Relationship between the Guinea Current and the Coastal Upwelling in Northern of Gulf of Guinea

The variability of ocean circulation and sea surface temperature (SST) in the tropical Atlantic, especially in the Gulf of Guinea (GG), defines this region as exceptionally rich from an oceanographic perspective. The Guinea Current (GC), as the major surface current, plays a significant role in marine productivity and coastal upwelling in the GG. This coastal upwelling is known to influence the climate of the surrounding region, primary productivity and local fisheries. Studies on GC variability and its impact on this coastal upwelling have highlighted that the upwelling downstream of Cape Palmas is influenced by GC detachment, topographic variations and advective processes leading to significant vertical mixing. This study aims to analyze the interannual variability of the GC and its impact on coastal upwelling using the Coastal and Regional Ocean COmmunity model (CROCO). The model’s evaluation is conducted using observational data, specifically Geostrophic and EKman Current Observatory (GEKCO) and Ocean Surface Current Analysis (OSCAR) for currents, and Air-sea Fluxes for the global Tropic ocean-description (TROPFLUX) and Optimum Interpolation-Sea Surface Temperature (OI-SST) for temperature. Thus, the model evaluation indicates that it accurately replicates ocean circulation and SST patterns in the tropical Atlantic and the GG. The joint analysis of upwelling indices (surface and intensity) and the position of the GC core allowed us to conclude that the displacement of the GC core does indeed influence the upwelling indices in the northern part of GG. However, other oceanic and atmospheric mechanisms such as vertical diffusion and horizontal advection as proposed by previous studies may also affect the year-by-year variability of coastal upwelling in the northern GG.

Hydrodynamic Simulation of the Pagasitikos Gulf, Greece

Semi-enclosed sea basins have difficulty in recharging their waters due to limited communication with larger water bodies, with understandable consequences for their environmental status. This paper aims at the computational simulation of the hydrodynamic characteristics of the waters of the Pagasitikos Gulf (Greece), which has limited communication and water exchange with the Aegean Sea and is subject to intense environmental pressures The Estuary, Lake & Coastal Ocean 3d hydrodynamic Model (ELCOM 2.2) combined with its later version Aquatic Ecosystem Model-3d (AEM3D) were used for the simulation. The simulation included the topography of the area, the bay’s bottom geometry, atmospheric loadings, tides, the influence of the Coriolis force and boundary conditions. The hydrodynamic behaviour of the bay, water circulation, velocities at the surface and in depth, water recharge and residence time throughout the bay, density variation and other factors were examined to determine the impact of all these on the aquatic ecosystem.

Effects of Neo-Tethyan evolution on the petroleum system of Persian Gulf Superbasin

Considering the Neo-Tethyan tectonic process and the resulting environmental changes,a geodynamic model of“one-way train loading”is proposed to analyze the formation and evolution mechanism of the Persian Gulf Superbasin with the most abundant hydrocarbons in the world.The Persian Gulf Superbasin has long been in a passive continental margin setting since the Late Paleozoic in the process of unidirectional subduction,forming a superior regional space of hydrocarbon accu-mulation.During the Jurassic-Cretaceous,the Persian Gulf Superbasin drifted slowly at low latitudes,and developed multiple superimposed source-reservoir-caprock assemblages as a combined result of several global geological events such as the Hadley Cell,the Equatorial Upwelling Current,and the Jurassic True Polar Wander.The collision during the evolution of the foreland basin since the Cenozoic led to weak destruction,which was conducive to the preservation of oil and gas.Accordingly,it is be-lieved that the slow drifting and long retention in favorable climate zone of the continent are the critical factors for hydrocarbon enrichment.Moreover,the prospects of hydrocarbon potential in other continents in the Neo-Tethyan were proposed.

Multi-scenario Simulation for 2060 and Driving Factors of the Eco-spatial Carbon Sink in the Beibu Gulf Urban Agglomeration, China

Since China announced its goal of becoming carbon-neutral by 2060, carbon neutrality has become a major target in the development of China's urban agglomerations. This study applied the Future Land Use Simulation(FLUS) model to predict the land use pattern of the ecological space of the Beibu Gulf urban agglomeration, in 2060 under ecological priority, agricultural priority and urbanized priority scenarios. The Integrated Valuation of Ecosystem Services and Trade-offs(In VEST) model was employed to analyse the spatial changes in ecological space carbon storage in each scenario from 2020 to 2060. Then, this study used a Geographically Weighted Regression(GWR) model to determine the main driving factors that influence the changes in land carbon sinking capacity. The results of the study can be summarised as follows: firstly, the agricultural and ecological priority scenarios will achieve balanced urban expansion and environmental protection of resources in an ecological space. The urbanized priority scenario will reduce the carbon sinking capacity. Among the simulation scenarios for 2060, carbon storage in the urbanized priority scenario will decrease by 112.26 × 10^(6) t compared with that for 2020 and the average carbon density will decrease by 0.96 kg/m^(2) compared with that for 2020. Carbon storage in the agricultural priority scenario will increase by 84.11 × 10^(6) t, and the average carbon density will decrease by 0.72 kg/m^(2). Carbon storage in the ecological priority scenario will increase by 3.03 × 10^(6) t, and the average carbon density will increase by 0.03 kg/m^(2). Under the premise that the population of the town will increases continuously, the ecological priority development approach may be a wise choice.Secondly, slope, distance to river and elevation are the most important factors that influence the carbon sink pattern of the ecological space in the Beibu Gulf urban agglomeration, followed by GDP, population density, slope direction and distance to traffic infrastructure.At the same time, urban space expansion is the main cause of the changes of this natural factors. Thirdly, the decreasing trend of ecological space is difficult to reverse, so reasonable land use policy to curb the spatial expansion of cities need to be made.

Progression of intervention-focused research for Gulf War illness

The Persian Gulf War of 1990 to 1991 involved the deployment of nearly 700,000 American troops to the Middle East.Deployment-related exposures to toxic substances such as pesticides,nerve agents,pyridostigmine bromide(PB),smoke from burning oil wells,and petrochemicals may have contributed to medical illness in as many as 250,000 of those American troops.The cluster of chronic symptoms,now referred to as Gulf War Illness(GWI),has been studied by many researchers over the past two decades.Although over$500 million has been spent on GWI research,to date,no cures or condition-specific treatments have been discovered,and the exact pathophysiology remains elusive.Using the 2007 National Institute of Health(NIH)Roadmap for Medical Research model as a reference framework,we reviewed studies of interventions involving GWI patients to assess the progress of treatment-related GWI research.All GWI clinical trial studies reviewed involved investigations of existing interventions that have shown efficacy in other diseases with analogous symptoms.After reviewing the published and ongoing registered clinical trials for cognitivebehavioral therapy,exercise therapy,acupuncture,coenzyme Q10(CoQ10),mifepristone,and carnosine in GWI patients,we identified only four treatments(cognitive-behavioral therapy,exercise therapy,CoQ10,and mifepristone)that have progressed beyond a phase II trial.We conclude that progress in the scientific study of therapies for GWI has not followed the NIH Roadmap for Medical Research model.Establishment of a standard case definition,prioritized GWI research funding for the characterization of the pathophysiology of the condition,and rapid replication and adaptation of early phase,single site clinical trials could substantially advance research progress and treatment discovery for this condition.

Seasonal Variability of Biofouling Community Structure in the Gulf of Mannar,Southeast Coast of India:A Multivariate Approach

In this research,an Underwater Biofouling Panel(UWBFP)system was erected for the qualitative and quantitative estimation of macro fouling organisms in the Gulf of Mannar.Forty-four biofoulers were identified from four types of selected test panels.Among these biofoulers,Amphibalanus amphitrite(Darwin,1854)was the dominant one.The concrete panel encouraged the highest barnacle density compared to the other panels.Three series of test panels were used to assess the seasonal density of biofouling communities.The overall variation in barnacle count in the seaward and shoreward sides of all these three series were tested.They were found to be significantly different from each other.The greater variations in the barnacle density observed in this study in A-series of test panels could be due to the lack of or absence of other foulers to compete within the fortnight.The Shannon-Wiener species diversity index showed the highest diversity in wood substratum among the three series with greater accumulation of different types of fouling organisms.Multivariate analyses were also performed to understand the seasonal variation as well as the settlement pattern on the different directions of test panels based on validated data.PCA showed a strong variability(PC1 between 70.8%and 98.6%variance)between the directions of the panels in connection with barnacle density.The shade plot and CAP analysis segregated the short-term A-series test panels from the long-term(B-and C-series)test panels.Hence,the output was helpful in understanding the recruitment status of various faunal resources involved in the biofouling processes.

Study on Wave Characteristics from the South Atlantic Ocean to the Gulf of Guinea Based on Short-Term Numerical Simulation in Winter Season

Waves play a major role in the ocean phenomena in the Gulf of Guinea(GoG). In order to reveal the spatial-temporal distribution characteristics and the propagation mechanism of waves from the South Atlantic Ocean to the GoG, 4typical points located in mid-latitude of South Atlantic(14°30′W, 30°0′S), south of the GoG(10°30′W, 15°0′S), offshore of the GoG(0°0′, 0°0′) and near shore of the GoG(6°4′58.8″W, 4°3′36″S) are selected, and waves from Atlantic Ocean to GoG are simulated by using a two-layer-nesting wave numerical model SWAN(Simulating Waves Nearshore). The results show that the hybrid waves(waves hereafter) and the swells have strong relationship with local wind in Roaring Forties and at mid-latitude of South Atlantic Ocean, while there is no obvious correlation between waves and local winds in the GoG. Swells are generated in the South Atlantic Ocean and propagate into the GoG. 2D wave spectra at the four selected typical points are simulated. The spectral pattern and wave component structure indicate that the wave system in GoG is dominated by the S-SW swells generated from Roaring Forties and mid-latitude of South Atlantic, whether it is at maximum(2.2-2.8 m), medium(1.8-2.2 m) or minimum(1.2 m) significant wave height in the GoG during simulation period.

Chemical exposures and suspected impacton Gulf War Veterans

Gulf War Illness(GWI) encompass a spectrum of maladies specific to troops deployed during the Persian Gulf War(1990–1991). There are several hypothesized factors believed to contribute to GWI, including(but not limited to)exposures to chemical agents and a foreign environment(e.g., dust, pollens, insects, and microbes). Moreover, the inherent stress associated with deployment and combat has been associated with GWI. While the etiology of GWI remains uncertain, several studies have provided strong evidence that chemical exposures, especially neurotoxicants,may be underlying factors for the development of GWI. This mini style perspective article will focus on some of the major evidence linking chemical exposures to GWI development and persistence decades after exposure.

Forty-year investigation of wave power in energetic region of Persian Gulf in Iranian territorial waters by using short-term and new long-term stability assessment parameters

The wave power in high potential area of the northern Persian Gulf(near to Iranian coastal areas)is assessed by taking into account the temporal and spatial distributions of wave power for a period of forty years.For this purpose,assimilated wind data of European Centre for Medium-Range Weather Forecasting Interim Reanalysis(ERA-Interim),and hydrography data of General Bathymetric Chat of the oceans(GEBCO)are used as SWAN model.Seven locations are investigated in the study area by considering the amount of coefficient of variation,the amount of average annual power,and the short-term and a new long-term(decadal variability index)power stability assessment parameters.The results showed more stability in the eastern parts of the study area and concluded that a narrow line between the point which is in the middle and another point which is in the eastern middle part of the study area may be the best locations for more investigation and the feasibility study for energy converter farms.Also,it is found that the middle part of the study region with about 2.5 kW/m power is the most energetic area.It is concluded that the dominant direction of wave power distribution in all points is the northeast,and this dominant direction has not changed during the forty-year period.It is observed that the mean annual energy increases with a slight slope in the total 40 a,and this increasing trend is more obvious in the fourth decade.Although it is observed that the wave power of the second decade has the most stability and the least variation,the wave power in the fourth decade has the most variation.Moreover,the results showed that the study region’s wave power increase by approximately a mean change rate of 0.027 kW/(m·a);and the maximum change rate of wave power was in the northwest part and the minimum change rate of wave power was in the southeast part which were about 0.036 kW/(m·a)and 0.014 kW/(m·a),respectively.

Gravity anomalies determined from mean sea surface model data over the Gulf of Mexico

With the improvements in the density and quality of satellite altimetry data,a high-precision and high-resolution mean sea surface model containing abundant information regarding a marine gravity field can be calculated from long-time series multi-satellite altimeter data.Therefore,in this study,a method was proposed for determining marine gravity anomalies from a mean sea surface model.Taking the Gulf of Mexico(15°–32°N,80°–100°W)as the study area and using a removal-recovery method,the residual gridded deflections of the vertical(DOVs)are calculated by combining the mean sea surface,mean dynamic topography,and XGM2019e_2159 geoid,and then using the inverse Vening-Meinesz method to determine the residual marine gravity anomalies from the residual gridded DOVs.Finally,residual gravity anomalies are added to the XGM2019e_2159 gravity anomalies to derive marine gravity anomaly models.In this study,the marine gravity anomalies were estimated with mean sea surface models CNES_CLS15MSS,DTU21MSS,and SDUST2020MSS and the mean dynamic topography models CNES_CLS18MDT and DTU22MDT.The accuracy of the marine gravity anomalies derived by the mean sea surface model was assessed based on ship-borne gravity data.The results show that the difference between the gravity anomalies derived by DTU21MSS and CNES_CLS18MDT and those of the ship-borne gravity data is optimal.With an increase in the distance from the coast,the difference between the gravity anomalies derived by mean sea surface models and ship-borne gravity data gradually decreases.The accuracy of the difference between the gravity anomalies derived by mean sea surface models and those from ship-borne gravity data are optimal at a depth of 3–4 km.The accuracy of the gravity anomalies derived by the mean sea surface model is high.

A three-dimensional Moho depth model beneath the Yemeni highlands and rifted volcanic margins of the Red Sea and Gulf of Aden, Southwest Arabia

Knowing Moho discontinuity undulation is fundamental to understanding mechanisms of lithosphereasthenosphere interaction, extensional tectonism and crustal deformation in volcanic passive margins such as the study area, which is located in the southwestern corner of the Arabian Peninsula bounded by the Red Sea and the Gulf of Aden. In this work, a 3D Moho depth model of the study area is constructed for the first time by inverting gravity data from the Earth Gravitational Model(EGM2008) using the ParkerOldenburg algorithm. This model indicates the shallow zone is situated at depths of 20 km to 24 km beneath coastal plains, whereas the deep zone is located below the plateau at depths of 30 km to 35 km and its deepest part coincides mainly with the Dhamar-Rada ’a Quaternary volcanic field. The results also indicate two channels of hot magmatic materials joining both the Sana’a-Amran Quaternary volcanic field and the Late Miocene Jabal An Nar volcanic area with the Dhamar-Rada’a volcanic field. This conclusion is supported by the widespread geothermal activity(of mantle origin) distributed along these channels,isotopic data, and the upper mantle low velocity zones indicated by earlier studies.

Regional Intrusive Signature from the Cameroon Coastal Basins to Bioko Island in Equatorial Guinea (Gulf of Guinea) Using Gravity Studies

The Gulf of Guinea constitutes an area of great petroleum potential yet with very limited geophysical research information. Consequently in this study, a Bouguer anomaly map has been computed from gravity data covering regions stretching from the Cameroon coastal basins to Bioko island (formerly Fernando Po) which is part of Equatorial Guinea. The data were further processed for Source Edge Detection (SED), Euler 3D deconvolution, 3D surface oriented models and 3D voxel solutions. The results confirmed the presence of previously identified intrusive bodies around the Douala and Kribi/Campo sedimentary sub-basins and went ahead to suggest a probable continuity between these two. A possible extension of this body offshore the Gulf of Guinea right up to Bioko island with very striking similarities was also highlighted and it shows characteristic variations in the depth to the surface of the body at different locations.

The Impact of Climate Change on the Stratification of Coastal Areas of the Euboean Gulf and the Diffusion of Urban Wastewater in Them

Hydrodynamic circulation in a marine environment, characterized by the influence of strong tides, atmospheric loading and bathymetry, is a complex phenomenon. The physical and hydrodynamic characteristics of this flow are absolutely crucial for the vertical mixing of the sea masses and consequently for the mixing of their physico-chemical parameters, such as nutrients and oxygen, as well as for the diffusion and dispersion of passive pollutants, the recharge of the waters and the general environmental situation. This paper examines the effect of a future increase in mean air temperature on the water column stratification of coastal areas of interest, which are subject to the above loadings and receive treated urban wastewater, and how this increase could affect their diffusion and mixing of conservative pollutants contained therein.

The Hydrodynamic Behaviour of Euboean Gulf Coastal Areas and the Mixing of the Physico-Chemical Characteristics of Urban Sewage Discharged into Them under the Influence of Climate Change

The hydrodynamic circulation within the marine environment is a complex phenomenon, characterized by the interplay of strong tidal forces, atmospheric influences, and bathymetric features. The physical and hydrodynamic attributes of this flow play a pivotal role in promoting vertical mixing of seawater masses, thereby facilitating the integration of their physical and chemical parameters, including nutrients and oxygen. Additionally, they are instrumental in governing the dispersion and diffusion of pollutants originating from urban sewage, contributing to the overall water renewal process and environmental quality. This study investigates the potential impact of anticipated increases in average air temperatures on water column stratification in coastal regions susceptible to these dynamic influences. These areas receive treated urban sewage, and the study aims to assess how these temperature changes might influence the dispersion and mixing of pollutant loads present in these coastal waters.

RMPP-based Study on the Oceanfront Ecotourism Development Mode——A Case Study of the Beibu Gulf in Guangxi Zhuang Autonomous Region of China

By taking the Beibu Gulf in Guangxi Zhuang Autonomous Region of China for example,RMPP mode was proposed on the basis of the original RMP analysis to analyze the relationship among resource,market,product and protection of local oceanfront tourism.Sustainable development mode of oceanfront ecotourism was discussed,and implementation strategies were given.It was stressed that resource development should be transformed from resource planning to ecological protection,production design should follow the road of innovative development,market development should be transformed from 3S to 3N,regional cooperation should be enhanced to ensure the government instruction and community participation.This study was to propose new concepts for the protection and development of oceanfront ecotourism resources,and also references for the ecotourism development of Beibu Gulf.

Lower blood malondialdehyde is associated with past pesticide exposure:findings in Gulf War illness and healthy controls

Background: Malondialdehyde(MDA) is a candidate general marker of oxidative stress(OS). We sought to assess the relation of MDA to Gulf War illness(GWI) and to a variety of exposures.Methods: This is an observational study involving subjects from Southern California recruited from October 2011 to May 2014. MDA was assessed in 81 participants(41 GWI-cases, 40 controls). General and Gulf-specific exposures were elicited. MDA case–control comparison was restricted to 40 matched pairs. The potential association between MDA and exposures was assessed using regression analyses. Gulf-specific exposures were incorporated into a case-specific model.Results: Plasma MDA was significantly lower in GWI-cases than controls. Composite pesticide and fuel-solvent exposures negatively predicted MDA in the total sample, as well as in the analyses that included either GWI-cases or controls only. Self-reported exposure to organophosphate(OP) nerve gas was a strong predictor for lower MDA level in veterans with GWI.Conclusions: Past pesticide exposures predicted lower MDA in both veterans with GWI and in healthy controls.

Contribution of Gulf of Aqaba Water(GAW)to Red Sea waters

Data obtained on hydrography and currents in meridional sections in the Gulf of Aqaba and the Red Sea in November 2013 and March 2015 were used to determine the extent of contribution of Gulf of Aqaba Water(GAW)to the formation of Red Sea waters.The southward flow across the Strait of Tiran was^0.02 Sv in both periods which is direct evidence of significant contribution of GAW to Red Sea waters in autumn-winter.A multiple tracer analysis using temperature,salinity,and dissolved oxygen showed that the GAW,on entry into Red Sea,bifurcates into two branches.The upper branch exiting the Strait in the depth range 150-220 m has densities between 28.3 and 28.5,continues to flow at the same depths,and feeds the Red Sea Overflow Water(RSOW).The lower branch that exits between 220 and 250 m above the sill cascades down its southern face,mixes with northward recirculating branch of Red Sea Deep Water(RSDW)and sinks to the bottom and forms part of southward-flowing RSDW.Contribution of GAW to northern Red Sea waters below 100 m depth was 36±0.4%in November 2013 and 42.1±5.4%in March 2015.GAW is traceable down to 17-19°N in RSDW and RSOW.Volume contribution of GAW to RSOW was 9.6*1012 m3,about 50%higher than that for RSDW(6*1012 m3).Analyses of the data from R.V.Maurice Ewing cruise in 2001 gave similar results and lend support for these deductions.

Modern sedimentation rates in the intertidal zone on the west coast of the Bohai Gulf

On the basis of the measurement of 210Pbex and 137Cs activities in the sediment cores taken from the intertidal zone on the west coast of the Bohai Gulf, the average sedimentation rates of modern sediments are calculated. The results indicate that in the sandy area of the intertidal zone (from Daogouzi to the Duliujian River), the sedimentation rate from 1955 to 1963 is 3.43-4.06 cm/a, and is within the range of 0.65￣1.59 cm/a since 1963. The average sedimentation rate in the muddy area (around Qikou) is approximately 1.81 cm/a. The results above suggest that the sandy area of the intertidal zone has experienced rapid sedimentation from the 1950s to the 1960s, and the sedimentation slows down after the 1960s, and the sedimentation rates increase from north to south spatially. The rapid sedi- mentation from the 1950s to the 1960s in the sandy area is due to the fact that North China has plentiful precipitation during this period and the intertidal zone is supplied with abundant matter sources for sedimentation. After the 1960s, the weakened sedimentation may be a result of the reduction of sand transported to the intertidal zone, which is a consequence of diminished rainfall in North China and intensive human activities in the Haihe basin.

Antimicrobial potential of selected brown seaweeds from Vedalai coastal waters,Gulf of Mannar

Objective:To evaluate the antimicrobial activity of Turbinaria conoides(T.conoides).Padina gymnospora(P.gymnospora) and Sargassum tenerrimum against human bacterial and fungal pathogens.Methods:The antimicrobial activities of the extracts against various organisms were tested by using disc diffusion method.Results:The methanol extract showed the better result than the other extracts.Whereas,the strong antibacterial inhibition was noted in methanol extracts of P.gymnospora against Bacillus subtilus(26.33±1.86) and the mild inhibition of ethanol extracts from T.conoides against Klebsiella pneumoniae(2.33±0.51).Acetone extraction of P. gymnospora had strong antifungal inhibition against Cryptococcus neoformans(23.00±1.78), and acetone extract of T.conoides had mild inhibition against Aspergillus niger(3.00±0.89). Conclusions:The seven different solvent extracts of seaweeds used in the present study have shown significant bacterial action.Further,a detailed study on the principle compound in the seaweeds which is responsible for antimicrobial activity is still needed and it can be achieved by using advanced separation techniques.

The application of geostatistics in grain size trend analysis： A case study of eastern Beibu Gulf

There are 71 surface sediment samples collected from the eastern Beibu Gulf. The moment parameters （i.e. mean size, sorting and skewness） were obtained after applying grain size analysis. The geostatistical analysis was then applied to study the spatial autocorrelation for these parameters; while range, a parameter in the semivariogram that meters the scale of spatial autocorrelation, was estimated. The results indicated that the range for sorting coefficient was physically meaningful. The trend vectors calculated from grain size trend analysis model were consistent with the annual ocean circulation patterns and sediment transport rates according to previous studies. Therefore the range derived from the semivariogram of mean size can be used as the characteristic distance in the grain size trend analysis, which may remove the bias caused by the traditional way of basing on experiences or testing methods to get the characteristic distance. Hence the results from geostatistical analysis can also offer useful information for the determination of sediment sampling density in the future field work.