Low Connectivity Research Articles

GIS and geographical analysis of the main harbors in the world

Abstract This paper points out the possibilities of better exploitation of marine traffic as well as its connection with other kinds of traffic. Special attention is given to the analysis of 1,081 harbors about their availability during the year. The methods and algorithms used in GIS are buffers, cluster, method of interpolations, and network analysis. The methods used for the purpose of conducting numerical analyses are algorithms that served for the analysis of the network, its transport features, and the connectivity with harbors in terms of geospace. The main results found in this research showed that harbors have good connectivity in the first place with road traffic and after that with air and railroad traffic. According to data from 2019, all traffic lines cover 4.1 × 1015 km, and the road traffic has the most significant potential in connection with the harbors. The most connected harbors and airports are in the east coast of North America, west coast, north Europe, southern Europe, south-east Australia, a central part of Oceania, and south-east Africa. The results in the modified Likert scale between airports and harbors showed medium results. The densest road network is located in the eastern part of USA, western and central part of Europe, and east coast of China. The number of possible connected lines between main road nodes and harbors is 0.8 × 109. This type of traffic showed excellent results and connection with harbors. The number of possible connected lines per month between railroads and harbors is 1.3 × 103. This type of traffic showed low connectivity with the harbors. In the end comparison of harbors with air, road and railroad networks were established. The geographical position of harbors was analyzed, and better understanding was performed on a global scale.

Potential local adaptation of corals at acidified and warmed Nikko Bay, Palau

Ocean warming and acidification caused by increases of atmospheric carbon dioxide are now thought to be major threats to coral reefs on a global scale. Here we evaluated the environmental conditions and benthic community structures in semi-closed Nikko Bay at the inner reef area in Palau, which has high pCO2 and seawater temperature conditions with high zooxanthellate coral coverage. Nikko Bay is a highly sheltered system with organisms showing low connectivity with surrounding environments, making this bay a unique site for evaluating adaptation and acclimatization responses of organisms to warmed and acidified environments. Seawater pCO2/Ωarag showed strong gradation ranging from 380 to 982 µatm (Ωarag: 1.79–3.66), and benthic coverage, including soft corals and turf algae, changed along with Ωarag while hard coral coverage did not change. In contrast to previous studies, net calcification was maintained in Nikko Bay even under very low mean Ωarag (2.44). Reciprocal transplantation of the dominant coral Porites cylindrica showed that the calcification rate of corals from Nikko Bay did not change when transplanted to a reference site, while calcification of reference site corals decreased when transplanted to Nikko Bay. Corals transplanted out of their origin sites also showed the highest interactive respiration (R) and lower gross photosynthesis (Pg) to respiration (Pg:R), indicating higher energy acquirement of corals at their origin site. The results of this study give important insights about the potential local acclimatization and adaptation capacity of corals to different environmental conditions including pCO2 and temperature.

Multiple facets of macrophyte beta diversity are shaped by environmental factors, directional spatial processes, and connectivity across tropical floodplain lakes in the dry season

A multi-faceted approach is needed to better understand how the beta diversity of aquatic assemblages responds to ecological gradients. Using distance-based RDA and variance partitioning, we explored the different components of total beta diversity (replacement and richness difference) based on taxonomic, functional, and phylogenetic data of aquatic macrophytes along environmental and spatial gradients across 49 tropical floodplain lakes in the Pantanal of Mato Grosso in the dry season. We found that taxonomic beta diversity was driven by species replacement, while functional beta diversity was mostly contributed by richness difference and phylogenetic beta diversity was equally contributed by both components. Taxonomic and functional beta diversities were driven by environmental variables, connectivity variables, and directional spatial processes. Phylogenetic beta diversity was mainly affected by the connectivity between the sites and their distance from the river. The relationship between environmental variables and beta diversity indicates that a selection of species with similar functional and phylogenetic characteristics co-occurs at a site. The low connectivity between sites and the increased distance between the lakes and the river suggested dispersal limitation, which was due to the absence of directional exchange of species between lakes. Our findings provided new insights into the beta diversity patterns of aquatic macrophytes and their underlying causes in tropical floodplains.

Geometrical and statistical analysis of dynamic crack morphology in shrink-swell soils with addition of maize roots or salinity (NaCl)

Cracks generated in shrink-swell soils detrimentally affect hydraulic and mechanical properties of soils, and alter soil-water processes, such as gas diffusion, water flow, solute transport, and root penetration. Root additives and salinity beget physicochemical changes in soils, resulting in variations of crack morphology. Understanding these variations provides effective means of crack utilization or prevention. In this study, we investigated the effects of maize roots and sodium chloride (NaCl) on crack dynamics and morphology in shrink-swell light clays. Drying experiments were conducted in soils containing roots (root densities: 0, 0.5, 1.0 and 1.5 cm/cm3) or NaCl (mass contents: 0.03, 1.0, 1.5 and 2.0 %). Crack evolution patterns were photographed at regular intervals and crack parameters were calculated from the resulting images using morphological algorithms. We investigated the dynamic geometry, topology, and statistical behaviors of cracks. Results indicate that incorporating maize roots effectively restrained crack area and width, but increased crack length, tortuosity, and number of cracks. Crack networks in root-treated soils contained a vast number of dead-ends and displayed pronounced fragmentation and low connectivity. Distribution of crack intersection angle well approximate normality with a mean around 120°. The bonding and friction between roots and particles, the bridging effects, stiffness, and ductility of roots improved the soil tensile strength and altered the intrinsic release criteria of tensile stress. The NaCl treatments increased crack area and width but decreased total crack length and tortuosity. With a slight amount of NaCl, the crack network tended to be highly connected with no dead-ends. Distribution of crack intersection angle in sodic soils exhibited asymmetric bimodality and was well described by a mixture of two Gaussian distributions, with primary and secondary peaks around 105° and 165°, respectively. We proposed a statistical function that describes crack area probability distribution considering water content as a variable, which proved to be a good fit in modeling dynamic statistics of crack patterns. Our results provide compelling evidence of how roots and salinity alter crack evolution, dynamics, and morphology in shrink-swell soils, which will be beneficial in crack inhibition and utilization, and in hydrological use such as water management in saline-sodic soils and prevention of preferential flow. However, cracking behaviors are highly susceptible to sample size effects and basal boundary. We hypothesize cracking behaviors (in roots- or salinity-treated soils) in small scale and in-situ scale are dimensionally similar, and the validity of these conclusions being generalized to in-situ cracked soils should be further investigated.

Monitoring of Electric Buses Within an Urban Smart City Environment

A practical experience on monitoring the data generated by electric buses is presented, focusing on energy consumption, charge and state of the batteries. The work is carried out in the framework of a global smart city strategy developed by the H2020 Smart City Lighthouse STARDUST project. The crucial role of the data collection and transmission from electric buses has become evident in this work, so the adopted solutions are covered in detail. A practical electric bus charging station configuration is considered, operating within the city of Pamplona, Spain, with an urban route setting in which electric charging is performed. Various key factors for the practical implementation of the necessary communication infrastructure, including wireless Low Power Wide Area connectivity challenges within the urban scenario settings, based in LoRa/LoRaWAN communication system nodes. The monitoring system architecture is also presented, in which specific machine learning modules in order to collect patterns and visualization of data to enhance planning, operation and maintenance procedures.

Effect of Restoration Actions on Organic Carbon Pools in the Lagoon—Delta Ciénaga Grande de Santa Marta, Colombian Caribbean

Mangroves provide multiple ecosystem services and are essential for mitigating global warming owing to their capacity to store large carbon (C) stocks. Due to widespread mangrove degradation, actions have been implemented to restore them worldwide. An important representative case in Colombia is the Ciénaga Grande de Santa Marta’s restoration plan. This management intervention focused on restoring the natural hydrological functioning after massive mangrove mortality (~25,000 ha) due to soil hyper-salinization after river water input from the Magdalena River was eliminated. A partial recovery occurred during subsequent years, and hydrological management is still being implemented today. To understand how the degradation and subsequent management have affected mangrove C stocks, we compared C stocks in stands with different intervention levels reflected in their current forest structure. We found that the total C stock (398–1160 Mg C ha−1) was within the range measured in other neotropical mangroves without vegetation deterioration. The aboveground C was significantly higher in the stands where hydraulic connectivity was restored. By contrast, the belowground C was higher in the stands with low hydraulic connectivity due to channel clogging and a lack of sufficient maintenance. Our results show that hydrological management measures influenced above- and belowground C stocks, even at a 2 m depth. In addition, a strong indirect relationship useful for estimating carbon content from organic matter content was found.

Continent-wide modelling of potential habitats and connectivity for the Eurasian lynx (Lynx lynx) in Europe

Eurasian lynx (Lynx lynx) once inhabited almost the whole of the European continent. After facing nearly complete extinction about a century ago, they now form a more or less connected metapopulation with eleven broad-scale populations and numerous isolated habitat patches throughout Europe. Increasing public interest and a favourable legislative status by the EU give rise to hope for the return of the felide to parts of Central and Western Europe, where it is currently absent. In this context, a solid understanding of the overall suitability of the European landscape for a well-connected lynx population is crucial. Therefore, this work is looking into the current situation as well as potential habitats, ease of movement between those habitats, and potential future distribution, with the main focus on broad-scale spatial patterns. In addition to existing populations, eight habitat clusters were identified across Europe, using a modelling approach, rooted in a rule-based assessment accompanied by least-cost path identification, generating possible movement corridors. Key findings include large areas of potential habitat, yet overall low connectivity, with lynx movement restricted by a lack of forest cover as well as human land use, including mainly linear barriers like highways and dense road networks. This situation provides a number of challenges and opportunities for national and international conservation: The results clearly indicate that for a recolonisation of many parts of the European landscape reintroduction measures are indispensable in many parts of Europe. They also offer a first step towards a general understanding of how large carnivores like the Eurasian lynx might exist within a landscape increasingly shaped by anthropogenic actions and land use.

The Time Varying Networks of the Interoceptive Attention and Rest.

Focused attention to spontaneous sensations is a dynamic process that demands interoceptive abilities. Failure to control it has been linked to neuropsychiatric disorders like illness-anxiety disorder. Regulatory strategies, such as focused attention meditation (FAM), may enhance the ability to control focused attention particularly to body sensations, which can be reflected on functional neuroanatomy. The functional connectivity (FC) related to focused attention has been described, however, the dynamic brain organization associated to this process and the differences to the resting state remains to be studied. To quantify the cerebral dynamic counterpart of focused attention to interoception, we examined fifteen experienced meditators while performing a 20-min attentional task to spontaneous sensations. Subjects underwent three scanning sessions obtaining a resting-state scan before and after the task. Sliding window dynamic FC (DFC) and k-means clustering identified five recurrent FC patterns along the dorsal attention network (DAN), default mode network (DMN), and frontoparietal network (FPN). Subjects remained longer in a low connectivity brain pattern during the resting conditions. By contrast, subjects spent a higher proportion of time in complex patterns during the task than rest. Moreover, a carry-over effect in FC was observed following the interoceptive task performance, suggestive of an active role in the learning process linked to cognitive training. Our results suggest that focused attention to interoceptive processes, demands a dynamic brain organization with specific features that distinguishes it from the resting condition. This approach may provide new insights characterizing the neural basis of the focused attention, an essential component for human adaptability.

A method for generating geomodels conditioned to well data with high net:gross ratios but low connectivity

The sand connectivity in object- and pixel-based models is inevitably controlled by the proportion of sand present, and these methods seem unable to generate models that reproduce systems with low connectivity at high net:gross ratios. A new workflow is described which addresses this limitation and permits poorly connected facies models conditioned to well data to be built. The approach combines the compression algorithm with multiple-point statistics (MPS) modelling. Geometrically transformed wells and appropriately scaled training images provide the inputs to the MPS modelling. The inverse transformation is applied to the resultant MPS model, leading to the creation of reservoir geomodels with realistic, user-defined connectivity while also honouring well data. The approach is described and validated using a range of models. Considerations of other potential workflows using different types of training image suggest that application of the compression algorithm may be necessary in general to achieve models with realistic connectivity using the simplest and most widely-available pixel-based MPS method (the SNESIM algorithm).

Mechanical response of composite fiber networks subjected to local contractile deformation

The extracellular matrix (ECM), forming the cell microenvironment, is a random fiber network whose heterogeneous microstructure serves a vital role in cellular functions such as migration, proliferation, and differentiation. Although prior computational studies used a network of randomly crosslinked fibers for investigating the ECM mechanical response due to the cell contraction, we hereby investigate the cell-induced deformation by considering the interplay between the collagen fibers and soft proteoglycan matrix domain. For this purpose, we represent the complex ECM microstructure by a double network model in which a random network of relatively stiff fibers (representing collagens) is embedded in a homogeneous network (representing the matrix domain). We demonstrate that the interaction between the network of stiff fibers and the network of matrix fibers plays a significant role in the propagation of cell-induced displacements. In particular, as the stiffness of the matrix domain increases, the long-range displacement propagation becomes suppressed. Furthermore, the degree of inhomogeneity in the displacement propagation is controlled by the relative stiffness of fiber and matrix networks. The influence of matrix stiffness becomes prominent for composite networks with random networks having a low average network connectivity and/or composed of fibers with low bending rigidity.

How hydrological connectivity regulates the plant recovery process in salt marshes

Abstract Designing effective restoration strategies is a priority in recovering salt marsh plants. Hydrological connectivity is a main driver underpinning the success of the plant recovery process and can regulate life‐history process‐based restoration strategies. However, the relationship between these is unclear. Plant recovery needs to go through a whole life‐history process, from seed to adult. Common restoration strategies are seed addition (SA) or seedling transplantation (ST), which start from seed germination and seedling growth stage. Besides these two strategies, another strategy starting from seed retention stage, microtopographic adjustment (MA), was designed to study the relationship with hydrological connectivity. A framework was also constructed to assess a gradient of hydrological connectivity between marsh plain and sea. We conducted several field experiments to test their relationships. The composite measurement of hydrological connectivity with five geomorphic variables can well represent the variation of environmental factors. Soil moisture, inundation frequency and sediment deposition were positively correlated, while soil salinity and hardness were negatively correlated with hydrological connectivity. The success of different restoration strategies varied with hydrological connectivity. MA showed a monotone decreasing trend, while SA and ST showed a unimodal trend as hydrological connectivity increased. Importantly, each strategy occupies a non‐overlapping optimum range along the hydrological connectivity gradient. There is low hydrological connectivity for MA (0–0.28), middle hydrological connectivity for SA (0.28–0.55) and high hydrological connectivity for ST (0.55–1). Synthesis and applications. Our findings expand the quantification of the hydrological environment beyond elevation, distance or other single index to include a range of elements of hydrological connectivity, thus illustrating the underlying mechanisms of hydrological connectivity which regulate restoration strategies based on different life stages. The results provide a reliable framework to assess hydrological connectivity and offer guidance to select the optimum restoration strategy under different hydrological connectivities or to regulate the hydrological connectivity variables (topography on marsh plain and morphology of tidal creeks) to relief stresses. These findings will be beneficial to ecological restoration and coastal management.

Environmental connectivity controls diversity in soil microbial communities

Interspecific interactions are thought to govern the stability and functioning of microbial communities, but the influence of the spatial environment and its structural connectivity on the potential of such interactions to unfold remain largely unknown. Here we studied the effects on community growth and microbial diversity as a function of environmental connectivity, where we define environmental connectivity as the degree of habitat fragmentation preventing microbial cells from living together. We quantitatively compared growth of a naturally-derived high microbial diversity community from soil in a completely mixed liquid suspension (high connectivity) to growth in a massively fragmented and poorly connected environment (low connectivity). The low connectivity environment consisted of homogenously-sized miniature agarose beads containing random single or paired founder cells. We found that overall community growth was the same in both environments, but the low connectivity environment dramatically reduced global community-level diversity compared to the high connectivity environment. Experimental observations were supported by community growth modeling. The model predicts a loss of diversity in the low connectivity environment as a result of negative interspecific interactions becoming more dominant at small founder species numbers. Counterintuitively for the low connectivity environment, growth of isolated single genotypes was less productive than that of random founder genotype cell pairs, suggesting that the community as a whole profited from emerging positive interspecific interactions. Our work demonstrates the importance of environmental connectivity for growth of natural soil microbial communities, which aids future efforts to intervene in or restore community composition to achieve engineering and biotechnological objectives.

Microscopic pore-throat grading evaluation in a tight oil reservoir using machine learning: a case study of the Fuyu oil layer in Bayanchagan area, Songliao Basin central depression

Tight oil reservoirs are key research targets of petroleum geological exploration. Due to their strong heterogeneity, reservoir classification is fuzzy and efficiency is low, which affects reservoir evaluation accuracy. This study aims to improve the accuracy of the evaluation of microscopic pore throats of tight reservoir. Tight oil reservoir is classified on the basis of microscopic pore-throat grading with machine learning technology including Box-Cox transformations, Grey relational analysis, Q-cluster analysis, and discriminant analysis, in combination with traditional measures of reservoir quality in the Fuyu oil layer, Bayanchagan area, Songliao Basin. The results show that Class I reservoirs are high-quality, medium compaction-strong dissolution-weak cementation reservoirs, with large pore-throat radii, concentrated from 0.16 μm to 1.00 μm. Class II reservoirs have medium potential, with strong compaction-medium dissolution-medium cementation. Pore throats have relatively uniform distribution with low connectivity, and radii mainly between 0.016 μm to 0.16 μm. The Class III reservoir has the lowest potential and strong heterogeneity, with strong compaction, weak dissolution, and strong cementation. Small pore-throat radii range from 0.002 μm to 0.016 μm. We infer that this method can effectively evaluate tight oil reservoirs and provide a basis for the prediction of favorable areas for tight oil exploration and development.

Non-indigenous and Invasive Freshwater Species on the Atlantic Islands of the Azores Archipelago

Freshwater systems on remote oceanic islands are particularly vulnerable to biological invasions. The case of freshwater ecosystems in the Azores Archipelago is especially relevant considering the islands’ youth and remoteness, and low natural connectivity. This study presents a review of the introduction and presence of non-indigenous freshwater species in the Azores, retrieved from various historical records, paleoenvironmental reconstructions, published records, and field data from two decades of the Water Framework Directive (WFD) monitoring programs. At least 132 non-indigenous freshwater species have successfully established in the Azores, belonging to several taxonomic groups: cyanobacteria (10), synurophytes (1), desmids (1), diatoms (20), plants (41), invertebrates (45), amphibia (2), and fishes (12). Intentional and accidental introductions have been occurring since the establishment of the first human settlers on the archipelago, impacting freshwater ecosystems. The first reported introductions in the Azores were intentional fish stocking in some lakes. Non-deliberate introductions have recently increased through transport-contaminants (51%) associated with the aquarium trade or agricultural products. In the Azores, the highest number of non-indigenous species occur on the largest and most populated island, São Miguel Island (116), followed by Flores (68). Plants constitute the most representative group of introduced species on all islands, but invertebrates, diatoms, and fishes are also well established on most islands. Among invertebrates, non-indigenous arthropods are the most well-established group on all islands except on the smallest Corvo Island. Many non-indigenous species will likely benefit from climate change and magnified by globalization that increases the probability of the movement of tropical and subtropical species to the Azores. Present trends in international trade, importations, and enhanced connectivity of the archipelago by increasing flights and shipping will probably promote the arrival of new species. Augmented connectivity among islands is likely to improve non-indigenous species dispersal within the archipelago as accidental transportation seems to be an essential pathway for non-indigenous freshwater species already present in the Azores.

The Importance of Think Talk Write Learning Model on the Mathematical Connection Ability and Self-Confidence

The use of a monotonous and less attractive learning model results in low connectivity and low confidence. The purpose of this study was to determine the effect of the Think Talk Write (TTW) learnng model on the mathematical connection ability and self-confidence students class IV fraction material. The formulation of the problem in this study is wether there is an effect of the Think Talk Write learning model on the mathematical connection ability and self-confidence students class IV fraction material. This research is conducted to students class IV. This study is a quantitative research with Quasi Experimental Design in the form Nonequivalent Control Group Design. Data collection techniques method the test and questionnaries. Data analysis uses normality test, homogeneity test and hypothesis test. The results show that: 1) There is an effect of the Think Talk Write learning model on the mathematical connection ability, as evidenced by the results of the Independent Sample T-Test, there is a sig. (2-tailed) 0.038 <0.05 then Ho is rejected and Ha is accepted in the Paired Sample T-Test there is a sig. (2-tailed) 0.000 <0.05 then Ho is rejected and Ha is accepted. 2) There is an influence of the Think Talk Write learning model on self-confidence from the independent calculation there is a sig. (2-tailed) 0.000 < 0.05 means that Ho is rejected and Ha is accepted, while in Paired the results are Sig. (2-tailed) 0.000 <0.05 means that Ho is rejected and Ha is accepted. This research implies that the TTW learning model can improve the mathematical connection ability and self-confidence students class IV fraction material.

Health and environmental co-benefits of city urban form in Latin America: an ecological study

BackgroundUrban design features are often studied in relation to health and behavioural outcomes. They can also have major implications for environmental outcomes. However, the impact of these features on both health and environmental outcomes (co-benefits) is rarely examined. We investigated how urban landscape and street design profiles are related to jointly occurring health and environmental outcomes in Latin America cities. MethodsWe used data from the Salud Urbana en América Latina (SALURBAL) project, which has compiled and harmonised data on built environment, environmental exposures, and health outcomes for 370 cities in 11 countries: Argentina, Brazil, Chile, Colombia, Costa Rica, El Salvador, Guatemala, Mexico, Nicaragua, Panama, and Peru. Eight city profiles were identified using finite mixture models. Four urban-landscape profiles were defined measuring patch (contiguous area of urban development) fragmentation, shape, and isolation, and four street-design profiles were defined using street connectivity, length, and directness. Multilevel regression models were used to assess associations between the city profiles and several health and environmental outcomes. FindingsOur preliminary results show that compared with the urban-landscape profile labelled scattered pixels (comprising low fragmentation, compact shape, and high isolation), the proximate-stones profile (moderate fragmentation, irregular shape, and moderate isolation) had significantly higher levels of PM2·5 and nitrogen dioxide (NO2), and the proximate-inkblots profile (moderate-to-high fragmentation, complex shape, and moderate isolation) had significantly higher levels of violence-related deaths. Compared with the labyrinthine street design profile (low connectivity, moderate length, and moderate directness), the semi-hyperbolic grid (moderate connectivity, moderate length, and moderate directness) and spiderweb (high connectivity, low length, and moderate directness) profiles had significantly higher levels of PM2·5 and NO2, whereas the hyperbolic grid profile (moderate connectivity, high length, and low directness) had significantly higher levels of NO2 and lower levels of obesity. InterpretationIdentifying how city profiles are related to environment and health outcomes can shed light on the urban policies that could have the greatest environment and health co-benefits. FundingThe SALURBAL/Urban Health in Latin America project is funded by the Wellcome Trust (205177/Z/16/Z).

Decoding space syntax on the translation of site cluster permeability into building courtyard

An urban environment leads to tropical building adaptation by providing sufficient thermal comfort and energy efficiency. For generating the physiological cooling, interconnected attribute of site cluster permeability is translated into lower context such as building scale to provide optimal wind speed to restore thermal comfort. It will be expected to find the critical factor which most influences the performance. Meanwhile, the encoding of the space connectivity to accelerate air movement has been evaluated by previous studies. In this paper, the counter reading of visibility relationships analysis on computational fluid dynamics is conducted and decoded by DepthmapX simulation. The site clusters type of grid, cul-de-sac, and the open area plan of a loop represent housing estates in some tropical regions as the cases. The results highlighted that 50% or more translated air movement from the site to the building scale environment is determined by the dominated warmest connectivity of open space. The potency of energy efficiency is indicated by the capability of accommodating both social connectivity and environmental performance. Furthermore, the code of irregular building patterns by increasing air movement has low spatial and social connectivity because of space depthless. Providing open space for site planning encourages both environmental and social qualities.

Integrating petrophysical attributes with saturation data in a geological framework, Permian–Triassic reservoirs of the central Persian Gulf

In this research, an integrated geological and petrophysical approach was applied to understanding the most critical factors affecting the water saturation exponent in the Permian–Triassic Kangan and Dalan carbonate formations in the central Persian Gulf in Iran. Economically, water saturation has a fundamental role in reservoir characterisation. A total of 8 sedimentary facies were recognised with multiple diagenetic phases. Diagenetic processes include marine cementation, moldic dissolution, early dolomitisation, recrystallisation, anhydrite cementation, compaction, and fracturing, which have influenced reservoir properties. Four third-order sequences were distinguished in the study area accompanied by nine fourth-order sequences. Petrographic analysis, scanning electron microscopy, petrophysical core analysis, wireline log data as well as mercury injection tests integrated through flow zone indicator, Lucia classes, and Lorenz plot approaches. Consequently, 4 integrated rock types (IRTs) were identified with particular depositional and diagenetic features. IRT1 with dominant interparticle pore type and strong porosity–permeability correlation (average 9.1% porosity and 27 mD permeability, R2 = 0.98), has a high saturation exponent (n = 2.2). IRT4 with grain-to mud-dominated facies, low porosities (average 1.4%), and a mean value of 4.54 mD permeability has the lowest saturation exponent (n = 1.07). Moldic dissolution with low pore connectivity is the dominant pore type in IRT2 and IRT3 which have a medium and relatively high saturation exponent, respectively (IRT2 n = 1.53 and IRT3 n = 1.78). Accordingly, a conceptual model was suggested for saturation exponent variations in a high-frequency sequence stratigraphic framework. In order to evaluate the heterogeneity of the studied formations and its impact on the reservoir properties, the characteristics of the determined rock units were studied. This study integrates microscopic to macroscopic geological and petrophysical factors to understand the saturation exponent distribution in a heterogeneous carbonate reservoir, leading to obtaining a more accurate water saturation estimation of such reservoirs.

Whole genome genotyping reveals discrete genetic diversity in north-east Atlantic maerl beds.

Maerl beds are vital habitats for a diverse array of marine species across trophic levels, but they are increasingly threatened by human activities and climate change. Furthermore, little is known about the genetic diversity of maerl‐forming species and the population structure of maerl beds, both of which are important for understanding the ability of these species to adapt to changing environments and for informing marine reserve planning. In this study, we used a whole genome genotyping approach to explore the population genomics of Phymatolithon calcareum, a maerl‐forming red algal species, whose geographical distribution spans the north‐east Atlantic, from Norway to Portugal. Our results, using 14,150 genome‐wide SNPs (single nucleotide polymorphisms), showed that P. calcareum maerl beds across the north‐east Atlantic are generally structured geographically, a pattern likely explained by low dispersal potential and limited connectivity between regions. Additionally, we found that P. calcareum from the Fal Estuary, south‐west England, is genetically distinct from all other P. calcareum sampled, even from The Manacles, a site located only 13 km away. Further analysis revealed that this finding is not the result of introgression from two closely related species, Phymatolithon purpureum or Lithothamnion corallioides. Instead, this unique diversity may have been shaped over time by geographical isolation of the Fal Estuary maerl bed and a lack of gene flow with other P. calcareum populations. The genomic data presented in this study suggest that P. calcareum genetic diversity has accumulated over large temporal and spatial scales, the preservation of which will be important for maximizing the resilience of this species to changes in climate and the environment. Moreover, our findings underline the importance of managing the conservation of maerl beds across western Europe as distinct units, at a site‐by‐site level.

3D Multi-scale Reconstruction of Fractured Shale and Influence of Fracture Morphology on Shale Gas Flow

Quantitative characterization of shale gas flow in fractured shale is a key problem in shale gas extraction. In this study, 3D multi-scale structures in fractured shale were reconstructed, firstly, by X-ray micro-computerized tomography (CT), high-resolution scanning electron microscope (SEM), and fractal function. Then, a REV (representative elementary volume)-scale lattice Boltzmann (LB) model, considering Klinkenberg’s effect and gas absorption, was built, and the effects of fracture complexity and gas pressure on shale gas flow and shale permeability were analyzed and studied quantitatively. The simulation results indicate that the gas flow behaviors in the fractured shale are related strongly to fracture morphology and gas pressure. The decreased fracture fractal dimension or increased complexity of the fracture network leads to increase in permeability of the fractured shale. The gas velocity in the shale matrix decreases with increasing fracture roughness. Increased fracture network connectivity contributes to the formation of local high-intensity velocity fields and the improvement of gas flow in the shale matrix. The gas rarefaction effect has a significant influence on gas flow in the fractured shale, and permeability of the fractured shale must be regarded as a dynamic shale reservoir parameter. The gas flow behavior in the fractured shale is more sensitive at low-pressure condition whereas the gas rarefaction effect is more sensitive to the fractured shale with highly rough fracture or low fracture connectivity.