Shoal Research Articles

Contributions to the study of higher fungi on Sable Island, Nova Scotia

This study documents 27 taxa of Higher Fungi found on Sable Island, a remote emergent sand bar 160 km east of the Nova Scotia mainland. Of these, two are new basidiomycete records for the province, Deconica subcoprophila and Volvopluteus aff. gloiocephalus. Thirteen other taxa represent range extensions within Nova Scotia. Suillus luteus is suggested as the probable identity of the only ectomycorrhizal fungusdescribed colonizing the roots of the solitary pine tree growing on Sable Island. Keywords: coprophilous fungi, coastal dunes, Deconica, Suillus luteus, Volvopluteus

Riverscape-Scale Modeling of Fundamentally Suitable Habitat for Mussel Assemblages in an Ozark River System, Missouri

Identifying the physical habitat characteristics associated with riverine freshwater mussel assemblages is challenging but crucial for understanding the causes of mussel declines. The occurrence of mussels in multispecies beds suggests that common physical factors influence or limit their occurrence. Fine-scale geomorphic and hydraulic factors (e.g., scour, bed stability) are predictive of mussel-bed occurrence, but they are computationally challenging to represent at intermediate or riverscape scales. We used maximum entropy (MaxEnt) modeling to evaluate associations between riverscape-scale hydrogeomorphic variables and mussel-bed presence along 530 river km of the Meramec River basin, USA, to identify river reaches that are fundamentally suitable for mussels as well as those that are not. We obtained the locations of mussel beds from an existing, multiyear dataset, and we derived river variables from high-resolution, open-source datasets of aerial imagery and topography. Mussel beds occurred almost exclusively in reaches identified by our model as suitable; these were characterized by laterally stable channels, absence of adjacent bluffs, proximity to gravel bars, higher stream power, and larger areas of contiguous water (a proxy for drought vulnerability). We validated our model findings based on model sensitivity using a set of mussel-bed locations not used in model development. These findings can inform how resource managers allocate survey, monitoring, and conservation efforts.

Two New Species of Parastenocaris (Copepoda, Harpacticoida) from a Hyporheic Zone and Overview of the Present Knowledge on Stygobiotic Copepoda in Vietnam

The number of freshwater species belonging to the genus Parastenocaris reported from ten countries of Southeast Asia is quite limited. Only two species have been reported so far from freshwater habitats there, compared to over 290 described species of the family Parastenocarididae worldwide. During the first study of the hyporheic zone of two small rivers in central Vietnam, two new species of the family Parastenocarididae were collected, Parastenocaris sontraensis sp. nov. and Parastencaris vugiaensis sp. nov. Both were collected from the gravel bar along the rivers (Suoi Da and Vu Gia river) using the Karaman–Chappuis method. Both the new species belong to the brevipes group of the genus Parastenocaris Kessler, 1913 sensu Lang (1948), and Reid (1995). Parastenocaris sontraensis sp. nov. is similar to P. hinumaensis Kikuchi, 1970 and Parastenocaris jane Karanovic, 2006 in the brevipes-group. Parastenocaris sontraensis sp. nov. differs from both Parastenocaris species by (i) Exp P3 with three segments in the male, (ii) caudal rami with seven setae, and (iii) caudal rami about 2.4 times as long as wide. Parastencaris vugiaensis sp. nov. can be distinguished from its congeners by the unique combination of the following characters: (i) the elliptical shape of caudal rami, (ii) apical seta (V) with bulbous base, and (iii) anal operculum extends beyond the end of anal somite. Until now, 14 stygobiotic species of Copepoda have been recorded in Vietnam (including two new species in this paper), which is relatively few compared with nearby Thailand with 25 species. Short comments on other stygobiotic Copepoda from Vietnam are added.

Basin‐wide hydromorphological analysis of ephemeral streams using machine learning algorithms‡

AbstractSustainable river management now encompasses a much wider concept that includes hydromorphological and fluvial habitat studies. In ephemeral streams, the geomorphological characterization of channels is complex due to episodic flows and riparian vegetation dynamics. Stream channel survey and classification at the watershed scale provide the basis for geomorphological conservation, process interpretation, assessing sensitivity to disturbance, and identifying reaches that supply and store sediment. Here, we present a stream classification based on a two‐step approach: (1) automatic river segmentation based on spatial variability in channel/valley morphology from topographic measurements (LiDAR, light, detection and ranging), and (2) fluvial landform and vegetation density mapping derived from multispectral open‐source satellite images (Sentinel‐2) using support vector machine (SVM) and Random Forest (RF) algorithms. These analyses provide continuous, quantitative spatial values of geometric (channel/valley width, slope gradient, and route distance), landform (active channel and gravel bars with five densities of vegetation cover), and hydraulic (specific stream power) variables. Four stream types were identified in the Rambla de la Viuda catchment (~1500 km2), an ephemeral gravel‐bed river in eastern Spain. The spatial distribution of channel types is explained by differences in geometry (active channel width, valley width, and slope gradient) and a hydraulic parameter (specific stream power). The landforms/vegetation patterns provided insight on causal relationships between erosion and deposition processes during high flow periods and the time since the most recent large disruptive flood event. Channel type distribution provided first‐order predictions about the location of reaches that supply and store sediment and thus information on sediment continuity along the river. Dam effects on downstream reaches resulted in geomorphological disequilibrium, producing narrowing of the active channel, slope reduction, and a decrease of gravel bar areal extension. The proposed catchment scale analysis provides a comprehensive and replicable methodology for environmental planning in Mediterranean ephemeral streams to guide further hydromorphological surveys at the reach scale.

Underwater Sound Propagation Modeling in a Complex Shallow Water Environment

Three-dimensional (3D) effects can profoundly influence underwater sound propagation in shallow-water environments, hence, affecting the underwater soundscape. Various geological features and coastal oceanographic processes can cause horizontal reflection, refraction, and diffraction of underwater sound. In this work, the ability of a parabolic equation (PE) model to simulate sound propagation in the extremely complicated shallow water environment of Long Island Sound (United States east coast) is investigated. First, the 2D and 3D versions of the PE model are compared with state-of-the-art normal mode and beam tracing models for two idealized cases representing the local environment in the Sound: (i) a 2D 50-m flat bottom and (ii) a 3D shallow water wedge. After that, the PE model is utilized to model sound propagation in three realistic local scenarios in the Sound. Frequencies of 500 and 1500 Hz are considered in all the simulations. In general, transmission loss (TL) results provided by the PE, normal mode and beam tracing models tend to agree with each other. Differences found emerge with (1) increasing the bathymetry complexity, (2) expanding the propagation range, and (3) approaching the limits of model applicability. The TL results from 3D PE simulations indicate that sound propagating along sand bars can experience significant 3D effects. Indeed, for the complex shallow bathymetry found in some areas of Long Island Sound, it is challenging for the models to track the interference effects in the sound pattern. Results emphasize that when choosing an underwater sound propagation model for practical applications in a complex shallow-water environment, a compromise will be made between the numerical model accuracy, computational time, and validity.

FISHERY OF OTOLITHOIDES PAMA (HAMILTON, 1822) IN NARMADA ESTUARY

Total estuarine area under Gujarat state is reported to be 0.21 lakh ha. Narmada estuary is a freshwater estuary under the tidal effect, which mainly influences the salinity regimes. The actual estuarine region starts from Bharuch (situated 220 25' 78 N, 730 53' 91 E) and joins Arabian Sea at Ambetha (210 40'81 N, 720 35' 70 E) in Bharuch district, Gujarat. The funnel-shaped 72 km-long estuarine occupies an area of 6,346 km2 (Kumar et al., 2014). The southwest monsoon brings rainfall, and about 70% of the rainfall occurs during the period from June to September. The development of sand bars at the mouth of the estuary reduces the tidal ingress into the system. Narmada estuary is influenced by semi-diurnal tides with unequal variability. The estuarine production reduced drastically from 15889 t (2006-2007) to 1618 t (2014-15). Habitat shifting of species due to salinity industrial effluents and formation of sand bar in the mouth of the estuary indicates restricted fish migration may be the cause

Laboratory investigation on morphology response of submerged artificial sandbar and its impact on beach evolution under storm wave condition

The Submerged Artificial sandBar (SAB), recognized as one of the nature-based solutions for beach protection and restoration, has become increasingly popular in coastal engineering applications. However, its morphological response to waves and the resulting impacts on beach evolution are yet not well understood. Here, laboratory experiments are conducted considering different background profiles and various SAB designs. Morphological evolution of the SAB and berm are inspected from the measured beach profile data in the wave flume. Results show that the SAB migrates onshore with its bar shape decaying, providing a paradigm shift away from the traditional understanding that the net subaqueous sediment transport is always offshore directed under storm wave conditions. SAB can alter the beach state and berm behavior by triggering onshore sediment transport locally and temporarily. The stability of the SAB is controlled by its seaward slope and the ratio of crest water depth to the bar height. A morphological coupling is found between the SAB and berm, and an empirical relationship is proposed to quantitatively capture it. Finally, the experiment results are used to validate a process-based beach profile evolution numerical model, and an explanation for the morphological coupling is provided from the perspective of wave energy dissipation.

Automatic Features Detection in a Fluvial Environment through Machine Learning Techniques Based on UAVs Multispectral Data

The present work aims to demonstrate how machine learning (ML) techniques can be used for automatic feature detection and extraction in fluvial environments. The use of photogrammetry and machine learning algorithms has improved the understanding of both environmental and anthropic issues. The developed methodology was applied considering the acquisition of multiple photogrammetric images thanks to unmanned aerial vehicles (UAV) carrying multispectral cameras. These surveys were carried out in the Salbertrand area, along the Dora Riparia River, situated in Piedmont (Italy). The authors developed an algorithm able to identify and detect the water table contour concerning the landed areas: the automatic classification in ML found a valid identification of different patterns (water, gravel bars, vegetation, and ground classes) in specific hydraulic and geomatics conditions. Indeed, the RE+NIR data gave us a sharp rise in terms of accuracy by about 11% and 13.5% of F1-score average values in the testing point clouds compared to RGB data. The obtained results about the automatic classification led us to define a new procedure with precise validity conditions.

Sedimentological and microfossil records of modern typhoons in a coastal sandy lagoon off southern China coast

To determine the characteristics and potential indicators of modern typhoon deposition in a sandy lagoon off the coast of Guangdong Province (southern China), we analysed the 210Pb, sedimentology, and microfossils of samples from ten cores obtained before and after the passage of Typhoon Rammasun in 2014. Typhoon deposition showed a thinning trend from internal areas of the lagoon to its mouth, with the maximum thickness inside the lagoon of ∼35 cm. These typhoon deposits are dominated by overwash and differ from sediments deposited under normal weather conditions. Under normal weather conditions, lagoon sediment has a 210Pb curve that follows a model of exponential decay, has a unimodal granularity frequency curve, and lacks organic matter and microfossils (diatoms and foraminifera). However, 210Pb is low in the typhoon deposits, the grain size is coarse, and the granularity frequency curve is obviously bimodal. There are also abundant foraminifera in the typhoon deposits. We found a clear double-layered structure in the typhoon deposits, which was caused by strong hydrodynamic disturbance that mixed sediments originally from the offshore area with those of the lagoon. The lower layer has coarse-grained particles with medium sorting, low organic matter content, and low diatom content. The upper layer has fine-grained particles with poor sorting, high organic matter content, and abundant diatoms. The rate of fragmentation of diatoms in the upper layer was very high (40%–60%). The diatom assemblage contained offshore and freshwater species carried by storm runoff. Therefore, we believe that the sediments of this typical sand bar–lagoon environment retain evidence of typhoon events along the southern China coast that is displayed in the marked sedimentological and microfossil characteristics.

Profiling the microbial community structure and functional diversity of a dam‐regulated river undergoing gravel bar restoration

Abstract Comprehensive restoration programs are expected to influence sediment‐associated microbial community structure and functional diversity following changes attributed to the restoration of habitat characteristics in the dam‐impacted channel. To address if the construction or recreation of in‐channel structures, i.e., gravel bars, by implementing gravel augmentation and ecological flow restoration, resulted in habitat restoration and enhanced environmental heterogeneity, we profiled the community composition, estimated diversity, and annotated putative metabolic functions of the sediment microbial communities of the dam‐regulated Trinity River in northern California. Our results provided supporting evidence on the positive impact of habitat restoration conducted in the Trinity River with the non‐dam influenced, undisturbed tributaries as the basis of comparison. In addition, gravel bar recreation and restoration contributed to the increased microbial beta diversity, possibly through the increased environmental heterogeneity at the river scale. The significant positive correlation between the taxonomic and functional diversity of the identified microbial taxa suggests that differences in the detected putative metabolic functions were closely related to dissimilarities in community composition. We also provided valuable insights into the potential microbial processes in the sediment that might be contributing to the biogeochemical processes carried out by the microbial communities in the river. The results of this study have implications on the impact of construction and restoration of gravel bars in a dam‐impacted river on environmental heterogeneity and how this influences the taxonomic and functional diversities of sediment‐associated microbial communities.

Geochemistry and Petrography of the Sediments From the Marginal Areas of Qinghai Lake, Northern Tibet Plateau, China: Implications for Weathering and Provenance

The provenance study of the sediments from Qinghai Lake is of great significance for the understanding of geological and climatic evolution processes of the Tibet Plateau on the one hand and for evaluating the controlling factors of the sediment components on the other hand. The samples were collected from five rivers, foreshore, beach, beach bar, and aeolian sand dune in the Qinghai Lake. The bulk geochemical composition, petrography, and mineralogy features of the samples are analyzed. The results show that: 1) Qinghai Lake sediments experienced low-intensity chemical weathering from the source areas to the deposition sites and were affected by some recycled detrital materials and 2) the source rocks for the sediments include felsic rocks (granite, granodiorite, and felsic volcanic rocks), carbonate, metamorphic rocks (marble and meta-volcanic rocks), and clastic rocks with the felsic source rocks to have the most important impact on the chemical compositions of the sediments. The geochemical indicator of Al2O3/TiO2 reflects that the provenance of fine-grained sediments from the center of Qinghai Lake is more mafic than the coarse-grained sediments from the margin of the Qinghai Lake, suggesting that the hydraulic sorting of grain size probably plays an important role in the geochemical compositions of the sediments. The mafic elements were probably preferentially enriched in muds.

Characterization of reservoir sands using 3D seismic attributes in the coastal swamp area of Niger Delta Basin

Hydrocarbon accumulation and production within the Niger Delta Basin are controlled by varieties of geologic features guided by the depositional environment and tectonic history across the basin. In this study, multiple seismic attribute transforms were applied to three-dimensional (3D) seismic data obtained from “Reigh” Field, Onshore Niger Delta to delineate and characterize geologic features capable of harboring hydrocarbon and identifying hydrocarbon productivity areas within the field. Two (2) sand units were delineated from borehole log data and their corresponding horizons were mapped on seismic data, using appropriate check-shot data of the boreholes. Petrophysical summary of the sand units revealed that the area is characterized by high sand/shale ratio, effective porosity ranged from 16 to 36% and hydrocarbon saturation between 72 and 92%. By extracting attribute maps of coherence, instantaneous frequency, instantaneous amplitude and RMS amplitude, characterization of the sand units in terms of reservoir geomorphological features, facies distribution and hydrocarbon potential was achieved. Seismic attribute results revealed (1) characteristic patterns of varying frequency and amplitude areas, (2) major control of hydrocarbon accumulation being structural, in terms of fault, (3) prospective stratigraphic pinch-out, lenticular thick hydrocarbon sand, mounded sand deposit and barrier bar deposit. Seismic Attributes analysis together with seismic structural interpretation revealed prospective structurally high zones with high sand percentage, moderate thickness and high porosity anomaly at the center of the field. The integration of different seismic attribute transforms and results from the study has improved our understanding of mapped sand units and enhanced the delineation of drillable locations which are not recognized on conventional seismic interpretations.

Quantitative Study on Bed Load Proppant Transport during Slickwater Hydraulic Fracturing

Abstract Bed load proppant transport is a significant phenomenon during slickwater hydraulic fracturing. However, the mechanism of bed load proppant transport is still unclear. In the present study, the proppant transport process during slickwater hydraulic fracturing was simulated with a coupled computational fluid dynamics- (CFD-) discrete element method (DEM) model, and the mechanism of the bed load proppant transport was analyzed. A model for calculating the mass flux of the bed load layer was proposed and verified with experimental results from the literature. The results show that bed load migration is an essential mechanism of proppant transport. When the shear force of fluid acting on the surface of the sand bank reaches the critical Shields number, the proppant in the upper layer of the sand bank begins to migrate in the form of bed load. The movement of the bed load layer increases the time for the sand bank to reach the equilibrium height. In addition, the mass flux of the bed load layer significantly affects the equilibrium height of the sand bank. The mass flux of the bed load layer decreases, and the equilibrium height increases as the proppant density, proppant diameter, or rolling friction coefficient and static friction coefficient of the proppant increase, but the mass flux of the bed load layer increases, and the equilibrium height decreases as the fluid viscosity increases.

LONG-TERM CHANGES IN THE AREA OF LAKES ON THE BAR OF THE TYLIGULSKYI LIMAN (BLACK SEA)

Problems Statement and Purpose. The estuarine area of Tyligulskyi Liman is located within the limits of north-western limans coastal area between the Odesa bay and Berezans’kyi Liman. Tyligulskyi Liman is separated from the sea by a wide sandy-shell bay-bar, in which an artificial liman-sea connecting channel is laid. The bay-bar of the Tyligulskyi liman is one of the most powerful sea-land contact zones in the region. The Tyligulskyi Liman and its bay-bar are officially recognized as Ramsar wetlands. The need to study and protect the bay-bar is associated with both its international status of the wetlands and the preservation of natural conditions and resources for the planning of nature management and sustainable development of the geosystem. The Lakes of the bay-bar were insufficiently studied in comparison with biota and hydrology of the adjacent part of the Black Sea, the Tyligulskyi Liman and the connecting channel. Data & Methods. The study of the water bodies of the Tyligulskyi Liman bay-bar was carried out by field and cameral methods. Field mapping and survey work were carried out, sediment samples were taken. The cartographic method made it possible to analyse the cartographic materials of 1793–1982 edition suitable for their decoding and analysis. GIS methods were used to process cartographic images, satellite images and field measurements. Cameral work was performed in ‘Saga Gis’ software. To study the numerical values of the dynamics and development of the water bodies at the Tyligulskyi Liman bay-bar, the total lake percentage is calculated. Results. The water bodies at the Tyligulskyi liman bay-bar exist and develop during all its forming time. In their development, they experienced significant changes along with changes of the bay-bar caused by the channel connecting the Black Sea with the Tyligulskyi Liman, individual lakes to an artificial channel. According to the genesis of the lake basin are presented on the bar the remaining coastal lakes, anthropogenic and anthropogenic-transformed. At the present stage, the water bodies’ development is determined by operation frequency of the artificial connecting channel, level fluctuations, up and down surges. The inflow of estuary water into the water bodies of the bay-bar is constant at all stages of their development, in contrast to its inflow from the sea. On the Tyligulskyi liman bay-bar, there are constantly three water bodies: the northern lake, a chain of central and eastern lakes, and the channel. Commissioning of the channel connecting the Black Sea with the Tyligulskyi liman has led to an increase in the total lake percentage of the bay-bar from 3.9–11.1% in its natural state to 20.4–26.5% at present. With all its insignificant parameters, the connecting channel performs a system-forming function – it provides water exchange and the functioning of the natural complexes of the inner part of the Tiligul bay-bar. Further research the lakes on sand bar will provide an understanding of the functioning of the Tyligulskyi Liman bay-bar from a geosystem point of view, which will contribute to sound rational nature management at the bay-bar, preservation of natural diversity and sustainable development of the territory.

Sequence stratigraphy, sedimentary characteristics of barrier coastal sedimentary system of the Benxi Formation (Gaoqiao area, Ordos basin) and favorable reservoir distribution

Benxi Formation is an abundant natural gas reservoir in Gaoqiao area. Therefore, it is essential to analyze the sequence and sedimentary characteristics of the Benxi Formation to predict the distribution of favorable gas reservoirs . After the comprehensive use of the core, thin section, drilling, and logging data, the sequence framework, sedimentary microfacies, planar distribution and vertical microfacies associations of the Benxi formation were studied. The Benxi Formation in the Gaoqiao area is barrier coastal sedimentary system, which is divided into eight sedimentary microfacies, namely, tidal delta, tidal channel, sand flat, mixed flat, mud flat, peat flat, barrier bar, and lagoon mud microfacies. In addition, we concluded that i) From west to east, peat flat, mud flat, mixed flat, sand flat, lagoon mud, and barrier bar have been developed in the study area. ii) Four typical vertical sequences were identified: MA1, MA2, MA1, and MA4. The first three sequences developed extensively and completely in the study area, whereas the last one generally has one or more microfacies missing. iii) The sedimentary system of the Benxi Formation in the Gaoqiao area was primarily vulnerable to tectonism, sequence, and sea-level changes. The Second Member was the target gas-producing stratum of the Formation. Both barrier bar and sand flat microfacies exhibited an excellent gas display. However, the barrier bar microfacies were the most favorable natural gas distribution zones with giant and premium gas reserves.

Facies analysis of the Quaternary fluvial system of Khor Eit, Red Sea coast, Sudan

This research article is a field-oriented facies analysis of Quaternary fluvial sediments of the ephemeral braided stream Khor Eit, located on the Sudanese Red Sea coast north of Port Sudan town. Although these sediments represent the main groundwater aquifers of the Red Sea coast of the Sudan, they have attracted less geoscientific attention. The present study is intended to fill part of this gap. Eleven fluvial facies were identified: three gravel facies, six sand facies and two mud facies. Based on the downstream geomorphic variation and systematic changes in the facies distribution, the study divides the Khor Eit into a proximal, middle and distal part. The high-energy flow regime in the proximal part is reflected in a characteristic fluvial facies association of channelized, sheet-like and erosive channelized gravel bodies and horizontally stratified gravels of the gravel bars. In the middle part, where the general slope becomes gentler, the facies display distinct fining-upwards dominated by scour-fill facies associations and elongated sheet-like interlayered sand dominated bodies. The fluvial sedimentation in the distal part is characterized by sheet-flood, and low-water accretionary deposits of thin interlayered sand and mud, and the mud drape facies associations. The analysis of the sedimentary architectural elements of the Khor Eit identified six major architectural elements: Gravel bars and bedforms (GB), Channels (CH), Sediment gravity flows (SG), Sandy bedforms (SB), Laminated sand sheets (LS) and Overbank fines (FF). Factors controlling sedimentation processes in the study area (rainfall, morphological aspects and vegetation cover) have been discussed. Identification and detailed documentation of the different fluvial facies types, facies associations the and the study of their lateral and vertical changes downstream allow the construction of a fluvial facies model for khor Eit.

Quick and cost-effective mapping of subsistence and artisanal fishing areas within and adjacent to a marine protected area

Spatial information on artisanal fisheries is largely lacking, making subsequent management and threat or impact assessments difficult. Local knowledge, current and readily available mapping software and Global Positioning System (GPS) techniques were used to map small-scale (subsistence and artisanal) fishing areas within and adjacent to the western boundary of the Ponta do Ouro Partial Marine Reserve in southern Mozambique. Data on habitat types were collected in the field and combined with available literature. Thirty-one fishing areas were identified and mapped resulting in a total area of 293.1 km2 with a perimeter of 396.7 km, from the Inhaca Island lighthouse in the north to the Maputo River mouth in the south. Habitats within the fishing areas included isolated intertidal sand banks, seagrass beds, estuarine channels, as well as intertidal muddy areas adjacent to the coast. The fishing areas covered on average 9.5 km2 (SD=12.0) and varied immensely in size (0.3–50.1 km2). Overall, 58.4 % (171.2 km2) of the total fishing area mapped was located inside the reserve. Costs associated with data collection equated to an average of U$D 3.61 per mapped km2 or U$D 2.63 per km tracked. The method was found to be quick, cost-effective and easily replicable elsewhere.

Quantitative Characterization of Tidal Couplets in Oil Sands Reservoir, the Upper McMurray Formation, Northeastern Alberta, Canada

AbstractThe McMurray Formation, NE Alberta, Canada, is one of the most significant bitumen bearing deposits worldwide. This formation deposited and reworked in fluvial, tidal, or estuarine environments results in a huge number of tidal couplets (TCs) which is consisted of mm-cm scale sandy and muddy interlayers. These couplets not only increase the geologic heterogeneity of the oil sand reservoir but also make it hard to predict the performance of in situ thermal processes. In this paper, based on literatures, lab analysis, core photos, logging, and drilling data, a quantitative characterization procedure for mm-cm scale tidal couplets was proposed. This procedure, which includes identification, classification, quantitative description, and spatial distribution prediction, was presented. Five parameters, thickness, mud volume, laminae frequency, spatial scale, and effective petrophysical properties, were selected to describe the TCs quantitatively. To show the procedure practically, TCs in the oil sand reservoir of McMurray Formation, Mackay River Project, and CNPC, were selected to demonstrate this procedure. The results indicate that the TCs are in mm-cm thickness, densely clustered, and in a variety of geometries. Based on geologic origins, these couplets were divided into four types: tidal bar couplets (TBCs), sand bar couplets (SBCs), mix flat couplets (MFCs), and tidal channel couplets (TCCs). The thickness, mud volume, and frequency were calculated by mathematical morphological processed core photos. The spatial scale of TCs was estimated by high-density well correlations. The effective petrophysical properties were estimated by bedding scale modeling and property modeling via REV. Finally, the spatial distribution of TCs was predicted by object-based modeling.

Lines in the Sand(bar): Collective Perspectives and Shifting Temporalities in Char... The No Man's Island

The tasks of documenting and narrating stories of climate change and border environments have become increasingly urgent in recent years, and discussions around effective approaches to environmental storytelling have intensified accordingly. The film Char… The No Man’s Island (2012), directed by Sourav Sarangi, is a noteworthy example of a work that seeks to represent one such unstable environment that exists on the border between India and Bangladesh and to explore the daily lives of the beings who inhabit it. Although the documentary has a specific regional focus, its scope is far from limited, as the film examines various dimensions of life in this border environment as well as the historical and political factors that have led to the current realities of the space and the communities established there. In this paper, I examine how Sarangi’s inclusion of a multitude of distinct human and non-human perspectives throughout the film signals a move towards a form of environmental storytelling grounded in the notion of a collective, wherein narrative agency is distributed amongst multiple entities rather than invested in a single individual. Moreover, the paper argues that the usage of these various perspectives also enables Char to depict alternate temporalities and experiences of time which contrast heavily with ideas of linear time and progress and invites audiences to consider the multifaceted temporal and spatial realities of life in a precarious border environment.

Coastal Wetland Shoreline Change Monitoring: A Comparison of Shorelines from High-Resolution WorldView Satellite Imagery, Aerial Imagery, and Field Surveys

Shoreline change analysis is an important environmental monitoring tool for evaluating coastal exposure to erosion hazards, particularly for vulnerable habitats such as coastal wetlands where habitat loss is problematic world-wide. The increasing availability of high-resolution satellite imagery and emerging developments in analysis techniques support the implementation of these data into shoreline monitoring. Geospatial shoreline data created from a semi-automated methodology using WorldView (WV) satellite data between 2013 and 2020 were compared to contemporaneous field-surveyed Global Position System (GPS) data. WV-derived shorelines were found to have a mean difference of 2 ± 0.08 m of GPS data, but accuracy decreased at high-wave energy shorelines that were unvegetated, bordered by sandy beach or semi-submergent sand bars. Shoreline change rates calculated from WV imagery were comparable to those calculated from GPS surveys and geospatial data derived from aerial remote sensing but tended to overestimate shoreline erosion at highly erosive locations (greater than 2 m yr−1). High-resolution satellite imagery can increase the spatial scale-range of shoreline change monitoring, provide rapid response to estimate impacts of coastal erosion, and reduce cost of labor-intensive practices.