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Based on the comparison of zircon ages with source terranes, they inferred that the likely source for Cenozoic zircon grains was the Eastern Alkaline Province of Mexico, which comprises various volcanic fields of Cenozoic age. Armstrong-Altrin et al. (2021) reported the detrital zircon grain surface features, chemistry, and U-Pb ages in the Chachalacas beach sediments, Gulf of Mexico. Armstrong-Altrin et al. (2020) discussed the U-Pb ages of detrital zircon grains, which we reported from the Chachalacas beach in the western Gulf of Mexico. [Extracted from the article]

We utilize a coupled economy–agroecology–hydrology modeling framework to capture the cascading impacts of climate change mitigation policy on agriculture and the resulting water quality cobenefits. We analyze a policy that assigns a range of United States government’s social cost of carbon estimates ($51, $76, and $152/ton of CO2-equivalents) to fossil fuel–based CO2 emissions. This policy raises energy costs and, importantly for agriculture, boosts the price of nitrogen fertilizer production. At the highest carbon price, US carbon emissions are reduced by about 50%, and nitrogen fertilizer prices rise by about 90%, leading to an approximate 15% reduction in fertilizer applications for corn production across the Mississippi River Basin. Corn and soybean production declines by about 7%, increasing crop prices by 6%, while nitrate leaching declines by about 10%. Simulated nitrate export to the Gulf of Mexico decreases by 8%, ultimately shrinking the average midsummer area of the Gulf of Mexico hypoxic area by 3% and hypoxic volume by 4%. We also consider the additional benefits of restored wetlands to mitigate nitrogen loading to reduce hypoxia in the Gulf of Mexico and find a targeted wetland restoration scenario approximately doubles the effect of a low to moderate social cost of carbon. Wetland restoration alone exhibited spillover effects that increased nitrate leaching in other parts of the basin which were mitigated with the inclusion of the carbon policy. We conclude that a national climate policy aimed at reducing greenhouse gas emissions in the United States would have important water quality cobenefits. [ABSTRACT FROM AUTHOR]

The Gulf of Mexico (GOM) is a regionally important marine ecosystem with valuable fisheries that may be detrimentally impacted by anthropogenic climate change. In recent years, our scientific understanding of climate change impacts on the GOM water quality has advanced considerably. Such advancements include increased understanding of climate change impacts on the GOM's hypoxia and sediment, and subsequent impacts on the region's marine ecosystem. This paper reviews these developments and highlights gaps in our understanding of climate change impacts on marine water quality and its implications in the GOM region. There is broad scientific agreement that physical changes induced by anthropogenic climate change are determining factors of water quality and biodiversity in the GOM. However, the scientific community should work toward a greater understanding of species and ecosystem specific changes through modeling studies exclusive to the GOM region and this should inform the development of broader multi-disciplinary mitigation strategies. [ABSTRACT FROM AUTHOR]

The cornerstone assumption of all Flood Geology models is that rocks can form quickly (i.e., within the timeframe of months to years). However, to date, only isolated examples from the field have been used to support the hypothesis without any quantitative justification. This paper therefore presents the theoretical basis (originally set out by Terzaghi, 1922) for determining the timescales for the first phase of lithification, the mechanical compaction of the sediment under its self-weight (otherwise known as consolidation). The paper demonstrates that when basic soil mechanics theory is applied to the consolidation of thick clay layers of the order of 1,000 m such as those found in the North Sea, Gulf of Mexico, and the Caspian Sea, the timescales predicted for compaction are orders of magnitude greater than is currently assumed. Additionally, it is shown that there is a physical limit to the rate at which sediment can accumulate without creating excessive pore pressure and inducing geotechnical failures. For clay, this limit is approximately 0.1 m/yr, and, for silt, approximately 10 m/yr. [ABSTRACT FROM AUTHOR]

This paper shows the observation and estimation of convective wind gusts by different satellite sensors at the C-band (Sentinel-1 SAR) and L-band (ALOS-1 SAR and SMAP radiometer) over Lake Victoria, the Gulf of Guinea, and the Gulf of Mexico. These areas are significantly impacted by deep convection associated with strong surface winds and heavy rainfall. In particular, the collocation of Sentinel-1 and SMAP images enables the observation of the movement of surface wind gusts corresponding to that of deep convective clouds. The convective wind intensity estimated from Sentinel-1 and SMAP data varies from 10 to 25 m/s. Additionally, we present an agreement in the observation of deep convective clouds, dynamics, and strong surface winds by different satellite sensors, including Meteosat geostationary (GEO), Aeolus Lidar, and Sentinel-1 SAR, respectively. We also evaluate the estimated convective wind gusts by comparison with the in situ measurements of the weather stations installed in the Gulf of Mexico, where deep convection occurs regularly. The result shows an agreement between the two wind sources estimated and measured. Likewise, the peaks of the measured wind gusts correspond to the occurrence of deep convective clouds observed by the GOES-16 GEO satellite. [ABSTRACT FROM AUTHOR]

The storage potential of hydrocarbon reservoirs in the central Gulf of Mexico (GOM) makes future development of CO2 storage projects in those areas promising for secure, large-scale, and long-term storage purposes. Focusing on the producing and depleted hydrocarbon fields in the continental slope of the central GOM, this paper analyzed, assessed, and screened the producing sands and evaluated their CO2 storage potential. A live interactive CO2 storage site screening system was built in the SAS® Viya system with a broad range of screening criteria combined from published studies. This offers the users a real-time assessment of the storage sites and enables them to adjust the filters and visualize the results to determine the most suitable filter range. The CO2 storage resources of the sands were estimated using a volumetric equation and the correlation developed by the National Energy Technology Laboratory (NETL). The results of this study indicate that 1.05 gigatons of CO2 storage resources are available in the developed reservoirs at the upper slope area of the central GOM. The Mississippi Canyon and Green Canyon protraction areas contain the fields with the largest storage resources. [ABSTRACT FROM AUTHOR]

Vessel electronic monitoring (EM) systems used in fisheries around the world apply a variety of cameras to record catch as it is brought on deck and during fish processing activities. In EM work conducted by the Center for Fisheries Electronic Monitoring at Mote (CFEMM) in the Gulf of Mexico commercial reef fish fishery, there was a need to improve upon current technologies to enhance camera views for accurate species identification of large sharks, particularly those that were released while underwater at the vessel side or underneath the hull. This paper describes how this problem was addressed with the development of the first known EM system integrated underwater camera (UCAM) with a specialized vessel-specific deployment device on a bottom longline reef fish vessel. Data are presented based on blind video reviews from CFEMM trained reviewers of the resulting UCAM video footage compared with video from only the overhead EM cameras from 68 gear retrievals collected from eight fishing trips. Results revealed that the UCAM was a successful tool for capturing clear underwater video footage of released large (>2m) sharks to enable reviewers to improve individual species identification, determination, and fate by 34.4%. This was particularly important for obtaining data on incidental catches of large protected shark species. It also provided clear underwater imagery of the presence of potential predators such as marine mammals close to the vessel, more specifically bottlenose dolphin (Tursiops truncatus) during gear retrieval, which often damaged or removed catch. This information is intended to assist researchers in need of gathering critical data on bycatch in close proximity to a vessel in which conventional overhead EM cameras are limited. [ABSTRACT FROM AUTHOR]

This paper for the first time, to the best of our knowledge, reports 10 case histories of jack-up rig installation in different locations of the Gulf of Mexico consisting of seabed soil stratigraphy with weak surface (soft) clay over strong (stiff) clay or sand underlying layers. For each case, site investigation data are analyzed, leading to the selection of design undrained shear strength profile for the clay layers and relative density for the sand layers. A statistical averaging method recommended in the InSafeJIP guidelines (adopted in ISO 19905-1) is used to obtain the best fit of the undrained shear strength profile in the clay layers. The spudcan shape and dimensions and load-penetration profiles are presented. Measured load-penetration profiles are compared with the calculated profiles using the squeezing methods presented in ISO 19905-1, Clarom, and recently published papers. Large deformation finite element analyses were conducted for some sites to provide supporting insight into the penetration resistance profiles and potentially mobilized squeezing mechanisms. The lessons learned are noted, which will provide valuable insights for practitioners for estimating the behavior of jack-up installations in seabed soil consisting of surface weak-over-underlying strong soil stratigraphy. [ABSTRACT FROM AUTHOR]

A content analysis challenges the notion that elite newspapers can speak for local dailies. Gulf dailies focused on the environment until the well was capped and then shifted to the local economy, while the national dailies focused on the accident. [ABSTRACT FROM AUTHOR]

Natural methane hydrate has often been observed in sand layers that contain no particulate organic carbon (POC), but are surrounded by organic-rich, fine-grained marine muds. In this paper, we develop a reactive transport model (RTM) of a microbially-mediated set of POC degradation reactions, including hydrolysis of POC driven by extracellular enzymes, fermentation of the resulting high-molecular weight dissolved organic carbon (HMW-DOC), and methanogenesis that consumes low-molecular weight dissolved organic carbon (LMW-DOC). These processes are mediated by two groups of microbes, fermenters and methanogens that are heterogeneously distributed in different lithologies, with the largest numbers of microbes in the large pores of coarse-grained layers. We find that the RTM can reproduce methane hydrate occurrences observed in two different geological environments, at Walker Ridge Site 313-H (Gulf of Mexico) and IODP Site U1325 (Cascadia Margin). We also find that microbes can degrade POC even if they are physically separated, as extracellular enzymes and DOC can diffuse away from where they are produced by microbes. Microbial activity is highest at relatively early times after burial at shallow depths and near lithological boundaries, where concentration gradients transport solutes to intervals that contain the most microbes. [ABSTRACT FROM AUTHOR]

The dryline, often associated with the development of severe storms in the Southern Great Plains of the United States of America, is a boundary layer phenomenon that occurs when a warm and moist air mass from the Gulf of Mexico meets a hot and dry air mass from the southwest desert area. An accurate knowledge of the water vapor spatio-temporal variability in the lower part of the atmosphere is crucial for a better understanding of the evolution of the dryline. The tropospheric refractivity, directly related to water vapor content, is a proxy for the water vapor content of the troposphere. It has already been demonstrated that the refractivity and the refractivity vertical gradient can be jointly estimated from radar phase measurements. In fact, it has been shown that using kriging interpolation techniques, accurate refractivity maps within the coverage area of the radar can be obtained with high temporal resolution. In this paper, a detailed analysis of the time series of radar-based refractivity maps obtained during a dryline that occurred on the afternoon of 22 May 2002 during the International H 2 O Project ( I H O P _ 2002 ) is presented. Comparisons between the time series of radar refractivity maps, obtained with the NCAR S-Pol radar, and the refractivity measurements derived from automatic ground-based weather stations and the AERI instrument, placed at different locations within the coverage area of the NCAR S-Pol radar, demonstrate the accuracy of radar refractivity estimates even for highly variable conditions, both in time and space, in the troposphere. Correlation coefficients higher than 0.95 are obtained in all weather station locations. Regarding the RMSE, errors less than 6 N-units are obtained for all cases, being even as low as 2.92 N-units at some locations. [ABSTRACT FROM AUTHOR]

Previous studies have demonstrated that the influence of the El Niño–Southern Oscillation (ENSO) on the Euro-Atlantic atmospheric circulation varies considerably during the boreal winter. Compared to the late winter (January–March) relationship, the early winter (November–December) teleconnection is more uncertain and less understood. In this paper, we revisited this early winter regional ENSO teleconnection using the Hadley Centre Global Sea Ice and Sea Surface Temperature (HadISST) and the European Centre for Medium-Range Weather Forecasting (ECMWF) fifth generation reanalysis (ERA5) datasets for the period 1979–2022. It was found that the signal projected well onto the second dominant mode of Euro-Atlantic atmospheric variability, the East Atlantic Pattern (EAP), rather than the previously mentioned North Atlantic Oscillation (NAO). This influence is associated with ENSO-induced dipolar convection anomalies in the Gulf of Mexico and Caribbean Sea (GMCA), which leads to an EAP via exciting Rossby waves propagating northward into the North Atlantic. We further revealed that this ENSO–EAP teleconnection underwent a pronounced interdecadal strengthening around the late 1990s. Prior to the late 1990s, the convective response to ENSO in the GMCA was weak. The atmospheric responses over the Euro-Atlantic were mainly driven by the ENSO-induced convective forcing in the tropical Indian Ocean, which favors an NAO-like pattern. In contrast, since the late 1990s, ENSO has induced stronger precipitation anomalies in the GMCA, which exert a dominant influence on the Euro-Atlantic atmospheric circulation and produce an EAP. These results have useful implications for the further understanding of ENSO-related early winter atmospheric and climate variability in the Euro-Atlantic region. [ABSTRACT FROM AUTHOR]

Simple Summary: This study reports the results of a multidisciplinary research on Mediterranean pelagic octopods belonging to the species Argonauta argo, Ocythoe tuberculata, Tremoctopus gracilis and Tremoctopus violaceus for the first time. The study area was the Strait of Messina and southern Tyrrhenian Sea. We used information from stranding events, accidental fishing catches and stomach contents of large predators (albacore, bluefin tuna, swordfish and Mediterranean spearfish). We analysed 47 fresh octopods, including exceptional records of rare males, and 330 individuals found in the stomachs of 800 predators. The analysis of genetic aspects was used to provide further details on the life and identity of these species. The present paper represents the first all-encompassing study on all Mediterranean holopelagic octopods belonging to Argonautoidea (Argonauta argo, Ocythoe tuberculata, Tremoctopus gracilis, Tremoctopus violaceus). Argonautoidea octopuses were collected by different sampling methods in the Strait of Messina and southern Tyrrhenian Sea. The aim of this paper was to improve knowledge, using information from different data sources, such as the study of stranded individuals or accidental caught specimens, as well as the analysis of stomach content of large pelagic fishes. Moreover, we investigated their taxonomic profile through the amplification of the mitochondrial cytochrome c oxidase subunit I (COI). Overall, 47 fresh holopelagic octopods were collected, including valuable records of rare males. Moreover, 330 Argonautoidea octopuses were found in the stomachs of 800 predators. The results provided evidence that these cephalopods are more abundant than thought in the past. The molecular approach supported the ecological results with interesting insights. The similarity-based identifications and tree-based methods indicated that three females could be identified as Tremoctopus violaceus in agreement with their morphological classifications. The sequences obtained from the two T. gracilis individuals were clustered with the sequences of Tremoctopus violaceus from the Gulf of Mexico and were differentiated from the sequences attributed to T. gracilis and T. robsoni. The study represents a valuable contribution to the genetic characterization of Mediterranean individuals of the genera Tremoctopus, Argonauta and Ocythoe. [ABSTRACT FROM AUTHOR]

Information on recreation site amenities is often sparse. Not only does this information scarcity have the potential to limit recreation activity, particularly if it causes users to forego recreation opportunities, but it also limits the ability of coastal communities to best allocate resources across site amenities to meet the needs of current and potential users and maximize the value of marine resources. In this paper, we estimate travel cost models that make use of a new dataset on fishing site characteristics to investigate the degree to which a large vector of amenities influences the site choice decisions of recreational anglers fishing in the Gulf of Mexico. We also uncover an important role of racial, ethnic, and income diversity considerations in recreation decision-making. We contextualize the valuation estimates, and combined with the findings of angler tendencies to avoid diversity, discuss the implications for coastal resource management. [ABSTRACT FROM AUTHOR]

The Sustainable Development Goals Science Satellite-1 (SDGSAT-1) Glimmer Imager for Urbanization (GIU) data is very sensitive to low radiation and capable of detecting weak light sources from vessels at night while significantly improving the spatial resolution compared to similar products. Most existing methods fail to use the relevant characteristics of vessels effectively, and it is difficult to deal with the complex shape of vessels in high-resolution Nighttime Light (NTL) data, resulting in unsatisfactory detection results. Considering the overall sparse distribution of vessels and the light source diffusion phenomenon, a novel vessel detection method is proposed in this paper, utilizing the high spatial resolution of the SDGSAT-1. More specifically, noise separation is completed based on a local contrast-weighted RPCA. Then, artificial light sources are detected based on a density clustering algorithm, and an inter-cluster merging method is utilized to realize vessel detection further. We selected three research areas, namely, the Bohai Sea, the East China Sea, and the Gulf of Mexico, to establish a vessel dataset and applied the algorithm to the dataset. The results show that the total detection accuracy and the recall rate of the detection algorithm in our dataset are 96.84% and 96.67%, which is significantly better performance than other methods used for comparison in the experiment. The algorithm overcomes the dataset's complex target shapes and noise conditions and achieves good results, which proves the applicability of the algorithm. [ABSTRACT FROM AUTHOR]

The thin layers in the ocean are temporally-coherent aggregations of phytoplankton with high concentrations at small vertical scales, presenting important hotspots of ecological activity. Lidar could identify thin phytoplankton layers at a large spatial scale due to its capabilities of profile detection with a high efficiency. However, studies that linked thin layers to environmental factors are few, which limits our understanding of the layer formation mechanism. This paper investigates the characteristics and formation conditions of thin phytoplankton layers in the northern Gulf of Mexico using airborne lidar. The results depict that the chlorophyll concentration determines the formation probability of the phytoplankton layer. The layer is mainly formed at concentrations less than 6 mg m−3 and mostly distributed at 2 mg m−3. In addition, layer thicknesses were within 5 m and layer depths were mainly in the range of 10–15 m. Layer depths in the nearshore region were shallower than those in the offshore region. We conclude that the characteristics and formation conditions of the thin phytoplankton layers depend on the nutrients and light that are related to the seabed topography, turbidity, eddies and upwelling. The findings of this paper will enhance the understanding of layer formation mechanisms. [ABSTRACT FROM AUTHOR]

The recycling or burial of carbon dioxide in depleted petroleum reservoirs and re-imagining exploration strategies that focus on hydrogen reservoirs (with any associated hydrocarbon gas as the upside potential) are a necessity in today's environmental and geopolitical climate. Given that geologic hydrogen and hydrocarbon gases may occur in the same or different reservoirs, there will be gains in efficiency when searching for both resources together since they share some commonalities, but there is no geophysical workflow available yet for this purpose. Three-dimensional (3D) marine controlled-source electromagnetic (CSEM) and magnetotelluric (MT) methods provide valuable information on rock-and-fluid variations in the subsurface and can be used to investigate hydrogen and hydrocarbon reservoirs, source rocks, and the migration pathways of contrasting resistivity relative to the host rock. In this paper, a process-oriented CSEM-MT workflow is proposed for the efficient combined investigation of reservoir hydrocarbon and hydrogen within a play-based exploration and production framework that emphasizes carbon footprint reduction. It has the following challenging elements: finding the right basin (and block), selecting the right prospect, drilling the right well, and exploiting the opportunities for sustainability and CO2 recycling or burial in the appropriate reservoirs. Recent methodological developments that integrate 3D CSEM-MT imaging into the appropriate structural constraints to derive the geologically robust models necessary for resolving these challenges and their extension to reservoir monitoring are described. Instructive case studies are revisited, showing how 3D CSEM-MT models facilitate the interpretation of resistivity information in terms of the key elements of geological prospect evaluation (presence of source rocks, migration and charge, reservoir rock, and trap and seal) and understanding how deep geological processes control the distribution and charging of potential hydrocarbon, geothermal, and hydrogen reservoirs. In particular, evidence is provided that deep crustal resistivity imaging can map serpentinized ultramafic rocks (possible source rocks for hydrogen) in offshore northwest Borneo and can be combined with seismic reflection data to map vertical fluid migration pathways and their barrier (or seal), as exemplified by the subhorizontal detachment zones in Eocene shale in the Mexican Ridges fold belt of the southwest of the Gulf of Mexico, raising the possibility of using integrated geophysical methods to map hydrogen kitchens in different terrains. The methodological advancements and new combined investigative workflow provide a way for improved resource mapping and monitoring and, hence, a technology that could play a critical role in helping the world reach net-zero emissions by 2050. [ABSTRACT FROM AUTHOR]

The Gulf of Mexico (GOM) is a semi-closed basin that supports high marine biodiversity, and is also an important economic area where the Exclusive Economic Zones (EEZs) of the United States, Mexico and Cuba converge. Twenty-one species of cetaceans are commonly sighted in the GOM, and although the population traits of most species are well known in the U.S. EEZ, the development of regional management plans complicated because of the apparent lack of ecological data in the Mexican EEZ, which comprises about 50% of the entire GOM. The state of knowledge of cetaceans in Mexican waters was reviewed to identify current research trends and gaps. The results clearly show that the Mexican research effort is focused on a few coastal popu- lations of a single species, the bottlenose dolphin Tursiops truncatus), while the offshore cetacean populations are ignored; therefore, there are insuf- ficient data to assess diversity, distribution, and abundance. Moreover, due to the high mobility of cetaceans and the transboundary nature of their ranges, the scientific community is currently not prepared to detect population trends in cetacean populations of the GOM. To accomplish this, two priorities were identified: (1) to expand and refo- cus the Mexican research capabilities, and (2) to implement binational monitoring programs. [ABSTRACT FROM AUTHOR]

Over the past decade, Multibeam Echosounders (MBES) have become one of the most used techniques in sea exploration. Modern MBES are capable of acquiring both bathymetric information on the seafloor and the reflectivity of the seafloor and water column. Water column imaging MBES surveys acquire significant amounts of data with rates that can exceed several GB/h depending on the ping rate. These large file sizes obtained from recording the full water column backscatter make remote transmission difficult if not prohibitive with current technology and bandwidth limitations. In this paper, we propose an algorithm to decorrelate water column and bathymetry data, focusing on the KMALL format released by Kongsberg Maritime in 2019. The pre-processing stage is integrated into FAPEC, a data compressor originally designed for space missions. Here, we test the algorithm with three different datasets: two of them provided by Kongsberg Maritime and one dataset from the Gulf of Mexico provided by Fugro USA Marine. We show that FAPEC achieves good compression ratios at high speeds using the pre-processing stage proposed in this paper. We also show the advantages of FAPEC over other lossless compressors as well as the quality of the reconstructed water column image after lossy compression at different levels. Lastly, we test the performance of the pre-processing stage, without the constraint of an entropy encoder, by means of the histograms of the original samples and the prediction errors. [ABSTRACT FROM AUTHOR]

The Gulf of Mexico is a widely explored and producing region for offshore oil and gas resources, with significant submarine methane hydrates. Estimates of hydrate saturation and distribution rely on drilling expeditions and seismic surveys that tend to provide either large-scale estimates or highly localized well data. In this study, hydrate reserve characterization is done using numerical simulation at Green Canyon block 955 (GC955). In addition, coupled thermo-hydro-mechanical (THM) simulation results show that hydrate saturation and geobody distribution are determined by the thermodynamic conditions as well as reservoir structures, stratigraphic differences, and permeability differences. Hydrate formation due to upflow of free gas and dissociation due to gas production and oceanic temperature rise due to climate change are simulated. The abundance of free gas under the hydrate stability zone and favorable pressure and temperature meant little hydrate was depleted from the reservoir. Furthermore, the maximum displacement due to warming reached 0.5 m in 100 years and 4.2 m in 180 days based on a simulation of constant production of methane gas. The displacement direction and magnitude suggest that there is little possibility of slope failure. Therefore, the GC955 site studied in this paper can be considered a favorable site for potential hydrate exploitation. [ABSTRACT FROM AUTHOR]

This paper reports 12 species of Costellariidae and 6 species of Mitridae dredged by the R/V Pelican in the Gulf of Mexico off the coasts of Louisiana, Mississippi, Alabama, Florida and Bahía de Campeche, Mexico, between 1996 and 2019. Each species is accompanied by accurate coordinates and depth and, in most cases, benthic composition. [ABSTRACT FROM AUTHOR]

The geotechnical design of partially mobile subsea foundations (mudmats) for pipeline/flowline end terminals (PLETs) is presented in this paper. A partially mobile mudmat represents a fit-for-purpose engineering solution that has significant commercial competitiveness. The partially mobile design lies between that of a fully anchored mudmat (which is designed for negligible movements but may be too large, causing installation issues or requiring corner piles to anchor) and a fully mobile mudmat (which moves to fully accommodate the expansion of the connected pipeline, but may suffer excessive settlements that compromise the structural integrity). The partially mobile mudmat is suited to deepwater soft soil conditions. The aim of this work is to help mature this new concept and technology for practical design and to inspire future research to improve the accuracy of predictions. The objective of the paper is to present simple new analytical solutions to predict the long-term accumulated displacements and rotations of a partially mobile mudmat on soft clayey deposits subjected to cyclic loading. The proposed displacement prediction framework combines established elements of consolidation theory, plasticity theory, and critical-state soil mechanics (CSSM). Typical ranges of soil properties pertinent to a partially mobile mudmat are provided for deepwater Gulf of Mexico (GoM) soft clays, and a design analysis example is provided. For these conditions, it is concluded that the dominant displacements of a partially mobile mudmat are caused by primary consolidation and plastic failure. Recommendations for further improvement are provided to inspire further research. [ABSTRACT FROM AUTHOR]

We present information about new records of 11 species of chondrichthyans in the southern Gulf of Mexico, adding information about new specimens and occurrence of the species in Mexican waters. The second record of the Bathytoshia centroura, Mustelus sinusmexicanus, Mobula hypostoma and Squalus clarkae species for Mexico is presented, as well as new records in marine areas and the Lagoon Alvarado system corresponding to Hexanchus vitulus, Heptranchrias perlo, Scyliorhinus retifer and Squalus cubensis. In this paper increase the number of records for species of elasmobranchs to the southwestern region of the Gulf of Mexico, increase the distribution range and knowledge about the chondrichthyofauna of Mexico. [ABSTRACT FROM AUTHOR]

The gas plume is a direct manifestation of sea cold seep and one of the most significant symbol indicators of the presence of gas hydrate reservoirs. The multibeam water column (MWC) data can be used to extract and identify the gas plume efficiently and accurately. The current research methods mostly start from the perspective of image theory, which cannot identify the three-dimensional (3D) spatial structure features of gas plumes, reducing the efficiency and accuracy of detection. Therefore, this paper proposes a method for identifying and extracting the gas plume based on an MWC point cloud model, which calculates the spatially resolved homing of MWC data and constructs a 3D point cloud model of MWC containing acoustic reflection intensity information. It first performs noise suppression of the 3D point cloud of the MWC based on the symmetric subtraction and Otsu algorithm by leveraging the noise distribution of the MWC and the reflection intensity characteristics of the gas plume. Then, it extracts the point cloud clusters containing the gas plume based on Density-Based Spatial Clustering of Applications with Noise (DBSCAN) according to the density difference between the gas plume point cloud and the background MWC point cloud and next identifies the point cloud clusters by feature matching based on fast point feature histograms (FPFHs). Finally, it extracts the gas plume point cloud set in the MWC. As evidenced by the MWC data collected from gas hydrate enrichment zones in the Gulf of Mexico, the location of gas plume extracted by this method is highly consistent with that of gas leakage points measured during the cruise. Using this method, we obtained the point cloud data set of gas plume for the first time and accurately characterized the 3D spatial morphology of the subsea gas plume, providing technical support for gas hydrate exploration, subsea gas seepage area delineation, and subsea seepage gas flux estimation. [ABSTRACT FROM AUTHOR]

In this paper, we study the materials used for the construction of earthen structure in the La Joya archaeological site, on the Gulf of Mexico coast, built on top of a paleodune, from the Late Preclassic (400 BC) to the Classic period (AD 100-1000). The first constructions arise around 100 BC, on a paleodune top rising slightly above the surrounding alluvial terraces of the Jamapa river; then it grows into a 15-ha monumental compound. The total construction volume reaches 250,000 m3, all made of earth, surrounded by large artificial water pounds (reservoirs). To understand the kind of components found in the structures and their provenance, we compare the micromorphological features of the materials from the earthen constructions with the sediments and paleosols located in the surrounding areas. Samples were taken from the fills of three first building stages, as well as from a natural soil profile and the natural paleosol horizons found beneath the structures. Micromorphological features found in fills permit to establish the correlation between them and their parent material. The fills from the first stage of construction have fragments of a Btb horizon, mixed with an A horizon, compacted and crushed, in which abundant artifacts are identified. However, these artifacts were not intentionally incorporated to the fills, but had been accumulated on the pre-occupation A horizon as residential and agriculture trash. Particular attention was paid to a gley material occurring in the third building stage, that was believed to come from the sediments accumulated in the original borrow pits transformed into water reservoirs, enclosing the main architectural compound. These reservoir fills share properties of the natural sediments and paleosols but transformed by the waterlogging conditions. In consequence, these materials are interpreted as a case of anthropogenic pedogenesis, where the gley micromorphology indicates waterlogging conditions, but in artificially made reservoirs, as they do not have dark organic sediments that would result of the vegetation typical of a natural pond in a humid tropical environment. [ABSTRACT FROM AUTHOR]

• Decision-making processes of GCS projects in saline aquifers require a multitude of forward reservoir simulations. • DL surrogate models ease the computational cost of GCS management and operation optimization. • A DL-based workflow incorporating dimension reduction methods was proposed. • A novel strategy was proposed for effective dimension reduction and reconstruction of 3D CO2 saturation data. • The results suggest the proposed workflow provides sufficient predictive fidelity across temporal and spatial scales. Deep learning (DL) models are extensively used as surrogate models for high-fidelity simulations of multiphase fluid flow in porous media at large scales, enabling fast forecasts of the spatial–temporal evolution of three-dimensional (3D) state variables in geological carbon storage (GCS). However, training these models in high-dimensional space remains computationally demanding and prone to overfitting because of limited training data. This paper presents a novel workflow to address these challenges by integrating dimension reduction (DR) methods. The proposed workflow employed pre-trained DR models to extract the latent variables of geological models and state variables and utilized the multi-layer perceptron (MLP) for constructing mapping functions between the input and output variables in latent spaces. Subsequently, the pre-trained reconstruction models converted the MLP-predicted latent state variables to their original high-dimensional form. Furthermore, we proposed a novel strategy for the DR and reconstruction of 3D saturation fields to account for the unique data characteristics of sparsity, nonuniformity, and discontinuity. The proposed strategy applied PCA and inverse PCA for 2D average saturation fields and developed a DL-based 3D reconstruction model, leveraging three 2D average saturation fields as input to produce a 3D saturation field as output. The pre-training of DR and reconstruction models and training of MLP models were conducted on 84 Gulf of Mexico (GoM) simulations and evaluated on 12 testing simulations. Each simulation contained 720 monthly time steps, with the first 360 months as the injection period and the rest as the post-injection period. The proposed workflow, incorporating DR and DL models, accurately predicts the normalized 3D pressure fields, achieving mean square error (MSE) of 2.92 × 10−7 compared to the ground truth obtained from a full-physics simulator. Furthermore, the proposed strategy outperformed PCA and convolutional autoencoder (CAE) models on 3D saturation fields, resulting in minor workflow prediction errors with an MSE of 2.93 × 10−5. The results suggest the proposed workflow provides sufficient predictive fidelity across temporal and spatial scales, and enables a speedup of 160 times compared to the full-physics simulator, facilitating improved decision-making and risk assessment for large-scale GCS management in real-time scenarios. [ABSTRACT FROM AUTHOR]

The small Lumbrineridae Gallardoneris iberica Martins, Carrera-Parra, Quintino & Rodrigues, 2012 was first described as new to science based on specimens from Portuguese waters. Then, it was successively reported from several south European areas, including Spain, Italy, Greece, and Cyprus. Here evidence is presented that G. iberica should be placed in synonymy with Lumbrineris nonatoi Ramos, 1976, originally described from NW Mediterranean waters, a species that fits with the diagnosis of Gallardoneris. Based on specimens from the French coasts of the NW Mediterranean, this paper (1) redescribes the species using the new combination Gallardoneris nonatoi (Ramos, 1976) and (2) provides a morphometric analysis of its main morphological characters. The lack of recent reports of G. nonatoi comb. nov. in Mediterranean waters is presumably due to the recent redescription of the species as L. nonatoi based on specimens from the Gulf of Mexico. However, these specimens belong to Lumbrineris, as currently defined. By assessing their morphological differences, it is concluded that the specimens from the Gulf of Mexico represent a different and new species, namely Lumbrineris jan sp. nov. Also discussed is the possible assignation of Lumbrineris longipodiata Cantone, 1990, a poorly known species seldom recorded since its original description from the Gulf of Catania (Mediterranean Sea) to Gallardoneris, as well as on whether it is a valid species or may be an additional junior synonym of G. nonatoi comb. nov. [ABSTRACT FROM AUTHOR]

The data set represents the Regional Meteoric Water Line (RMWL) for the Yucatan Peninsula (Mexico), a region with karstic aquifers but little knowledge of the isotopic composition of meteoric water. This data paper comprises the isotopic composition of meteoric water collected from November 2018 to November 2019 as monthly composite samples expressed as weighted monthly mean precipitation from 16 locations across the Yucatan Peninsula. The RMWL was δ2H = 7.803 δ18O + 12.075, with a slope and intercept suggesting precipitation from air that has undergone condensation, air masses with variable moisture or recycled moisture. The average δ18O is −2.57‰ (−12.23 to 1.2‰) and δ2H is −7.94‰ (−83.39 to 18.32‰). This data set was collected by the implementation of an isotopic monitoring network, gathering information useful as a tool for better understanding of the hydrology and hydrogeochemistry of karstic aquifers, and to develop proxies for paleohydrology, ecohydrology, climate change and paleoclimate studies in the Gulf of Mexico and the Great Caribbean Area. [ABSTRACT FROM AUTHOR]

Offshore infrastructure often interacts cyclically with the seabed over the operational life of a project. Previous research on the evolution of soil's undrained strength under long-term, large-amplitude cyclic loading has focused on contractile clays and demonstrated that this cyclic interaction can lead to the initial generation and later dissipation of positive excess pore pressure in the soil. This process generally leads to an initial strength reduction, with subsequent densification and soil strength gains that can have consequences on the performance of seabed infrastructure during its design life. In this paper, new experimental data from T-bar penetrometer testing in kaolin and reconstituted Gulf of Mexico clays is presented. The data illustrate how the stress history, quantified via the overconsolidation ratio, affects soil strength changes during large-amplitude cyclic loading. The experiments explore both long-term continuous loading cycles and episodic loading with packets of undrained cycles followed by quiescent consolidation periods. A critical state-based framework is used to interpret the experimental data and provide predictions of the long-term steady-state strength of both soils as a function of the initial in situ state of the soil. [ABSTRACT FROM AUTHOR]

This review covers selected 2019 articles on the biological effects of pollutants, including human physical disturbances, on marine and estuarine plants, animals, ecosystems, and habitats. The review, based largely on journal articles, covers field, and laboratory measurement activities (bioaccumulation of contaminants, field assessment surveys, toxicity testing, and biomarkers) as well as pollution issues of current interest including endocrine disrupters, emerging contaminants, wastewater discharges, marine debris, dredging, and disposal. Special emphasis is placed on effects of oil spills and marine debris due largely to the 2010 Deepwater Horizon oil blowout in the Gulf of Mexico and proliferation of data on the assimilation and effects of marine debris microparticulates. Several topical areas reviewed in the past (e.g., mass mortalities ocean acidification) were dropped this year. The focus of this review is on effects, not on pollutant sources, chemistry, fate, or transport. There is considerable overlap across subject areas (e.g., some bioaccumulation data may be appeared in other topical categories such as effects of wastewater discharges, or biomarker studies appearing in oil toxicity literature). Therefore, we strongly urge readers to use keyword searching of the text and references to locate related but distributed information. Although nearly 400 papers are cited, these now represent a fraction of the literature on these subjects. Use this review mainly as a starting point. And please consult the original papers before citing them. [ABSTRACT FROM AUTHOR]

Oil spills on the ocean surface are a serious threat to the marine ecosystem. Automation of oil spill detection through full/dual polarimetric Synthetic Aperture Radar (SAR) images is considered a good aid for oil spill disaster management. This paper uses the power of log transformation to discern the scattering behavior more effectively from the coherency matrix (T3). The proposed coherency matrix is tested on patches of the clean sea surface and four different classes of oil spills, viz. heavy sedimented oil, thick oil, oil-water emulsion, fresh oil; by analyzing the entropy (H), anisotropy (A), and mean scattering angle alpha (α), following the H/A/ α decomposition. Experimental results show that not only does the proposed T3 matrix differentiate between Bragg scattering of the clean sea surface from a random scattering of thick oil spills but is also able to distinguish between different emulsions of oil spills with water and sediments. Moreover, unlike classical T3, the proposed method distinguishes concrete-like structures and heavy sedimented oil even though both exhibit similar scattering behavior. The proposed algorithm is developed and validated on the data acquired by the UAVSAR full polarimetric L band SAR sensor over the Gulf of Mexico (GOM) region during the Deepwater Horizon (DWH) oil spill accident in June 2010. [ABSTRACT FROM AUTHOR]

This paper discusses the application of acoustic Doppler current profilers (ADCP) for the quantification of transport of water and the underlining physical mechanism. The transport of water through estuaries and tidal inlets is affected by tide, river flow, and wind. It is often assumed that wind effects in such systems are negligible unless under severe weather conditions. This study compares the ADCP-measured flows across a tidal inlet under weak wind conditions in late spring and those after the passage of an atmospheric cold front in winter. The Barataria Pass is a major inlet connecting Barataria Bay and northern Gulf of Mexico. The water exchange between the bay and coastal ocean is influenced by wind, especially in winter, because tide in the region is small (microtidal). The winter weather and late spring–summer weather are different. This difference results in different estuarine circulations. To examine this, two surveys were carried out with ship-mounted ADCPs—one in winter (19 December 2014) shortly after the passage of a cold front from the northwest, and the other in late spring (4 May 2015) with weak southeasterly winds. Distinctly different features of mean transport through the inlet were observed between the two surveys. The results from the first survey in winter showed that the total water transport was from the bay to the coastal ocean under northerly winds with intense outflows in shallow water, which is a typical signature of wind effects. The net flow was outward when the water level dropped. Data from the second survey in spring showed that the mid-channel water flew out of the bay (against the wind), whilst inflow appeared at both ends across the inlet, which was also a response to the weak wind stress and outward pressure gradient force set by the estuarine flow. The inflow at the eastern end (exceeding 0.1 m/s) is consistent with the idea that the coastal current resulted from the Mississippi River outflow enters the bay from the eastern end. The influence of tidal oscillations on water exchange appeared to be higher in the late spring data. The hydrographic observations in spring showed typical tidal straining features of an inverse estuary during the ebb–flood cycle, while salinity in the eastern shallow water generally varied with time, indicating the inflow of fresher water into the bay, confirming previous observations from summer 2008. [ABSTRACT FROM AUTHOR]

Accurate estimation of extreme wave condition is desired for the rational design of offshore structures, but the estimation results are known to have uncertainty from various sources. The quality and quantity of the available extreme wave data differ among ocean regions since the atmospheric causes of extreme waves are not identical. This paper provides insight into how the different extreme wave behaviors influence the uncertainty of extreme wave estimation at each location. A review of extreme waves in four regions, namely the Gulf of Mexico, North West Pacific, Adriatic Sea, and the North Sea, revealed the difference in data uncertainty, shape parameter, and frequency of occurrence. The likelihood-weighted method was introduced to quantitatively assess the impact of each parameter on the uncertainty of extreme wave analysis. Case study based on representative parameters of the Gulf of Mexico and the North Sea revealed the large epistemic uncertainty for a region dominated by tropical cyclones. The assessment conducted in this paper is unique as it evaluates the epistemic uncertainty inherited in the extreme sample data. When the epistemic uncertainty is large, such as the case illustrated for the Gulf of Mexico, the variance from different approaches may not be significant against the epistemic uncertainty inherited in the sample data. [ABSTRACT FROM AUTHOR]

We present a regional‐scale integrated modeling system (IMS) that includes Environmental Policy Integrated Climate (EPIC), Weather Research and Forecast (WRF), Community Multiscale Air Quality (CMAQ), and Soil and Water Assessment Tool (SWAT) models. The centerpiece of the IMS is the Fertilizer Emission Scenario Tool for CMAQ (FEST‐C), which includes a Java‐based interface and EPIC adapted to regional applications along with built‐in database and tools. The SWAT integration capability is a key enhanced feature in the current release of FEST‐C v1.4. For integrated modeling demonstration and evaluation, FEST‐C EPIC is simulated over three individual years with WRF/CMAQ weather and N deposition. Simulated yearly changes in water and N budgets along with yields for two major crops (corn grain and soybean) match those inferred from intuitive physical reasoning and survey data given different‐year weather conditions. Yearlong air quality simulations with an improved bidirectional ammonia flux modeling approach directly using EPIC‐simulated soil properties including NH3 content helps reduce biases of simulated gas‐phase NH3 and NH4+ wet deposition over the growing season. Integrated hydrology and water quality simulations applied to the Mississippi River Basin show that estimated monthly streamflow and dissolved N near the outlet to the Gulf of Mexico display similar seasonal patterns as observed. Limitations and issues in different parts of the integrated multimedia simulations are identified and discussed to target areas for future improvements. Plain Language Summary: Computer modeling tools with land‐water‐air processes are important for understanding nutrient cycling and its negative impacts on air and water quality. We have developed an integrated modeling system that includes agriculture, atmosphere, and hydrology components. The centerpiece of the system is a computer system that includes an agricultural ecosystem model and tools used to connect different modeling components. The agricultural system can conduct simulations for 42 types of grassland and cropland with the influence of site, soil, and management information along with weather and nitrogen deposition from the atmosphere component. An air quality computer model then uses information from the agricultural model, such as how much ammonia is in the soil, to predict how much ammonia gets in the air. Then, the watershed hydrology and water quality model uses the information from the agricultural and atmospheric models to understand the influence of agriculture and atmosphere on water quality. The paper demonstrates and evaluates the integrated modeling system on issues mainly related to N cycling. The system performs reasonably well in comparison with survey and observation data given the configured modeling constraints. The paper also identifies and discusses the advantages and limitations in each part of the system for future applications and improvements. Key Points: Modeling components representing agriculture, atmosphere, and hydrology are integrated and evaluatedIntegrated agriculture, hydrology, and water quality respond to different‐year weather conditions as expectedAir quality linked with simulated agriculture improves NH3 flux estimation and results in better performance of N cycling in atmosphere [ABSTRACT FROM AUTHOR]

This review covers selected 2018 articles on the biological effects of pollutants, including human physical disturbances, on marine and estuarine plants, animals, ecosystems, and habitats. The review, based largely on journal articles, covers field and laboratory measurement activities (bioaccumulation of contaminants, field assessment surveys, toxicity testing, and biomarkers) as well as pollution issues of current interest including endocrine disrupters, emerging contaminants, wastewater discharges, marine debris, dredging, and disposal. Special emphasis is placed on effects of oil spills and marine debris due largely to the 2010 Deepwater Horizon oil blowout in the Gulf of Mexico and proliferation of data on the assimilation and effects of marine debris. Several topical areas reviewed in the past (e.g., mass mortalities ocean acidification) were dropped this year. The focus of this review is on effects, not on pollutant sources, chemistry, fate, or transport. There is considerable overlap across subject areas (e.g., some bioaccumulation data may be appear in other topical categories such as effects of wastewater discharges, or biomarker studies appearing in oil toxicity literature). Therefore, we strongly urge readers to use keyword searching of the text and references to locate related but distributed information. Although nearly 400 papers are cited, these now represent a fraction of the literature on these subjects. Use this review mainly as a starting point. And please consult the original papers before citing them. [ABSTRACT FROM AUTHOR]

• The XGBoost method and its incremental learning method are introduced to successfully predict missing S-wave velocity data from a limited number of samples in actual logging data. • The SHAP visualization tool is employed to establish the connection between S-wave velocity and other well log parameters within the XGBoost model, uncovering valuable empirical information. • The predicted S-wave velocity data using XGBoost contributes to the identification and estimation of the morphology and saturation of gas hydrates in the well logs of the target reservoir. As an elastic parameter of formations, shear-wave (S-wave) velocity has important significance for assessing the morphology and saturation of gas hydrates but is often incompletely measured in actual drilling. To acquire missing S-wave velocity data for gas hydrate research in the Gulf of Mexico Gas Hydrate Joint Industry Project Leg II (GOM JIP Leg II), this paper introduces Extreme Gradient Boosting (XGBoost). Meanwhile, three additional machine learning models were trained for comparative analysis. The results show that XGBoost has better predictive performance than Gradient Boosting Decision Tree (GBDT) and Ordinary Least Squares (OLS) regression, and is more suitable for the small-sample well-log data in this study than Long Short-Term Memory (LSTM) networks. Based on this, Shapley Additive Explanations (SHAP) were used to explain the importance and specific contributions of well-logging parameters in XGBoost, and incremental learning was employed to overcome the issue of insufficient data for initial model training. Finally, the application of the prediction results provides hydrate morphology identification and saturation estimation based on S-wave velocity. This research opens a new intelligent path for recovering missing S-wave velocity in GOM JIP Leg II and enhances in-depth assessment of gas hydrate potential in the region. [ABSTRACT FROM AUTHOR]

On September 18, Category 4 Hurricane Ian made landfall near Fort Myers Beach and Sanibel Island, two barrier islands on the northern Gulf of Mexico. In this paper, we present a novel set of observations from a post-event High Water Mark field survey as well as wavelet analysis of in-situ wave data. We also present a qualitative overview of some erosive effects and infrastructure damage. Measured peak surge elevations exceed 5 m, and wave plus surge elevations exceed 6.0 m (NAVD88). High Water Mark observations are consistent within the expected range produced by numerical hindcast models. A wavelet analysis, from one of the few wave records available during the storm, demonstrates the presence of long-period basin mode waves at a 40-min period. The 40-min wave appeared on the wave record before the storm surge, and the peak of this motion also occurred before the peak of the surge. In addition, the wavelet analysis reveals the presence of infragravity wave energy (periods between 30 s and 20 min). Together, these intermediate and long-period waves add over 40 cm to the total water level at peak energy. The measured field data shows a rapidly decreasing surge elevation within the first 300 m from the pre-storm shoreline, and we observe no statistically meaningful attenuation difference between the highly developed shoreline of Fort Myers and the more vegetated shoreline of Sanibel Island. However, the structural survey team observed more infrastructure damage in Fort Myers than Sanibel Island. • On September 28, 2022 Hurricane Ian made landfall in Fort Myers Beach and Sanibel Island, Florida, USA. • Post-storm, our field survey team observed High Water Mark (HWM) and wave impacts in these areas. • Wavelet analysis reveals a peak in energy near a 40-min period that arrived before the main surge. • Long-period motions have the potential to add at least 40 cm to the quasi-steady surge. • Field observations reveal a rapid decrease in wave impact observations in the first 300 m from the shoreline in both study sites. • Sanibel, more vegetated, and Fort Myers, more developed, showed no statistically meaningful difference in surge attenuation. • However, Fort Myers experienced higher infrastructure damage than Sanibel Island. [ABSTRACT FROM AUTHOR]

Micro‐organisms are known to change fluid flow and permeability processes in subsurface environments, but this has only been demonstrated for coarse‐grained sediments and fractures. For fine‐grained sediments (mudstones), little is known about the effects of micro‐organisms on hydromechanical properties. Here, we investigated the influence of micro‐organisms on the porosity, permeability, and compressibility of fine‐grained sediments. We performed resedimentation experiments with and without micro‐organisms added to two reconstituted, fine‐grained sediment samples. These sediments were collected from the Ursa and Brazos‐Trinity Basins in the Gulf of Mexico during Integrated Ocean Drilling Program Expedition 308. Micro‐organisms caused a systematic, yet small increase in compression index for both sediments. Changes to permeability caused by micro‐organisms, while relatively minor, were greater for the Ursa sediment than the Brazos‐Trinity sediment. Additionally, the effect of micro‐organisms on permeability is greater at higher porosities and lower vertical effective stresses. Differences in permeability behavior between the two sediments are likely due to differences in sediment properties and nutrients for microbial growth. We therefore suggest that the effectiveness of micro‐organisms at altering fluid flow in fine‐grained sediments is dependent on burial depth (porosity as a function of vertical effective stress) and the grain size, pore and pore throat size, and specific surface area of a sediment. Characterizing the effects of micro‐organisms on the hydromechanical properties of fine‐grained sediments can further our understanding of the controls on pore pressure near the sediment–water interface in marine environments and aid in bioclogging practices around contaminated sites in terrestrial environments. Plain Language Summary: Micro‐organisms dwell in the pore space between sediments (porosity) all across Earth's surface. This could potentially affect the rate at which porosity is lost as clay‐rich sediments are buried (compressibility) and the ease at which fluids flow through clay‐size sediments (permeability). In this paper, we investigate if and how micro‐organisms change the compressibility and permeability of fine‐grained sediments (sediments dominated by clay‐size grains). To do this, we experimentally compress these fine‐grained sediments in the vertical direction with micro‐organisms added and without micro‐organisms added (control experiment) while measuring sediment porosity, compressibility, and permeability. We find that micro‐organisms cause a small increase in the rate of porosity loss during compression and a small decrease in permeability. However, the amount of permeability decrease caused by micro‐organisms is dependent on multiple properties of the clay‐size sediment. These findings can be used to help understand how water pressures in ocean sediments can become elevated, which could lead to damage of seafloor infrastructure, or benefit geotechnical engineering practices that use micro‐organisms to prevent fluid flow around contaminated sediments. Key Points: We experimentally determine the effects of micro‐organisms on the compression and permeability behavior of fine‐grained sedimentsMicro‐organisms cause a small increase in compression index and small decrease in permeability for fine‐grained sedimentsThe degree to which micro‐organisms decrease permeability in fine‐grained sediments is controlled by multiple sediment properties [ABSTRACT FROM AUTHOR]

The highlights for the manuscript, "Ocean Drifter Velocity Data Assimilation, Part 2: Forecast Validation", include: • 3DVAR velocity data assimilation within an operational prediction system. • Eularian velocities inferred from surface drifter position observations. • Velocity assimilation reduces temperature and salinity forecast error. • Including velocity observations improves the position of fronts and eddies. A large deployment of drifters conducted during August-December, 2020 in the Gulf of Mexico offers a test bed for a data assimilation system developed specifically to include velocity observations. This updated Navy Coupled Ocean Data Assimilation system employs the three-dimensional variational approach and is described in part one of this two-part paper (Helber et al, 2023). In this paper, we examine the impact of velocity data assimilation on the ensuing forecasts of the ocean state including not only velocity but also temperature and salinity fields below the surface. Two high-resolution (1 km) experiments were performed in the Gulf of Mexico; one with velocity data assimilation and the other without. The resulting 48 h forecasts of temperature, salinity, and velocity are examined and compared relative to the observations being assimilated (including the inferred velocities from the drifters) and unassimilated observations of temperature, salinity, and velocity from two gliders near the drifters. In addition, we assess eddy positioning and Lagrangian trajectory separation. Comparisons of these two experiments, with and without velocity data assimilation, suggest that adding velocity observations to the assimilation increases skill in predicting velocity and the subsurface temperature and salinity. [ABSTRACT FROM AUTHOR]

The article outlines the research of Jake Bailey in disproving the pre-historic microfossils discovered in 1998 in South China as fossils of Algae. Two researchers influenced his work. Samantha Joye presented evidence of reductive cell division in giant sulfur bacteria from the Gulf of Mexico. Heide Schulz researched in biochemical activities in giant sulfur bacteria in the formation of phosphorite. In his paper, Jake Bailey declares the microfossils as fossilized giant sulfur bacteria.

During the last interglacial (LIG) the volume of additional water in the world's oceans was large enough to raise global sea levels about 6–9 m higher than present levels. However, LIG sea levels vary regionally and those regional differences hold clues about the past distribution of ice sheets and local rates of subsidence and tectonic uplift. In this study, I used a standardized database template to review and summarize the existing constraints on LIG sea levels across the northern Gulf of Mexico and Caribbean shoreline of the Yucatán Peninsula. In total, I extracted 32 sea-level indicators including the insertion of 16 U-series ages on corals, 1 electron spin resonance age, 2 amino acid racemization ages, and 26 luminescence ages. Most dated sea-level indicators for the northern Gulf of Mexico are based on optically stimulated luminescence (OSL) ages of beach deposits of a mappable LIG shoreline. This shoreline extends from the Florida Panhandle through south Texas but is buried or removed by the Mississippi River across most of Louisiana. A similar feature is observed in satellite images south of the Rio Grande within the Mexican portions of the Gulf of Mexico but has yet to be dated. Elevations measured on portions of this feature close to the modern coast point to sea levels less than 1 m to ∼5 m higher than present for much of the northern Gulf of Mexico. However, a few, albeit undated, portions of the same shoreline located at more inland locations point to sea levels up to +7.2 m, attesting to up to 7 m of differential subsidence between the inland and coastal sites. Across the Yucatán Peninsula, U-series dating of corals has provided the main index points for LIG sea levels. Other carbonate coastal features such as beach ridges and eolianites have also been described but rely on corals for their dating. The maximum elevation of the LIG coral-based relative sea-level (RSL) estimates decrease from around +6 m across the Caribbean shoreline of the Yucatán Peninsula near Cancún, Mexico, to as low as -6 m to the south beneath the southern atolls of Belize, although discussion continues as to the validity of the ages for these southern corals. If these lower-elevation corals are LIG in age, their below-present elevations may be a result of vertical motion along faults dipping into the Cayman Trough. South of Belize only one purported LIG coral has been dated on the Isla de Roatán off the coast of Honduras at a likely tectonically uplifted elevation of 37.2 m. Thus the elevation of LIG sea levels within the inland siliciclastic shorelines of Guatemala and Honduras as well as the southwestern Gulf of Mexico remains poorly constrained and a potential venue for future research. The database described in this paper is available open access in spreadsheet format as Simms (2020), at this link: 10.5281/zenodo.4556163. [ABSTRACT FROM AUTHOR]

The proliferation of drilling expeditions focused on characterizing natural gas hydrate as a potential energy resource has spawned widespread interest in gas hydrate reservoir properties and associated porous media phenomena. Between 2017 and 2019, a Special Section of this journal compiled contributed papers elucidating interactions between gas hydrate and sediment based on laboratory, numerical modeling, and field studies. Motivated mostly by field observations in the northern Gulf of Mexico and offshore Japan, several papers focus on the mechanisms for gas hydrate formation and accumulation, particularly with vapor phase gas, not dissolved gas, as the precursor to hydrate. These studies rely on numerical modeling or laboratory experiments using sediment packs or benchtop micromodels. A second focus of the Special Section is the role of fines in inhibiting production of gas from methane hydrate, controlling the distribution of hydrate at a pore scale, and influencing the bulk behavior of seafloor sediments. Other papers fill knowledge gaps related to the physical properties of hydrate‐bearing sediments and advance new approaches in coupled thermal‐mechanical modeling of these sediments during hydrate dissociation. Finally, one study addresses the long‐standing question about the fate of methane hydrate at the molecular level when CO2 is injected into natural reservoirs under hydrate‐forming conditions. Key Points: The arc of laboratory and modeling research focused on hydrate‐bearing sediments has been based on the findings of major field programsThe Special Section highlights hydrate formation from vapor phase methane in porous media and the role of fines in hydrate reservoirsThe Special Section underscores the importance of coupled mechanical and thermodynamic models for tracking gas hydrate reservoir evolution [ABSTRACT FROM AUTHOR]

• We summarize studies that have successfully conducted cross-site science in the Gulf of Mexico. • Describe the LTER network and the cross-site initiatives built into their mission. • Discuss funding sources for cross-site synthesis and research. • Highlight considerations for data sharing policies and agreements for cross-site research. Ecological and fisheries research continues to shift emphasis from single isolated studies, to studies focused on understanding more regional and global processes. At the same time, the growing and wide-spread use of acoustic telemetry has inspired the formation of telemetry networks. A potential way to increase the impact of acoustic telemetry networks, and answer broad scale ecological questions is the promotion of cross-site ecosystem studies, or the comparison and synthesis of animal behavior among spatially distinct units. In this introduction paper we 1) Overview papers featured in the special issue, ' Using telemetry for cross-ecosystem comparisons of animal behaviors' 2) provide a summary of one network that has integrated cross-site research into their mission, the National Science Foundation's Long Term Ecological Research network (LTER, U.S.) And, 3) offer suggestions on ways telemetry researchers and networks can facilitate cross-ecosystem study using the LTER network as a model. Understanding processes related to global change, better defining stock structure, and other larger spatial scale questions are at the forefront of conservation and science. Pairing telemetry networks with cross-site initiatives provides a great venue to facilitate these broad scale science questions. [ABSTRACT FROM AUTHOR]

This paper discusses the flotation of cables and pipelines that have been trenched using jet trenching during reconsolidation of the seabed soil. Utilising previously published data on the variation of clay strength with liquidity index, it is demonstrated for the first time that, while current industry guidance is appropriate for the low-plasticity clays for which much previous research has been carried out, it may be overly conservative for high-plasticity clays such as those found in the Gulf of Guinea or the Gulf of Mexico, owing to the differing strength and density characteristics of these soils. [ABSTRACT FROM AUTHOR]

Research funded under the Gulf of Mexico Research Initiative provided new insights into the biogeochemical processes influencing the fate of petroleum chemicals entering the Gulf of Mexico from the Deepwater Horizon (DWH) accident. This overview of that work is based on detailed recent reviews of aspects of the biogeochemistry as well as on activities supported by the US Natural Resource Damage Assessment. The main topics presented here are distribution of hydrocarbons in the water column; the role of photo-oxidation of petroleum compounds at the air-sea interface; the role of particulates in the fate of the DWH hydrocarbons, especially marine oil snow (MOS) and marine oil snow sedimentation and occulent accumulation (MOSSFA); oil deposition and accumulation in sediments; and fate of oil on beaches and in marshes. A brief discussion of bioaccumulation is also included. Microbial degradation is addressed in a separate paper in this special issue of Oceanography. Important future research recommendations include: conduct a more robust assessment of the mass balance of various chemical groupings and even individual chemicals during specific time intervals; seek a better understanding of the roles of photo-oxidation products, MOS, and MOSSFA and their relationships to microbial degradation; and determine the fates of the insoluble highly degraded and viscous oil residues in the environment. [ABSTRACT FROM AUTHOR]

This paper presents a novel petrophysical experiment for measuring the 3D permeability tensor at reservoir conditions in fractured vuggy carbonate rock. The permeability variation with confining pressure is demonstrated through the experimental investigation; the permeability ellipse plots show the decrease of permeability, as a function of the increase in effective stress. The experiment was developed at reservoir conditions (120 °C temperature and variable confining pressure) in a native whole rock sample, from the Gulf of Mexico naturally fractured and vuggy reservoir. The analysis of the laboratory data reveals the elliptical behavior of permeability. Two ellipses were generated, one corresponding to the fracture network (secondary porosity system) and another for matrix porosity and permeability (primary porosity system). An important result is the compaction of the representative fracture network ellipse until it fuses with the matrix porosity ellipse at a high confining pressure state. The test contributes to the understanding of the mechanical and flow aspects of permeability, for naturally fractured reservoirs. The experimental results provide a basis for improving reservoir simulation studies, to obtain realistic predictions of reservoir behavior. [ABSTRACT FROM AUTHOR]