1,006 research outputs found
DNA sequencing as a tool to monitor marine ecological status
© 2017 Goodwin, Thompson, Duarte, Kahlke, Thompson, Marques and Caçador. Many ocean policies mandate integrated, ecosystem-based approaches to marine monitoring, driving a global need for efficient, low-cost bioindicators of marine ecological quality. Most traditional methods to assess biological quality rely on specialized expertise to provide visual identification of a limited set of specific taxonomic groups, a time-consuming process that can provide a narrow view of ecological status. In addition, microbial assemblages drive food webs but are not amenable to visual inspection and thus are largely excluded from detailed inventory. Molecular-based assessments of biodiversity and ecosystem function offer advantages over traditional methods and are increasingly being generated for a suite of taxa using a "microbes to mammals" or "barcodes to biomes" approach. Progress in these efforts coupled with continued improvements in high-throughput sequencing and bioinformatics pave the way for sequence data to be employed in formal integrated ecosystem evaluation, including food web assessments, as called for in the European Union Marine Strategy Framework Directive. DNA sequencing of bioindicators, both traditional (e.g., benthic macroinvertebrates, ichthyoplankton) and emerging (e.g., microbial assemblages, fish via eDNA), promises to improve assessment of marine biological quality by increasing the breadth, depth, and throughput of information and by reducing costs and reliance on specialized taxonomic expertise
Muon spin rotation/relaxation measurements of the non-centrosymmetric superconductor Mg10Ir19B16
We have searched for time-reversal symmetry breaking fields in the
non-centrosymmetric superconductor MgIrB via muon spin
relaxation in zero applied field, and we measured the temperature dependence of
the superfluid density by muon spin rotation in transverse field to investigate
the superconducting pairing symmetry in two polycrystalline samples of
signficantly different purities. In the high purity sample, we detected no
time-reversal symmetry breaking fields greater than 0.05 G. The superfluid
density was also found to be exponentially-flat as T0, and so can be fit
to a single-gap BCS model. In contrast, the lower purity sample showed an
increase in the zero-field SR relaxation rate below T corresponding to
a characteristic field strength of 0.6 G. While the temperature-dependence of
the superfluid density was also found to be consistent with a single-gap BCS
model, the magnitude as T0 was found to be much lower for a given applied
field than in the case of the high purity sample. These findings suggest that
the dominant pairing symmetry in high quality MgIrB
samples corresponds to the spin-singlet channel, while sample quality
drastically affects the superconducting properties of this system.Comment: 6 pages, 5 figures, revised version resubmitted to PR
A communal catalogue reveals Earth’s multiscale microbial diversity
Our growing awareness of the microbial world\u27s importance and diversity contrasts starkly with our limited understanding of its fundamental structure. Despite recent advances in DNA sequencing, a lack of standardized protocols and common analytical frameworks impedes comparisons among studies, hindering the development of global inferences about microbial life on Earth. Here we present a meta-analysis of microbial community samples collected by hundreds of researchers for the Earth Microbiome Project. Coordinated protocols and new analytical methods, particularly the use of exact sequences instead of clustered operational taxonomic units, enable bacterial and archaeal ribosomal RNA gene sequences to be followed across multiple studies and allow us to explore patterns of diversity at an unprecedented scale. The result is both a reference database giving global context to DNA sequence data and a framework for incorporating data from future studies, fostering increasingly complete characterization of Earth\u27s microbial diversity
Bio-GO-SHIP: The Time is Right to Establish Global Repeat Sections of Ocean Biology
In this article, we present Bio-GO-SHIP, a new ocean observing program that will incorporate sustained and consistent global biological ocean observations into the Global Ocean Ship-based Hydrographic Investigations Program (GO-SHIP). The goal of Bio-GO-SHIP is to produce systematic and consistent biological observations during global ocean repeat hydrographic surveys, with a particular focus on the planktonic ecosystem. Ocean plankton are an essential component of the earth climate system, form the base of the oceanic food web and thereby play an important role in influencing food security and contributing to the Blue Economy. Despite its importance, ocean biology is largely under-sampled in time and space compared to physical and chemical properties. This lack of information hampers our ability to understand the role of plankton in regulating biogeochemical processes and fueling higher trophic levels, now and in future ocean conditions. Traditionally, many of the methods used to quantify biological and ecosystem essential ocean variables (EOVs), measures that provide valuable information on the ecosystem, have been expensive and labor- and time-intensive, limiting their large-scale deployment. In the last two decades, new technologies have been developed and matured, making it possible to greatly expand our biological ocean observing capacity. These technologies, including cell imaging, bio-optical sensors and \u27omic tools, can be combined to provide overlapping measurements of key biological and ecosystem EOVs. New developments in data management and open sharing can facilitate meaningful synthesis and integration with concurrent physical and chemical data. Here we outline how Bio-GO-SHIP leverages these technological advances to greatly expand our knowledge and understanding of the constituents and function of the global ocean plankton ecosystem
Metagenomic covariation along densely sampled environmental gradients in the Red Sea
Oceanic microbial diversity covaries with physicochemical parameters. Temperature, for example, explains approximately half of global variation in surface taxonomic abundance. It is unknown, however, whether covariation patterns hold over narrower parameter gradients and spatial scales, and extending to mesopelagic depths. We collected and sequenced 45 epipelagic and mesopelagic microbial metagenomes on a meridional transect through the eastern Red Sea. We asked which environmental parameters explain the most variation in relative abundances of taxonomic groups, gene ortholog groups, and pathways—at a spatial scale of <2000 km, along narrow but well-defined latitudinal and depth-dependent gradients. We also asked how microbes are adapted to gradients and extremes in irradiance, temperature, salinity, and nutrients, examining the responses of individual gene ortholog groups to these parameters. Functional and taxonomic metrics were equally well explained (75–79%) by environmental parameters. However, only functional and not taxonomic covariation patterns were conserved when comparing with an intruding water mass with different physicochemical properties. Temperature explained the most variation in each metric, followed by nitrate, chlorophyll, phosphate, and salinity. That nitrate explained more variation than phosphate suggested nitrogen limitation, consistent with low surface N:P ratios. Covariation of gene ortholog groups with environmental parameters revealed patterns of functional adaptation to the challenging Red Sea environment: high irradiance, temperature, salinity, and low nutrients. Nutrient-acquisition gene ortholog groups were anti-correlated with concentrations of their respective nutrient species, recapturing trends previously observed across much larger distances and environmental gradients. This dataset of metagenomic covariation along densely sampled environmental gradients includes online data exploration supplements, serving as a community resource for marine microbial ecology
Bio-GO-SHIP: the time is right to establish global repeat sections of ocean biology
© The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Clayton, S., Alexander, H., Graff, J. R., Poulton, N. J., Thompson, L. R., Benway, H., Boss, E., & Martiny, A. Bio-GO-SHIP: the time is right to establish global repeat sections of ocean biology. Frontiers in Marine Science, 8, (2022): 767443, https://doi.org/10.3389/fmars.2021.767443.In this article, we present Bio-GO-SHIP, a new ocean observing program that will incorporate sustained and consistent global biological ocean observations into the Global Ocean Ship-based Hydrographic Investigations Program (GO-SHIP). The goal of Bio-GO-SHIP is to produce systematic and consistent biological observations during global ocean repeat hydrographic surveys, with a particular focus on the planktonic ecosystem. Ocean plankton are an essential component of the earth climate system, form the base of the oceanic food web and thereby play an important role in influencing food security and contributing to the Blue Economy. Despite its importance, ocean biology is largely under-sampled in time and space compared to physical and chemical properties. This lack of information hampers our ability to understand the role of plankton in regulating biogeochemical processes and fueling higher trophic levels, now and in future ocean conditions. Traditionally, many of the methods used to quantify biological and ecosystem essential ocean variables (EOVs), measures that provide valuable information on the ecosystem, have been expensive and labor- and time-intensive, limiting their large-scale deployment. In the last two decades, new technologies have been developed and matured, making it possible to greatly expand our biological ocean observing capacity. These technologies, including cell imaging, bio-optical sensors and 'omic tools, can be combined to provide overlapping measurements of key biological and ecosystem EOVs. New developments in data management and open sharing can facilitate meaningful synthesis and integration with concurrent physical and chemical data. Here we outline how Bio-GO-SHIP leverages these technological advances to greatly expand our knowledge and understanding of the constituents and function of the global ocean plankton ecosystem.The Bio-GO-SHIP pilot program was funded under the National Oceanographic Partnership Program as an inter-agency partnership between NOAA and NASA, with the US Integrated Ocean Observing System and NOAA's Global Ocean Monitoring and Observing program (HA, SC, JG, AM, and NP). HA was supported by a WHOI Independent Research and Development award. AM was supported by funding from NSF OCE-1848576 and 1948842 and NASA 80NSSC21K1654. JG was funded by NASA from grants 80NSSC17K0568 and NNX15AAF30G. LT was supported by award NA06OAR4320264 06111039 to the Northern Gulf Institute by NOAA's Office of Oceanic and Atmospheric Research, U.S. Department of Commerce
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Travelling for Umrah:destination attributes, destination image, and post-travel intentions
This paper examines the links between cosmopolitanism, self-identity, and a desire for social interaction perceived destination image and behavioural intentions. A model tested using a sample of 538 Iranian visitors to Mecca for the purpose of Umrah. The result from the structural model suggests that destination attributes influence perceived destination image. Further, such tourists are likely to revisit or recommend Islamic destinations if their experience matches their perceived image of the destination. This implies that, while the religious characteristics of the destination remain important, destination managers cannot disregard the tangential, non-religious attributes of a destination which are crucial in order to satisfy more conventional tourist desires. As such, this study suggests that those managing religious travel destinations should endeavour to foster a welcoming image, where experience, interaction and tolerance are at the forefront of the destination’s offering
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