Atlantic Coastline Research Articles

Chemical Survey and Antifungal Efficacy of Sargassum muticum's Alkaloids and Phenolic-Rich Fraction Against Airborne Toxigenic and Nosocomial Opportunistic Molds Isolates.

The Atlantic coastline of El-Jadida, Morocco, is renowned for its plentiful algae, especially brown seaweed, which is rich in active compounds known for their antifungal properties. This valuable resource offers an exciting opportunity to tackle the numerous challenges posed by invasive fungal infections, allergies, mycotoxin-related food poisoning, and drug-resistant strains. Underscoring the urgent need to explore alternative, sustainable, and environmentally friendly antifungal agents derived from algae. This study aimed to evaluate the antifungal activity of total alkaloids and phenolic-rich fractions derived from seven species of Pheophyceae: Sargassum muticum, Sargassum vulgare, Bifurcaria bifurcata, Cystoseira tamariscifolia, Cystoseira humilis, Laminaria ochroleuca, and Fucus spiralis against four fungi: airborne toxigenic isolates of Aspergillus westerdijkiae and Chaetomium globosum as well as nosocomial opportunistic isolates of Aspergillus nidulans and Scopulariopsis brevicaulis. The study also aimed to identify the most effective alga and its specific active compounds through LC-MS and GC-MS analysis. The invasive Sargassum muticum was chosen as the most potent alga in inhibiting the growth of mycelium. For the first time, the alkaloids palmatine and jatrorrhizine, along with caulerpin, have been identified. The chloroform fraction revealed the prevalence of phenolic compounds including, phenolic acids, flavonoids, and phlorotannins. The lowest minimum inhibitory concentrations (MICs), with a maximum fungal load of 108 colony-forming unit (CFU), recorded ranged from 3.12 to 6.25μg/mL by the phenolic-rich fraction against airborne toxigenic isolates, and from 100 to 200μg/mL against nosocomial opportunistic isolates by the total alkaloids. In comparison, the positive control, ketoconazole, showed higher MICs and resistance against A. nidulans. The valorization of Sargassum muticum is proposed as a green strategy to preserve the ecological balance, combat antifungal resistance, and address public health challenges.

The Timing, Magnitude, and Relative Composition of Extreme Total Water Levels Vary Seasonally Along the U.S. Atlantic Coast

AbstractThe annual maximum (AM) method, which subsamples time series to retain the maximum event per year, and the peak‐over‐threshold (POT) method, which extracts values exceeding a threshold to define extremes, have long histories in determining flood event frequency. In practice, extreme value distributions applied to AM and POT events often assume that the data comes from the same statistical population. Locations across the world, like the United States (U.S.) Atlantic coastline, however, experience high coastal water levels driven by various individual processes and storms with different driving mechanisms during different seasons. This research investigates when extreme total water levels (TWLs) occur during the year along the U.S. Atlantic coast and whether individual components, like waves, tides, and storm surge, contributing to TWLs vary across regions and during the year. From 1980 to 2020, extreme TWLs occurred during the extratropical and tropical seasons, with the relative proportion of extreme TWLs occurring during the extratropical season increasing northward. Still water levels drive spatial variability in extreme TWL magnitude, while wave climate drives differences in extreme TWL magnitude between extratropical and tropical seasons. Month‐to‐month variability in the composition of extreme TWLs varies more than spatial variability, highlighting the importance of understanding the components driving extremes at different times of the year. Variations across storm seasons in the processes contributing to extreme TWLs may have implications for how large‐scale changes to the climate impact hazards along open sandy coastlines and influence the robustness of extrapolating rare events from models fit to a single population.

The potential for kelp (order Laminariales) aquaculture in South Africa: a biological review

Abstract The Benguela upwelling region on the west coast of South Africa/Namibia has the only major kelp forests on the African continent. South Africa has four species of laminarian kelps; Ecklonia maxima, Laminaria pallida dominate kelp forests in the west coast Benguela upwelling system, with Macrocystis pyrifera occurring rarely in this region and Ecklonia radiata largely confined to the more nutrient-poor south and east coasts. Growth studies on these species have been limited to laboratory experiments and very few initial, small-scale coastal studies. As in other Atlantic regions, there is growing interest in the potential for kelp aquaculture in Southern Africa, and recent pilot initiatives. A comprehensive summary of available literature on South African kelps, their biology and ecology, distribution and growth parameters, is presented, and the potential for kelp aquaculture discussed in relation to recent developments elsewhere on Atlantic and Eastern Pacific coastlines. Recommendations are made with respect to the choice of potential species and sites.

Let’s measure it: An approach of high-resolution estimates of bottom fixed net fishing effort at national level

Fisheries are one of the most important food sources for human consumption whilst being amongst the most impacting and extractive activities happening within the marine environment, which makes it imperative to properly manage this activity. To improve fisheries management, the precise quantification of fishing effort is of the outmost importance. Yet, present methods for effort estimation, especially at broad scales, are hampered by difficulties in data access and usually rely on coarse effort metrics or on costly data collection for quantifying fishing effort with higher resolution. In the present work, we propose an approach of high-resolution fishing effort estimates of net fishing, as length of nets operated by a given fleet, at the national level. It relies on sampling of effort, derived from classified and easy to access vessel tracking data – AIS, and fishery dependent data – logbook and landings data. The proposed methodology combines trip-based effort estimates, derived from AIS data, as a foundation to extrapolate the total fishing effort, through the number of fishing trips linked to official landings and logbook data. It is estimated that in the years from 2014 to 2020 an average of 180 200 km of static nets (gillnets and trammel nets), which corresponds to approximately 4.5 and 210 times the lengths of the equator and the Portuguese Atlantic coastline respectively, are used in Portuguese mainland waters each year, by a fleet of slightly more than 100 vessels. The presented methodology allows to quantify and study the variation of the nominal fishing effort, at country level, with a higher resolution than what is usually used and at very low cost. We argue that such methodologies need to be developed and explored in order to have better and more comprehensive estimates of fishing effort which will contribute and improve the sustainable management of fisheries and the marine environment.

Biogeographic and seasonal differences in consumer pressure underlie strong predation in the tropics.

Biotic interactions play a critical role in shaping patterns of global biodiversity. While several macroecological studies provide evidence for stronger predation in tropical regions compared with higher latitudes, results are variable even within the tropics, and the drivers of this variability are not well understood. We conducted two complementary standardized experiments on communities of sessile marine invertebrate prey and their associated predators to test for spatial and seasonal differences in predation across the tropical Atlantic and Pacific coastlines of Panama. We further tested the prediction that higher predator diversity contributes to stronger impacts of predation, using both direct observations of predators and data from extensive reef surveys. Our results revealed substantially higher predation rates and stronger effects of predators on prey in the Pacific than in the Atlantic, demonstrating striking variation within tropical regions. While regional predator diversity was high in the Atlantic, functional diversity at local scales was markedly low. Peak predation strength in the Pacific occurred during the wet, non-upwelling season when ocean temperatures were warmer and predator communities were more functionally diverse. Our results highlight the importance of regional biotic and abiotic drivers that shape interaction strength and the maintenance of tropical communities, which are experiencing rapid environmental change.

Conceptualizing Controlling Factors for PFAS Salting Out in Groundwater Discharge Zones Along Sandy Beaches.

Understanding fate and transport processes for per- and poly-fluoroalkyl substances (PFAS) is critical for managing impacted sites. "PFAS Salting Out" in groundwater, defined herein, is an understudied process where PFAS in fresh groundwater mixes with saline groundwater near marine shorelines, which increases sorption of PFAS to aquifer solids. While sorption reduces PFAS mass discharge to marine surface water, the fraction that sorbs to beach sediments may be mobilized under future salinity changes. The objective of this study was to conceptually explore the potential for PFAS Salting Out in sandy beach environments and to perform a preliminary broad-scale characterization of sandy shoreline areas in the continental U.S. While no site-specific PFAS data were collected, our conceptual approach involved developing a multivariate regression model that assessed how tidal amplitude and freshwater submarine groundwater discharge affect the mixing of fresh and saline groundwater in sandy coastal aquifers. We then applied this model to 143 U.S. shoreline areas with sandy beaches (21% of total beaches in the USA), indirectly mapping potential salinity increases in shallow freshwater PFAS plumes as low (<10 ppt), medium (10-20 ppt), or high (>20 ppt) along groundwater flow paths before reaching the ocean. Higher potential salinity increases were observed in West Coast bays and the North Atlantic coastline, due to the combination of moderate to large tides and large fresh groundwater discharge rates, while lower increases occurred along the Gulf of Mexico and the southern Florida Atlantic coast. The salinity increases were used to estimate potential perfluorooctane sulfonic acid (PFOS) sorption in groundwater due to salting out processes. Low-category shorelines may see a 1- to 2.5-fold increase in sorption of PFOS, medium-category a 2.0- to 6.4-fold increase, and high-category a 3.8- to 25-fold increase in PFOS sorption. The analysis presented provides a first critical step in developing a large-scale approach to classify the PFAS Salting Out potential along shorelines and the limitations of the approach adopted highlights important areas for further research.

Biochemical and Physical Screening Using Optical Oxygen-Sensing and Multispectral Imaging in Sea Oats Seeds

Physical, physiological, and biochemical traits control critical seed functions such as germination, longevity, persistence, and seedling establishment. These traits are diverse between and among species, and they are also controlled by the environment in which the seed originated. Therefore, screening seed traits and understanding their roles in seed functions is crucial to facilitate the economical use of resources in collecting, sorting, and conserving seed materials of agronomical and ecological importance. We hypothesized the existence of physical and biochemical traits in sea oats seeds that can be used as proxies to predict viability and vigor to develop underpinnings for survival after non-optimal storage conditions. Using multispectral imaging and optical oxygen-sensing analyses, we evaluated the physical and biochemical traits of Uniola paniculata L. (sea oats) seeds collected from the US Atlantic and Gulf coastlines. Our results showed that several traits correlate to aging stress survival in sea oats seeds. These results confirm the potential of using physical and biochemical screening to predict seed quality while offering insights into extended seed longevity periods. Therefore, exploring and analyzing the physical and biochemical properties of seeds could reveal salient markers that contribute to viability and longevity.

Monitoring post-spawning movement, habitat use, and survival of adult anadromous rainbow smelt using acoustic telemetry in a New Hampshire estuary.

Anadromous rainbow smelt (Osmerus mordax, [Mitchill 1814]) are found along the northeast Atlantic coastline of North America, with their range now limited to north of Cape Cod, Massachusetts, USA. Although their anadromous life cycles are described broadly, gaps remain regarding how adult rainbow smelt use estuaries post-spawning, including movement behaviors, habitats used, and specific timing of emigration to coastal waters. In spring 2021, we used acoustic telemetry to characterize movements during and after the spawning season of rainbow smelt captured in tributaries to Great Bay, New Hampshire, USA, a large estuarine system near the southern edge of their range. Forty-four adult rainbow smelt (n = 35 male, n = 9 female) were tagged with Innovasea V5 180-kHz transmitters and an array of 22,180 kHz VR2W receivers were deployed throughout Great Bay to detect movements of tagged fish from March to October 2021. Rainbow smelt were detected 14,186 times on acoustic telemetry receivers, with 41 (93%) of the tagged individuals being detected at least once post-tagging. Individuals were detected moving between tributaries, revealing that rainbow smelt can use multiple rivers during the spawning season (March-April). Mark-recapture Cormack-Jolly-Seber models estimated 83% (95% confidence interval 66%-92%) of rainbow smelt survived to the mainstem Piscataqua River, and a minimum of 50% (22 of 44) reached the seaward-most receivers and were presumed to have survived emigration. Most individuals that survived remained in the estuary for multiple weeks (average = 19.47 ± 1.99 standard error days), displaying extended use of estuarine environments. Downstream movements occurred more frequently during ebb tides and upstream movements with flood tides, possibly a mechanism to reduce energy expenditures. Fish emigrated from the estuary by mid-May to the coastal Gulf of Maine. Our results underscore that rainbow smelt need access to a variety of habitats, including multiple tributaries and high-quality estuarine habitat, to complete their life cycle.

French coastal network for carbonate system monitoring: the CocoriCO2 dataset

Abstract. Since the beginning of the industrial revolution, atmospheric carbon dioxide (CO2) concentrations have risen steadily and have induced a decrease of the averaged surface ocean pH by 0.1 units, corresponding to an increase in ocean acidity of about 30 %. In addition to ocean warming, ocean acidification poses a tremendous challenge to some marine organisms, especially calcifiers. The need for long-term oceanic observations of pH and temperature is a key element to assess the vulnerability of marine communities and ecosystems to these pressures. Nearshore productive environments, where a large majority of shellfish farming activities are conducted, are known to present pH levels as well as amplitudes of daily and seasonal variations that are much larger than those observed in the open ocean. Yet, to date, there are very few coastal observation sites where these parameters are measured simultaneously and at high frequency. To bridge this gap, an observation network was initiated in 2021 in the framework of the CocoriCO2 project. Six sites were selected along the French Atlantic and Mediterranean coastlines based on their importance in terms of shellfish production and the presence of high- and low-frequency monitoring activities. At each site, autonomous pH sensors were deployed, both inside and outside shellfish production areas, next to high-frequency CTD (conductivity–temperature–depth) probes operated through two operating monitoring networks. pH sensors were set to an acquisition rate of 15 min, and discrete seawater samples were collected biweekly in order to control the quality of pH data (laboratory spectrophotometric measurements) as well as to measure total alkalinity and dissolved inorganic carbon concentrations for full characterization of the carbonate system. While this network has been up and running for more than 2 years, the acquired dataset has already revealed important differences in terms of pH variations between monitored sites related to the influence of diverse processes (freshwater inputs, tides, temperature, biological processes). Data are available at https://doi.org/10.17882/96982 (Petton et al., 2023a).

Shoreline Change Assessment of the Moroccan Atlantic Coastline Using DSAS Techniques

Shoreline Change Assessment of the Moroccan Atlantic Coastline Using DSAS Techniques

Using marine mammal necropsy data in animal health surveillance: the case of the harbor porpoise in the Southern North Sea

Rapid changes of marine ecosystems resulting from human activities and climate change, and the subsequent reported rise of infectious diseases in marine mammals, highlight the urgency for timely detection of unusual health events negatively affecting populations. Studies reporting pathological findings in the commonly stranded harbor porpoise (Phocoena phocoena) on North Atlantic coastlines are essential to describe new and emerging causes of mortality. However, such studies often cannot be used as long-term health surveillance tools due to analytical limitations. We tested 31 variables gained from stranding-, necropsy-, dietary- and marine debris data from 405 harbor porpoises using applied supervised and unsupervised machine learning techniques to explore and analyze this large dataset. We classified and cross-correlated the variables and characterized the importance of the different variables for accurately predicting cause-of-death categories, to allow trend assessment for good conservation decision. The variable ‘age class’ seemed most influential in determining cause-of-death categories, and it became apparent that juveniles died more often due to acute causes, including bycatch, grey-seal-predation and other trauma, while adults of infectious diseases. Neonates were found in summer, and mostly without prey in their stomach and more often stranded alive. The variables assigned as part of the external examination of carcasses, such as imprints from nets and lesions induced by predators, as well as nutritional condition were most important for predicting cause-of-death categories, with a model prediction accuracy of 75%. Future porpoise monitoring, and in particular the assessment of temporal trends, should predominantly focus on influential variables as determined in this study. Pathogen- and contaminant assessment data was not available for all cases, but would be an important step to further complete the dataset. This could be vital for drawing population-inferences and thus for long-term harbor porpoise population health monitoring as an early warning tool for population change.

Evaluating bottom-up forcing of a rocky intertidal resource harvest on a high trophic-level consumer group

The importance of ecosystem-based management (EBM) frameworks for resource harvest has increased over the past several decades as ecosystems face numerous anthropogenic stressors. In these frameworks, resource managers must consider the suite of interactions that comprise food webs and how resource harvest drives responses in non-target organisms. In rocky intertidal zones along North Atlantic coastlines, rockweed (Ascophyllum nodosum)—a canopy-forming brown seaweed—has been commercially harvested for centuries, yet most research on the effects of harvest have focused on the responses of the target resource and the macroinvertebrate assemblage. In this study, we used a Before-After Control-Impact experiment to assess the bottom-up effects of commercial rockweed harvest on a high trophic-level consumer group (birds) in Maine (USA). Overall, there was no evidence for strong bottom-up forcing of rockweed harvest on birds' site visitation. There was a small (fewer than two birds) positive effect size of harvest during the one-year post-harvest recovery interval. Several of the trends observed for the full bird assemblage appear to be driven more strongly by the low tide than the high tide bird assemblage. Independent of treatment, site visitation by birds was low in our study (60% of surveys recorded no birds) and highlights questions about the use of rocky intertidal habitats relative to other habitat types in coastal birds' home ranges. To our knowledge, there are no comparable assemblage-level bird studies in this system that can provide context to our results. Further research on coastal birds’ habitat use within home ranges and food-web connections with rockweed-associated macroinvertebrates is needed to more confidently incorporate this high trophic-level consumer group into an EBM framework for a rocky intertidal resource harvest.

Morocco’s Atlantic coast: Exploring and discovering sites at high risk of marine erosion

Morocco's Atlantic coastline stretches from Tangier to Lagouira over a distance of around 3,000 km. It displays considerable geomorphological diversity depending on the structural domains, the nature and age of the terrain adjacent to the coastal profile, and even the degree of human covetousness and activity. In addition to a wealth of climato-eustatic records, coastal sedimentary dynamics, and prehistoric seismicity, there is evidence of an alarming retreat of the shoreline at sites such as Larache, Rabat, Safi, and Agadir. A project to research and map vulnerable sites with a view to forecasting risks in the field of coastal zone development is needed to avoid the dangers of marine aggression, which is likely to be amplified by extreme climate change and anthropogenic action in the context of increasingly strong littoralization.

Exploring marine biofouling on anthropogenic litter in the Atlantic coastline of Morocco

Today, the world is increasingly concerned about marine litter and its interaction with marine biodiversity. However, knowledge concerning the fouling organisms associated with marine litter is very limited in many of the world's marine environments. In this survey, we investigated biofouling on different types of marine litter washed up on all the coasts of the central Atlantic of Morocco. The findings revealed 21 fouling species belonging to 9 phyla (Arthropoda, Mollusca, Echinodermata, Annelida, Bryozoa, Porifera, Chlorophyta, Ochrophyta, and Ascomycota). More specifically, frequently observed fouling species include Mytilus galloprovincialis, Balanus laevis, Megabalanus coccopoma, and Pollicipes pollicipes species. Large marine litter items recorded the highest colonization of marine organisms in comparison to small ones. The frequency of occurrence (FO) of the species most commonly fouled on all coasts was Perforatus perforatus (FO = 48.60), followed by Mytilus galloprovincialis (FO = 45.80), Balanus trigonus (FO = 32.05), Balanus laevis (FO = 30.25), Megabalanus coccopoma (FO = 25.25), Bryozoa species (FO = 19.40), Spirobranchus triqueter (FO = 18.18), Lepas pectinata (FO = 14.45), and Pollicipes pollicipes (FO = 13.05). The majority of the species registered in this study are sessile. Substrate coverage by fouling taxa was significantly different between plastic substrate and other types of marine litter. Likewise, this study revealed that the proportion of fouling organisms is higher on rough surfaces. Overall, this research could be crucial to understanding the little-known subject of marine litter and its colonization by marine biota. Given that these marine litters can act as vectors and cause ecological, biogeographical, and conservation issues in the marine environment, minimizing the quantity of anthropogenic litter reaching the Moroccan Atlantic could significantly reduce its accumulation on the sea surface and seabed, thereby reducing the risk of invasion by non-indigenous species.

Teachers’ Utilization of Computer and Internet facilities for Effective Service Delivery in Secondary Schools in Calabar Education Zone; Cross River State, Nigeria

Aim: The main aim of this study is to examine teachers’ utilization of computer and internet facilities on effective service delivery in secondary schools in Calabar Education Zone.&#x0D; Study Design: The research design adopted for this study is a survey design to discover schools with the needed Information and Communication Technology (ICT) facilities and to seek the opinion of the respondent on utilization of computer and internet facilities for effective service delivery in government secondary schools.&#x0D; Area of the Study: This study was carried out in Calabar educational zone. The zone under research has seven (7) Local Government Area namely; Calabar south, Akpabuyo, Municipality, Akamkpa, Bakassi, Odukpani and Biase. The zone has eighty-one (81) secondary schools. The geographical locations of the study area are described as follows. The area share common boundary with Akwa Ibom State with the latitude of 5°4'52.46"N and a longitude of 8°20'59.7"E, Cameroon with latitude 4° 5' and 5° 40' and longitude 8° 25' and 8° 32 East. It lies within the vegetation belt of southern Nigeria and shares the Atlantic coastline with Bakassi to the East and the Republic of Cameroon to the West. Central Senatorial district of Cross River State with latitude of 5019’8.32”N and a longitude of 8020’59.7”E and Guinea the peninsula lies between latitudes 4°25′ and 5°10′N and longitudes 8°20′ and 9°08′E. It consists of a number of low-lying, largely mangrove covered islands covering an area of 665 km² (257 sq mi). &#x0D; Methodology: the instrument used in this study to enable data collection is ‘Teachers’ utilization of computer and internet facilities for effective service delivery questionnaire (TUCIFESDQ)’. The population of 1,796 teachers and the sample of 914 teachers out of the population are drawn for the study. 50 percent of the teachers in each of the schools in the zone with the expected ICT facilities were selected using simple random sampling for the study making a total of 914 teaching staff. Out of 914 copies of questionnaire distributed only 879 copies were return and used for the data analysis. Simple percentages, bar graph and One – way analysis of variance is used for the data analysis.&#x0D; Results: The result shows that there is a significant influence of teachers’ utilization of computer and internet facilities on service delivery in secondary school. This implies that 51.39% and 17.69% of teachers’ level of utilization of computers and internet in lesson delivery is low.&#x0D; Conclusion: Giving the outcome of this study, it is therefore concluded that utilization of ICT facilities such as; computers and internet will improve teachers’ effectiveness on service delivery and prepare students for a role in an information age.

Observed increases in North Atlantic tropical cyclone peak intensification rates

Quickly intensifying tropical cyclones (TCs) are exceptionally hazardous for Atlantic coastlines. An analysis of observed maximum changes in wind speed for Atlantic TCs from 1971 to 2020 indicates that TC intensification rates have already changed as anthropogenic greenhouse gas emissions have warmed the planet and oceans. Mean maximum TC intensification rates are up to 28.7% greater in a modern era (2001–2020) compared to a historical era (1971–1990). In the modern era, it is about as likely for TCs to intensify by at least 50 kts in 24 h, and more likely for TCs to intensify by at least 20 kts within 24 h than it was for TCs to intensify by these amounts in 36 h in the historical era. Finally, the number of TCs that intensify from a Category 1 hurricane (or weaker) into a major hurricane within 36 h has more than doubled in the modern era relative to the historical era. Significance tests suggest that it would have been statistically impossible to observe the number of TCs that intensified in this way during the modern era if rates of intensification had not changed from the historical era.

Colombian Orchidaceae: A Catalogue of the Pleurothallidinae

&#x0D; &#x0D; &#x0D; Colombia is a major biodiversity hotspot, having one of the richest orchid floras in the world. The country spans over a million square kilometers of land, hosting a multitude of different ecosystems thanks to the complexity of its mountainous systems and influences from neighboring countries in Central and South America, as well as the Atlantic and Pacific coastlines. Prior studies found an estimated 3591–4270 species of orchids occurring in Colombia, making it the most species-rich plant family in the country. About 35% of those orchids are members of the Pleurothallidinae subtribe, the largest group in the family and also that with the highest rate of species discovery. Here we record 1862 species of pleurothallids for the country, a significant increase from the 1286–1529 range estimated just a few years ago. We expect Pleurothallidinae to represent close to half the Colombian orchid flora. Colombia hosts roughly one third of all currently known taxa in the subtribe, and close to 60% of these species are found nowhere else in the world. These are clear indicators that the country is a highly important center of pleurothallid diversity and a key target for their conservation. The most species rich genera in the country are Stelis (521 species), Lepanthes (377 species), Pleurothallis (248 species) and Masdevallia (171 species). Country-level distribution is given for each accepted species. The closest floristic affinity is found with Ecuador, with which Colombia shares over 76% of the non-endemic Pleurothallidinae species, followed in the distance by Venezuela and Peru with just above one quarter of the non-endemics being shared. Numerous new country records are presented in the catalogue, many of which are illustrated with color photographs. We provide a full list of homotypic synonyms for each accepted taxon, as well as an annotated list of excluded taxa and newly proposed synonyms. Heterotypic synonyms are not listed, unless they are based on Colombian material. Typification for each accepted species is presented, with lectotypes, neotypes and epitypes being selected whenever necessary and available, as well as information regarding published illustrations. &#x0D; &#x0D; &#x0D;

68 Urinary Biomarkers of Benzene Exposure and Oxidative Damage in Residents of the Oil Extraction Area of Muanda, Dr Congo

Abstract The territory of Muanda, on the Atlantic coastline of the DR Congo, is an area of off-shore and on-shore oil extraction. Following concerns of the local population about the possible environmental and health consequences of these activities, a pilot study was performed in December 2015 to assess, among other issues, the exposure of residents of various relevant locations to oil-derived chemicals. We measured metabolites of benzene (t,t-Muconic Acid, MA, and S-Phenylmercapturic acid, S-PMA) by LC-MS and 8-hydroxy-2’-deoxyguanosine (8-OHdG, as an indicator of DNA damage) by ELISA, in urine spot samples of 53 volunteers (34 adults, 19 children, recruited by convenience sampling) living within areas of oil extraction with flaring (n=27), in an area where petroleum products were handled (n=14), and in a control area in the Mangroves National Park (n=12). Concentrations of both MA and S-PMA were increased among residents of the oil extraction areas (0.23±0.05 mg/L, 1.04±0.30 µg/L, respectively) and petroleum products area (0.32±0.08 mg/L, 1.74±0.63 µg/L, respectively) compared with controls (0.06±0.01 mg/L, 0.40±0.13 µg/L, respectively). Concentrations of of MA and S-PMA correlated with levels of 8-OHdG (RSpearman = 0.37, p&amp;lt;0.01). Our biomonitoring study revealed a low degree of benzene exposure among residents living in the oil extraction and petroleum handling areas compared to a control area. Although the levels of benzene metabolites were low, the positive correlation with 8-OHdG possibly indicates that pollution by hydrocarbons induced oxidative damage in this study population.

Iron–titanium sands of the Atlantic beaches between Tan-Tan and Tarfaya (southwest Morocco): Characterisation and origin

In Morocco, the most important placers of ferrotitanium minerals are found along the Laâouina–Cape Juby Atlantic coastline, where they accumulate in the upper parts of the foreshores. The heavy minerals would come from the dismantling of the acidic to intermediate magmatic rocks of the Precambrian Anti-Atlasic buttonholes and from the Meseta basement where crystallophyllous rocks predominate. The sands emanating from this erosion, once ejected by the rivers in the Atlantic, are transported by the littoral drift in the direction of the south before being trapped at the level of the great virgation of the shoreline of Laâouina–Cape Juby. The wind deflation, in its turn, reinforces this sorting by carrying away the white sands towards the continent and also the black sands sometimes. The cliffs along the coast of Laâouina–Sidi Akhfenir are, however, barriers against wind loss unlike the sector of Sidi-Akhfenir–Cape Juby where the continuous migration of sands to the hinterland is facilitated by the absence of cliffs. The conjunction of these factors has the consequence of weakening the retention of sands' ferrotitanium in the sector Sidi Akhfenir–Cape Juby compared with its counterpart of Laâouina–Sidi Akhfenir. In general, the Laâouina–Cape Juby coastline can be considered a morphological and hydrodynamic trap whose concentrations in ferrotitanium minerals are likely to earn the quality of a mining district despite its seasonal instability and the difficulty of estimating reserves. Indeed, in this supposed district, heavy minerals total about 95 % of the raw sediments and ilmenite predominates and its alteration state is only superficial.

Relative contributions of water-level components to extreme water levels along the US Southeast Atlantic Coast from a regional-scale water-level hindcast

A 38-year hindcast water-level product is developed for the US Southeast Atlantic coastline from the entrance of Chesapeake Bay to the southeast tip of Florida. The water-level modeling framework utilized in this study combines a global-scale hydrodynamic model (Global Tide and Surge Model, GTSM-ERA5), a novel ensemble-based tide model, a parameterized wave setup model, and statistical corrections applied to improve modeled water-level components. Corrected water-level data are found to be skillful, with an RMSE of 13 cm, when compared to observed water-level measurement at tide gauge locations. The largest errors in the hindcast are location-based and typically found in the tidal component of the model. Extreme water levels across the region are driven by compound events, in this case referring to combined surge, tide, and wave forcing. However, the relative importance of water-level components varies spatially, such that tides are found to be more important in the center of the study region, non-tidal residual water levels to the north, and wave setup in the north and south. Hurricanes drive the most extreme water-level events within the study area, but non-hurricane events define the low to mid-level recurrence interval water-level events. This study presents a robust analysis of the complex oceanographic factors that drive coastal flood events. This dataset will support a variety of critical coastal research goals including research related to coastal hazards, landscape change, and community risk assessments.