Lagoons are ecosystems for biodiversity and the livelihoods of coastal communities. The main objective of the study was to analyze the variability of arsenic concentrations in gastropods and bivalves in the Aby and Te...Lagoons are ecosystems for biodiversity and the livelihoods of coastal communities. The main objective of the study was to analyze the variability of arsenic concentrations in gastropods and bivalves in the Aby and Tendo lagoons, taking into account spatial, seasonal and hydrological variations. The study was carried out in four stages spread over two successive hydroclimatic cycles, including two seasons during the rainy season and two more during the dry season. The samples were taken in two areas of the Aby and Tendo lagoons. Arsenic levels were measured by ICP-MS. The results showed that mean arsenic concentrations in the muscles of organisms in Aby Lagoon ranged from 0.01 to 1.26 μg As/g, with a mean and median of 0.17 and 0.06 μg As/g, respectively. Fish had the highest levels of arsenic, followed by crustaceans, while molluscs and plants had lower and comparable concentrations of As. Arsenic concentrations in tilapia and jawbones varied significantly between sites and seasons, with higher concentrations at Tendo and during the rainy season. Arsenic concentrations in gastropods and bivalves were significantly higher than those of other species, with averages of 0.74 and 1.03 mg As/kg, respectively.展开更多
Selenium is a trace element that can have both beneficial and harmful effects on aquatic life. The Aby Lagoon is a coastal environment in Côte d’Ivoire that receives selenium inputs from various natural and anth...Selenium is a trace element that can have both beneficial and harmful effects on aquatic life. The Aby Lagoon is a coastal environment in Côte d’Ivoire that receives selenium inputs from various natural and anthropogenic sources. The aim of this study was to assess the levels of selenium in the sediments of the Aby Lagoon and its tributaries, the Tanoe River and the Tendo Lagoon, and to examine the spatial and seasonal variations of selenium concentrations. Sediment samples were collected from different sites and seasons, and selenium concentrations were measured by atomic fluorescence spectrometry. The results showed that the average concentration of selenium in the sediments of the Aby Lagoon was 0.82 mg/kg, indicating moderate contamination. The concentration of selenium varied between sites and seasons, with higher values in the channel of the Tendo Lagoon and during the dry season. The study highlighted the complexity of selenium dynamics in aquatic ecosystems, and the need to take into account seasonal and spatial variability as well as interactions between environmental factors. The study also suggested potential ecotoxicological risks for some sensitive organisms in certain areas of the lagoon. This study contributes to the knowledge of the dynamics of selenium in lagoon ecosystems and to the assessment of the environmental risks associated with its presence.展开更多
The aim of this study was to investigate temporal changes in mangrove root fouling species settled on artificial substrates in the mangrove zone of the Port Royal lagoons and to determine the effect of stress as part ...The aim of this study was to investigate temporal changes in mangrove root fouling species settled on artificial substrates in the mangrove zone of the Port Royal lagoons and to determine the effect of stress as part of a larger project to determine appropriate indicators of eutrophication in mangrove lagoons. Five Perspex? panels were suspended in the prop root zone at five contrasting stations within the Port Royal mangroves and the fouling organisms were monitored fortnightly using underwater digital photography. Nine taxonomic categories of epibionts were recorded of which the most prevalent group was the ascidians. Barnacles and hydroids were initially found to have established on the artificial substrates at all stations but were quickly replaced by ascidians and bryozoans at most. Species composition was similar between all stations by the end of the study, however, the dominant taxa were different. Sheltered lagoons like Fort Rocky lagoon (north and south) had a clear dominance of non-shelled species (ascidians and polychaetes) by the end of the study, while molluscs- bivalves and barnacles dominated Hurricane Refuge lagoon. This station, deemed to be experiencing greatest stress due to exposure to the eutrophic Kingston Harbour, also had the greatest proportion of shelled taxa represented in the epibiont biomass at the end of the study. Differences in biomass and species composition of root fouling species can therefore be used to indicate water quality in the mangrove lagoons.展开更多
Calanoida copepod, Drepanopus bispinosus occurred in both saline lakes, Burton ( S=40) and Fletcher ( S = 56) in Vestfold Hills, Antarctica. Evident differences between two populations in biology and physiology were o...Calanoida copepod, Drepanopus bispinosus occurred in both saline lakes, Burton ( S=40) and Fletcher ( S = 56) in Vestfold Hills, Antarctica. Evident differences between two populations in biology and physiology were observed in September and December, 1984. The population in the Burton lake was denser with stronger body and more tolerant to temperature and salinity than that in the Fletcher Lake, reflecting their possible differences of genetic or nongenetic adaptation. The population in the Burton lake has been adaptated to the lake environment, and the population in the Flethcer Lake is in the acclimatization course in the lake habitat.展开更多
The genetic diversity and the potential toxicity of bloom-forming cyanobacteria were studied in four lagoons located in the state of Sao Paulo (Campinas, Limeira and Piracicaba cities). Bloom samples were collected on...The genetic diversity and the potential toxicity of bloom-forming cyanobacteria were studied in four lagoons located in the state of Sao Paulo (Campinas, Limeira and Piracicaba cities). Bloom samples were collected on the water surface and cyanobacterial communities were evaluated using DGGE fingerprinting and 16S rDNA clone library. The amplification of genes encoding secondary metabolites such as microcystin (mcy), anatoxin (ana), cylindrospermopsin (cyr), saxitoxin (sxt), cyanopeptolin (mcn) and aeruginosin (aer) was performed and their production analyzed by LC-MS. The comparison of DGGE banding pattern among the different water samples suggested that some operational taxonomic units (OTUs) in these locations were predominant over others. The 16S rDNA clone libraries sequences matched with nine different known cyanobacterial genera available in NCBI, identified as Anabaena, Brasilonema, Cylindrospermopsis, Limnococcus, Microcystis, Nostoc, Pseudanabaena, Synechococcus and Woronichinia. The lagoons ESALQ2, Taquaral and Limeira had more than 80% of the cyanobacterial community assigned to the genus Microcystis. Genes encoding aeruginosin, cyanopeptolin and microcystin synthetases and saxitoxin synthase were amplified, and LC-MS/MS confirmed the production of aeruginosin, cyanopeptolin and microcystin. Rapid and sensitive methods for the detection of these secondary metabolites, especially toxins, using chemical and molecular tools together, can be used for a faster diagnostic of toxic cyanobacterial blooms.展开更多
The salt conservation law was applied, for the first time, in order to compare the real and calculated values of water outflow (m3/s) and residence time (days) in the lagoons of Ayla Oasis at the northernmost tip of t...The salt conservation law was applied, for the first time, in order to compare the real and calculated values of water outflow (m3/s) and residence time (days) in the lagoons of Ayla Oasis at the northernmost tip of the Gulf of Aqaba. The aim is to obtain the scientific bases of monitoring beside the real observation in areas that could not be measured directly by the current meters. The real measurements of water current by Acoustic Doppler Current Profiler (ADCP) workhorse 600 kHz, salinity and density by the Conductivity, Temperature and Depth meter (CTD 19plusV2), were collected during the period June 2012-May 2013. The statistical analysis was performed using Statview (5.0) software. The results revealed highly significant correlation between the real and calculated values for both water flow (r = 0.90;P = 0.0001) and residence time (r = 0.89;P 3/s) and residence time (0.80 ± 0.72 days) should be taken into consideration to correct the calculated values.展开更多
This study presents a biotic index （∧） for measuring environmental quality in the coastal lagoons of the Mediterranean. Index A considers combined anthropogenic （pollution） and natural factors （prohibitive salin...This study presents a biotic index （∧） for measuring environmental quality in the coastal lagoons of the Mediterranean. Index A considers combined anthropogenic （pollution） and natural factors （prohibitive salinity, anoxia, toxic blooms, isolation from sea, etc.） of deterioration. The method is based on the principle of indicator species and on the conceptual scheme developed by Frisoni et al. （1984） according to which there are six possible sub-assemblages （Zones） of benthic macrofauna, each indicating a different level of environmental quality. The procedure requires defining the relative extent of the Zones in the lagoon under study, and the number of species and the mean biomass of benthic macrofauna present in each. The three metrics are applied in the index formula and the resulting number from one to ten indicates increasing environmental quality. The authors have validated the index by applying it to two lagoons, Lesina and Varano （S.Adriatic, Italy）.展开更多
The management of living resources and space requires continuous assessments in order to adjust deviations as necessary for sustainable use. It is in this context that the present study was conducted and aims on the o...The management of living resources and space requires continuous assessments in order to adjust deviations as necessary for sustainable use. It is in this context that the present study was conducted and aims on the one hand to assess the dynamics of land use in the basin of the five-finger lagoons and on the other hand to assess the degree of their vulnerability to organic pollution. Thus, the satellite images were collected in free access on the site http://earthexplorer.usgs.gov/ of the USGS (US Geological Survey) of NASA. Image correction was performed with ENVI 5.1 software and classification was performed with ArcGIS 10.8 software. The degree of vulnerability was evaluated through the weighting of different parameters (slope, land use, type of pass, runoff, and density of the hydrobiological network) by the multi-criteria method of Saaty (Analytic Hierarchy Process Methods) and the application of mapping. It is found that for the dynamics of land use, forests, savannahs and plantations have experienced a significant reduction in their area (respectively 98.9%, 99.60% and 77.10%) between 1990 and 2020. As for settlements, water bodies and swamps, they have increased in area to different proportions. The soils are more denuded (Tc = 1264%). This makes the living space vulnerable and therefore facilitates the transfer of pollutants to the aquatic environment. The evaluation of the degree of vulnerability to pollution of the lagoons of the basin showed that the Toho-and Todougba lagoons are under a very high degree of vulnerability (73% - 100%) and do not augur well for the living resources. The other lagoons, notably the Dathi and Djonou lagoons, are also under stress from the pressures of surrounding activities. It is therefore important to assess the level of pollution of the Toho and Todougba lagoons through pollution indices in order to make decisions that will allow their sustainable use, especially for aquaculture.展开更多
In this research, three existing dynamic mathematical models for aerated lagoons were applied to an aerated facultative lagoon (AFL) plant for municipal wastewater treatment. The models’ ability to describe the behav...In this research, three existing dynamic mathematical models for aerated lagoons were applied to an aerated facultative lagoon (AFL) plant for municipal wastewater treatment. The models’ ability to describe the behavior of the primary lagoon was evaluated, and the advantages and limitations of the three models were compared. For this purpose, 7-year operational data from the municipal WWTP were collected and processed;other necessary data—like dynamic temperature values— were estimated. A 2-year period was used for model calibration, while the remaining 5 years served as validation period. One of the models showed poor calibration fit values in the effluent concentration description (R2 of 0.242 and RMSE of 16.8 mg/L);however, with some modifications the adjust was enhanced (R2 of 0.409 and RMSE of 14.0 mg/L);a second model displayed a poor to moderate adjust (0.489 and 13.0 mg/L, respectively), and the third model achieved a moderate fit (0.528 and 11.9 mg/L), though it provided an overestimation of effluent concentration, especially in periods of heavy and frequent rain;this model with some adaptations the adjust was enhanced (R2 of 0.575 and RMSE of 11.4 mg/L). The validation fits are even lower, illustrating the inability of these models to properly describe the AFL behavior. The possible causes of the models’ inadequacy are discussed. Finally, it is established that in terms of AFL behavior description more research and model development are needed.展开更多
The article summarizes 34 years (1980-2014) of the original observations of the genesis and evolution stages of the Caspian lagoons. A model of the formation and evolution of the coastal lagoons has been worked out. I...The article summarizes 34 years (1980-2014) of the original observations of the genesis and evolution stages of the Caspian lagoons. A model of the formation and evolution of the coastal lagoons has been worked out. It can be applied to the modelling of the global geoecological scenario along all the world’s coasts characterized by a steady transgression of their marine areas. The lagoons had been formed in a “bottleneck”, a narrow migration corridor, traversed by the largest migration route of trans-Palearctic species in Russia. This route is part of the West Siberian-East African migration range. Year round bird censuses (n = 746) were taken by the author in 1995-2014 along two key routes in the regions of Turalinskaya and Sulakskaya lagoons of Daghestan (the western coast of the Middle Caspian Sea). The meridional orientation of lagoons, location of the migration trajectory and a wide range of habitats in the study area contribute to the preservation of 294 Eurasian bird species. After formation of the lagoons, the breeding avifauna of the Caspian Sea Region of Central Daghestan has added 32 taxa. Among the species recorded at the lagoons, 50 are included in the IUCN Red List, Red Data Books of Russia and Daghestan. The reconstruction analysis of the migration trajectory compiled according to the data of the Russian Bird Ringing Centre allowed us to determine the population distribution geography for the birds regularly migrating along the western coast of the Caspian Sea and refine borders of theWest Siberian-East African migration range. Thus, according to the information received, the current migratory range should be greatly extended to cover the area from the British Isles in the West Palearctic to Lake Baikal in the east, including the extreme west and south of Africa.展开更多
Lagoons are a major coastal environment in West Africa.They provide a plethora of resources,ecosystem services and economic benefits yet a diverse set of inter-connected stressors are a challenge to their sustainabili...Lagoons are a major coastal environment in West Africa.They provide a plethora of resources,ecosystem services and economic benefits yet a diverse set of inter-connected stressors are a challenge to their sustainability.A scoping study of the published literature pertaining to lagoons within the region was undertaken to reveal the nature of these stressors and identify gaps in knowledge,providing a resource to inform coastal management practices and reveal areas for future study.Thirty-one lagoons were identified from the scoping exercise covering Nigeria,Benin,Togo,Ghana,Cote D’Ivoire,Liberia and Senegal.The DAPSI(W)R(M)framework was used to structure analysis of the litera-ture and surface key environmental themes.Key drivers and activities established are the use of lagoon resources and expansion of lagoon settlements.The resultant identified pressures are waste,overuse of resources,and urban growth as well as climate change.Resultant stage changes are the degradation of water quality and ecosystems with impacts for the health of lagoon organisms and humans.Responses to changes were identified as a combina-tion of punitive legislation,participatory management approaches and solutions focused on ecosystem restoration and engineering of the physical environment.Gaps identified include research on waste and aspects of climate change mitigation and adaptation.Also notable is a lack of multi-and interdisciplinary studies that address the inter-connecting stressors experienced at lagoons and studies of multiple lagoons.Studies also tend to be problem-focused with solutions rarely presented,limiting their applicability to inform management practices.展开更多
Abstract Lagoon-based municipal wastewater treatment plants （WWTPs） are facing difficulties meeting the needs of rapid population growth as well as the more stringent requirements of discharge permits. Three municip...Abstract Lagoon-based municipal wastewater treatment plants （WWTPs） are facing difficulties meeting the needs of rapid population growth as well as the more stringent requirements of discharge permits. Three municipal WWTPs were modified using a high surface area media with upgraded fine-bubble aeration systems. Performance data collected showed very promising results in terms of five-day biochemical oxygen demand （BOD5）, ammonia （NH3） and total suspended solids （TSS） removal. Two-year average ammonia effluents were 4.1 mg. L-1 for Columbia WWTP, 4 mg. L-1 for Larchmont WWTP and 2.1 mg. L-1 for Laurelville WWTE respectively. Two- year average BOD5 effluents were 6.8, 4.9 and 2.7 mg.Ll, and TSS effluents were 15.0, 9.6 and 7.5 mg.L-L The systems also showed low fecal coliform （FC） levels in their effluents.展开更多
Nutrient flux,net metabolism,and N2 fixation and denitrification processes were estimated and compared in two semi-arid subtropical coastal lagoons in the Gulf of California:El Soldado(ES),where no wastewater is disch...Nutrient flux,net metabolism,and N2 fixation and denitrification processes were estimated and compared in two semi-arid subtropical coastal lagoons in the Gulf of California:El Soldado(ES),where no wastewater is discharged,and El Rancho(ER),where shrimp farm effluents are regularly discharged.Biogeochemical processes were evaluated with the LOICZ model.Flushing time was<2 days in both systems.Nutrient fluxes were higher in ER than in ES and both systems acted as nutrient sinks for most of the year.ER showed a larger nutrient flow rate in the summer and autumn due to the input of shrimp-farm effluents.Nitrogen fluxes increased in both ER and ES in the winter in response to the increased nutrient supply from coastal upwellings.ER and ES both showed autotrophic metabolism and N2 fixation in the spring,autumn,and winter,but heterotrophic metabolism and denitrification in the summer.Denitrification dominated in ER(−2.21 mmol m^(2)day^(−1))and values were higher than those estimated in ES(−0.45 mmol m^(2)day^(−1)).The comparative analysis between ES and ER evidenced the significant changes in its biogeochemical performance caused by the input of anthropogenic nutrients,and can orient the environmental management of coastal lagoons.展开更多
Salinity is a fundamental variable of watermass chemistry,often varying strongly in coastal,estuarine,lagoonal,restricted-marine basinal,and non-freshwater lacustrine systems(Figure 1).Salinity variation commonly cont...Salinity is a fundamental variable of watermass chemistry,often varying strongly in coastal,estuarine,lagoonal,restricted-marine basinal,and non-freshwater lacustrine systems(Figure 1).Salinity variation commonly controls other watermass properties(e.g.,redox,temperature,p H,and chemical composition)as well as nutrient levels(and thus bioproductivity).展开更多
This study examines the socio-economic profile of livestock farmers in coastal Côte d’Ivoire. A total of 43 people were interviewed using well-structured questionnaires. The collected data were analyzed using de...This study examines the socio-economic profile of livestock farmers in coastal Côte d’Ivoire. A total of 43 people were interviewed using well-structured questionnaires. The collected data were analyzed using descriptive methods. The results showed that local Lagoon breeders are divided into two zones: southwest and southeast. Breeders in the south-western region are generally located in two sub-prefectures of the Tabou Department (Grabo and Oulodio). Tabou’s department alone accounts for 42% of the Lagoon breed in Côte d’Ivoire. Agriculture in this area is traditionally sedentary, practiced for social reasons. On the other hand, the south-eastern zone, located in the departments of Aboisso, Adzopé, Agboville, Grand-Lahou, Jacqueville, Abidjan, Dabou and Sikensi, represents 58% of the Lagoon breeding area in Côte d’Ivoire. This second group is characterised by improved breeding. Most of the farmers interviewed in this zone breed for economic reasons. However, the risk of cross-breeding, which already affects the local Lagoon breed, could be increased by the presence of other species such as the Zebu and Ndamas, or even the Baoulé, in this south-eastern herd.展开更多
Oyster aquaculture in Oualidia Lagoon,Morocco,has suffered from poor water quality and water confinement in its upstream region.Tidal asymmetry(TA)has been suggested as a possible cause,and a sediment trap was dredged...Oyster aquaculture in Oualidia Lagoon,Morocco,has suffered from poor water quality and water confinement in its upstream region.Tidal asymmetry(TA)has been suggested as a possible cause,and a sediment trap was dredged in 2011 to mitigate this condition.This study addresses TA in the lagoon using field measurements and numerical modeling in the presence of the sediment trap.Results indicate that the lagoon is flood-dominated mostly in its upstream end,where frictional forces exceed inertia accelerations during the tidal cycle and fine sediments settle on the tidal flats and inside the sediment trap.However,this study shows that a large mass of suspended sediments is exported to the ocean,which is contrary to expectations in flood-dominated lagoons.Defining the sediment trap as the rehabilitation scenario S1,the impacts of three additional scenarios on TA are examined.These are scenario S2(dredging the upstream section of the main channel),scenario S3(dredging the channels surrounding the flood delta near the inlets),and scenario S4(raising the ocean level by 0.5 m following climate change predictions).Results show that none of these scenarios modify the tidal flood dominance in the lagoon,although scenarios S2 and S4 decrease its intensity in the upstream region.Nevertheless,all scenarios still contribute to a significant export of sediments to the ocean.This suggests that lagoon management activities should not rely on tidal asymmetry analyses that normally predict upstream sediment transport in flood-dominated lagoons.展开更多
The importance of this study lies in the in-depth exploration of the ecological diversity of otoliths in Elopes lacerta, based on the analysis of data from 260 individuals collected from various sites, including the P...The importance of this study lies in the in-depth exploration of the ecological diversity of otoliths in Elopes lacerta, based on the analysis of data from 260 individuals collected from various sites, including the Porto Novo lagoon, the Cotonou lagoon, Lake Nokou, and the Atlantic coast in southern Benin. The results highlight significant variations in otolith morphology, establishing relevant links with the biological parameters of the fish at each site. Exploration of the asymmetry between the right and left sides reveals notable distinctions between these two aspects. Analysis of otolith shape thus emerges as a valuable tool for discriminating between stocks and providing a better understanding of ecological variations. The local diversity observed highlights the crucial importance of implementing adaptive management strategies to ensure effective conservation of the species and its habitat.展开更多
This study examined the right and left otoliths of 174 individuals of Pseudotolithus senegalensis from the Porto-Novo lagoon, Lake Nokoué and the Atlantic coast. The results show a significant variation in the po...This study examined the right and left otoliths of 174 individuals of Pseudotolithus senegalensis from the Porto-Novo lagoon, Lake Nokoué and the Atlantic coast. The results show a significant variation in the population according to geographic location. Mixed-effects linear analysis showed no significant variation by site, side or sex (p > 0.05). Analysis of otolith shape using ANOVA showed significant differences for length, width and area (p 0.05). Canonical discriminant analysis revealed significant differences between sites (p < 0.05). Finally, shape analyses showed significant differences between sites (p = 0.0001) and between right and left sides (p = 0.007), but no difference by sex (p = 0.395). The study of otolith morphology is therefore proving to be a valuable tool for differentiating stocks and understanding ecological variations.展开更多
Existing empirical methods for interpreting the consolidation yield stress and the overconsolidation ratio （OCR） in clays from piezocone tests are briefly reviewed. It can be seen that no universal correlation exist...Existing empirical methods for interpreting the consolidation yield stress and the overconsolidation ratio （OCR） in clays from piezocone tests are briefly reviewed. It can be seen that no universal correlation exists for all worldwide sites. However, for a given clay deposit, there does exist a most appropriate method to reflect the consolidation yield stress and the OCR based on piezocone test data. Three empirical methods are compared based on the piezocone test data collected on Lixia River lagoonal deposit soil sites in the north of Jiangsu province. The objective of this study is to evaluate the validity of the existing relationships linking the consolidation yield stress to piezocone test data and identify the appropriate method for Lixia River lagoonal deposit soil. It is shown that the correlation based on the net tip resistance has much higher accuracy for estimating the consolidation yield stress of lagoonal deposit soil than other methods.展开更多
The Marano and Grado Lagoon is well known for being contaminated by mercury（Hg） from the Idrija mine（Slovenia） and the decommissioned chlor-alkali plant of Torviscosa（Italy）.Experimental activities were conducte...The Marano and Grado Lagoon is well known for being contaminated by mercury（Hg） from the Idrija mine（Slovenia） and the decommissioned chlor-alkali plant of Torviscosa（Italy）.Experimental activities were conducted in a local fish farm to understand Hg cycling at the sediment–water interface. Both diffusive and benthic fluxes were estimated in terms of chemical and physical features. Mercury concentration in sediments（up to 6.81 μg/g）showed a slight variability with depth, whereas the highest methylmercury（MeHg） values（up to 10 ng/g） were detected in the first centimetres. MeHg seems to be produced and stored in the 2–3 cm below the sediment–water interface, where sulphate reducing bacteria activity occurs and hypoxic–anoxic conditions become persistent for days. DMeHg in porewaters varied seasonally（from 0.1 and 17% of dissolved Hg（DHg）） with the highest concentrations in summer. DHg diffusive effluxes higher（up to 444 ng/m^2/day） than those reported in the open lagoon（~ 95 ng/m^2/day）, whereas DMeHg showed influxes in the fish farm（up to-156 ng/m^2/day）. The diurnal DHg and DMeHg benthic fluxes were found to be higher than the highest summer values previously reported for the natural lagoon environment. Bottom sediments, especially in anoxic conditions, seem to be a significant source of MeHg in the water column where it eventually accumulates. However, net fluxes considering the daily trend of DHg and DMeHg, indicated possible DMeHg degradation processes. Enhancing water dynamics in the fish farm could mitigate environmental conditions suitable for Hg methylation.展开更多
文摘Lagoons are ecosystems for biodiversity and the livelihoods of coastal communities. The main objective of the study was to analyze the variability of arsenic concentrations in gastropods and bivalves in the Aby and Tendo lagoons, taking into account spatial, seasonal and hydrological variations. The study was carried out in four stages spread over two successive hydroclimatic cycles, including two seasons during the rainy season and two more during the dry season. The samples were taken in two areas of the Aby and Tendo lagoons. Arsenic levels were measured by ICP-MS. The results showed that mean arsenic concentrations in the muscles of organisms in Aby Lagoon ranged from 0.01 to 1.26 μg As/g, with a mean and median of 0.17 and 0.06 μg As/g, respectively. Fish had the highest levels of arsenic, followed by crustaceans, while molluscs and plants had lower and comparable concentrations of As. Arsenic concentrations in tilapia and jawbones varied significantly between sites and seasons, with higher concentrations at Tendo and during the rainy season. Arsenic concentrations in gastropods and bivalves were significantly higher than those of other species, with averages of 0.74 and 1.03 mg As/kg, respectively.
文摘Selenium is a trace element that can have both beneficial and harmful effects on aquatic life. The Aby Lagoon is a coastal environment in Côte d’Ivoire that receives selenium inputs from various natural and anthropogenic sources. The aim of this study was to assess the levels of selenium in the sediments of the Aby Lagoon and its tributaries, the Tanoe River and the Tendo Lagoon, and to examine the spatial and seasonal variations of selenium concentrations. Sediment samples were collected from different sites and seasons, and selenium concentrations were measured by atomic fluorescence spectrometry. The results showed that the average concentration of selenium in the sediments of the Aby Lagoon was 0.82 mg/kg, indicating moderate contamination. The concentration of selenium varied between sites and seasons, with higher values in the channel of the Tendo Lagoon and during the dry season. The study highlighted the complexity of selenium dynamics in aquatic ecosystems, and the need to take into account seasonal and spatial variability as well as interactions between environmental factors. The study also suggested potential ecotoxicological risks for some sensitive organisms in certain areas of the lagoon. This study contributes to the knowledge of the dynamics of selenium in lagoon ecosystems and to the assessment of the environmental risks associated with its presence.
文摘The aim of this study was to investigate temporal changes in mangrove root fouling species settled on artificial substrates in the mangrove zone of the Port Royal lagoons and to determine the effect of stress as part of a larger project to determine appropriate indicators of eutrophication in mangrove lagoons. Five Perspex? panels were suspended in the prop root zone at five contrasting stations within the Port Royal mangroves and the fouling organisms were monitored fortnightly using underwater digital photography. Nine taxonomic categories of epibionts were recorded of which the most prevalent group was the ascidians. Barnacles and hydroids were initially found to have established on the artificial substrates at all stations but were quickly replaced by ascidians and bryozoans at most. Species composition was similar between all stations by the end of the study, however, the dominant taxa were different. Sheltered lagoons like Fort Rocky lagoon (north and south) had a clear dominance of non-shelled species (ascidians and polychaetes) by the end of the study, while molluscs- bivalves and barnacles dominated Hurricane Refuge lagoon. This station, deemed to be experiencing greatest stress due to exposure to the eutrophic Kingston Harbour, also had the greatest proportion of shelled taxa represented in the epibiont biomass at the end of the study. Differences in biomass and species composition of root fouling species can therefore be used to indicate water quality in the mangrove lagoons.
文摘Calanoida copepod, Drepanopus bispinosus occurred in both saline lakes, Burton ( S=40) and Fletcher ( S = 56) in Vestfold Hills, Antarctica. Evident differences between two populations in biology and physiology were observed in September and December, 1984. The population in the Burton lake was denser with stronger body and more tolerant to temperature and salinity than that in the Fletcher Lake, reflecting their possible differences of genetic or nongenetic adaptation. The population in the Burton lake has been adaptated to the lake environment, and the population in the Flethcer Lake is in the acclimatization course in the lake habitat.
文摘The genetic diversity and the potential toxicity of bloom-forming cyanobacteria were studied in four lagoons located in the state of Sao Paulo (Campinas, Limeira and Piracicaba cities). Bloom samples were collected on the water surface and cyanobacterial communities were evaluated using DGGE fingerprinting and 16S rDNA clone library. The amplification of genes encoding secondary metabolites such as microcystin (mcy), anatoxin (ana), cylindrospermopsin (cyr), saxitoxin (sxt), cyanopeptolin (mcn) and aeruginosin (aer) was performed and their production analyzed by LC-MS. The comparison of DGGE banding pattern among the different water samples suggested that some operational taxonomic units (OTUs) in these locations were predominant over others. The 16S rDNA clone libraries sequences matched with nine different known cyanobacterial genera available in NCBI, identified as Anabaena, Brasilonema, Cylindrospermopsis, Limnococcus, Microcystis, Nostoc, Pseudanabaena, Synechococcus and Woronichinia. The lagoons ESALQ2, Taquaral and Limeira had more than 80% of the cyanobacterial community assigned to the genus Microcystis. Genes encoding aeruginosin, cyanopeptolin and microcystin synthetases and saxitoxin synthase were amplified, and LC-MS/MS confirmed the production of aeruginosin, cyanopeptolin and microcystin. Rapid and sensitive methods for the detection of these secondary metabolites, especially toxins, using chemical and molecular tools together, can be used for a faster diagnostic of toxic cyanobacterial blooms.
文摘The salt conservation law was applied, for the first time, in order to compare the real and calculated values of water outflow (m3/s) and residence time (days) in the lagoons of Ayla Oasis at the northernmost tip of the Gulf of Aqaba. The aim is to obtain the scientific bases of monitoring beside the real observation in areas that could not be measured directly by the current meters. The real measurements of water current by Acoustic Doppler Current Profiler (ADCP) workhorse 600 kHz, salinity and density by the Conductivity, Temperature and Depth meter (CTD 19plusV2), were collected during the period June 2012-May 2013. The statistical analysis was performed using Statview (5.0) software. The results revealed highly significant correlation between the real and calculated values for both water flow (r = 0.90;P = 0.0001) and residence time (r = 0.89;P 3/s) and residence time (0.80 ± 0.72 days) should be taken into consideration to correct the calculated values.
文摘This study presents a biotic index （∧） for measuring environmental quality in the coastal lagoons of the Mediterranean. Index A considers combined anthropogenic （pollution） and natural factors （prohibitive salinity, anoxia, toxic blooms, isolation from sea, etc.） of deterioration. The method is based on the principle of indicator species and on the conceptual scheme developed by Frisoni et al. （1984） according to which there are six possible sub-assemblages （Zones） of benthic macrofauna, each indicating a different level of environmental quality. The procedure requires defining the relative extent of the Zones in the lagoon under study, and the number of species and the mean biomass of benthic macrofauna present in each. The three metrics are applied in the index formula and the resulting number from one to ten indicates increasing environmental quality. The authors have validated the index by applying it to two lagoons, Lesina and Varano （S.Adriatic, Italy）.
文摘The management of living resources and space requires continuous assessments in order to adjust deviations as necessary for sustainable use. It is in this context that the present study was conducted and aims on the one hand to assess the dynamics of land use in the basin of the five-finger lagoons and on the other hand to assess the degree of their vulnerability to organic pollution. Thus, the satellite images were collected in free access on the site http://earthexplorer.usgs.gov/ of the USGS (US Geological Survey) of NASA. Image correction was performed with ENVI 5.1 software and classification was performed with ArcGIS 10.8 software. The degree of vulnerability was evaluated through the weighting of different parameters (slope, land use, type of pass, runoff, and density of the hydrobiological network) by the multi-criteria method of Saaty (Analytic Hierarchy Process Methods) and the application of mapping. It is found that for the dynamics of land use, forests, savannahs and plantations have experienced a significant reduction in their area (respectively 98.9%, 99.60% and 77.10%) between 1990 and 2020. As for settlements, water bodies and swamps, they have increased in area to different proportions. The soils are more denuded (Tc = 1264%). This makes the living space vulnerable and therefore facilitates the transfer of pollutants to the aquatic environment. The evaluation of the degree of vulnerability to pollution of the lagoons of the basin showed that the Toho-and Todougba lagoons are under a very high degree of vulnerability (73% - 100%) and do not augur well for the living resources. The other lagoons, notably the Dathi and Djonou lagoons, are also under stress from the pressures of surrounding activities. It is therefore important to assess the level of pollution of the Toho and Todougba lagoons through pollution indices in order to make decisions that will allow their sustainable use, especially for aquaculture.
基金GrupoProagua SA de CV and its staff for the data supply and Consejo Nacional de Ciencia y Tecnologia(CONACYT)for Carlos Joel Abrego-Gongora’s scholarship(No.166201).
文摘In this research, three existing dynamic mathematical models for aerated lagoons were applied to an aerated facultative lagoon (AFL) plant for municipal wastewater treatment. The models’ ability to describe the behavior of the primary lagoon was evaluated, and the advantages and limitations of the three models were compared. For this purpose, 7-year operational data from the municipal WWTP were collected and processed;other necessary data—like dynamic temperature values— were estimated. A 2-year period was used for model calibration, while the remaining 5 years served as validation period. One of the models showed poor calibration fit values in the effluent concentration description (R2 of 0.242 and RMSE of 16.8 mg/L);however, with some modifications the adjust was enhanced (R2 of 0.409 and RMSE of 14.0 mg/L);a second model displayed a poor to moderate adjust (0.489 and 13.0 mg/L, respectively), and the third model achieved a moderate fit (0.528 and 11.9 mg/L), though it provided an overestimation of effluent concentration, especially in periods of heavy and frequent rain;this model with some adaptations the adjust was enhanced (R2 of 0.575 and RMSE of 11.4 mg/L). The validation fits are even lower, illustrating the inability of these models to properly describe the AFL behavior. The possible causes of the models’ inadequacy are discussed. Finally, it is established that in terms of AFL behavior description more research and model development are needed.
文摘The article summarizes 34 years (1980-2014) of the original observations of the genesis and evolution stages of the Caspian lagoons. A model of the formation and evolution of the coastal lagoons has been worked out. It can be applied to the modelling of the global geoecological scenario along all the world’s coasts characterized by a steady transgression of their marine areas. The lagoons had been formed in a “bottleneck”, a narrow migration corridor, traversed by the largest migration route of trans-Palearctic species in Russia. This route is part of the West Siberian-East African migration range. Year round bird censuses (n = 746) were taken by the author in 1995-2014 along two key routes in the regions of Turalinskaya and Sulakskaya lagoons of Daghestan (the western coast of the Middle Caspian Sea). The meridional orientation of lagoons, location of the migration trajectory and a wide range of habitats in the study area contribute to the preservation of 294 Eurasian bird species. After formation of the lagoons, the breeding avifauna of the Caspian Sea Region of Central Daghestan has added 32 taxa. Among the species recorded at the lagoons, 50 are included in the IUCN Red List, Red Data Books of Russia and Daghestan. The reconstruction analysis of the migration trajectory compiled according to the data of the Russian Bird Ringing Centre allowed us to determine the population distribution geography for the birds regularly migrating along the western coast of the Caspian Sea and refine borders of theWest Siberian-East African migration range. Thus, according to the information received, the current migratory range should be greatly extended to cover the area from the British Isles in the West Palearctic to Lake Baikal in the east, including the extreme west and south of Africa.
文摘Lagoons are a major coastal environment in West Africa.They provide a plethora of resources,ecosystem services and economic benefits yet a diverse set of inter-connected stressors are a challenge to their sustainability.A scoping study of the published literature pertaining to lagoons within the region was undertaken to reveal the nature of these stressors and identify gaps in knowledge,providing a resource to inform coastal management practices and reveal areas for future study.Thirty-one lagoons were identified from the scoping exercise covering Nigeria,Benin,Togo,Ghana,Cote D’Ivoire,Liberia and Senegal.The DAPSI(W)R(M)framework was used to structure analysis of the litera-ture and surface key environmental themes.Key drivers and activities established are the use of lagoon resources and expansion of lagoon settlements.The resultant identified pressures are waste,overuse of resources,and urban growth as well as climate change.Resultant stage changes are the degradation of water quality and ecosystems with impacts for the health of lagoon organisms and humans.Responses to changes were identified as a combina-tion of punitive legislation,participatory management approaches and solutions focused on ecosystem restoration and engineering of the physical environment.Gaps identified include research on waste and aspects of climate change mitigation and adaptation.Also notable is a lack of multi-and interdisciplinary studies that address the inter-connecting stressors experienced at lagoons and studies of multiple lagoons.Studies also tend to be problem-focused with solutions rarely presented,limiting their applicability to inform management practices.
文摘Abstract Lagoon-based municipal wastewater treatment plants （WWTPs） are facing difficulties meeting the needs of rapid population growth as well as the more stringent requirements of discharge permits. Three municipal WWTPs were modified using a high surface area media with upgraded fine-bubble aeration systems. Performance data collected showed very promising results in terms of five-day biochemical oxygen demand （BOD5）, ammonia （NH3） and total suspended solids （TSS） removal. Two-year average ammonia effluents were 4.1 mg. L-1 for Columbia WWTP, 4 mg. L-1 for Larchmont WWTP and 2.1 mg. L-1 for Laurelville WWTE respectively. Two- year average BOD5 effluents were 6.8, 4.9 and 2.7 mg.Ll, and TSS effluents were 15.0, 9.6 and 7.5 mg.L-L The systems also showed low fecal coliform （FC） levels in their effluents.
基金Julio Medina-Galván is a recipient of a CONACYT student fellowship[#769282]This study was conducted with funding from the project CONAGUA-CONACyT[#2007-66573].
文摘Nutrient flux,net metabolism,and N2 fixation and denitrification processes were estimated and compared in two semi-arid subtropical coastal lagoons in the Gulf of California:El Soldado(ES),where no wastewater is discharged,and El Rancho(ER),where shrimp farm effluents are regularly discharged.Biogeochemical processes were evaluated with the LOICZ model.Flushing time was<2 days in both systems.Nutrient fluxes were higher in ER than in ES and both systems acted as nutrient sinks for most of the year.ER showed a larger nutrient flow rate in the summer and autumn due to the input of shrimp-farm effluents.Nitrogen fluxes increased in both ER and ES in the winter in response to the increased nutrient supply from coastal upwellings.ER and ES both showed autotrophic metabolism and N2 fixation in the spring,autumn,and winter,but heterotrophic metabolism and denitrification in the summer.Denitrification dominated in ER(−2.21 mmol m^(2)day^(−1))and values were higher than those estimated in ES(−0.45 mmol m^(2)day^(−1)).The comparative analysis between ES and ER evidenced the significant changes in its biogeochemical performance caused by the input of anthropogenic nutrients,and can orient the environmental management of coastal lagoons.
文摘Salinity is a fundamental variable of watermass chemistry,often varying strongly in coastal,estuarine,lagoonal,restricted-marine basinal,and non-freshwater lacustrine systems(Figure 1).Salinity variation commonly controls other watermass properties(e.g.,redox,temperature,p H,and chemical composition)as well as nutrient levels(and thus bioproductivity).
文摘This study examines the socio-economic profile of livestock farmers in coastal Côte d’Ivoire. A total of 43 people were interviewed using well-structured questionnaires. The collected data were analyzed using descriptive methods. The results showed that local Lagoon breeders are divided into two zones: southwest and southeast. Breeders in the south-western region are generally located in two sub-prefectures of the Tabou Department (Grabo and Oulodio). Tabou’s department alone accounts for 42% of the Lagoon breed in Côte d’Ivoire. Agriculture in this area is traditionally sedentary, practiced for social reasons. On the other hand, the south-eastern zone, located in the departments of Aboisso, Adzopé, Agboville, Grand-Lahou, Jacqueville, Abidjan, Dabou and Sikensi, represents 58% of the Lagoon breeding area in Côte d’Ivoire. This second group is characterised by improved breeding. Most of the farmers interviewed in this zone breed for economic reasons. However, the risk of cross-breeding, which already affects the local Lagoon breed, could be increased by the presence of other species such as the Zebu and Ndamas, or even the Baoulé, in this south-eastern herd.
基金supported by the Funding from the Ministry of Equipment and Transport,Kingdom of Morocco.
文摘Oyster aquaculture in Oualidia Lagoon,Morocco,has suffered from poor water quality and water confinement in its upstream region.Tidal asymmetry(TA)has been suggested as a possible cause,and a sediment trap was dredged in 2011 to mitigate this condition.This study addresses TA in the lagoon using field measurements and numerical modeling in the presence of the sediment trap.Results indicate that the lagoon is flood-dominated mostly in its upstream end,where frictional forces exceed inertia accelerations during the tidal cycle and fine sediments settle on the tidal flats and inside the sediment trap.However,this study shows that a large mass of suspended sediments is exported to the ocean,which is contrary to expectations in flood-dominated lagoons.Defining the sediment trap as the rehabilitation scenario S1,the impacts of three additional scenarios on TA are examined.These are scenario S2(dredging the upstream section of the main channel),scenario S3(dredging the channels surrounding the flood delta near the inlets),and scenario S4(raising the ocean level by 0.5 m following climate change predictions).Results show that none of these scenarios modify the tidal flood dominance in the lagoon,although scenarios S2 and S4 decrease its intensity in the upstream region.Nevertheless,all scenarios still contribute to a significant export of sediments to the ocean.This suggests that lagoon management activities should not rely on tidal asymmetry analyses that normally predict upstream sediment transport in flood-dominated lagoons.
文摘The importance of this study lies in the in-depth exploration of the ecological diversity of otoliths in Elopes lacerta, based on the analysis of data from 260 individuals collected from various sites, including the Porto Novo lagoon, the Cotonou lagoon, Lake Nokou, and the Atlantic coast in southern Benin. The results highlight significant variations in otolith morphology, establishing relevant links with the biological parameters of the fish at each site. Exploration of the asymmetry between the right and left sides reveals notable distinctions between these two aspects. Analysis of otolith shape thus emerges as a valuable tool for discriminating between stocks and providing a better understanding of ecological variations. The local diversity observed highlights the crucial importance of implementing adaptive management strategies to ensure effective conservation of the species and its habitat.
文摘This study examined the right and left otoliths of 174 individuals of Pseudotolithus senegalensis from the Porto-Novo lagoon, Lake Nokoué and the Atlantic coast. The results show a significant variation in the population according to geographic location. Mixed-effects linear analysis showed no significant variation by site, side or sex (p > 0.05). Analysis of otolith shape using ANOVA showed significant differences for length, width and area (p 0.05). Canonical discriminant analysis revealed significant differences between sites (p < 0.05). Finally, shape analyses showed significant differences between sites (p = 0.0001) and between right and left sides (p = 0.007), but no difference by sex (p = 0.395). The study of otolith morphology is therefore proving to be a valuable tool for differentiating stocks and understanding ecological variations.
基金Jiangsu Transportation Research Program Fund (No03Y007)
文摘Existing empirical methods for interpreting the consolidation yield stress and the overconsolidation ratio （OCR） in clays from piezocone tests are briefly reviewed. It can be seen that no universal correlation exists for all worldwide sites. However, for a given clay deposit, there does exist a most appropriate method to reflect the consolidation yield stress and the OCR based on piezocone test data. Three empirical methods are compared based on the piezocone test data collected on Lixia River lagoonal deposit soil sites in the north of Jiangsu province. The objective of this study is to evaluate the validity of the existing relationships linking the consolidation yield stress to piezocone test data and identify the appropriate method for Lixia River lagoonal deposit soil. It is shown that the correlation based on the net tip resistance has much higher accuracy for estimating the consolidation yield stress of lagoonal deposit soil than other methods.
基金supported by the University of Trieste (Finanziamento di Ateneo per progetti di ricerca scientifica-FRA 2014,ref.Stefano Covelli)
文摘The Marano and Grado Lagoon is well known for being contaminated by mercury（Hg） from the Idrija mine（Slovenia） and the decommissioned chlor-alkali plant of Torviscosa（Italy）.Experimental activities were conducted in a local fish farm to understand Hg cycling at the sediment–water interface. Both diffusive and benthic fluxes were estimated in terms of chemical and physical features. Mercury concentration in sediments（up to 6.81 μg/g）showed a slight variability with depth, whereas the highest methylmercury（MeHg） values（up to 10 ng/g） were detected in the first centimetres. MeHg seems to be produced and stored in the 2–3 cm below the sediment–water interface, where sulphate reducing bacteria activity occurs and hypoxic–anoxic conditions become persistent for days. DMeHg in porewaters varied seasonally（from 0.1 and 17% of dissolved Hg（DHg）） with the highest concentrations in summer. DHg diffusive effluxes higher（up to 444 ng/m^2/day） than those reported in the open lagoon（~ 95 ng/m^2/day）, whereas DMeHg showed influxes in the fish farm（up to-156 ng/m^2/day）. The diurnal DHg and DMeHg benthic fluxes were found to be higher than the highest summer values previously reported for the natural lagoon environment. Bottom sediments, especially in anoxic conditions, seem to be a significant source of MeHg in the water column where it eventually accumulates. However, net fluxes considering the daily trend of DHg and DMeHg, indicated possible DMeHg degradation processes. Enhancing water dynamics in the fish farm could mitigate environmental conditions suitable for Hg methylation.
