrast to East Murman. Highest density of Macoma balthica reaching 1535 ind. m−2 was observed in the Kola Inlet. Cerastoderma edule was less abundant; its density rarely exceeded 10 ind. m−2 in all but one site, where 282 ind. m−2 was registered. Reconstruction of abundance distribution across the European geographic range of Macoma balthica revealed that it does not match an ‘abundant-centre’ pattern, having features of ramped north. On the other hand, distribution of Cerastoderma edule abundance across the range generally follows an ‘abundant-centre’ pattern but southern edge populations show relatively higher abundances as compared with those at the north edge (the Barents Sea).
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  • 77
    Publication Date: 2019-06-05
    Description: Underwater photogrammetry and in particular systematic visual surveys of the deep sea are by far less developed than similar techniques on land or in space. The main challenges are the rough conditions with extremely high pressure, the accessibility of target areas (container and ship deployment of robust sensors, then diving for hours to the ocean floor), and the limitations of localization technologies (no GPS). The absence of natural light complicates energy budget considerations for deep diving flash-equipped drones. Refraction effects influence geometric image formation considerations with respect to field of view and focus, while attenuation and scattering degrade the radiometric image quality and limit the effective visibility. As an improvement on the stated issues, we present an AUV-based optical system intended for autonomous visual mapping of large areas of the seafloor (square kilometers) in up to 6000 m water depth. We compare it to existing systems and discuss tradeoffs such as resolution vs. mapped area and show results from a recent deployment with 90,000 mapped square meters of deep ocean floor.
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  • 78
    Publication Date: 2020-06-19
    Description: This review covers 214 marine natural compounds and 23 of their synthetic analogs, which were discovered and/or synthesized from mid-2009 to August 2014. The antifouling (AF) compounds reported have medium to high bioactivity (with a threshold of EC(50) 〈 15.0 mg ml(-1)). Among these compounds, 82 natural compounds were identified as new structures. All the compounds are marine-derived, demonstrating that marine organisms are prolific and promising sources of natural products that may be developed as environmentally friendly antifoulants. However, this mini-review excludes more than 200 compounds that were also reported as AF compounds but with rather weak bioactivity during the same period. Also excluded are terrestrial-derived AF compounds reported during the last five years. A brief discussion on current challenges in AF compound research is also provided to reflect the authors' own views in terms of future research directions.
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  • 79
    Publication Date: 2019-09-23
    Description: Filamentous fungi are well known for their capability of producing antibiotic natural products. Recent studies have demonstrated the potential of antimicrobials with vast chemodiversity from marine fungi. Development of such natural products into lead compounds requires sustainable supply. Marine biotechnology can significantly contribute to the production of new antibiotics at various levels of the process chain including discovery, production, downstream processing, and lead development. However, the number of biotechnological processes described for large-scale production from marine fungi is far from the sum of the newly-discovered natural antibiotics. Methods and technologies applied in marine fungal biotechnology largely derive from analogous terrestrial processes and rarely reflect the specific demands of the marine fungi. The current developments in metabolic engineering and marine microbiology are not yet transferred into processes, but offer numerous options for improvement of production processes and establishment of new process chains. This review summarises the current state in biotechnological production of marine fungal antibiotics and points out the enormous potential of biotechnology in all stages of the discovery-to-development pipeline. At the same time, the literature survey reveals that more biotechnology transfer and method developments are needed for a sustainable and innovative production of marine fungal antibiotics.
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  • 80
    Publication Date: 2020-07-09
    Description: The White Shrimp (Litopenaeus vannamei) is reared in several types of systems. Changes in pH in some can produce sub-lethal effects that result in poor growth and survival. The aim of the present study was to detennine the acidic and basic pH 50% lethal limits after 96 h exposure (pH50_96 h) and to evaluate the sub-lethal effects of pH on oxidative stress parameters in juvenile L. vannamei. The experimental design comprised nine treatments with three replications of each. The nine treatments consisted of pH 10.5, 10.0, 9.5, 9.0, 7.0, 5.0, 4.5, 4.0 and 3.5. The treatment at 7.0 was used as the control. The sub~lethal pH tests were: basic pH 9.5, neutral pH 7.0 (control) and acidio pH 4.5. For each experimental pH and sampling point, the hemolymph of six shrimp was collected to determine catalase and glutathione S-transferase's activities and total antioxidant capacity. The values of lethat pH50 at 24, 48, 72 and 96 h for juvenile L. vannamei had basic pH values equal to 9.82, 9.62, 9.59 and 9.58 and acidic pH values of 3.86, 3.92, 3.94 and 4.04, respectively. The shrimp exposed to basic and acidic pH levels showed antioxidant responses with changes in antioxidant activity.
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  • 81
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    Taylor & Francis
    In:  Marine Behaviour and Physiology, 10 (4). pp. 259-271.
    Publication Date: 2020-07-14
    Description: Illex illecebrosus squid appear to have a species‐typical and internally organized spatial arrangement of their groups. Squid maintained an average angle of 25° with respect to their nearest neighbour, and mostly had angular deviations between 5° and 20°. They maintained distances to nearest, second and third neighbours in a ratio of 1:1.5:2. The distances were strongly affected by group size (4, 20, or 38), with larger groups maintaining closer distances. Interindividual distances were not affected by two variables, day‐night and presence of a current in the large pool in which they were kept. The similarity of this organization to that of fish schools is discussed.
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  • 82
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    Taylor & Francis
    In:  Biological Oceanography, 2 (2-4). pp. 433-456.
    Publication Date: 2019-04-23
    Description: There are many kinds of squid and cuttlefish in the oceans of the world, and the stock sizes of some are presumed to be large. However, few attempts have been made to quantitatively assess standing stocks. In Japan, the commercial yield ranges from 400,000 to 900,000 metric tons annually, accounting for about 50 to 80% of the total cephalopod catch in the world. Jigging surveys have been conducted since 1971 in the Sea of Japan and since 1973 in the Pacific Ocean off Japan. Their purpose has been to assess the abundance of oceanic squid. The stock size index (N) and the density index (F) for Todarodes pacificus, Ommastrephes bartrami, and Onychoteuthis borealijaponica were calculated for the Pacific from 1968 to 1979 and for the Sea of Japan from 1971 to 1979. N and F correspond reasonably well to periodic changes in the annual yield (Y) of T. pacificus in the Pacific and the Sea of Japan. Since Y is presumed to correspond well to abundance, the results of these surveys give rough estimates of T. pacificus abundance. Changes in N and F for O. bartrami and O. borealijaponica do not show good correspondence with Y, probably because the study area covers only a part of the range of the two species.
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  • 83
    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.
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  • 84
    Publication Date: 2020-05-28
    Description: Growth is described from size-at-age data. Size-at-age was determined from counts of daily growth rings on the statoliths of 65 individuals. A mean growth rate of 2 mm/day was calculated for a dorsal mantle length range of 15-52 cm. The month in which each individual hatched was back-calculated from the age data. A histogram of the frequency of hatching through the year is presented and shows peaks in May and October.
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  • 85
    Publication Date: 2019-06-05
    Description: During the past decades, tremendous advances have been made in the possibilities to study the diversity of microbial communities in the environment. The development of methods to study these communities on the basis of 16S rRNA gene sequences analysis was a first step into the molecular analysis of environmental communities and the study of biodiversity in natural habitats. A new dimension in this field was reached with the introduction of functional genes of ecological importance and the establishment of genetic tools to study the diversity of functional microbial groups and their responses to environmental factors. Functional gene approaches are excellent tools to study the diversity of a particular function and to demonstrate changes in the composition of prokaryote communities contributing to this function. The phylogeny of many functional genes largely correlates with that of the 16S rRNA gene, and microbial species may be identified on the basis of functional gene sequences. Functional genes are perfectly suited to link culture-based microbiological work with environmental molecular genetic studies. In this review, the development of functional gene studies in environmental microbiology is highlighted with examples of genes relevant for important ecophysiological functions. Examples are presented for bacterial photosynthesis and two types of anoxygenic phototrophic bacteria, with genes of the Fenna-Matthews-Olson-protein (fmoA) as target for the green sulfur bacteria and of two reaction center proteins (pufLM) for the phototrophic purple bacteria, with genes of adenosine-5′phosphosulfate (APS) reductase (aprA), sulfate thioesterase (soxB) and dissimilatory sulfite reductase (dsrAB) for sulfur oxidizing and sulfate reducing bacteria, with genes of ammonia monooxygenase (amoA) for nitrifying/ammonia-oxidizing bacteria, with genes of particulate nitrate reductase and nitrite reductases (narH/G, nirS, nirK) for denitrifying bacteria and with genes of methane monooxygenase (pmoA) for methane oxidizing bacteria.
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  • 86
    Publication Date: 2019-09-23
    Description: The properties and the production of new metabolites from the fungal strain LF657 isolated from the Herodotes Deep (2800 m depth) in the Mediterranean Sea are reported in this study. The new isolate was identified as Biscogniauxia mediterranea based on ITS1-5.8S-ITS2 and 28S rRNA gene sequences. A new isopyrrolonaphthoquinone with inhibitory activity against glycogen synthase kinase (GSK-3β) was isolated from this fungus. This is the first report of this class of compounds from a fungus isolated from a deep-sea sediment, as well as from a Biscogniauxia species.
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  • 87
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    American Association for the Advancement of Science (AAAS)
    In:  Science, 213 (4512). pp. 1113-1114.
    Publication Date: 2019-01-21
    Description: During an almost yearlong period of observations made with a current meter in the fracture zone between the Falkland Islands (Islas Malvinas) and South Georgia, several overflow events were recorded at a depth of 3000 meters carrying cold bottom water from the Scotia Sea into the Argentine Basin. The outflow bursts of Scotia Sea bottom water, a mixing product of Weddell Sea and eastern Pacific bottom water, were associated with typical speeds of more than 28 centimeters per second toward the northwest and characteristic temperatures below 0.6°C. The maximum 24-hour average speed of 65 centimeters per second, together with a temperature of 0.29°C, was encountered on 14 November 1980 at a water depth of 2973 meters, 35 meters above the sea floor.
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  • 88
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    MDPI
    In:  Atmosphere, 7 (6). p. 82.
    Publication Date: 2019-06-05
    Description: European Centre for Medium-Range Weather Forecasts (ECMWF) ERA-Interim reanalysis total precipitation estimates are validated against ten years of in situ precipitation measurements onboard of ships over the Baltic Sea. A statistical analysis for binary forecasts and mean rain rates derived from all data show a good agreement with observations. However, a closer look reveals an underestimation of ERA-Interim total precipitation in spring and an overestimation in autumn, obviously related to stability. Deriving stability and evaporation by a bulk flux scheme it could be shown, in fact, that ERA-Interim underestimates precipitation for conditions with low evaporation and strongly overestimates it for conditions with high evaporation. Since ERA-Interim surface fields become too dry with increasing evaporation compared to independent synoptic ship observations, uncertainties in the ECMWF convection scheme may possibly cause these biases in seasonal precipitation.
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  • 89
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    MDPI
    In:  Marine Drugs, 14 (1). p. 19.
    Publication Date: 2019-06-05
    Description: Marine fungi represent a huge potential for new natural products and an increased number of new metabolites have become known over the past years, while much of the hidden potential still needs to be uncovered. Representative examples of biodiversity studies of marine fungi and of natural products from a diverse selection of marine fungi from the author's lab are highlighting important aspects of this research. If one considers the huge phylogenetic diversity of marine fungi and their almost ubiquitous distribution, and realizes that most of the published work on secondary metabolites of marine fungi has focused on just a few genera, strictly speaking Penicillium, Aspergillus and maybe also Fusarium and Cladosporium, the diversity of marine fungi is not adequately represented in investigations on their secondary metabolites and the less studied species deserve special attention. In addition to results on recently discovered new secondary metabolites of Penicillium species, the diversity of fungi in selected marine habitats is highlighted and examples of groups of secondary metabolites produced by representatives of a variety of different genera and their bioactivities are presented. Special focus is given to the production of groups of derivatives of metabolites by the fungi and to significant differences in biological activities due to small structural changes.
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  • 90
    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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  • 91
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    Cambridge University Press
    In:  Journal of the Marine Biological Association of the United Kingdom, 62 (04). p. 799.
    Publication Date: 2020-07-16
    Description: Five hundred and twenty-eight specimens of Loligo forbesi Steenstrup, from landings in Horta, Faial, Azores, during the year 1 March 1980 to 28 February 1981, were tudied; 59·3 % were males, 40·7 % females. Of the males 80·2 % were sexually mature, of the females 91·6 %, both sexes showing the highest degree of maturity in spring and he lowest in autumn. The mean dorsal mantle length of the mature males was 56·5 cm, or females 33·5 cm. A weight-length relationship was calculated. he stomachs of 622 specimens were sampled, of which 306 contained food. The prey omponents were studied qualitatively. The main prey was fish (82·0%), of which 0·5 % were horse mackerel, Trachurus picturatus, this being the most important food rganism. Preliminary results of statolith readings are given.
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  • 92
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    Taylor & Francis
    In:  Biological Oceanography, 2 (2-4). pp. 357-377.
    Publication Date: 2019-05-02
    Description: Three large data sets on cephalopods are critically examined with respect to several sources of error: day-night avoidance, net size, mode of fishing, and patchiness. Catches are low and variable and results only suggest problems with present sampling techniques. Specific field sampling is suggested to quantify several of these sources of error. Volume filtered and time fished are compared as measures of "effort." Variability of volume filtered and net speed within a single tow are examined.
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  • 93
    Publication Date: 2019-04-30
    Description: This is a study of larval abundance and distributional pattern of the winter population of the Japanese common squid, Todarodes pacificus Steenstrup, based on plankton net collections made by the R/V Soyo-Maru during January to March (1959–1976) in the seas extending from the south of Kyushu to the Pacific coast of central and eastern Honshu. The larval abundance index (LI) was compared with CPUE (catch per boat day), an index of recruitment of adult stock size. The main spawning ground of this population is located to the southwest of Kyushu. The larvae (rhynchoteuthion) grow while they are advected by the Kuroshio Current to the northeast. Hence early larvae are more abundant in the west, while advanced larvae are more abundant in the east. Mortality seems to be highest for stages up to several millimeters DML than for later stages. The stock size of the Pacific winter population has fluctuated greatly. It declined since the peak 1960 year class to very low levels. The decrease of the stock size took place in three phases. 1960–1963: While the stock size (CPUE) of the 1960 year class was large, the larval population (LI) produced by this year class was very low, resulting in a decrease of recruitment (CPUE) in following years. 1964–1969: The larval abundance for the 1964 year class was second highest (next to 1960) but the recruitment was remarkably low, probably because of unfavorable conditions for survival during the period between larval and advanced stages. This failure caused a further decrease of larval abundance for the 1965 and subsequent year classes. 1970–1976: The larval abundance remains at a very low level and CPUE has declined since 1970. Because of the short life-span (one year) of this squid, abrupt decreases of larval abundance and/or recruitment have a serious effect on stock size. The future recovery of the stock will depend on biotic and physical conditions that are favorable for the survival of early stages south of Kyushu. A significant positive correlation between catch per effort of adults and the abundance of larvae (LI) in the following year indicates that larval abundance can be used to assess the size of the spawning stock of the winter population of T. pacificas.
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  • 94
    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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  • 95
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    Taylor & Francis
    In:  Biological Oceanography, 2 (2-3-4). pp. 379-399.
    Publication Date: 2019-04-16
    Description: An examination of the knowledge about sampling Loligo opalescens populations leads to two general conclusions regarding the assessment of their abundance. First, it is suggested that studies concentrate on spawning ground organisms, since they aggregate during spawning, are commercially fished at this time, and their numbers can be assessed using a combination of data from market catch, adult and egg case densities, acoustic sensing, and perhaps larval densities. Second, it is suggested that large-scale acoustic surveys coupled with large midwater trawling activities be used to qualitatively assess adult organisms off the spawning grounds.
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  • 96
    Publication Date: 2019-02-01
    Description: Lake Urmia, the second largest saline Lake on earth and a highly endangered ecosystem, is on the brink of a serious environmental disaster similar to the catastrophic death of the Aral Sea. Progressive drying has been observed during the last decade, causing dramatic changes to Lake Urmia’s surface and its regional water supplies. The present study aims to improve monitoring of spatiotemporal changes of Lake Urmia in the period 1975–2015 using the multi-temporal satellite altimetry and Landsat (5-TM, 7-ETM+ and 8-OLI) images. In order to demonstrate the impacts of climate change and human pressure on the variations in surface extent and water level, Lake Sevan and Van Lake with different characteristics were studied along with the Urmia Lake. Normalized Difference Water Index-Principal Components Index (NDWI-PCs), Normalized Difference Water Index (NDWI), Modified NDWI (MNDWI), Normalized Difference Moisture Index (NDMI), Water Ratio Index (WRI), Normalized Difference Vegetation Index (NDVI), Automated Water Extraction Index (AWEI), and MultiLayer Perceptron Neural Networks (MLP NNs) classifier were investigated for the extraction of surface water from Landsat data. The presented results revealed that MLP NNs has a better performance in the cases where the other models generate poor accuracy. The results show that the area of Lake Sevan and Van Lake have increased while the area of Lake Urmia has decreased by ~65.23% in the past decades, far more than previously reported (~25% to 50%). Urmia Lake’s shoreline has been receding severely between 2010 and 2015 with no sign of recovery, which has been partly blamed on prolonged droughts, aggressive regional water resources development plans, intensive agricultural activities, and anthropogenic changes to the system. The results also indicated that (among the proposed factors) changes in inflows due to overuse of surface water resources and constructing dams (mostly during 1995–2005) are the main reasons for Urmia Lake’s shoreline receding. The model presented in this manuscript can be used by managers as a decision support system to find the effects of building new dams or other infrastructures
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  • 97
    Publication Date: 2019-09-23
    Description: The glycogen-synthase-kinase 3 (GSK-3) is an important target in drug discovery. This enzyme is involved in the signaling pathways of type 2 diabetes, neurological disorders, cancer, and other diseases. Therefore, inhibitors of GSK-3 are promising drug candidates for the treatment of a broad range of diseases. Here we report pannorin (1), alternariol (2), and alternariol-9-methylether (3) to be promising inhibitors of the isoform GSK-3β showing sub-μM IC50 values. The in vitro inhibition is in the range of the known highly active GSK-3β inhibitor TDZD-8. Compounds 1–3 have a highly oxygenated benzocoumarin core structure in common, which suggests that this may be a new structural feature for efficient GSK-3β inhibition
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  • 98
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    Taylor & Francis
    In:  Alcheringa: An Australasian Journal of Palaeontology, 4 (4). pp. 289-297.
    Publication Date: 2016-08-08
    Description: The distribution of benthic foraminifera in Miocene deposits of the continental margin of southeastern South America is compared with that in the Recent. The comparison indicates that Miocene zoogeographic boundaries were located in higher latitudes than at present, suggesting that the climate at that time was warmer than now. In the Pliocene, temperatures were lower than at present. This signifies that a considerable decrease in water temperature took place in the latest Miocene or at the Miocene/Pliocene boundary in the southwestern Atlantic. The main reason for this drop in temperature was the opening of the Drake Passage and the establishment of the Circumpolar Antarctic Current and a branch — the Malvin Current. The opening resulted from strong orogenic movements, in the latest Miocene, which created the main part of the Andes. Prior to the opening of the passage, the anticyclonic (counterclockwise) gyre of surface currents in the South Atlantic was much larger and warm Brazilian waters reached higher latitudes. The Austral Strait, connecting the Pacific and Atlantic Oceans, may have existed from the Cretaceous in the southern part of South America, but its location and character did not permit the establishment of the true Circumpolar Antarctic Current. The Austral Strait was closed simultaneously with the opening of the Drake Passage.
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  • 99
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    Cambridge University Press
    In:  Journal of the Marine Biological Association of the United Kingdom, 61 (04). pp. 901-916.
    Publication Date: 2020-07-16
    Description: Symbiotic luminous bacteria have been described in, and cultured from, a number of species offish and cephalopod. Indeed only in these two groups are extracellular luminous bacteria believed to be utilized as a source of light (see Buchner (1965) and Herring (1978) for references). Despite several earlier investigations of such symbioses in cephalopods the bacteria in these animals have not been adequately identified, nor has the extent of their role been clarified. The ultrastructural relationships between bacteria and the tissues of the squid accessory nidamental gland have been investigated in the non-luminous species Loligo pealei (Lesueur) (Bloodgood, 1977) and Sepia officinalis L. (Van den Branden et al. 1979) but no comparative work on luminous species has been undertaken apart from that on Heteroteuthis dispar (Rüppell), whose photophore does not contain typical luminous bacteria (Dilly & Herring, 1978; cf. Leisman, Cohn & Nealson, 1980). The order Sepioidea contains five families, among which are the two families Sepiolidae and Spirulidae. Though the presence of luminous bacteria is known in some sepiolids (as well as in certain loliginids (order Teuthoidea)) some doubt remains about the source of light in the photophore of Spirula spirula Hoyle. The steady luminescence of this species has prompted speculation that bacteria may be involved (Harvey, 1952). In this paper we compare the anatomy and ultrastructure of the photophores of both Sepiola and Spirula in order to clarify some of these problems.
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  • 100
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    Cambridge University Press
    In:  Journal of the Marine Biological Association of the United Kingdom, 60 (01). p. 151.
    Publication Date: 2020-07-16
    Description: This is the first detailed analysis of cephalopod beaks from the stomach of a northern bottlenosed whale, Hyperoodon ampullatus (Forster, 1770). The digestive action of many predators barely affects the chitinous beaks of cephalopods and some cetaceans accumulate the beaks in considerable numbers in their stomachs. The present beaks are clean and unbroken. Identification of cephalopod beaks from stomachs of predators such as sperm whales (see Clarke, 1977), seals (Clarke & Trillmich, 1980) and albatrosses (Clarke, Croxall & Prince, 1980) throws considerable light on the biology and relative ecological importance of the species of cephalopods concerned as well as providing useful information on the diet of the predators.
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