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The U.S. Gulf of Mexico contains a complex network of existing, decommissioned, and abandoned oil and gas pipelines, which are susceptible to a number of stressors in the natural-engineered offshore system including corrosion, environmental hazards, and human error. The age of these structures, coupled with extreme weather events increasing in intensity and occurrence from climate change, have resulted in detrimental environmental and operational impacts such as hydrocarbon release events and pipeline damage. To support the evaluation of pipeline infrastructure integrity for reusability, remediation, and risk prevention, the U.S. Gulf of Mexico Pipeline and Reported Incident Datasets were developed and published. These datasets, in addition to supporting advanced analytics, were constructed to inform regulatory, industry, and research stakeholders. They encompass more than 490 attributes relating to structural information, incident reports, environmental loading statistics, seafloor factors, and potential geohazards, all of which have been spatially, and in some cases temporally matched to more than 89,000 oil and gas pipeline locations. Attributes were acquired or derived from publicly available, credible resources, and were processed using a combination of manual efforts and customized scripts, including big data processing using supercomputing resources. The resulting datasets comprise a spatial geodatabase, tabular files, and metadata. These datasets are publicly available through the Energy Data eXchange®, a curated online data and research library and laboratory developed by the U.S. Department of Energy's National Energy Technology Laboratory. This article describes the contents of the datasets, details the methods involved in processing and curation, and suggests application of the data to inform and mitigate risk associated with offshore pipeline infrastructure in the Gulf of Mexico.

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Cagarras Islands Archipelago, a no-take MPA in Southeast Brazil, was designated as Natural Monument (MONA Cagarras) and, more recently, recognized as Hope Spot for biodiversity conservation. This study aimed to assess plastic contamination by analyzing marine litter and microplastics in MONA Cagarras and surrounding waters. Marine litter (34.12 kg) was caught by artisanal fishermen in MONA Cagarras proximities, and plastics represented ∼79 %. Personal hygiene items and strains of hair were found, suggesting sewage-derived contamination from Ipanema SSO. Microplastics were detected in MONA Cagarras surface waters. Fragments and black particle were the most frequently found microplastic shape and color, respectively. µ-FTIR analysis identified, in descending order of occurrence, polystyrene-PS, polyethylene-PE, polyvinyl chloride-PVC, polypropylene-P, and polyamide-PA. Our integrated results of macro and microplastic contamination highlight an issue of effective conservation and health of marine biodiversity in MONA Cagarras and surrounding waters and a concern for better management of Brazilian MPAs.

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This work proposes exposure limits for carbon monoxide in the nuclear submarine environment. Linear and non-linear forms of the Coburn-Foster-Kane equation were used to evaluate carbon monoxide exposure for an environment with low oxygen content, different exposure times and crew physical activity levels. We evaluated the 90-day Continuous Exposure Guidance Level, 24-h and 1-h Emergency Exposure Guidance Levels and 10-day and 24-h Submarine Escape Action Levels. The results showed that the concentration of carbon monoxide in the environment must not exceed 9 ppm for the 90-day Continuous Exposure Guidance Level, 35 ppm for the 24-h Emergency Exposure Guidance Level, 90 ppm 1-h Emergency Exposure Guidance Level, 60 ppm for the 10-day Submarine Escape Action Level and 80 ppm for the 24-h Submarine Escape Action Level. Comparing these values with those established by the National Research Council for the United States Navy, the limits proposed by this work are verified to be lower, which may indicate a risk to the health of the crew. They also show the impact of the crew's level of physical activity on the formation of carboxyhemoglobin.

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Submarine outfalls have been employed to convey urban effluents to their fate in the open ocean due to their dilution capacity and organic matter decay. This work analysed Escherichia coli concentrations in the Barra da Tijuca (Rio de Janeiro, Brazil) submarine outfall plume, considering an hourly variable bacterial die-off due to environmental parameters associated with dynamic changes, vertical plume position, and thickness in response to hydrodynamic conditions. The adopted modelling procedure included coupling a near-field mixing zone model, NRFIELD, with the far-field Lagrangian transport and water quality model of the SisBaHiA® ( http://www.sisbahia.coppe.ufrj.br ). The coupling methodology simulated E. coli concentrations considering simultaneous variations in temperature, salinity, solar radiation, and hydrodynamic conditions. The results showed substantial variability in E. coli concentrations in the marine environment due to variable environmental conditions, regulating solar radiation levels over the submerged plume.

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The USA recently announced it is planning on deploying 30 GW of offshore wind by 2030 (national goal for offshore wind). Part of this development will be in the Gulf of Mexico, which has both wind potential and pre-existing oil and gas pipelines, only a portion of which is currently being used. Examining whether these assets can be used to economically transport power back from future Gulf wind farms should be a first step for developers. The question of whether laying new high-voltage direct current submarine cable versus repurposing pipeline to transport wind power will be examined. This paper looks at the hydrogen market and its use to transport wind power, what it would take to retrofit pipeline to carry hydrogen, a cost analysis given available data, and a look at potential policy support. There is a need to assess pipelines individually; however, retrofitting existing infrastructure should be considered an alternative to laying new submarine transmission cables. Additionally, alleviating the issue of oil and gas stranded assets through pipeline reuse may provide political support in hastening the energy transition.

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The resident and tourist population in the Mexican Caribbean has grown exponentially, increasing the availability of dissolved inorganic nutrients in coastal waters through submarine groundwater discharge (SGD). Recently, a new massive drift of Sargassum spp. has occurred that can provide new organic matter and enrich coastal water with nutrients. In different sites in the Mexican Caribbean, the chemical composition of the water was analyzed, and the δ15N of Thalassia testudinum was determined between 2016 and 2019. Evidence of SGD was observed in Akumal Bay due to high silicate concentrations and its negative correlation with salinity. Seasonal and interannual variation in NH4+ concentration was observed at these sites. In October 2018, SGD contributed ∼70 times more nitrogen and ∼194 times more phosphorus than the decomposition of the pelagic macroalgae Sargassum spp. The δ15N data showed that Akumal Bay received nitrogen of anthropogenic origin and that nitrogen fixation processes or probably assimilation of nitrogen of the leachates of pelagic Sargassum spp were dominant at Mahahual and Xahuayxol.

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How mine tailings storage facilities (TSF) are managed reflects the history, regulatory framework, and environment of a country and locale of the mine. Despite many attempts to find an environmentally friendly strategy for tailings management and governance that balances the needs of society and the ecosystem, there is no worldwide agreement regarding the best practices for tailings management and governance. This article reviews the evolution of copper tailings management and governance in Chile, current practices, and changes that could be or may need to be made to improve practices in response to local environmental conditions and local tolerance for risk. The progress to date in developing a holistic tailings management strategy is summarized. This article also describes recent proposals for the best available technologies (BATs), case histories of Chilean TSF using conventional technology, thickened tailings, paste tailings, filtered tailings, water use reduction, tailings reprocessing to obtain rare earth elements (REEs), circular economy, submarine deep-sea tailings disposal, and ways to avoid failure in a seismic region. Finally, the Chilean tailings industry's pending issues and future challenges in reducing the socioenvironmental impacts of tailings are presented, including advances made and lessons learned in developing more environmentally friendly solutions.

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Harmful Algal Blooms (HAB) pose a severe socio-economic problem worldwide. The dinoflagellate species Alexandrium catenella produces potent neurotoxins called saxitoxins (STXs) and its blooms are associated with the human intoxication named Paralytic Shellfish Poisoning (PSP). Knowing where and how these blooms originate is crucial to predict blooms. Most studies in the Chilean Patagonia, were focused on coastal areas, considering that blooms from the adjacent oceanic region are almost non-existent. Using a combination of field studies and modelling approaches, we first evaluated the role of the continental shelf off northern Chilean Patagonia as a source of A. catenella resting cysts, which may act as inoculum for their toxic coastal blooms. This area is characterized by a seasonal upwelling system with positive Ekman pumping during spring-summer, and by the presence of six major submarine canyons. We found out that these submarine canyons increase the vertical advection of bottom waters, and thus, significantly enhance the process of coastal upwelling. This is a previously unreported factor, among those involved in bloom initiation. This finding put this offshore area at high risk of resuspension of resting cysts of A. catenella. Here, we discuss in detail the physical processes promoting this resuspension.

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To determine how submarine groundwater discharge (SGD) magnitudes and composition (fresh or saline/recirculated) vary in nearshore low inflow estuaries across ⁓125 km of a semiarid coastline, this study assessed three south Texas estuaries, using radon [222Rn], radium [226Ra and 224Ra], and water isotopes [δ18O and δD]. Mass balance models of time-series 222Rn, found to be representative of total SGD in this study, revealed much higher SGD inputs to the Nueces Estuary (average [x̅] Nueces, Corpus Christi and Oso Bays: 120, 83, and 44 cm·d-1, respectively), attributed to anthropogenically-disturbed substrates and potentially surfacing growth-faults. The lowest 222Rn-derived SGD occurred in the Upper Laguna Madre Estuary (x̅: Upper Laguna Madre and Baffin Bay: 21 and 18 cm·d-1, respectively), explained by the drier climate, lower anthropogenic disturbance, and neighboring groundwater cone of depression. Aransas Bay in the Mission Aransas Estuary received greater average annual precipitation but exhibited low total SGD rates (x̅: 23 cm·d-1). Seasonally, average 222Rn-derived SGD rates increased following Hurricane Harvey (43 cm·d-1 in spring to 64 cm·d-1 in summer). In the Nueces Estuary, the overall 222Rn-derived SGDs were substantially higher than SGDs from 224Ra and 226Ra. The closer agreement between 224Ra and 222Rn-derived SGD and larger 224Ra rates in the Upper Laguna Madre Estuary, Aransas Bay and Oso Bay indicate that saline/recirculated SGD contributions were significant. Values of δ18O and δD confirm these types of inputs, with effects of evaporation/salinization more pronounced where recirculation was predominant and the opposite where terrestrial/222Rn-derived SGD inputs dominate. 226Ra-derived SGDs were lower than the 224Ra due to different behavior of the two isotopes while released into water following transport through saline and fine-grained estuarine sediments or due to wind-driven disturbances.

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Submarines are considered extremely strategic for any naval army due to their stealth capability. Periscopes are crucial sensors for these vessels, and emerging to the surface or periscope depth is required to identify visual contacts through this device. This maneuver has many procedures and usually has to be fast and agile to avoid exposure. This paper presents and implements a novel architecture for real submarine periscopes developed for future Brazilian naval fleet operations. Our system consists of a probe that is connected to the craft and carries a 360 camera. We project and take the images inside the vessel using traditional VR/XR devices. We also propose and implement an efficient computer vision-based MR technique to estimate and display detected vessels effectively and precisely. The vessel detection model is trained using synthetic images. So, we built and made available a dataset composed of 99,000 images. Finally, we also estimate distances of the classified elements, showing all the information in an AR-based interface. Although the probe is wired-connected, it allows for the vessel to stand in deep positions, reducing its exposure and introducing a new way for submarine maneuvers and operations. We validate our proposal through a user experience experiment using 19 experts in periscope operations.

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Knowledge of homoscleromorph sponge biodiversity has greatly improved during the last decade thanks to the increasing use of integrative taxonomy and extensive exploration of remote ecosystems. Indeed, recently described species have mostly been small sponges living in dark and near-impenetrable habitats. This work integrates morphological, cytological, ecological and molecular data to describe a new species belonging to the Plakina genus. Plakina doudou sp. nov. was found first during close inspection of photographs taken previously in a submarine cave on Martinique Island, where several new species had already been revealed. The new species lives in syntopy with P. arletensis. It is thinly encrusting, whitish in vivo, and its skeleton harbors a unique composition of diods, triods, monolophose triods and monolophose, dilophose and trilophose calthrops. Sequencing of a portion of the mitochondrial gene cox-1 indicates that the new species belongs to a well-supported clade containing the Mediterranean P. crypta and P. trilopha. However, at the time of publication of this work, we have not yet managed to identify synapomorphies that would support the different clades of Plakina. This genus includes a total of 39 species to date, of which 10 have been recorded in the Western Tropical Atlantic, and 4 in Caribbean submarine caves.

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Water quality in the Mexican Caribbean is affected by increases in tourism infrastructure and poor wastewater treatment. Additionally, karst geomorphology facilitates the infiltration of organic matter to subterranean water and coastal fresh water that originates from submarine groundwater discharges (SGDs), altering the environment. The tourism infrastructure grows at different rates along the Caribbean coast, characterizing zones with diverse levels of tourism impact. The aim of this work was to measure nutrient concentrations in superficial coastal water and fresh water to evaluate the water quality through different zones along a gradient from intermediate- (Riviera Maya) to low-tourism (Costa Maya) development regions. Furthermore, this study aimed to compare the measured nutrient concentrations with the Mexican ecological criteria of water quality 001/89 (CE-CCA-001/89), detect possible contributions by SGDs, and determine whether the nitrogen (N) sources are anthropogenic using stable nitrogen isotopes in the seagrass Thalassia testudinum. According to the results, nutrient concentrations (ammonium, nitrate, nitrite, and orthophosphate) differed significantly between the Riviera Maya and Costa Maya (P = 0.0001). Sites such as Shambala, Chávez, Tankah, Mahahual 2, Tulum, Akumal, and Xahuayxol exceeded the upper levels set by the CE-CCA-001/89. Tankah, Shambala, and Chávez were influenced by SGDs. The nitrogen isotope ratio in Akumal and Tulum coast water shows that they are under N loading derived to the sewage percentage of δ15N in Akumal, Tulum, and Mahahual, showing that these sites suffer N loading due to sewage. Our study recommends continuous monitoring and coastal characterization to detect SGD and to regulate, treat, and dispose of sewage.

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The ophiuroid species listed were collected by benthic faunal surveys from 2016 to 2018 in submarine caves of the Ryukyu Islands, southwestern Japan. The material includes 20 species from 8 families, Amphiuridae, Ophiocomidae, Ophiodermatidae, Ophiolepididae, Ophioleucidae, Ophiomyxidae, Ophionereididae and Ophiotrichidae. This is the first comprehensive report of submarine cave-dwelling ophiuroids from Japanese waters. Also provided is a redescription of a rare species, Dougaloplus echinatus (Ljungman, 1867), with a detailed description of its ossicle morphology. The species has previously been reported from Brazil, Australia, Eastern Indian Ocean to Southern China, in 11-118 m depth, and this is the first record of D. echinatus from Japanese waters. A brief discussion of the scarcity of submarine cave systems, and the need for their conservation, is provided.

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BACKGROUND: We analyse the distribution of Gastropods and Chitons from shallow to deep waters along the southwestern Atlantic Ocean off Argentina and discuss possible factors determining the observed biogeographic patterns. RESULTS: Three major biogeographic groups are defined on the basis of Gastropod and Chiton species associations, i.e., continental shelf (< 350 m), upper continental slope (> 350-2000 m) and lower continental slope (2000-3000 m). Bathymetry appears as the main factor modifying large-scale distribution of the fauna at a. In this scenario, species associations are determined by marine currents that clearly occur at a particular and well defined depth. No arrangement of species by geographic location was found in assemblages from the continental shelf and upper continental slope. CONCLUSIONS: We hypothesize that depth and marine currents are the main factor affecting the distribution of Gastropods and Chitons along the SW Atlantic between 200 and 3000 m depth.

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Illicit drugs and their metabolites represent a new class of emerging contaminants. These substances are continuously discharged into wastewater which have been detected in the aquatic environment in concentrations ranging from ng.L-1 to µg.L-1. Our study detected the occurrence of cocaine (COC) and benzoylecgonine (BE) in a subtropical coastal zone (Santos Bay, SP, Brazil) within one year. Water samples (surface and bottom) were collected from the Santos Submarine Sewage Outfall (SSOS) area. COC and BE were measured in the samples using ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-ESI-MS/MS). Concentrations ranged from 12.18 to 203.6 ng.L-1 (COC) and 8.20 to 38.59 ng.L-1 (BE). Higher concentrations of COC were observed during the end of spring, following the population increase at summer season. COC and its metabolite occurrence in this coastal zone represent a threat to coastal organisms.

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The sponge class Homoscleromorpha is a key model for the evolutionary biology of the Metazoa but its diversity remains poorly known. Here we describe six new species of the homoscleromorph family Plakinidae found in shaded habitats (submarine caves, tunnels and overhangs) of New Caledonia and Marquesas Islands, Central-Western Pacific. The new species belong to four genera: Corticium (Corticium vaceleti sp. nov.), Plakina (Plakina finispinata sp. nov.), Plakinastrella (Plakinastrella osculifera sp. nov., Plakinastrella nicoleae sp. nov. and Plakinastrella pseudolopha sp. nov.), and Plakortis (Plakortis ruetzleri sp. nov.). Plakinastrella pseudolopha sp. nov. has a novel spicule type called here 'pseudolophose spicules'. The diversity of Homoscleromorpha is raised to 50 species in the Pacific Ocean and 120 spp. worldwide.

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This work describes the modeling, control and development of a low cost Micro Autonomous Underwater Vehicle (µ-AUV), named AR2D2. The main objective of this work is to make the vehicle to detect and follow an object with defined color by means of the readings of a depth sensor and the information provided by an artificial vision system. A nonlinear PD (Proportional-Derivative) controller is implemented on the vehicle in order to stabilize the heave and surge movements. A formal stability proof of the closed-loop system using Lyapunov's theory is given. Furthermore, the performance of the µ-AUV is validated through numerical simulations in MatLab and real-time experiments.

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Todos os Santos Bay (BTS) is the 2nd largest bay in Brazil and an important resource for the people of the State of Bahia. We made measurements of radon and radium in selected areas of the bay to evaluate if these tracers could provide estimates of submarine groundwater discharge (SGD) and flushing times of the Paraguaçu Estuary and BTS. We found that there were a few areas along the eastern and northeastern shorelines that displayed relatively high radon and low salinities, indicating possible sites of enhanced SGD. A time-series mooring over a tidal cycle at Marina do Bonfim showed a systematic enrichment of the short-lived radium isotopes 223Ra and 224Ra during the falling tide. Assuming that the elevated radium isotopes were related to SGD and using measured radium activities from a shallow well at the site, we estimated groundwater seepage at about 70 m3/day per unit width of shoreline. Extrapolating to an estimated total shoreline length provided a first approximation of total (fresh + saline) SGD into BTS of 300 m3/s, about 3 times the average river discharge into the bay. Just applying the shoreline lengths from areas identified with high radon and reduced salinity results in a lower SGD estimate of 20 m3/s. Flushing times of the Paraguaçu Estuary were estimated at about 3-4 days based on changing radium isotope ratios from low to high salinities. The flushing time for the entire BTS was also attempted using the same approach and resulted in a surprisingly low value of only 6-8 days. Although physical oceanographic models have proposed flushing times on the order of months, a simple tidal prism calculation provided results in the range of 4-7 days, consistent with the radium approach. Based on these initial results, we recommend a strategy for refining both SGD and flushing time estimates.

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Underwater sensor networks represent an important and promising field of research due to the large diversity of underwater ubiquitous applications that can be supported by these networks, e.g., systems that deliver tsunami and oil spill warnings, or monitor submarine ecosystems. Most of these monitoring and warning systems require real-time communication in wide area networks that have a low density of nodes. The underwater communication medium involved in these networks is very harsh and imposes strong restrictions to the communication process. In this scenario, the real-time transmission of information is done mainly using acoustic signals, since the network nodes are not physically close. The features of the communication scenario and the requirements of the communication process represent major challenges for designers of both, communication protocols and monitoring and warning systems. The lack of models to represent these networks is the main stumbling block for the proliferation of underwater ubiquitous systems. This paper presents a real-time communication model for underwater acoustic sensor networks (UW-ASN) that are designed to cover wide areas with a low density of nodes, using any-to-any communication. This model is analytic, considers two solution approaches for scheduling the real-time messages, and provides a time-constraint analysis for the network performance. Using this model, the designers of protocols and underwater ubiquitous systems can quickly prototype and evaluate their solutions in an evolving way, in order to determine the best solution to the problem being addressed. The suitability of the proposal is illustrated with a case study that shows the performance of a UW-ASN under several initial conditions. This is the first analytic model for representing real-time communication in this type of network, and therefore, it opens the door for the development of underwater ubiquitous systems for several application scenarios.

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The present study determined environmental concentrations of pharmaceuticals, cocaine, and the main human metabolite of cocaine in seawater sampled from a subtropical coastal zone (Santos, Brazil). The Santos Bay is located in a metropolitan region and receives over 7367m(3) of wastewater per day. Five sample points under strong influence of the submarine sewage outfall were chosen. Through quantitative analysis by LC-MS/MS, 33 compounds were investigated. Seven pharmaceuticals (atenolol, acetaminophen, caffeine, losartan, valsartan, diclofenac, and ibuprofen), an illicit drug (cocaine), and its main human metabolite (benzoylecgonine) were detected at least once in seawater sampled from Santos Bay at concentrations that ranged from ng·L(-1) to µg·L(-1). In light of the possibility of bioaccumulation and harmful effects, the high concentrations of pharmaceuticals and cocaine found in this marine subtropical ecosystem are of environmental concern.

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