Mesoscale Regions Research Articles

Nanoscale Electron Transfer Variations at Electrocatalyst-Electrolyte Interfaces Resolved by in Situ Conductive Atomic Force Microscopy.

Rational innovation of electrocatalysts requires detailed knowledge of spatial property variations across the solid-electrolyte interface. We introduce correlative atomic force microscopy (AFM) to simultaneously probe, in situ and at the nanoscale, electrical conductivity, chemical-frictional, and morphological properties of a bimetallic copper-gold system for CO2 electroreduction. In air, water, and bicarbonate electrolyte, current-voltage curves reveal resistive CuOx islands in line with local current contrasts, while frictional imaging indicates qualitative variations in the hydration layer molecular ordering upon change from water to electrolyte. Nanoscale current contrast on polycrystalline Au shows resistive grain boundaries and electrocatalytically passive adlayer regions. In situ conductive AFM imaging in water shows mesoscale regions of low current and reveals that reduced interfacial electric currents are accompanied by increased friction forces, thus indicating variations in the interfacial molecular ordering affected by the electrolyte composition and ionic species. These findings provide insights into how local electrochemical environments and adsorbed species affect interfacial charge transfer processes and support building in situ structure-property relationships in catalysis and energy conversion research.

Chemical Structure and Distribution in Nickel-Nitrogen-Carbon Catalysts for CO2 Electroreduction Identified by Scanning Transmission X-ray Microscopy.

Atomically dispersed metal-nitrogen-carbon (M-N-C) materials are a class of electrocatalysts for fuel cell and electrochemical CO2 reduction (CO2R) applications. However, it is challenging to characterize the identity and concentration of catalytically active species owing to the structural heterogeneity of M-N-C materials. We utilize scanning transmission X-ray microscopy (STXM) as a correlative spectromicroscopy approach for spatially resolved imaging, identification, and quantification of structures and chemical species in mesoscale regions of nickel-nitrogen-carbon (Ni-N-C) catalysts, thereby elucidating the relationship between Ni content/speciation and CO2R activity/selectivity. STXM results are correlated with conventional characterization approaches relying on either bulk average (X-ray absorption spectroscopy) or spatially localized (scanning transmission electron microscopy with electron energy loss spectroscopy) measurements. This comparison illustrates the advantages of soft X-ray STXM to provide spatially resolved identification and quantification of active structures in Ni-N-C catalysts. The active site structures in these catalysts are identified to be atomically dispersed NiN x /C sites distributed throughout entire catalyst particles. The NiN x /C sites were notably demonstrated by spectroscopy to possess a variety of chemical structures with a spectroscopic signature that most closely resembles nickel(II) tetraphenylporphyrin molecules. The quantification and spatial distribution mapping of atomically dispersed Ni active sites achieved by STXM address a target that was elusive to the scientific community despite its importance in guiding advanced material designs.

Shelf Water Export at the Brazil-Malvinas Confluence Evidenced From Combined in situ and Satellite Observations

The Brazil-Malvinas Confluence (BMC) is the region where opposing and intense western boundary currents meet along the Southwestern Atlantic slope at about 38°S, generating one of the most energetic mesoscale regions of the global ocean. Based on shipborne observations acquired within the Uruguayan Economic Exclusive Zone (EEZ), combined with satellite data and an eddy tracking algorithm, we analyze the cross-shelf exchanges during May 2016, when the BMC was in an anomalous northern position. Two types of shelf water export were observed triggered by mesoscale dynamics: one was the export of shallow Rio de la Plata Plume waters driven off-shelf by the retroflection of the Brazil Current. This export formed a 70 km wide, 20 m deep filament that propagated offshore at 0.3 m s–1, with a transport of 0.42 Sv. It lasted about 10 days before being mixed with ambient Confluence waters by strong winds. An additional type of off-shelf transport consisted of a subsurface layer of Subantarctic Shelf Waters (SASW) about 60 m thick that subducted at the BMC reaching 130 m deep and transporting 0.91 ± 0.91 Sv. We show that geostrophic currents derived from satellite altimetry over the slope can be useful to track this subsurface off-shelf export as they are significantly correlated with absolute velocity measurements at this depth. Argo temperature and salinity profiles show evidence of these two types of shelf water export occurring between the BMC front and the separation of the Brazil Current from the shelf-break, suggesting this is a relatively frequent phenomenon, in agreement with previous observations.

Superelastic anisotropy and meso-scale interface regions in textured NiTi sheets

NiTi şekil hafızalı alaşımların tipik üretim yöntemleri arasında, malzemede kristalografik tekstüre ve süperelastik anizotropik davranışa yol açan çekme ve haddeleme işlemleri bulunmaktadır. Bu nedenle, yöne bağlı malzeme özelliklerinin ve altta yatan mekanizmaların derinlemesine araştırılarak anlaşılması; farklı mekanik özellikler gerektiren uygulamalar için uygun malzeme tekstürü oluşturabilmek adına üretim prosesisin dizayn edilmesine yardımcı olacaktır. Süperelastik NiTi alaşımların, çekme yüklenmesi altında lokalize deformasyon sergilediği bilinmektedir. Gerilim kaynaklı indüklenmiş martenzitik faz dönüşümü (SIMT) esnasında, makroskobik deformasyon sadece, tamamıyla martenzitik ve tamamıyla östenitik bölgeler arasında oluşan mezoscale arayüzey bölgelerinde gerçekleşmektedir. Bu yüzden, lokalize deformasyonda bu geçiş bölgelerinin detaylı karakterizasyonu teknik açıdan kritik bir öneme sahiptir. Bu çalışma kapsamında, kristalografik tekstürün ve numune geometrisinin polikristalin NiTi süperelastik sac levhaların mekanik davranışı ve lokal deformasyon karakteristiği üzerine etkisi sistematik bir şekilde analiz edilmiştir. Dijital görüntü korelasyonu (DIC) tekniği ile lokal yüzey gerinim alanları deformasyon sırasında ölçülerek, arayüzey geçiş bölgeleri detaylıca karakterize edilmiştir. Malzemenin mekanik davranışının belirgin şekilde yöne bağlı olduğu ve numune genişliği/kalınlığı oranının düşmesiyle oryantasyon/tekstür etkisinin azaldığı saptanmıştır. Ayrıca, farklı numune geometrileri ve oryantasyonlarında, lokalize deformasyonda oluşan martenzit/östenit arayüzeyinin numune yüklenme eksenine göre farklı açılarda oluştuğu ve faz dönüşümü süresince sürekli değiştiği gözlenmiştir. Elde edilen sonuçlar, faz dönüşüm özellikleri, kristalografik tekstür, süperelastik anizotropi ve numune geometrisi arasındaki, NiTi malzemenin mühendislik uygulamaları açısından büyük öneme sahip etkileşime dair yeni anlayışlar kazandırmaktadır.

The surface piezoresponse of tetragonal tungsten bronze oxides with different ordering of cations in A-sublattice

The piezoresponse (PR) images of microsized surface areas of the hot-pressed ceramics samples K4Bi2Nb10O30 , K2Sr4NbwO3 0, and Na2Sr4Nbl0O 30, presenting different types of the inter-octahedral cations ordering, were obtained. The Fourier analysis of the PR data showed that the mesoscale regions form subsystems responsible for the electrical activity of the sample, the contribution of which manifests itself depending on the type of cation ordering.

Global-Local Heat Demand Development for the Energy Transition Time Frame Up to 2050

Globally, the heat sector has a major share in energy consumption and carbon emission footprint. To provide reliable mitigation options for space heating, domestic hot water, industrial process heat and biomass for cooking for the energy transition time frame up to the year 2050, energy system modeling relies on a comprehensive and detailed heat demand database in high spatial resolution, which is not available. This study overcomes this hurdle and provides a global heat demand database for the mentioned heat demand types and in a resolution of 145 mesoscale regions up to the year 2050 based on the current heat demand and detailed elaboration of parameters influencing the future heat demand. Additionally, heat demand profiles for 145 mesoscale regions are provided. This research finds the total global heat demand will increase from about 45,400 TWhth in 2012 up to about 56,600 TWhth in 2050. The efficiency measures in buildings lead to a peak of space heating demand in around 2035, strong growth in standards of living leads to a steady rise of domestic hot water consumption, and a positive trend for the worldwide economic development induces a growing demand for industrial process heat, counterbalanced by the efficiency gain in already industrialised countries. For the case of biomass for cooking, a phase-out path until 2050 is presented. Literature research revealed a lack of consensus on future heat demand. This research intends to facilitate a more differentiated discussion on heat demand projections.

Patterns of bacterial motility in microfluidics-confining environments

Understanding the motility behavior of bacteria in confining microenvironments, in which they search for available physical space and move in response to stimuli, is important for environmental, food industry, and biomedical applications. We studied the motility of five bacterial species with various sizes and flagellar architectures (Vibrio natriegens, Magnetococcus marinus, Pseudomonas putida, Vibrio fischeri, and Escherichia coli) in microfluidic environments presenting various levels of confinement and geometrical complexity, in the absence of external flow and concentration gradients. When the confinement is moderate, such as in quasi-open spaces with only one limiting wall, and in wide channels, the motility behavior of bacteria with complex flagellar architectures approximately follows the hydrodynamics-based predictions developed for simple monotrichous bacteria. Specifically, V. natriegens and V. fischeri moved parallel to the wall and P. putida and E. coli presented a stable movement parallel to the wall but with incidental wall escape events, while M. marinus exhibited frequent flipping between wall accumulator and wall escaper regimes. Conversely, in tighter confining environments, the motility is governed by the steric interactions between bacteria and the surrounding walls. In mesoscale regions, where the impacts of hydrodynamics and steric interactions overlap, these mechanisms can either push bacteria in the same directions in linear channels, leading to smooth bacterial movement, or they could be oppositional (e.g., in mesoscale-sized meandered channels), leading to chaotic movement and subsequent bacterial trapping. The study provides a methodological template for the design of microfluidic devices for single-cell genomic screening, bacterial entrapment for diagnostics, or biocomputation.

Influence of the Distortion of Vertical Wavenumber Spectra on Estimates of Turbulent Dissipation using the Finescale Parameterization: Eikonal Calculations

AbstractThe finescale parameterization, formulated on the basis of a weak nonlinear wave–wave interaction theory, is widely used to estimate the turbulent dissipation rate, ε. However, this parameterization has previously been found to overestimate ε in the Antarctic Circumpolar Current (ACC) region. One possible reason for this overestimation is that vertical wavenumber spectra of internal wave energy are distorted from the canonical Garrett-Munk spectrum and have a spectral “hump” at low vertical wavenumbers. Such distorted vertical wavenumber spectra were also observed in other mesoscale eddy-rich regions. In this study, using eikonal simulations, in which internal wave energy cascades are evaluated in the frequency-wavenumber space, we examine how the distortion of vertical wavenumber spectra impacts on the accuracy of the finescale parameterization. It is shown that the finescale parameterization overestimates ε for distorted spectra with a low-vertical-wavenumber hump because it incorrectly takes into account the breaking of these low-vertical-wavenumber internal waves. This issue is exacerbated by estimating internal wave energy spectral levels from the low-wavenumber band rather than from the high-wavenumber band, which is often contaminated by noise in observations. Thus, in order to accurately estimate the distribution of ε in eddy-rich regions like the ACC, high-vertical-wavenumber spectral information free from noise contamination is indispensable.

A concurrent multiscale approach for modeling recycled aggregate concrete

The use of recycled concrete aggregates in new concrete is an alternative that can provide economical and environmental benefits. However, the influence of the inert particles on the mechanical behavior of concrete needs to be better understood. To provide a comprehensive simulator to predict the failure mechanism of this material taking into account its heterogeneity in mesoscale, a mesh fragmentation technique composed of interface solid finite elements equipped with a tensile damage model is employed. To minimize computational costs, a concurrent multiscale strategy based on the use of coupling finite elements to connect the macro and mesoscale regions is adopted. In mesoscale, the different phases of the recycled aggregate concrete (RAC) are explicitly represented, consisting of: (i) new mortar matrix; (ii) recycled aggregate composed of old matrix and crushed rock (natural aggregate); and (iii) interfacial transition zones in between all of them. For the regions where cracks are not expected, homogenized elastic parameters are assumed for the RAC. Three-point bending beams experimentally tested by Casuccio et al. [4] are numerically analyzed for concrete with compressive strength targets of 18, 37 and 48 MPa. These concrete beams were produced with coarse aggregates derived from natural crushed stone and another two coming from recycled concrete with high and normal strengths. The numerical results obtained show that the concurrent multiscale model is able to represent the tensile failure mechanism of the RAC, taking into account explicitly the effects of the recycled components on crack patterns and structural predictions.

Numerical study of the texture effect on deformation-induced surface roughening in titanium polycrystals

The influence of a texture on the mesoscale deformation-induced surface roughening in titanium polycrystals is studied using direct microstructure-based simulations. Relying on the experimental data for commercial purity titanium, equiaxed grain conglomerates are generated by the method of step-by-step packing. The grain constitutive behavior is described in terms of crystal plasticity, with the grain orientations being assigned randomly or representing a basal texture. The micro- and mesoscale roughness evolution in the model polycrystals under uniaxial tension is calculated using ABAQUS/Explicit. In order to quantify mesoscale roughening, a dimensionless roughness parameter is calculated for a set of experimental and numerical roughness profiles evolving in the course of tension. The mesoscale roughness parameter is shown to grow nonlinearly with the plastic strain of the evaluated mesoscale regions. Particularly, it begins increasing rapidly in the region of neck formation well before necking becomes macroscopically evident. The basal texture is shown to significantly affect the plastic strain localization and roughness patterns. The mesoscale roughness, strongly pronounced in the untextured polycrystal, is mostly suppressed in the presence of texture. A set of in-plane shear bands are formed in the textured polycrystal at an angle of 45° to the tensile axis much like those observed experimentally.

3D concurrent multiscale model for crack propagation in concrete

A new approach for concurrent multiscale modeling of three-dimensional crack propagation in concrete is proposed. A macroscopic model with homogenized elastic parameters is adopted in the regions where the material behaves elastically. For regions where cracks are expected to occur, a mesoscopic model based on a mesh fragmentation technique is used to represent the concrete as a heterogeneous three-phase material composed of mortar matrix, coarse aggregates and interfacial transition zone. In this technique, standard finite elements with high aspect ratio are inserted in between all regular finite elements of the mortar matrix and in between the mortar matrix and aggregate elements in order to describe the crack initiation and propagation process by using an appropriate tensile damage constitutive model. Coarse aggregates with regular shapes are generated from a grading curve and placed into the mortar matrix randomly, using the “take-and-place” method. Coupling finite elements are used for connecting the non-matching meshes corresponding to the macro and mesoscale regions, without increasing the total number of degrees of freedom of the problem. Realistic predictions of crack formation and propagation were obtained for different tests, replicating accurately the observed experimental patterns.

Adjoint Sensitivity Analysis of High-Impact Extratropical Cyclones

Abstract The initial state sensitivity of high-impact extratropical cyclones over the North Atlantic and United Kingdom is investigated using an adjoint modeling system that includes moist processes. The adjoint analysis indicates that the 48-h forecast of precipitation and high winds associated with the extratropical cyclone “Desmond” was highly sensitive to mesoscale regions of moisture at the initial time. Mesoscale moisture and potential vorticity structures along the poleward edge of an atmospheric river at the initialization time had a large impact on the development of Desmond as demonstrated with precipitation, kinetic energy, and potential vorticity response functions. Adjoint-based optimal perturbations introduced into the initial state exhibit rapidly growing amplitudes through moist energetic processes over the 48-h forecast. The sensitivity manifests as an upshear-tilted structure positioned along the cold and warm fronts. Perturbations introduced into the nonlinear and tangent linear models quickly expand vertically and interact with potential vorticity anomalies in the mid- and upper levels. Analysis of adjoint sensitivity results for the winter 2013/14 show that the moisture sensitivity magnitude at the initial time is well correlated with the kinetic energy error at the 36-h forecast time, which supports the physical significance and importance of the mesoscale regions of high moisture sensitivities.

100 Years of Progress in Mesoscale Planetary Boundary Layer Meteorological Research

Abstract This chapter outlines the development of our understanding of several examples of mesoscale atmospheric circulations that are tied directly to surface forcings, starting from thermally driven variations over the ocean and progressing inland to man-made variations in temperature and roughness, and ending with forced boundary layer circulations. Examples include atmospheric responses to 1) overocean temperature variations, 2) coastlines (sea breezes), 3) mesoscale regions of inland water (lake-effect storms), and 4) variations in land-based surface usage (urban land cover). This chapter provides brief summaries of the historical evolution of, and tools for, understanding such mesoscale atmospheric circulations and their importance to the field, as well as physical processes responsible for initiating and determining their evolution. Some avenues of future research we see as critical are provided. The American Meteorological Society (AMS) has played a direct and important role in fostering the development of understanding mesoscale surface-forced circulations. The significance of AMS journal publications and conferences on this and interrelated atmospheric, oceanic, and hydrological fields, as well as those by sister scientific organizations, are demonstrated through extensive relevant citations.

Visual search for object categories is predicted by the representational architecture of high-level visual cortex.

Here, we ask which neural regions have neural response patterns that correlate with behavioral performance in a visual processing task. We found that the representational structure across all of high-level visual cortex has the requisite structure to predict behavior. Furthermore, when directly comparing different neural regions, we found that they all had highly similar category-level representational structures. These results point to a ubiquitous and uniform representational structure in high-level visual cortex underlying visual object processing.

Mechanisms Influencing Cirrus Banding and Aviation Turbulence near a Convectively Enhanced Upper-Level Jet Stream

Abstract Mechanisms supporting a cold-season aviation turbulence outbreak over the northwest Atlantic Ocean and adjacent coastal regions of North America are investigated using high-resolution numerical simulations. Two distinct episodes of moderate-or-greater turbulence in the upper troposphere are observed, and the simulations suggest the turbulence is linked to eastward-translating mesoscale perturbations of negative potential vorticity (PV) emanating from upstream organized deep convection along the anticyclonic shear side of an upper-level jet. Within the exit region of the jet where the turbulence episodes occur, thermodynamic and kinematic fields in the vicinity of the PV perturbations exhibit structural characteristics of mesoscale inertia–gravity waves. These wavelike perturbations are shown to facilitate turbulence by influencing the vertical shear and static stability, which promotes mesoscale regions of banded cirrus clouds, near or within which the observed turbulence occurs. The simulations also suggest that the turbulence arises from fundamentally different mechanisms in the two episodes. In the first and most severe turbulence episode, mesoscale wave-related vertical shear enhancements lead to Kelvin–Helmholtz instability (KHI) near aircraft cruising altitudes (~8.9–11.2 km MSL). Simulated KHI is most prevalent near relatively isolated areas of shallow, moist convection, where smaller-scale internal gravity waves originating in the middle troposphere in response to the shallow convection may play a role in excitation of the KHI located above. The second turbulence episode is consistent with simulated thermal-shear instability related to wave-induced mesoscale reductions in upper-tropospheric static stability. However, unlike for the earlier episode of enhanced turbulence, cloud-radiative feedbacks are necessary for the instability and mesoscale regions of banded cirrus to develop.

On the Role of Inertial Instability in Stratosphere–Troposphere Exchange near Midlatitude Cyclones*

Abstract In simulations of midlatitude cyclones with the University of Wisconsin Nonhydrostatic Modeling System (UWNMS), mesoscale regions with large negative absolute vorticity commonly occur in the upper troposphere and lower stratosphere (UTLS), overlying thin layers of air with stratospheric values of ozone and potential vorticity (PV). These locally enhanced stratosphere–troposphere exchange (STE) events are related to upstream convection by tracing negative equivalent potential vorticity (EPV) anomalies along back trajectories. Detailed agreement between the patterns of negative absolute vorticity, PV, and EPV—each indicators of inertial instability in the UTLS—is shown to occur in association with enhanced STE signatures. Results are presented for two midlatitude cyclones in the upper Midwest, where convection develops between the subpolar and subtropical jets. Mesoscale regions of negative EPV air originate upstream in the boundary layer. As they are transported through convection, EPV becomes increasingly negative toward the tropopause. In association with the arrival of each large negative EPV anomaly, a locally enhanced poleward surge of the subpolar jet occurs, characterized by high turbulent kinetic energy and low Richardson number. Isosurfaces of wind speed show that gravity waves emanating from inertially unstable regions connect with and modulate the subpolar and subtropical jets simultaneously. Inertially unstable convective outflow surges can facilitate STE locally by fostering poleward acceleration in the UTLS, with enhanced folding of tropospheric air over stratospheric air underneath the poleward-moving jet.

Circulation patterns identified by spatial rainfall and ocean wave fields in Southern Africa

This paper presents the applications of Fuzzy Rule Based Circulation Patterns (CPs) classification in the description and modelling of two different physical consequences of their form: Rainfall regimes and Wind generated Ocean Waves. The choice of the CP groupings is made by searching for those CPs which generate (i) different daily rainfall patterns over mesoscale regions and (ii) wave directions and heights at chosen shoreline locations. The method used to choose the groupings of CPs is a bottom-up methodology using simulated annealing, ensuring that the causative CPs are responsible for the character of the results. This approach is in marked distinction to the top-down approaches such as k-means clustering or Self Organising Maps (SOMS) to identify several classes of CPs and then finding the effects of those CPs on the variables of choice on given historical days. The CP groups we define are quite different for the two phenomena rainfall and waves, simply because different details of the pressure fields are responsible for wind and for precipitation. Large ocean waves are typically generated over fetches of the order of thousands of kilometres far off shore, whereas rainfall is generated by local atmospheric variables including temperature, humidity, wind speed and radiation over the area of concern. The spatial representativeness of the CPs is discussed and classifications obtained for different regions are compared. The paper gives examples of applications of the ideas over South Africa.

Glycan-Based Connectivity Regulates the Hierarchical Organization of Membrane Receptors by Coupling their Micro- and Nano-Scale Lateral Mobility

Glycan-protein interactions are emerging as important modulators of membrane protein organization and dynamics, regulating multiple cellular functions. In particular, it has been postulated that glycan-mediated interactions regulate surface residence time of glycoproteins and endocytosis. How this precisely occurs is poorly understood. We applied a combination of super-resolution nanoscopy and single molecule-based approaches to study the role of glycan-based interactions on the dynamics of the glycosylated pathogen recognition receptor DC-SIGN, at the nano- and micrometer scale. We find that cell surface glycan-mediated interactions do not influence the nanoscale lateral organization of DC-SIGN in nanoclusters but restrict the mobility of the receptor to distinct micron-size membrane regions. These meso-scale regions are in turn enriched by the endocytic protein clathrin, thereby dynamically promoting DC-SIGN transient nano-scale arrest and interaction with clathrin. Disruption of glycan-based connectivity leads to larger membrane exploration, reduced clathrin interaction and compromised clathrin-dependent internalization of virus-like particles. Therefore, our work uncovers a novel mechanism through which glycan-protein interactions act as decision-makers in fine-tuning membrane-related functions by dynamically coupling micro- and nanoscale receptor lateral mobility, thus adding a new layer of regulation to the hierarchical spatiotemporal organization of the cell membrane.

Atmospheric Kinetic Energy Spectra from Global High-Resolution Nonhydrostatic Simulations

Abstract Kinetic energy (KE) spectra derived from global high-resolution atmospheric simulations from the Model for Prediction Across Scales (MPAS) are presented. The simulations are produced using quasi-uniform global Voronoi horizontal meshes with 3-, 7.5-, and 15-km mean cell spacings. KE spectra from the MPAS simulations compare well with observations and other simulations in the literature and possess the canonical KE spectra structure including a very-well-resolved shallow-sloped mesoscale region in the 3-km simulation. There is a peak in the vertical velocity variance at the model filter scale for all simulations, indicating the underresolved nature of updrafts even with the 3-km mesh. The KE spectra reveal that the MPAS configuration produces an effective model resolution (filter scale) of approximately 6Δx. Comparison with other published model KE spectra highlight model filtering issues, specifically insufficient filtering that can lead to spectral blocking and the production of erroneous shallow-sloped mesoscale tails in the KE spectra. The mesoscale regions in the MPAS KE spectra are produced without use of kinetic energy backscatter, in contrast to other results reported in the literature. No substantive difference is found in KE spectra computed on constant height or constant pressure surfaces. Stratified turbulence is not resolved with the vertical resolution used in this study; hence, the results do not support recent conjecture that stratified turbulence explains the mesoscale portion of the KE spectrum.

REVIEW: On the Front Line: frontal zones as priority at‐sea conservation areas for mobile marine vertebrates

Summary Identifying priority areas for marine vertebrate conservation is complex because species of conservation concern are highly mobile, inhabit dynamic habitats and are difficult to monitor. Many marine vertebrates are known to associate with oceanographic fronts – physical interfaces at the transition between water masses – for foraging and migration, making them important candidate sites for conservation. Here, we review associations between marine vertebrates and fronts and how they vary with scale, regional oceanography and foraging ecology. Accessibility, spatiotemporal predictability and relative productivity of front‐associated foraging habitats are key aspects of their ecological importance. Predictable mesoscale (10s–100s km) regions of persistent frontal activity (‘frontal zones’) are particularly significant. Frontal zones are hotspots of overlap between critical habitat and spatially explicit anthropogenic threats, such as the concentration of fisheries activity. As such, they represent tractable conservation units, in which to target measures for threat mitigation. Front mapping via Earth observation (EO) remote sensing facilitates identification and monitoring of these hotspots of vulnerability. Seasonal or climatological products can locate biophysical hotspots, while near‐real‐time front mapping augments the suite of tools supporting spatially dynamic ocean management. Synthesis and applications. Frontal zones are ecologically important for mobile marine vertebrates. We surmise that relative accessibility, predictability and productivity are key biophysical characteristics of ecologically significant frontal zones in contrasting oceanographic regions. Persistent frontal zones are potential priority conservation areas for multiple marine vertebrate taxa and are easily identifiable through front mapping via EO remote sensing. These insights are useful for marine spatial planning and marine biodiversity conservation, both within Exclusive Economic Zones and in the open oceans.