213 results on '"Karger, F."'
Search Results
202. LADUNGSTRAEGERVERLUSTMECHA-NISMEN IM SCHWACHIONISIERTEN TOROIDALEN MAGNETOPLASMA. (Particle Loss Mechanisms in a Weakly Ionized Toroidal Magnetoplasma).
- Author
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Karger, F
- Published
- 1967
203. Particle Losses in a Weakly Ionized Stationary DC Plasma in a Toroidal Magnetic Field; LADUNGSTRAEGERVERLUSTE IN EINEM SCHWACHIONISIERTEN STATIONAEREN GLEICHSTROMPLASMA IM TOROIDALEN MAGNETFELD
- Author
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Karger, F
- Published
- 1965
204. Effects of oceanographic conditions on fishery distribution: A case study of chub mackerel (Scomber japonicus) in northeastern Taiwan.
- Author
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Mondal S, Muller-Karger F, Ray A, Ito SI, Lee MA, and Lu HJ
- Abstract
Changes in oceanographic conditions can affect species distribution in marine habitats. Global climate change may negatively influence the oceanographic factor-species distribution relationship. Here, we assessed the influence of oceanographic conditions on chub mackerel (Scomber japonicus) distribution in northeastern Taiwan by constructing and using a habitat ensemble model incorporating chub mackerel fishery, climatic oscillation, and oceanography data. Our results indicated that the chub mackerel catch was mainly influenced by the Western Pacific Oscillation. Moreover, sea-surface height and mixed-layer depth exerted the most and least significant effects on chub mackerel distribution, respectively. The chub mackerel catch rate peaked in the study area with a sea-surface temperature of 29 °C, sea-surface chlorophyll of 0.25 mg/m
3 , sea-surface salinity of 33.7 psμ, and SSH of 0.575 m. Chub mackerel was the most widely distributed in the area between 25°N, 120.5°E and 26.2°N, 121.5°E. Our findings can be used to develop critical adaptation plans for managing chub mackerel fisheries in the northeastern waters of Taiwan. Considering changing climate conditions globally, the incorporation of this knowledge into managerial strategies may aid decision-makers in protecting not only other ocean fisheries but also individuals dependent on them., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)- Published
- 2024
- Full Text
- View/download PDF
205. The founding charter of the Omic Biodiversity Observation Network (Omic BON).
- Author
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Meyer R, Davies N, Pitz KJ, Meyer C, Samuel R, Anderson J, Appeltans W, Barker K, Chavez FP, Duffy JE, Goodwin KD, Hudson M, Hunter ME, Karstensen J, Laney CM, Leinen M, Mabee P, Macklin JA, Muller-Karger F, Pade N, Pearlman J, Phillips L, Provoost P, Santi I, Schigel D, Schriml LM, Soccodato A, Suominen S, Thibault KM, Ung V, van de Kamp J, Wallis E, Walls R, and Buttigieg PL
- Subjects
- Biodiversity, Knowledge
- Abstract
Omic BON is a thematic Biodiversity Observation Network under the Group on Earth Observations Biodiversity Observation Network (GEO BON), focused on coordinating the observation of biomolecules in organisms and the environment. Our founding partners include representatives from national, regional, and global observing systems; standards organizations; and data and sample management infrastructures. By coordinating observing strategies, methods, and data flows, Omic BON will facilitate the co-creation of a global omics meta-observatory to generate actionable knowledge. Here, we present key elements of Omic BON's founding charter and first activities., (© The Author(s) 2023. Published by Oxford University Press GigaScience.)
- Published
- 2022
- Full Text
- View/download PDF
206. Global genetic diversity status and trends: towards a suite of Essential Biodiversity Variables (EBVs) for genetic composition.
- Author
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Hoban S, Archer FI, Bertola LD, Bragg JG, Breed MF, Bruford MW, Coleman MA, Ekblom R, Funk WC, Grueber CE, Hand BK, Jaffé R, Jensen E, Johnson JS, Kershaw F, Liggins L, MacDonald AJ, Mergeay J, Miller JM, Muller-Karger F, O'Brien D, Paz-Vinas I, Potter KM, Razgour O, Vernesi C, and Hunter ME
- Subjects
- Conservation of Natural Resources methods, Genetic Variation, Humans, Population Density, Biodiversity, Ecosystem
- Abstract
Biodiversity underlies ecosystem resilience, ecosystem function, sustainable economies, and human well-being. Understanding how biodiversity sustains ecosystems under anthropogenic stressors and global environmental change will require new ways of deriving and applying biodiversity data. A major challenge is that biodiversity data and knowledge are scattered, biased, collected with numerous methods, and stored in inconsistent ways. The Group on Earth Observations Biodiversity Observation Network (GEO BON) has developed the Essential Biodiversity Variables (EBVs) as fundamental metrics to help aggregate, harmonize, and interpret biodiversity observation data from diverse sources. Mapping and analyzing EBVs can help to evaluate how aspects of biodiversity are distributed geographically and how they change over time. EBVs are also intended to serve as inputs and validation to forecast the status and trends of biodiversity, and to support policy and decision making. Here, we assess the feasibility of implementing Genetic Composition EBVs (Genetic EBVs), which are metrics of within-species genetic variation. We review and bring together numerous areas of the field of genetics and evaluate how each contributes to global and regional genetic biodiversity monitoring with respect to theory, sampling logistics, metadata, archiving, data aggregation, modeling, and technological advances. We propose four Genetic EBVs: (i) Genetic Diversity; (ii) Genetic Differentiation; (iii) Inbreeding; and (iv) Effective Population Size (N
e ). We rank Genetic EBVs according to their relevance, sensitivity to change, generalizability, scalability, feasibility and data availability. We outline the workflow for generating genetic data underlying the Genetic EBVs, and review advances and needs in archiving genetic composition data and metadata. We discuss how Genetic EBVs can be operationalized by visualizing EBVs in space and time across species and by forecasting Genetic EBVs beyond current observations using various modeling approaches. Our review then explores challenges of aggregation, standardization, and costs of operationalizing the Genetic EBVs, as well as future directions and opportunities to maximize their uptake globally in research and policy. The collection, annotation, and availability of genetic data has made major advances in the past decade, each of which contributes to the practical and standardized framework for large-scale genetic observation reporting. Rapid advances in DNA sequencing technology present new opportunities, but also challenges for operationalizing Genetic EBVs for biodiversity monitoring regionally and globally. With these advances, genetic composition monitoring is starting to be integrated into global conservation policy, which can help support the foundation of all biodiversity and species' long-term persistence in the face of environmental change. We conclude with a summary of concrete steps for researchers and policy makers for advancing operationalization of Genetic EBVs. The technical and analytical foundations of Genetic EBVs are well developed, and conservation practitioners should anticipate their increasing application as efforts emerge to scale up genetic biodiversity monitoring regionally and globally., (© 2022 The Authors. Biological Reviews published by John Wiley & Sons Ltd on behlaf of Cambridge Philosophical Society. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.)- Published
- 2022
- Full Text
- View/download PDF
207. Evaluation of marine zooplankton community structure through environmental DNA metabarcoding.
- Author
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Djurhuus A, Pitz K, Sawaya NA, Rojas-Márquez J, Michaud B, Montes E, Muller-Karger F, and Breitbart M
- Abstract
Zooplankton dominate the abundance and biomass of multicellular animals in pelagic marine environments; however, traditional methods to characterize zooplankton communities are invasive and laborious. This study compares zooplankton taxonomic composition revealed through metabarcoding of the cytochrome oxidase I (COI) and 18S rRNA genes to traditional morphological identification by microscopy. Triplicates of three different sample types were collected from three coral reef sites in the Florida Keys National Marine Sanctuary: (1) 1 L surface seawater samples prefiltered through 3 μ m filters and subsequently collected on 0.22 μ m filters for eDNA (PF-eDNA); (2) 1 L surface seawater samples filtered on 0.22 μ m pore-size filters (environmental DNA; eDNA), and (3) zooplankton tissue samples from 64 μ m, 200 μ m, and 500 μ m mesh size net tows. The zooplankton tissue samples were split, with half identified morphologically and tissue DNA (T-DNA) extracted from the other half. The COI and 18S rRNA gene metabarcoding of PF-eDNA, eDNA, and T-DNA samples was performed using Illumina MiSeq. Of the families detected with COI and 18S rRNA gene metabarcoding, 40% and 32%, respectively, were also identified through morphological assessments. Significant differences in taxonomic composition were observed between PF-DNA, eDNA, and T-DNA with both genetic markers. PF-eDNA resulted in detection of fewer taxa than the other two sample types; thus, prefiltering is not recommended. All dominant copepod taxa (> 5% of total abundance) were detected with eDNA, T-DNA, and morphological assessments, demonstrating that eDNA metabarcoding is a promising technique for future biodiversity assessments of pelagic zooplankton in marine systems.
- Published
- 2018
- Full Text
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208. Large-scale deposition of weathered oil in the Gulf of Mexico following a deep-water oil spill.
- Author
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Romero IC, Toro-Farmer G, Diercks AR, Schwing P, Muller-Karger F, Murawski S, and Hollander DJ
- Subjects
- Gulf of Mexico, Hydrocarbons analysis, Weather, Environmental Monitoring, Petroleum analysis, Petroleum Pollution analysis, Water Pollutants, Chemical analysis
- Abstract
The blowout of the Deepwater Horizon (DWH) drilling rig in 2010 released an unprecedented amount of oil at depth (1,500 m) into the Gulf of Mexico (GoM). Sedimentary geochemical data from an extensive area (∼194,000 km
2 ) was used to characterize the amount, chemical signature, distribution, and extent of the DWH oil deposited on the seafloor in 2010-2011 from coastal to deep-sea areas in the GoM. The analysis of numerous hydrocarbon compounds (N = 158) and sediment cores (N = 2,613) suggests that, 1.9 ± 0.9 × 104 metric tons of hydrocarbons (>C9 saturated and aromatic fractions) were deposited in 56% of the studied area, containing 21± 10% (up to 47%) of the total amount of oil discharged and not recovered from the DWH spill. Examination of the spatial trends and chemical diagnostic ratios indicate large deposition of weathered DWH oil in coastal and deep-sea areas and negligible deposition on the continental shelf (behaving as a transition zone in the northern GoM). The large-scale analysis of deposited hydrocarbons following the DWH spill helps understanding the possible long-term fate of the released oil in 2010, including sedimentary transformation processes, redistribution of deposited hydrocarbons, and persistence in the environment as recycled petrocarbon., (Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.)- Published
- 2017
- Full Text
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209. Spatial variability of Spanish sardine (Sardinella aurita) abundance as related to the upwelling cycle off the southeastern Caribbean Sea.
- Author
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Rueda-Roa D, Mendoza J, Muller-Karger F, Cárdenas JJ, Achury A, and Astor Y
- Subjects
- Animals, Caribbean Region, Ecosystem, Animal Distribution physiology, Biomass, Fisheries, Fishes physiology, Seasons
- Abstract
The Sardinella aurita fishery off northeastern Venezuela, region of seasonal wind-driven coastal-upwelling, accounts for 90% of the Caribbean Sea small pelagic catch. This law-protected artisanal fishery takes place up to ~10 km offshore. The spatial distribution, number of schools, and biomass of S. aurita were studied using eight hydro-acoustic surveys (1995-1998). The study included the analysis of satellite-derived sea surface temperature and chlorophyll-a. Surveys were grouped by strong, weak, and transitional upwelling seasons. Relationships between these observations were analyzed using Generalized Additive Models. Results show that during the primary upwelling season (January-May) sardines were widely distributed in upwelling plumes that extended up to 70 km offshore. In the other hand, during the weak upwelling season (September-October) higher sardine densities were found within 10 Km off the coastal upwelling foci. The number of small pelagic schools was directly correlated with small pelagic densities; however, regardless of the season, higher numbers of small pelagic schools were always closer to the shoreline, especially during warm conditions. These two behaviors increase the availability and catchability of sardines for the artisanal fishery during the warm season, regardless of the total stock size. Using this evidence, we pose the hypothesis that the collapse of the regional S. aurita fishery in 2005 was due to a combination of stressful habitat conditions sustained since 2004. These included bottom-up factors due to food scarcity caused by weak upwelling, combined with top-down stress due to overfishing, as sardines accumulated in narrow diminished upwelling plumes located close to the coast. The increased catchability within easily accessible upwelling foci led to the demise of this biological resource, which as of 2014 had not yet recovered. Environmental conditions affecting the sardine habitat needs to be taken into account for the management of this stock. For example, during years with weak upwelling, special measures should be taken during the warm season on the second half of the year to avoid further pressure on the stock.
- Published
- 2017
- Full Text
- View/download PDF
210. Reply to Brun et al.: Fingerprint of evolution revealed by shifts in realized phytoplankton niches in natural populations.
- Author
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Irwin AJ, Finkel ZV, Müller-Karger F, and Troccoli Ghinaglia L
- Subjects
- Adaptation, Physiological, Ecosystem, Oceans and Seas, Phytoplankton genetics
- Published
- 2015
- Full Text
- View/download PDF
211. Severe 2010 cold-water event caused unprecedented mortality to corals of the Florida reef tract and reversed previous survivorship patterns.
- Author
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Lirman D, Schopmeyer S, Manzello D, Gramer LJ, Precht WF, Muller-Karger F, Banks K, Barnes B, Bartels E, Bourque A, Byrne J, Donahue S, Duquesnel J, Fisher L, Gilliam D, Hendee J, Johnson M, Maxwell K, McDevitt E, Monty J, Rueda D, Ruzicka R, and Thanner S
- Subjects
- Animals, Florida, Geography, Oceans and Seas, Survival Analysis, Survival Rate, Anthozoa physiology, Cold Temperature, Coral Reefs, Seawater
- Abstract
Background: Coral reefs are facing increasing pressure from natural and anthropogenic stressors that have already caused significant worldwide declines. In January 2010, coral reefs of Florida, United States, were impacted by an extreme cold-water anomaly that exposed corals to temperatures well below their reported thresholds (16°C), causing rapid coral mortality unprecedented in spatial extent and severity., Methodology/principal Findings: Reef surveys were conducted from Martin County to the Lower Florida Keys within weeks of the anomaly. The impacts recorded were catastrophic and exceeded those of any previous disturbances in the region. Coral mortality patterns were directly correlated to in-situ and satellite-derived cold-temperature metrics. These impacts rival, in spatial extent and intensity, the impacts of the well-publicized warm-water bleaching events around the globe. The mean percent coral mortality recorded for all species and subregions was 11.5% in the 2010 winter, compared to 0.5% recorded in the previous five summers, including years like 2005 where warm-water bleaching was prevalent. Highest mean mortality (15%-39%) was documented for inshore habitats where temperatures were <11°C for prolonged periods. Increases in mortality from previous years were significant for 21 of 25 coral species, and were 1-2 orders of magnitude higher for most species., Conclusions/significance: The cold-water anomaly of January 2010 caused the worst coral mortality on record for the Florida Reef Tract, highlighting the potential catastrophic impacts that unusual but extreme climatic events can have on the persistence of coral reefs. Moreover, habitats and species most severely affected were those found in high-coral cover, inshore, shallow reef habitats previously considered the "oases" of the region, having escaped declining patterns observed for more offshore habitats. Thus, the 2010 cold-water anomaly not only caused widespread coral mortality but also reversed prior resistance and resilience patterns that will take decades to recover.
- Published
- 2011
- Full Text
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212. Atmospheric Correction of SeaWiFS Imagery: Assessment of the Use of Alternative Bands.
- Author
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Hu C, Carder KL, and Muller-Karger FE
- Abstract
Spatial inhomogeneity, or speckling, frequently occurs in Sea-viewing Wide Field-of-view Sensor (SeaWiFS) data products such as water-leaving radiance and chlorophyll concentration. We have found that this effect may be caused by high-altitude aerosols or thin cirrus clouds or even by digitization errors. For the scenes evaluated, whitecaps were ruled out as a likely cause of these errors. We tried to avoid using the 765-nm band, which is affected by O(2) absorption and is more sensitive to digitization errors, by instead using the 670-nm band in the atmospheric correction and found that speckling for either cloud-free areas or cloud-adjacent areas was significantly reduced.
- Published
- 2000
- Full Text
- View/download PDF
213. H mode of the W 7-AS stellarator.
- Author
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Erckmann V V, Wagner F, Baldzuhn J, Brakel R, Burhenn R, Gasparino U, Grigull P, Hartfuss HJ, Hofmann JV, Jaenicke R, Niedermeyer H, Ohlendorf W, Rudyj A, Weller A, Bogdanov SD, Bomba B, Borschegovsky AA, Cattanei G, Dodhy A, Dorst D, Elsner A, Endler M, Geist T, Giannone L, Hacker H, Heinrich O, Herre G, Hildebrandt D, Hiznyak VI VI, Il'in VI VI, Kasparek W, Karger F, Kick M, Kubo S, Kuftin AN, Kurbatov VI VI, Lazaros A, Malygin SA, Malygin VI VI, McCormick K, Müller GA, Orlov VB, Pech P, Roi IN, Sardei F, Sattler S, Schneider F, Schneider U, Schüller PG, Siller G, Stroth U, Tutter M, Unger E, Wolff H, Würsching E, and Zöpfel S
- Published
- 1993
- Full Text
- View/download PDF
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