scholarly journals A lattice-automaton bioturbation simulator for the coupled physics, chemistry, and biology of marine sediments (eLABS v0.1)

2019 ◽  
Author(s):  
Yoshiki Kanzaki ◽  
Bernard P. Boudreau ◽  
Sandra Kirtland Turner ◽  
Andy Ridgwell
Keyword(s):  
Marine Sediments ◽  
Environmental Changes ◽  
Benthic Fauna ◽  
Benthic Organism ◽  
Numerical Representation ◽  
Biological Engineering ◽  
Spatial And Temporal Scales ◽  
Wide Range ◽  
Sediment Mixing ◽  
The Impact

Abstract. Seawater-sediment interaction is a crucial factor in the dynamics of carbon and nutrient cycling on a wide range of spatial and temporal scales. This interaction is mediated not just through geochemistry, but also via biology. Infauna vigorously mix sediment particles, enhance porewater-seawater exchange and consequently facilitate chemical reactions. In turn, the ecology and activity of benthic fauna are impacted by their environment, amplifying the sensitivity of seawater-sediment interaction to environmental change. However, numerical representation of the bioturbation of sediment has often been treated simply as an enhanced diffusion of solutes and solids. Whilst reasonably successful in representing the mixing of bulk and predominantly oxic marine sediments, the diffusional approach to bioturbation is limited by lacking an environmental sensitivity. To better capture the mechanics and effects of sediment bioturbation, we summarize and extend a published bioturbation model (acronym: LABS) that adopts a novel lattice automaton method to simulate the behaviors of infauna that drive sediment mixing. In this new model (eLABS), simulated benthic organism behavior is combined with a deterministic calculation of water flow and oxygen and organic matter concentration fields to better reflect the physicochemical evolution of sediment. The predicted burrow geometry and mixing intensity thus attain a dependence on physicochemical sedimentary conditions. Such an interplay between biology, chemistry and physics can be important to mechanistically explain empirical observations of bioturbation and to account for the impact of environmental changes. As an illustrative example, we show how higher organic rain can drive more intense sediment mixing by luring benthic organisms deeper into sediments, while lower ambient dissolved oxygen restricts the oxic habitat depth and hence tends to reduce bulk mixing rates. Finally, our model, with its oxygen and food availability controls, represents a new tool to interpret the geological record of trace fossils, e.g., burrows, as well as to mechanistically explore biological engineering of early marine environments.

scholarly journals A lattice-automaton bioturbation simulator with coupled physics, chemistry, and biology in marine sediments (eLABS v0.2)

2019 ◽  
Vol 12 (10) ◽  
pp. 4469-4496
Author(s):  
Yoshiki Kanzaki ◽  
Bernard P. Boudreau ◽  
Sandra Kirtland Turner ◽  
Andy Ridgwell
Keyword(s):  
Marine Sediments ◽  
Environmental Changes ◽  
Benthic Fauna ◽  
Benthic Organism ◽  
Numerical Representation ◽  
Biological Engineering ◽  
Spatial And Temporal Scales ◽  
Wide Range ◽  
Sediment Mixing ◽  
The Impact

Abstract. Seawater–sediment interaction is a crucial factor in carbon and nutrient cycling on a wide range of spatial and temporal scales. This interaction is mediated not just through geochemistry but also via biology. Infauna vigorously mix sediment particles, enhance porewater–seawater exchange, and consequently, facilitate chemical reactions. In turn, the ecology and activity of benthic fauna are impacted by their environment, amplifying the sensitivity of seawater–sediment interaction to environmental change. However, numerical representation of the bioturbation of sediment has often been treated simply as an enhanced diffusion of solutes and solids. Whilst reasonably successful in representing the mixing of bulk and predominantly oxic marine sediments, the diffusional approach to bioturbation is limited by a lack of environmental sensitivity. To better capture the mechanics and effects of sediment bioturbation, we extend a published bioturbation model (Lattice-Automaton Bioturbation Simulator; LABS) by adopting a novel method to simulate realistic infaunal behavior that drives sediment mixing. In this new model (extended LABS – eLABS), simulated benthic organism action is combined with a deterministic calculation of water flow and oxygen and organic matter concentration fields to better reflect the physicochemical evolution of sediment in response to bioturbation. The predicted burrow geometry and mixing intensity thus attain a dependence on physicochemical sedimentary conditions. This interplay between biology, chemistry, and physics is important to mechanistically explain empirical observations of bioturbation and to account for the impact of environmental changes. As an illustrative example, we show how higher organic rain can drive more intense sediment mixing by “luring” benthic organisms deeper into sediments, while lower ambient dissolved oxygen restricts the oxic habitat depth and hence tends to reduce bulk mixing rates. Our model, with its oxygen and food availability controls, is a new tool to interpret the trace fossil record, e.g., burrows, as well as to explore biological engineering of past marine environments.

scholarly journals Land–atmosphere interactions in the tropics

2019 ◽  
Author(s):  
Pierre Gentine ◽  
Adam Massmann ◽  
Benjamin R. Lintner ◽  
Sayed Hamed Alemohammad ◽  
Rong Fu ◽  
...  
Keyword(s):  
Land Surface ◽  
Deep Convection ◽  
Lower Troposphere ◽  
Surface Fluxes ◽  
Surface Radiation ◽  
Spatial And Temporal Scales ◽  
Wide Range ◽  
Shallow Clouds ◽  
The Tropics ◽  
The Impact

Abstract. The continental tropics play a leading role in the terrestrial water and carbon cycles. Land–atmosphere interactions are integral in the regulation of surface energy, water and carbon fluxes across multiple spatial and temporal scales over tropical continents. We review here some of the important characteristics of tropical continental climates and how land–atmosphere interactions regulate them. Along with a wide range of climates, the tropics manifest a diverse array of land–atmosphere interactions. Broadly speaking, in tropical rainforests, light and energy are typically more limiting than precipitation and water supply for photosynthesis and evapotranspiration; whereas in savanna and semi-arid regions water is the critical regulator of surface fluxes and land–atmosphere interactions. We discuss the impact of the land surface, how it affects shallow clouds and how these clouds can feedback to the surface by modulating surface radiation. Some results from recent research suggest that shallow clouds may be especially critical to land–atmosphere interactions as these regulate the energy budget and moisture transport to the lower troposphere, which in turn affects deep convection. On the other hand, the impact of land surface conditions on deep convection appear to occur over larger, non-local, scales and might be critically affected by transitional regions between the climatologically dry and wet tropics.

scholarly journals THE FRENCH 47TH INFANTRY REGIMENT DURING THE FIRST WORLD WAR: AN ENVIRONMENTAL APPROACH

2021 ◽  
pp. 17-26
Author(s):  
E. Le Gall ◽  
Keyword(s):  
Environmental Changes ◽  
First World War ◽  
World War ◽  
Physical Strain ◽  
French Army ◽  
Wide Range ◽  
The First World War ◽  
Warfare Agents ◽  
The Impact ◽  
First World

The First World War can be examined from the perspective of traditional military history as well as the perspective of the relationship between combatants and the environment. The author reveals based on a wide range of archival materials, printed media and ego-documents (diaries, memoirs, letters) the question of combat peculiarities of the 47th Infantry Regiment of the French Army considering with the influence of environmental conditions on the soldiers. The author demonstrates the dependence of the regiment's intensity and efficiency of combat operations on the terrain, weather and climate changes on the Western Front of the First World War. In the first phase of the conflict, soldiers were extremely vulnerable to even the slightest temperature changes (extreme heat, cold) due to their uniforms' problems. Physical strain from long marches across unfamiliar terrain and an extended stay in the trenches also harmed their health. The combat unit's active influence on the environment is also emphasised, with the pollution of the battlefield by sewage, leftover ammunition and weapons. The soldiers' health being adversely affected by the polluted environment (above all, the spread of contagious diseases, poisoning by chemical and metal warfare agents) is also considered. Severe environmental changes during battles also made combat operations more difficult. Thus, during the First World War, both the soldiers of the 47th Infantry Regiment of the French Army and all the other poilus became hostages to a severely altered environment due to the impact of millions of combatants.

scholarly journals Land–atmosphere interactions in the tropics – a review

2019 ◽  
Vol 23 (10) ◽  
pp. 4171-4197 ◽  
Author(s):  
Pierre Gentine ◽  
Adam Massmann ◽  
Benjamin R. Lintner ◽  
Sayed Hamed Alemohammad ◽  
Rong Fu ◽  
...  
Keyword(s):  
Land Surface ◽  
Deep Convection ◽  
Feedback Mechanism ◽  
Surface Fluxes ◽  
Surface Radiation ◽  
Spatial And Temporal Scales ◽  
Leading Role ◽  
Wide Range ◽  
The Tropics ◽  
The Impact

Abstract. The continental tropics play a leading role in the terrestrial energy, water, and carbon cycles. Land–atmosphere interactions are integral in the regulation of these fluxes across multiple spatial and temporal scales over tropical continents. We review here some of the important characteristics of tropical continental climates and how land–atmosphere interactions regulate them. Along with a wide range of climates, the tropics manifest a diverse array of land–atmosphere interactions. Broadly speaking, in tropical rainforest climates, light and energy are typically more limiting than precipitation and water supply for photosynthesis and evapotranspiration (ET), whereas in savanna and semi-arid climates, water is the critical regulator of surface fluxes and land–atmosphere interactions. We discuss the impact of the land surface, how it affects shallow and deep clouds, and how these clouds in turn can feed back to the surface by modulating surface radiation and precipitation. Some results from recent research suggest that shallow clouds may be especially critical to land–atmosphere interactions. On the other hand, the impact of land-surface conditions on deep convection appears to occur over larger, nonlocal scales and may be a more relevant land–atmosphere feedback mechanism in transitional dry-to-wet regions and climate regimes.

Nonlinear Airy Wave Pulses on the Sea Surface

2019 ◽  
Author(s):  
Igor Shugan ◽  
Sergei Kuznetsov ◽  
Yana Saprykina ◽  
Yang-Yih Chen
Keyword(s):  
Wave Packet ◽  
Deep Water ◽  
Water Wave ◽  
Initial Conditions ◽  
Nonlinear Effects ◽  
Dispersive Waves ◽  
Spatial And Temporal Scales ◽  
Wide Range ◽  
Steep Waves ◽  
The Impact

Abstract The possibility of self-acceleration of the water-wave pulse with a permanent envelope in the form of the nonlinear Airy function during its long propagation in deep water is experimentally and theoretically analyzed. This wave packet has amazing properties — accelerates without any external force, and preserves shape in a dispersive medium. The inverted Airy envelope wave function can propagate at velocity that is faster than the group velocity. We experimentally study the behavior of Airy water-wave pulses in a super-tank and long scaled propagation, to investigate its main properties, nonlinear effects and stability. Theoretical modeling analysis is based on the nonlinear Schrodinger equation. We investigate the scope of applicability, feasibility and stability conditions of nonlinear Airy wave trains in the deep water conditions; defining regimes of self-acceleration of the main pulse, immutability shape of Airy envelope; assessing the impact of nonlinearity and dissipation on the propagation of Airy waves. We analyzed the influence of the initial pulse characteristics on self-acceleration of wave packet and the stability of the envelope form. The anticipated results allow extending the physical understanding of the evolution of nonlinear dispersive waves in a wide range of initial conditions and at different spatial and temporal scales, from both theoretical and experimental points of view. Steep waves start to become an unstable, we observe spectrum widening and downshifting. Wave propagation is accompained by the intensive wave breaking and the generation of water-wave solitons.

scholarly journals Natural Disturbance Dynamics Analysis for Ecosystem-Based Management—FORDISMAN

Forests ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 663
Author(s):  
Kalev Jõgiste ◽  
Lee E. Frelich ◽  
Floortje Vodde ◽  
Ahto Kangur ◽  
Marek Metslaid ◽  
...  
Keyword(s):  
Forest Ecosystems ◽  
Natural Disturbance ◽  
Anthropogenic Factors ◽  
Ecosystem Resilience ◽  
Special Issue ◽  
Spatial And Temporal Scales ◽  
Wide Range ◽  
Functional Features ◽  
Promising Line ◽  
The Impact

Forest ecosystems are shaped by disturbances and functional features of vegetation recovery after disturbances. There is considerable variation in basic disturbance characteristics, magnitude, severity, and intensity. Disturbance legacies provide possible explanations for ecosystem resilience. The impact (length and strength) of the pool of ecosystem legacies and how they vary at different spatial and temporal scales is a most promising line of further research. Analyses of successional trajectories, ecosystem memory, and novel ecosystems are required to improve modelling in support of forests. There is growing evidence that managing ecosystem legacies can act as a driver in adaptive management to achieve goals in forestry. Managers can adapt to climate change and new conditions through anticipatory or transformational strategies of ecosystem management. The papers presented in this Special Issue covers a wide range of topics, including the impact of herbivores, wind, and anthropogenic factors, on ecosystem resilience.

A geospatial and temporal analytics framework for flood risk mapping

2021 ◽  
Author(s):  
Tatsuya Ishikawa ◽  
Takao Moriyama ◽  
Paolo Fraccaro ◽  
Anne Jones ◽  
Blair Edwards
Keyword(s):  
Climate Change ◽  
Flood Risk ◽  
Climate Impact ◽  
Calibration Model ◽  
Parameter Uncertainties ◽  
Spatial And Temporal Scales ◽  
Wide Range ◽  
The Impact ◽  
Impact Models ◽  
Node Type

<div data-node-type="line"><span>Floods have significant impact on social and economic activities</span><span>,</span> <span>with</span><span> flood </span><span>frequency projected </span><span>to increase in the future in </span><span>many regions of the world</span> <span>due to</span><span> climate change</span><span>. Quantification of current and future flood risk at lead times of months to years are potentially of high value for planning activities in a wide range of humanitarian and business applications across multiple sectors. However, there are also many technical and methodological challenges in producing accurate, local predictions which also adequately quantify uncertainty. Multiple geospatial datasets are freely available to improve flood predictions, but their size and complexity mean they are difficult to store and combine. Generation of flood inundation risk maps requires the combination of several static geospatial data layers with potentially multiple simulation models and ensembles of climate inputs.</span></div><div> </div><div data-node-type="line"></div><div data-node-type="line"><span>Here w</span><span>e present a geospatial climate impact modelling framework, which we apply to the challenge of flooding </span><span>risk quantification</span><span>.  </span><span>Our framework</span><span> is modular, scalable cloud-based </span><span>and </span><span>allows for the easy deployment of different impact models and model components with a range of input datasets (different spatial and temporal scales) and model configurations.  </span></div><div data-node-type="line"><span> </span></div><div data-node-type="line"><span>The framework allows us to use automated tools to carry out AI-enabled parameter calibration, model validation and uncertainty quantification/propagation, with the ability to quickly run the impact models for any location where the appropriate data is available.  We can additionally trial different sources of input data, pulling data from IBM PAIRS Geoscope and other sources, and we have done this with our pluvial flood models.</span></div><div> </div><div data-node-type="line"></div><div data-node-type="line"><span>In this presentation, we provide pluvial flood risk assessments </span><span>generated through</span><span> our framework. We calibrate</span><span> our</span><span> flood models to accurately reproduce inundations derived from historical precipitation datasets</span><span>, validated </span><span>against flood maps obtained from corresponding satellite imager</span><span>y,</span><span> and quantify uncertainties for hydrological parameters. Probabilistic flood risk </span><span>is</span><span> generated through ensemble execution of </span><span>such</span><span> models</span><span>,</span><span> incorporating climate change and model parameter uncertainties.</span></div>

scholarly journals Microbiota mediated plasticity promotes thermal adaptation in Nematostella vectensis

2021 ◽  
Author(s):  
Laura Baldassarre ◽  
Hua Ying ◽  
Adam Reitzel ◽  
Sebastian Fraune
Keyword(s):  
High Temperature ◽  
Environmental Changes ◽  
Genetic Recombination ◽  
Thermal Adaptation ◽  
Nematostella Vectensis ◽  
Next Generation ◽  
Host Genotype ◽  
Wide Range ◽  
Long Term Experiment ◽  
The Impact

At the current rate of climate change, it is unlikely that multicellular organisms will be able to adapt to changing environmental conditions through genetic recombination and natural selection alo. Thus, it is critical to understand alternative mechanisms that allow organisms to cope with rapid environmental changes. Here, we used the sea anemone Nematostella vectensis as model to investigate the microbiota as putative source of rapid adaptation. Living in estuarine ecosystems, highly variable aquatic environments, N. vectensis has evolved the capability of surviving in a wide range of temperatures and salinities. In a long-term experiment, we acclimated polyps of Nematostella to low, medium and high temperatures, in order to test the impact of microbiota-mediated plasticity on animal acclimation. Using the same animal clonal line, propagated from a single polyp, allowed us to eliminate effects of the host genotype. Interestingly, the higher thermal tolerance of animals acclimated to high temperature, could be transferred to non-acclimated animals through microbiota transplantation. In addition, offspring survival was highest from mothers acclimated to high temperature, indicating the transmission of thermal resistance to the next generation. Microbial community analyses of the F1 generation revealed the transmission of the acclimated microbiota to the next generation. These results indicate that microbiota plasticity can contribute to animal thermal acclimation and its transmission to the next generation may represent a rapid mechanism for thermal adaptation.

scholarly journals Camouflage through colour change: mechanisms, adaptive value and ecological significance

2017 ◽  
Vol 372 (1724) ◽  
pp. 20160342 ◽  
Author(s):  
Rafael C. Duarte ◽  
Augusto A. V. Flores ◽  
Martin Stevens
Keyword(s):  
Developmental Plasticity ◽  
Environmental Changes ◽  
Colour Change ◽  
Hormonal Control ◽  
Dietary Factors ◽  
Spatial And Temporal Scales ◽  
Adaptive Value ◽  
Wide Range ◽  
Taxonomic Groups ◽  
Future Work

Animals from a wide range of taxonomic groups are capable of colour change, of which camouflage is one of the main functions. A considerable amount of past work on this subject has investigated species capable of extremely rapid colour change (in seconds). However, relatively slow colour change (over hours, days, weeks and months), as well as changes arising via developmental plasticity are probably more common than rapid changes, yet less studied. We discuss three key areas of colour change and camouflage. First, we review the mechanisms underpinning colour change and developmental plasticity for camouflage, including cellular processes, visual feedback, hormonal control and dietary factors. Second, we discuss the adaptive value of colour change for camouflage, including the use of different camouflage types. Third, we discuss the evolutionary–ecological implications of colour change for concealment, including what it can tell us about intraspecific colour diversity, morph-specific strategies, and matching to different environments and microhabitats. Throughout, we discuss key unresolved questions and present directions for future work, and highlight how colour change facilitates camouflage among habitats and arises when animals are faced with environmental changes occurring over a range of spatial and temporal scales. This article is part of the themed issue ‘Animal coloration: production, perception, function and application’.

scholarly journals Iron and sulfate reduction structure microbial communities in (sub-)Antarctic sediments

2021 ◽  
Author(s):  
Lea C. Wunder ◽  
David A. Aromokeye ◽  
Xiuran Yin ◽  
Tim Richter-Heitmann ◽  
Graciana Willis-Poratti ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Sulfate Reduction ◽  
Marine Sediments ◽  
Iron Reduction ◽  
Environmental Changes ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Geochemical Parameters ◽  
Dissimilatory Iron Reduction ◽  
The Impact

AbstractPermanently cold marine sediments are heavily influenced by increased input of iron as a result of accelerated glacial melt, weathering, and erosion. The impact of such environmental changes on microbial communities in coastal sediments is poorly understood. We investigated geochemical parameters that shape microbial community compositions in anoxic surface sediments of four geochemically differing sites (Annenkov Trough, Church Trough, Cumberland Bay, Drygalski Trough) around South Georgia, Southern Ocean. Sulfate reduction prevails in Church Trough and iron reduction at the other sites, correlating with differing local microbial communities. Within the order Desulfuromonadales, the family Sva1033, not previously recognized for being capable of dissimilatory iron reduction, was detected at rather high relative abundances (up to 5%) while other members of Desulfuromonadales were less abundant (<0.6%). We propose that Sva1033 is capable of performing dissimilatory iron reduction in sediment incubations based on RNA stable isotope probing. Sulfate reducers, who maintain a high relative abundance of up to 30% of bacterial 16S rRNA genes at the iron reduction sites, were also active during iron reduction in the incubations. Thus, concurrent sulfate reduction is possibly masked by cryptic sulfur cycling, i.e., reoxidation or precipitation of produced sulfide at a small or undetectable pool size. Our results show the importance of iron and sulfate reduction, indicated by ferrous iron and sulfide, as processes that shape microbial communities and provide evidence for one of Sva1033’s metabolic capabilities in permanently cold marine sediments.

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