scholarly journals Antarctic biodiversity predictions through substrate qualities and environmental DNA

2021 ◽  
Author(s):  
Paul Czechowski ◽  
Michel de Lange ◽  
Michael Knapp ◽  
Aleks Terauds ◽  
Mark Stevens
Keyword(s):  
Large Scale ◽  
Sequence Data ◽  
Spatial Scales ◽  
Environmental Dna ◽  
Distribution Modelling ◽  
Remote Areas ◽  
Long Term Effect ◽  
Substrate Properties ◽  
Substrate Ph

Antarctic conservation science is important to enhance Antarctic policy and to understand alterations of terrestrial Antarctic biodiversity. Antarctic conservation will have limited long-term effect in the absence of large-scale biodiversity data, but if such data were available, it is likely to improve environmental protection regimes. To enable Antarctic biodiversity prediction across continental spatial scales through proxy variables, in the absence of baseline surveys, we link Antarctic substrate-derived environmental DNA (eDNA) sequence data from the remote Antarctic Prince Charles Mountains to a selected range of concomitantly collected measurements of substrate properties. We achieve this using a statistical method commonly used in machine learning. We find neutral substrate pH, low conductivity, and some substrate minerals to be important predictors of presence for basidiomycetes, chlorophytes, ciliophorans, nematodes, or tardigrades. Our bootstrapped regression reveals how variations of the identified substrate parameters influence probabilities of detecting eukaryote phyla across vast and remote areas of Antarctica. We believe that our work may improve future taxon distribution modelling and aid targeting logistically challenging biodiversity surveys.

scholarly journals Variability of Cloudiness over Mountain Terrain in the Western United States

2017 ◽  
Vol 18 (5) ◽  
pp. 1227-1245 ◽  
Author(s):  
Edwin Sumargo ◽  
Daniel R. Cayan
Keyword(s):  
United States ◽  
Large Scale ◽  
Spatial Scales ◽  
High Elevation ◽  
Empirical Orthogonal Functions ◽  
Western United States ◽  
Spatial And Temporal Variability ◽  
Regional Patterns ◽  
Cloud Albedo

Abstract This study investigates the spatial and temporal variability of cloudiness across mountain zones in the western United States. Daily average cloud albedo is derived from a 19-yr series (1996–2014) of half-hourly Geostationary Operational Environmental Satellite (GOES) images. During springtime when incident radiation is active in driving snowmelt–runoff processes, the magnitude of daily cloud variations can exceed 50% of long-term averages. Even when aggregated over 3-month periods, cloud albedo varies by ±10% of long-term averages in many locations. Rotated empirical orthogonal functions (REOFs) of daily cloud albedo anomalies over high-elevation regions of the western conterminous United States identify distinct regional patterns, wherein the first five REOFs account for ~67% of the total variance. REOF1 is centered over Northern California and Oregon and is pronounced between November and March. REOF2 is centered over the interior northwest and is accentuated between March and July. Each of the REOF/rotated principal components (RPC) modes associates with anomalous large-scale atmospheric circulation patterns and one or more large-scale teleconnection indices (Arctic Oscillation, Niño-3.4, and Pacific–North American), which helps to explain why anomalous cloudiness patterns take on regional spatial scales and contain substantial variability over seasonal time scales.

scholarly journals Modelling large timescale and small timescale service variability

2019 ◽  
Vol 293 (1) ◽  
pp. 123-140
Author(s):  
Marco Gribaudo ◽  
Illés Horváth ◽  
Daniele Manini ◽  
Miklós Telek
Keyword(s):  
Service Time ◽  
Large Scale ◽  
Service Time Distribution ◽  
Efficient Computation ◽  
Short Term ◽  
Service Unit ◽  
Long Term Effect ◽  
Short And Long Term ◽  
Short Term Variability

Abstract The performance of service units may depend on various randomly changing environmental effects. It is quite often the case that these effects vary on different timescales. In this paper, we consider small and large scale (short and long term) service variability, where the short term variability affects the instantaneous service speed of the service unit and a modulating background Markov chain characterizes the long term effect. The main modelling challenge in this work is that the considered small and long term variation results in randomness along different axes: short term variability along the time axis and long term variability along the work axis. We present a simulation approach and an explicit analytic formula for the service time distribution in the double transform domain that allows for the efficient computation of service time moments. Finally, we compare the simulation results with analytic ones.

Generation of Low-Frequency Spiciness Variability in the Thermocline*

2011 ◽  
Vol 41 (2) ◽  
pp. 365-377 ◽  
Author(s):  
Thomas Kilpatrick ◽  
Niklas Schneider ◽  
Emanuele Di Lorenzo
Keyword(s):  
Markov Model ◽  
Large Scale ◽  
Spatial Scales ◽  
Low Frequency ◽  
Passive Tracer ◽  
Wind Stress Curl ◽  
Frequency Spectra ◽  
Low Frequencies ◽  
Geostrophic Advection

Abstract The generation of variance by anomalous advection of a passive tracer in the thermocline is investigated using the example of density-compensated temperature and salinity anomalies, or spiciness. A coupled Markov model is developed in which wind stress curl forces the large-scale baroclinic ocean pressure that in turn controls the anomalous geostrophic advection of spiciness. The “double integration” of white noise atmospheric forcing by this Markov model results in a frequency (ω) spectrum of large-scale spiciness proportional to ω−4, so that spiciness variability is concentrated at low frequencies. An eddy-permitting regional model hindcast of the northeast Pacific (1950–2007) confirms that time series of large-scale spiciness variability are exceptionally smooth, with frequency spectra ∝ ω−4 for frequencies greater than 0.2 cpy. At shorter spatial scales (wavelengths less than ∼500 km), the spiciness frequency spectrum is whitened by mesoscale eddies, but this eddy-forced variability can be filtered out by spatially averaging. Large-scale and long-term measurements are needed to observe the variance of spiciness or any other passive tracer subject to anomalous advection in the thermocline.

The role of Stokes drift in the dispersal of North Atlantic surface marine debris

2021 ◽  
Author(s):  
Sofia Bosi ◽  
Göran Broström ◽  
Fabien Roquet
Keyword(s):  
Large Scale ◽  
Marine Pollution ◽  
Stokes Drift ◽  
Marine Debris ◽  
Trade Winds ◽  
Virtual Particle ◽  
Long Term Effect ◽  
Particle Simulations ◽  
Floating Objects

<p>Understanding the physical mechanisms behind the transport and accumulation of floating objects in the ocean is crucial in order to efficiently tackle the issue of marine pollution. The main sinks of marine plastic are the coast and the bottom sediment. This study focuses on the former, investigating the timescales of dispersal from the ocean surface and onto coastal accumulation areas through a process called "beaching" in the presence of Stokes drift. Previous literature have found that the Stokes drift can reach the same magnitude as the Eulerian current speed and that it has a long-term effect on the trajectories of floating objects. Two virtual particle simulations are carried out and then compared, one with and one without Stokes drift, named SD and REF respectively. Eulerian velocity and Stokes drift data from global reanalysis datasets are used for particle advection. Particles in the SD model are found to beach at a yearly rate that is almost double the rate observed in the Eulerian model. The main coastal attractors are consistent with the direction of large-scale atmospheric circulation (Westerlies and Trade Winds). Long-term predictions carried out with the aid of adjacency matrices found that the concentration of particles in the subtropical accumulation zone after 100 years is 10 times lower in the presence of Stokes drift. The results confirm the need to accurately represent the Stokes drift in particle models attempting to predict the behaviour of marine debris, in order to avoid overestimation of its residence time in the ocean and guide policies towards prevention and removal more effectively.</p>

Interdisciplinary data-constrained 3-D potential field modelling with IGMAS+

2021 ◽  
Author(s):  
Denis Anikiev ◽  
Hans-Jürgen Götze ◽  
Judith Bott ◽  
Angela Maria Gómez-García ◽  
Maria Laura Gomez Dacal ◽  
...  
Keyword(s):  
Large Scale ◽  
Spatial Scales ◽  
Geophysical Methods ◽  
Receiver Functions ◽  
Research Centre ◽  
Small Scale ◽  
Gravity And Magnetic ◽  
Structural Density ◽  
Scale Models

<p>We introduce a modelling concept for the construction of 3-D data-constrained subsurface structural density models at different spatial scales: from large-scale models (thousands of square km) to regional (hundreds of square km) and small-scale (tens of square km) models used in applied geophysics. These models are important for understanding the drivers of geohazards, for efficient and sustainable extraction of resources from sedimentary basins such as groundwater, hydrocarbons or deep geothermal energy, as well as for investigation of capabilities of long-term underground storage of gas and radioactive materials.</p><p>The modelling concept involves interactive fitting of potential fields (gravity and magnetics) and their derivatives within IGMAS+ (Interactive Gravity and Magnetic Application System), a well-known software tool with almost 40 years of development behind it. The core of IGMAS+ is the analytical solution of the volume integral for gravity and magnetic effects of homogeneous bodies, bounded by polyhedrons of triangulated model interfaces. The backbone model is constrained by interdisciplinary data, e.g. geological maps, seismic reflection and refraction profiles, structural signatures obtained from seismic receiver functions, local surveys etc. The software supports spherical geometries to resolve the first-order effects related to the curvature of the Earth, which is especially important for large-scale models.</p><p>Currently being developed and maintained at the Helmholtz Centre Potsdam – GFZ German Research Centre, IGMAS+ has a cross-platform implementation with parallelization of computations and optimized storage. The powerful graphical interface makes the interactive modelling and geometry modification process user-friendly and robust. Historically IGMAS+ is free for research and education purposes and has a long-term plan to remain so.</p><p>IGMAS+ has been used in various tectonic settings and we demonstrate its flexibility and usability on several lithospheric-scale case studies in South America and Europe.</p><p>Both science and industry are close to the goal of treating all available geoscientific data and geophysical methods inside a single subsurface model that aims to integrate most of the interdisciplinary measurement-based constraints and essential structural trends coming from geology. This approach presents challenges for both its implementation within the modelling software and the usability and plausibility of generated results, requiring a modelling concept that integrates the data methods in a feasible way together with recent advances in data science methods. As such, we present the future outlook of our modelling concept in regards to these challenges.</p>

scholarly journals Unraveling Long-Term Flood Risk Dynamics Across the Murray-Darling Basin Using a Large-Scale Hydraulic Model and Satellite Data

2022 ◽  
Vol 3 ◽  
Author(s):  
Serena Ceola ◽  
Alessio Domeneghetti ◽  
Guy J. P. Schumann
Keyword(s):  
Flood Risk ◽  
Large Scale ◽  
Flood Hazard ◽  
Spatial Scales ◽  
Mitigation Strategies ◽  
Economic Losses ◽  
Human Society ◽  
Murray Darling Basin ◽  
Flooded Areas

River floods are one of the most devastating extreme hydrological events, with oftentimes remarkably negative effects for human society and the environment. Economic losses and social consequences, in terms of affected people and human fatalities, are increasing worldwide due to climate change and urbanization processes. Long-term dynamics of flood risk are intimately driven by the temporal evolution of hazard, exposure and vulnerability. Although needed for effective flood risk management, a comprehensive long-term analysis of all these components is not straightforward, mostly due to a lack of hydrological data, exposure information, and large computational resources required for 2-D flood model simulations at adequately high resolution over large spatial scales. This study tries to overcome these limitations and attempts to investigate the dynamics of different flood risk components in the Murray-Darling basin (MDB, Australia) in the period 1973–2014. To this aim, the LISFLOOD-FP model, i.e., a large-scale 2-D hydrodynamic model, and satellite-derived built-up data are employed. Results show that the maximum extension of flooded areas decreases in time, without revealing any significant geographical transfer of inundated areas across the study period. Despite this, a remarkable increment of built-up areas characterizes MDB, with larger annual increments across not-flooded locations compared to flooded areas. When combining flood hazard and exposure, we find that the overall extension of areas exposed to high flood risk more than doubled within the study period, thus highlighting the need for improving flood risk awareness and flood mitigation strategies in the near future.

scholarly journals Late Quaternary dynamics of Arctic biota from ancient environmental genomics

Nature ◽  
2021 ◽  
Author(s):  
Yucheng Wang ◽  
Mikkel Winther Pedersen ◽  
Inger Greve Alsos ◽  
Bianca De Sanctis ◽  
Fernando Racimo ◽  
...  
Keyword(s):  
Large Scale ◽  
Late Quaternary ◽  
Environmental Dna ◽  
Plant Genome ◽  
The Arctic ◽  
Last Glacial ◽  
Animal Diversity ◽  
Arctic Biota ◽  
The Last Glacial

AbstractDuring the last glacial–interglacial cycle, Arctic biotas experienced substantial climatic changes, yet the nature, extent and rate of their responses are not fully understood1–8. Here we report a large-scale environmental DNA metagenomic study of ancient plant and mammal communities, analysing 535 permafrost and lake sediment samples from across the Arctic spanning the past 50,000 years. Furthermore, we present 1,541 contemporary plant genome assemblies that were generated as reference sequences. Our study provides several insights into the long-term dynamics of the Arctic biota at the circumpolar and regional scales. Our key findings include: (1) a relatively homogeneous steppe–tundra flora dominated the Arctic during the Last Glacial Maximum, followed by regional divergence of vegetation during the Holocene epoch; (2) certain grazing animals consistently co-occurred in space and time; (3) humans appear to have been a minor factor in driving animal distributions; (4) higher effective precipitation, as well as an increase in the proportion of wetland plants, show negative effects on animal diversity; (5) the persistence of the steppe–tundra vegetation in northern Siberia enabled the late survival of several now-extinct megafauna species, including the woolly mammoth until 3.9 ± 0.2 thousand years ago (ka) and the woolly rhinoceros until 9.8 ± 0.2 ka; and (6) phylogenetic analysis of mammoth environmental DNA reveals a previously unsampled mitochondrial lineage. Our findings highlight the power of ancient environmental metagenomics analyses to advance understanding of population histories and long-term ecological dynamics.

scholarly journals The Role of Stokes Drift in the Dispersal of North Atlantic Surface Marine Debris

2021 ◽  
Vol 8 ◽  
Author(s):  
Sofia Bosi ◽  
Göran Broström ◽  
Fabien Roquet
Keyword(s):  
Large Scale ◽  
Marine Pollution ◽  
Stokes Drift ◽  
Marine Debris ◽  
Trade Winds ◽  
Physical Mechanisms ◽  
Long Term Effect ◽  
Floating Objects

Understanding the physical mechanisms behind the transport and accumulation of floating objects in the ocean is crucial to efficiently tackle the issue of marine pollution. The main sinks of marine plastic are the coast and the bottom sediment. This study focuses on the former, investigating the timescales of dispersal from the ocean surface and onto coastal accumulation areas through a process called “beaching.” Previous studies found that the Stokes drift can reach the same magnitude as the Eulerian current speed and that it has a long-term effect on the trajectories of floating objects. Two particle tracking models (PTMs) are carried out and then compared, one with and one without Stokes drift, named PTM-SD and PTM-REF, respectively. Eulerian velocity and Stokes drift data from global reanalysis datasets are used for particle advection. Particles in the PTM-SD model are found to beach at a yearly rate that is double the rate observed in PTM-REF. The main coastal attractors are consistent with the direction of large-scale atmospheric circulation (Westerlies and Trade Winds). After 12 years (at the end of the run), the amount of beached particles is 20% larger in PTM-SD than in PTM-REF. Long-term predictions carried out with the aid of adjacency matrices found that after 100 years all particles have beached in PTM-SD, while 8% of the all seeded particles are still floating in PTM-REF. The results confirm the need to accurately represent the Stokes drift in particle models attempting to predict the behaviour of marine debris, in order to avoid overestimation of its residence time in the ocean and effectively guide policies toward prevention and removal.

scholarly journals Effectiveness of Moxibustion for Allergic Rhinitis : a Systematic Review

2021 ◽  
Author(s):  
kaiyun pang
Keyword(s):  
Allergic Rhinitis ◽  
Large Scale ◽  
Clinical Symptoms ◽  
Nasal Congestion ◽  
Controlled Trial ◽  
Runny Nose ◽  
Long Term Effect ◽  
And Control

Abstract Objective: To explore the clinical efficacy of moxibustion to the treatment of allergic rhinitis. Methods: The randomized controlled trials (RCTs) of moxibustion to the treatment of AR was retrieved who search alone by two researchers in 31 August , 2021. The final 24 articles were retained by two other researchers based on inclusion criteria and exclusion criteria. Results: Moxibustion is effective in the treatment of AR among which heat-sensitive moxibustion has the most significant effect (P<0.00001) , followed by governor vessel moxibustion(P<0.0008), again is thunder fire moxibustion(P=0.003), the worst effect was herb-partitioned moxibustion(P=0.70). In the symptom subgroup comparison, moxibustion is effective in controlling sneezing(P=0.03) and runny nose(P=0.05), and the best is heat-sensitive moxibustion(P<0.00001) whether it is sneezing, nasal congestion, runny nose and nasal itching is the best. In the follow-up subgroup analysis, the efficacy of the follow-up of 3 months and 1 month was the same (P<0.00001) that the long-term efficacy of moxibustion for AR was better. In the IgE subgroup, moxibustion in the treatment of AR can make serum IgE down both after treatment(P<0.00001) and 6 months(P<0.0001). Conclusion: Moxibustion treatment of AR can not only improve the clinical symptoms of patients and control the attack, but also has a good long-term effect to prevent recurrence. Moxibustion treatment of AR heat-sensitive moxibustion effect is the best. Due to the limitations of this study, large-scale clinical high-quality randomized, a multi-center, controlled trial clinical study is needed in order to further verify our conclusions.

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