scholarly journals Prokaryotic responses to a warm temperature anomaly in northeast subarctic Pacific waters

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Sachia J. Traving ◽  
Colleen T. E. Kellogg ◽  
Tetjana Ross ◽  
Ryan McLaughlin ◽  
Brandon Kieft ◽  
...  
Keyword(s):  
Water Temperature ◽  
Large Scale ◽  
Heat Waves ◽  
Biodiversity Loss ◽  
Food Web Structure ◽  
Multivariate Statistical ◽  
Time Resolved ◽  
Subarctic Pacific ◽  
Temperature Anomalies ◽  
The Impact

AbstractRecent studies on marine heat waves describe water temperature anomalies causing changes in food web structure, bloom dynamics, biodiversity loss, and increased plant and animal mortality. However, little information is available on how water temperature anomalies impact prokaryotes (bacteria and archaea) inhabiting ocean waters. This is a nontrivial omission given their integral roles in driving major biogeochemical fluxes that influence ocean productivity and the climate system. Here we present a time-resolved study on the impact of a large-scale warm water surface anomaly in the northeast subarctic Pacific Ocean, colloquially known as the Blob, on prokaryotic community compositions. Multivariate statistical analyses identified significant depth- and season-dependent trends that were accentuated during the Blob. Moreover, network and indicator analyses identified shifts in specific prokaryotic assemblages from typically particle-associated before the Blob to taxa considered free-living and chemoautotrophic during the Blob, with potential implications for primary production and organic carbon conversion and export.

scholarly journals One-cell Doubling Evaluation by Living Arrays of Yeast, ODELAY!

2016 ◽  
Author(s):  
Thurston Herricks ◽  
David J. Dilworth ◽  
Fred D. Mast ◽  
Song Li ◽  
Jennifer J. Smith ◽  
...  
Keyword(s):  
Growth Analysis ◽  
Large Scale ◽  
Quantitative Methods ◽  
Growth Parameters ◽  
Single Cells ◽  
Growth Parameter ◽  
Population Heterogeneity ◽  
Time Resolved ◽  
Solid Media ◽  
The Impact

ABSTRACTCell growth is a complex phenotype widely used in systems biology to gauge the impact of genetic and environmental perturbations. Due to the magnitude of genome-wide studies, resolution is often sacrificed in favor of throughput, creating a demand for scalable, time-resolved, quantitative methods of growth assessment. We present ODELAY (One-cell Doubling Evaluation by Living Arrays of Yeast), an automated and scalable growth analysis platform. High measurement density and single cell resolution provide a powerful tool for large-scale multiparameter growth analysis based on the modeling of microcolony expansion on solid media. Pioneered in yeast but applicable to other colony forming organisms, ODELAY extracts the three key growth parameters (lag time, doubling time, and carrying capacity) that define microcolony expansion from single cells, simultaneously permitting the assessment of population heterogeneity. The utility of ODELAY is illustrated using yeast mutants, revealing a spectrum of phenotypes arising from single and combinatorial growth parameter perturbations.

scholarly journals Linking Terrestrial and Aquatic Biodiversity to Ecosystem Function Across Scales, Trophic Levels, and Realms

2021 ◽  
Vol 9 ◽  
Author(s):  
Kyla M. Dahlin ◽  
Phoebe L. Zarnetske ◽  
Quentin D. Read ◽  
Laura A. Twardochleb ◽  
Aaron G. Kamoske ◽  
...  
Keyword(s):  
Ecosystem Function ◽  
Large Scale ◽  
Information Science ◽  
Spatial Scales ◽  
Biodiversity Loss ◽  
Relative Strength ◽  
Trophic Levels ◽  
Aquatic Biodiversity ◽  
Patterns And Processes ◽  
The Impact

Global declines in biodiversity have the potential to affect ecosystem function, and vice versa, in both terrestrial and aquatic ecological realms. While many studies have considered biodiversity-ecosystem function (BEF) relationships at local scales within single realms, there is a critical need for more studies examining BEF linkages among ecological realms, across scales, and across trophic levels. We present a framework linking abiotic attributes, productivity, and biodiversity across terrestrial and inland aquatic realms. We review examples of the major ways that BEF linkages form across realms–cross-system subsidies, ecosystem engineering, and hydrology. We then formulate testable hypotheses about the relative strength of these connections across spatial scales, realms, and trophic levels. While some studies have addressed these hypotheses individually, to holistically understand and predict the impact of biodiversity loss on ecosystem function, researchers need to move beyond local and simplified systems and explicitly investigate cross-realm and trophic interactions and large-scale patterns and processes. Recent advances in computational power, data synthesis, and geographic information science can facilitate studies spanning multiple ecological realms that will lead to a more comprehensive understanding of BEF connections.

Role of Turbulence in Precessing Vortex Core Dynamics

2019 ◽  
Author(s):  
Ashwini Karmarkar ◽  
Mark Frederick ◽  
Sean Clees ◽  
Danielle Mason ◽  
Jacqueline O’Connor
Keyword(s):  
Large Scale ◽  
Swirling Flows ◽  
Base Flow ◽  
Van Der Pol Oscillator ◽  
Intensity Increase ◽  
Swirl Number ◽  
Time Resolved ◽  
Turbulent Fluctuations ◽  
Eddy Viscosity Model ◽  
The Impact

Abstract Precessing vortex cores (PVC), arising from a global instability in swirling flows, can dramatically alter the dynamics of swirl-stabilized flames. Previous study of these instabilities has identified their frequencies and potential for interaction with the shear layer instabilities also present in swirling flows. In this work, we investigate the dynamics of precessing vortex cores at a range of swirl numbers and the impact that turbulence, which tends to increase with swirl number due to the increase in mean shear, has on the dynamics of this instability. This is particularly interesting as stability predictions have previously incorporated turbulence effects using an eddy viscosity model, which only captures the impact of turbulence on the base flow, not on the instantaneous dynamics of the PVC itself. Time-resolved experimental measurements of the three-component velocity field at ten swirl numbers show that at lower swirl numbers, the PVC is affected by turbulence through the presence of vortex jitter. With increasing swirl number, the PVC jitter decreases as the PVC strength increases. There is a critical swirl number below which jitter of the PVC vortex monotonically increases with increasing swirl number, and beyond which the jitter decreases, indicating that the strength of the PVC dominates over turbulent fluctuations at higher swirl numbers, despite the fact that the turbulence intensities continue to rise with increasing swirl number. Further, we use a nonlinear van der Pol oscillator model to explain the competition between the random turbulent fluctuations and coherent oscillations of the PVC. The results of this work indicate that while both the strength of the PVC and magnitude of turbulence intensity increase with increasing swirl number, there are defined regimes where each of them hold a stronger influence on the large-scale, coherent dynamics of the flow field.

Lagrangian analysis of the dynamical and thermodynamic drivers of large-scale Greenland melt events during 1979-2017

2021 ◽  
Author(s):  
Mauro Hermann ◽  
Lukas Papritz ◽  
Heini Wernli
Keyword(s):  
Large Scale ◽  
Heat Waves ◽  
Lower Troposphere ◽  
Greenland Ice Sheet ◽  
Region Of Origin ◽  
Air Masses ◽  
Accumulation Zone ◽  
Warm Anomaly ◽  
Downward Longwave Radiation ◽  
The Impact

<p>We systematically investigate the dynamical and thermodynamic processes that lead to 77 large-scale melt events affecting high-elevation regions of the Greenland Ice Sheet (GrIS) in June-August (JJA) 1979-2017. For that purpose, we compute 8 day kinematic backward trajectories from the lowermost ~500 m above the GrIS. The key synoptic feature accompanying the melt events is an upper-tropospheric ridge over Southeast Greenland associated with a surface high-pressure system. This circulation pattern is favorable to induce rapid poleward transport (up to 40° latitude) of warm (~15 K warmer than climatological air masses arriving on the GrIS) and moist air masses from the lower troposphere to the western GrIS and subsequently to distribute them in the anticyclonic flow over north and east Greenland. During transport to the GrIS, the melt event air masses cool by ~15 K due to ascent and radiation, which keeps them just above the critical threshold to induce melting.</p><p>The thermodynamic analyses reveal that the final warm anomaly of the air masses is primarily owed to anomalous horizontal transport from a climatologically warm region of origin. However, before being transported to the GrIS, i.e., in their region of origin, these air masses were not anomalously warm. Latent heating from condensation of water vapor, occurring as the airstreams are forced to ascend orographically or dynamically, is of secondary importance. These characteristics were particularly pronounced during the most extensive melt event in early July 2012. In this event, importantly, the warm anomaly was not preserved from anomalously warm source regions such as North America experiencing a record heat wave. Considering the impact of moisture on the surface energy balance, we find that radiative effects are closely linked to the air mass trajectories and enhance melt over the entire GrIS accumulation zone due to (i) enhanced downward longwave radiation related to poleward moisture transport and a shift in the cloud phase from ice to liquid primarily west of the ice divide and (ii) increased shortwave radiation in clear-sky regions east of the ice divide.</p><p>The temporal evolution, positioning, and intensity of synoptic scale weather systems deserve further attention as they are responsible for strong and partly opposing atmospheric forcing of the GrIS surface mass balance. Also, the mechanisms identified here are in contrast to melt events in the low-elevation high Arctic and to midlatitude heat waves, where the upper-tropospheric ridge is essential to induce adiabatic warming by large-scale subsidence. Given the ongoing increase in the frequency and the melt extent of large-scale melt events, the understanding of upper-tropospheric ridges over the North Atlantic, i.e., also Greenland blocking, and its representation in climate models is crucial in determining future GrIS accumulation zone melt and thus global sea level rise. </p>

scholarly journals A Lagrangian analysis of the dynamical and thermodynamic drivers of large-scale Greenland melt events during 1979–2017

2020 ◽  
Vol 1 (2) ◽  
pp. 497-518 ◽  
Author(s):  
Mauro Hermann ◽  
Lukas Papritz ◽  
Heini Wernli
Keyword(s):  
Large Scale ◽  
Heat Waves ◽  
Lower Troposphere ◽  
Greenland Ice Sheet ◽  
Region Of Origin ◽  
Air Masses ◽  
Accumulation Zone ◽  
Warm Anomaly ◽  
Downward Longwave Radiation ◽  
The Impact

Abstract. In this study, we systematically investigate the dynamical and thermodynamic processes that lead to 77 large-scale melt events affecting high-elevation regions of the Greenland Ice Sheet (GrIS) in June–August (JJA) 1979–2017. For that purpose, we compute 8 d kinematic backward trajectories from the lowermost ∼500 m above the GrIS during these events. The key synoptic feature accompanying the melt events is an upper-tropospheric ridge southeast of the GrIS associated with a surface high-pressure system. This circulation pattern is favorable to induce rapid poleward transport (up to 40∘ latitude) of warm (∼15 K warmer than climatological air masses arriving on the GrIS) and moist air masses from the lower troposphere to the western GrIS and subsequently to distribute them in the anticyclonic flow over north and east Greenland. During transport to the GrIS, the melt event air masses cool by ∼15 K due to ascent and radiation, which keeps them just above the critical threshold to induce melting. The thermodynamic analyses reveal that the final warm anomaly of the air masses is primarily owed to anomalous horizontal transport from a climatologically warm region of origin. However, before being transported to the GrIS, i.e., in their region of origin, these air masses were not anomalously warm. Latent heating from condensation of water vapor, occurring as the airstreams are forced to ascend orographically or dynamically, is of secondary importance. These characteristics were particularly pronounced during the most extensive melt event in early July 2012, where, importantly, the warm anomaly was not preserved from anomalously warm source regions such as North America experiencing a record heat wave. The mechanisms identified here are in contrast to melt events in the low-elevation high Arctic and to midlatitude heat waves, where adiabatic warming by large-scale subsidence is essential. Considering the impact of moisture on the surface energy balance, we find that radiative effects are closely linked to the air mass trajectories and enhance melt over the entire GrIS accumulation zone due to (i) enhanced downward longwave radiation related to poleward moisture transport and a shift in the cloud phase from ice to liquid primarily west of the ice divide and (ii) increased shortwave radiation in clear-sky regions east of the ice divide. Given the ongoing increase in the frequency and the melt extent of large-scale melt events, the understanding of upper-tropospheric ridges over the North Atlantic, i.e., also Greenland blocking, and its representation in climate models is crucial in determining future GrIS accumulation zone melt and thus global sea level rise.

An approach towards addressing meteorological factors for extreme event impacts

2020 ◽  
Author(s):  
Uwe Ulbrich ◽  
Jens Grieger
Keyword(s):  
Extreme Events ◽  
Large Scale ◽  
Climate Models ◽  
Extreme Event ◽  
Heat Waves ◽  
Meteorological Factors ◽  
Ministry Of Education ◽  
Starting Point ◽  
Compound Events ◽  
The Impact

<p>The ClimXtreme program funded by the German Ministry of Education and Research is designed to address Physics and Processes, Statistics, and Impacts of meteorological extreme events, considering both the past period covered by instrumental measurements, and future climate scenarios. In its branch on impacts, the impact of hazards in Europe (convective events, severe precipitation, heat waves and droughts, and large scale storms) shall be considered in order to identify the underlying relevant weather situations and the antecedent meteorological factors. The specific characteristics of the extreme events shall also be explored. Aiming at a better understanding of the impacts of the extremes, investigations shall go beyond quantification of the local severity of a hazard. The assumption is that there is also an influence of weather and climate on exposure and vulnerability. These factors for the occurrence and the magnitude of damaging impacts  thus depend on local climatology, the occurrence of specific weather sequences augmenting vulnerability, or the occurrence of specific combinations of factors which individually needn’t be extreme (compound events).  One starting point are thus already existing impact models, which do not take (all of) these factors into account. Results from numerical climate models will be used to estimate the future change of risks under climate change.</p>

Heatwaves over Europe: Identification and connection to large-scale circulation

2020 ◽  
Author(s):  
Emmanuel Rouges ◽  
Laura Ferranti ◽  
Holger Kantz ◽  
Florian Pappenberger
Keyword(s):  
High Pressure ◽  
Heat Wave ◽  
Crop Production ◽  
Large Scale ◽  
Heat Waves ◽  
Early Warning Systems ◽  
Temperature Threshold ◽  
Large Scale Circulation ◽  
Circulation Patterns ◽  
The Impact

<p>                Heat waves have important impacts on society and our environment. In Europe for instance, the summer of 2003 caused upwards of 40000 fatalities. They also impact the crop production, ecosystems, and infrastructures. In a warming climate, heat wave intensity and frequency are likely to increase with potentially more dramatic consequences.</p><p>                Considering this, it is crucial to forecast such extreme events and therefore gain a better understanding of their triggering processes. The determination of these processes requires to identify heat wave patterns (timing and location) together with the correlated large-scale circulation patterns. This will enable to devise early warning systems, that could help mitigate the impact.</p><p>                This work is part of an ongoing PhD project focusing on improving the forecast of heat waves at sub-seasonal time scale. The main objectives are to evaluate the link between large scale weather patterns and severe warm events over Europe and measure current level of predictive skill. The first part will focus on defining an objective criteria to identify heat wave events in the ERA5 reanalaysis dataset from ECMWF. The identification of heat waves depends on three main criteria: temperature threshold, spatial and temporal extension. Meaning that the temperature should exceed a defined threshold over a large enough region and for a long enough period. We will consider daily means as well as maximum and minimum values of 2m temperature. We will identify the circulation patterns (persistent high pressure systems) associated with heat wave events and analyse the key differences with persistent high pressure systems that are not associated with heat waves.</p><p>                <strong>This work is part of the Climate Advanced Forecasting of sub-seasonal Extremes (CAFE) project, funded by the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grand agreement No 813844</strong>.</p>

scholarly journals Potential Impact of a Large-Scale Cascade Reservoir on the Spawning Conditions of Critical Species in the Yangtze River, China

Water ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 2027
Author(s):  
Meixiu Yu ◽  
Daqing Yang ◽  
Xiaolong Liu ◽  
Qiongfang Li ◽  
Guoqing Wang
Keyword(s):  
Water Temperature ◽  
Yangtze River ◽  
Large Scale ◽  
Flow Characteristics ◽  
Hydrological Regime ◽  
The Yangtze River ◽  
Chinese Sturgeon ◽  
Frequency Distributions ◽  
Gezhouba Reservoir ◽  
The Impact

Dam building and reservoir operations alter the downstream hydrological regime, and as a result, affect the health of the river aquatic ecosystem, particularly for large-scale cascade reservoirs. This study investigated the impact of the Gezhouba Reservoir (GR) and the Three Gorges Reservoir (TGR) on the spawning conditions of two critical taxa, i.e., the endemic four major carps and the endangered Chinese sturgeon in the Yangtze River. We analyzed the flow, sediment, and thermal regime in these two taxa spawning seasons and compared their features between the predam and postdam periods. Our results revealed that the GR and the TGR had altered the frequency distributions of flow, sediment, and water temperature to different degrees, with the impact by the GR on the carps and Chinese sturgeon ranked as water temperature > flow, sediment > water temperature > flow, and the effect of the TGR on these two taxa were ordered as flow > water temperature, sediment > flow > water temperature. For the GR, the satisfying degree of the suitable flow and water temperature of the carps increased, whilst the suitable flow, sediment, and water temperature for the Chinese sturgeon decreased. These changes in TGR showed a significant ascending (descending) trend in the suitable flow (water temperature) for the carps, and a clear decreasing trend in the flow, sediment, and temperature for Chinese sturgeon. Both the TGR and the GR had negative impacts on the spawning of these two taxa in terms of the rising/falling flow characteristics.

scholarly journals A Quantitative Morphological Method for Mapping Local Climate Types

2021 ◽  
Vol 6 (3) ◽  
pp. 240-257 ◽  
Author(s):  
Daniela Maiullari ◽  
Marjolein Pijpers-van Esch ◽  
Arjan Van Timmeren
Keyword(s):  
Urban Form ◽  
Large Scale ◽  
Heat Waves ◽  
Urban Climate ◽  
Morphological Characteristics ◽  
Urban Morphology ◽  
Mitigation Strategies ◽  
Local Climate ◽  
Analytical Tools ◽  
The Impact

Morphological characteristics of cities significantly influence urban heat island intensities and thermal responses to heat waves. Form attributes such as density, compactness, and vegetation cover are commonly used to analyse the impact of urban morphology on overheating processes. However, the use of abstract large-scale classifications hinders a full understanding of the thermal trade-off between single buildings and their immediate surrounding microclimate. Without analytical tools able to capture the complexity of cities with a high resolution, the microspatial dimension of urban climate phenomena cannot be properly addressed. Therefore, this study develops a new method for numerical identification of types, based on geometrical characteristics of buildings and climate-related form attributes of their surroundings in a 25m and 50m radius. The method, applied to the city of Rotterdam, combines quantitative descriptors of urban form, mapping GIS procedures, and clustering techniques. The resulting typo-morphological classification is assessed by modelling temperature, wind, and humidity during a hot summer period, in ENVI-met. Significant correlations are found between the morphotypes’ characteristics and local climate phenomena, highlighting the differences in performative potential between the classified urban patterns. The study suggests that the method can be used to provide insight into the systemic relations between buildings, their context, and the risk of overheating in different urban settings. Finally, the study highlights the relevance of advanced mapping and modelling tools to inform spatial planning and mitigation strategies to reduce the risk of urban overheating.

The Impact of Moisture and Temperature on Human Health in Heat Waves

2017 ◽  
Author(s):  
Michael Wehner ◽  
Federico Castillo ◽  
Dáithí Stone
Keyword(s):  
Public Health ◽  
Human Health ◽  
Large Scale ◽  
Heat Waves ◽  
Extreme Heat ◽  
Radiative Energy ◽  
Potential Contribution ◽  
The Future ◽  
The Impact ◽  
Intense Heat

Extremely high air temperatures are uncomfortable for everyone. For some segments of the population, they can be deadly. Both the physical and societal aspects of intense heat waves in a changing climate warrant close study. The large-scale meteorological patterns leading to such events lay the framework for understanding their underlying causal mechanisms, while several methods of quantifying the combination of heat and humidity can be used to determine when these patterns result in stressful conditions. We examine four historic heat waves as case studies to illustrate differences in the structure of heat waves and the variety of effects of extreme heat on humans, which are characterized in terms of demographic, geographic, and socioeconomic impacts, including mortality and economic ramifications. Weather station data and climate model projections for the future point to an increase in the frequency and intensity of extreme heat waves as the overall climate gets warmer. Changes in the radiative energy balance of the planet are the principal culprit behind this increase. Quantifying changes in the statistics of extreme heat waves allows for examination of changes in their potential contribution to human health risk. Large-scale mortality during heat waves always occurs within a context of other factors, including public health policy, rural and urban management and planning, and cultural practices. Consequently, the impacts of heat waves can be reduced, and may in many places be manageable into the future, through implementation of such measures as public health warning systems, effective land management, penetration of air conditioning, and increased monitoring of vulnerable or exposed individuals. Given the potential for severe impacts of the more intense heat waves that are virtually certain to occur in the warmer future, it is critical that both the physical and social sciences be considered together to enable society to adapt to these conditions.

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