Current studies are performed to review the past 20 years literature regarding the impact of global warming and climatic changes on water availability, its quality/quantity/yield and consequent effects on nutrients, freshwater and biota. Water resources are susceptible to changes in climate. The water holding capacity of the atmosphere is increased with the rise of temperature. Global warming will cause increased sea levels due to the spreading of oceans and melting of glaciers. The flow of affected freshwater into the oceans will cause variations in stratification, nutrient availability, salinity, and turbidity, which will affect tourism, agriculture, and industry. The total amount of organic carbon availability varies from winter to warming, and there are also changes in enzymes' activities. There is a vast shift in rainfall due to climate changes. The intense precipitation, runoff, erosion, and transfer of a vast number of pollutants into the groundwater affect drinking water quality. Many organisms such as animals and plants migrate to other regions, so the biological composition of natural ecosystem agriculture is modified. We cannot measure these complicated processes precisely, yet we roughly estimate these processes through the extinction of species and variation in productivity. The temperature has a pronounced effect on the distribution of various species in different geographical regions. Warming shows an impact on interspecific and intraspecific interaction. It also has an impact growth period and yield of crops. The use of future climate models enables us to understand the environmental issues and future climate changes thoroughly.

one of the most important issues in water resources today is pollution caused by heavy metals. Nickel is a heavy metal that is widely used in various industries. Nickel is one of the most important pollutants in the environment and its removal is very important. There are different methods for separating heavy metals from aqueous media. Among all methods, surface adsorption is a low-cost and simple method and for removing heavy metals in low and medium concentrations. The aim of this study was to investigate the adsorption efficiency of nickel ions from aqueous solutions using melamine modified nano-graphene oxide.The experiments were performed under discontinuous conditions and the five parameters of initial concentration, contact time, temperature, pH and adsorbent dose were optimized. The pseudo-first-order and psedo-second-order kinetic models were investigated. Finally, thermodynamic parameters such as enthalpy and entropy change and Gibbs free energy were calculated.In the kinetic study, by comparing the coefficient of explanation of the pseudo-first-order model (0.3084) and the pseudo -second-order model (0.997), it was found that pseudo -second-order model better shows the adsorption process of nickel by the adsorbent. oxide nanoparticles is spontaneous and the reaction is accompanied by an increase in irregularity and endotherm. The adsorbent surface is multilayered, non-uniform and the adsorbent material on the adsorbent is heterogeneous. Nano graphene oxide modified by melamine has a special surface and high potential and is a suitable adsorbent for removing nickel from aqueous solutions and has a high absorption.

International audience

Coastal water quality in urban cities is increasingly impacted by human activities such as agricultural runoff, sewage discharges, and poor sanitation. However, environmental factors controlling bacteria abundance remain poorly understood. The study employed multiple indicators to assess ten beach water qualities in Ghana during minor wet seasons. Environmental parameters (e.g. temperature, electrical conductivity, total dissolved solids) were measured in situ using the Horiba multiple parameter probe. Surface water samples were collected to measure total suspended solids, nutrients, and chlorophyll-a via standard methods and bacteria determination through membrane filtration. Environmental parameters measured showed no significant variation for the sample period. However, bacteria loads differ significantly (p = 0.024) among the beaches and influenced significantly by nitrate (55.3%, p = 0.02) and total dissolved solids (17.1%, p = 0.017). The baseline study detected an increased amount of total coliforms and faecal indicator bacteria (Escherichia coli and Enterococcus spp.) in beach waters along the coast of Ghana, suggesting faecal contamination, which can pose health risks. The mean ± standard deviations of bacteria loads in beach water are total coliforms (4.06 × 103 ± 4.16 × 103 CFU/100 mL), E. coli (7.06 × 102 ± 1.72 × 103 CFU/100 mL), and Enterococcus spp. (6.15 × 102 ± 1.75 × 103 CFU/100 mL). Evidence of pollution calls for public awareness to prevent ecological and health-related risks and policy reforms to control coastal water pollution. Future research should focus on identifying the sources of contamination in the tropical Atlantic region.

Marine traffic is the most pervasive underwater anthropogenic noise pollution which can mask acoustic communication in marine mammals and fish, but its effect in marine invertebrates remains unknown. Here, we performed an at sea experiment to study the potential of shipping noise to mask and alter lobster acoustic communication. We used hydrophones to record buzzing sounds and accelerometers to detect lobster carapace vibrations (i.e. the buzzing sounds' sources). We demonstrated that male individuals produced carapace vibrations under various ambient noise conditions, including heavy shipping noise. However, while the associated waterborne buzzing sounds could be recorded under natural ambient noise levels, they were masked by shipping noise. Additionally, lobsters significantly increased their call rates in presence of shipping noise, suggesting a vocal compensation due to the reduction of intraspecific communication. This study reports for the first time the potential acoustic masking of lobster acoustic communication by chronic anthropogenic noise pollution, which could affect ecologically important behaviors.

Despite their ecological role and multiple contributions to human societies, the distribution of Indo-Pacific seagrasses remains poorly known in many places. Herein, we outline a hierarchical spatially-explicit assessment framework to derive nation-wide synoptic knowledge of the distribution of seagrass species and communities. We applied the framework to New Caledonia (southwest Pacific Ocean) and its 36,200 km2 of reefs and lagoons. The framework is primarily field-based but can leverage various habitat maps derived from remote sensing. Field data collection can be stratified by map products and retrospectively contribute to developing new seagrass distribution maps. Airborne and satellite remote sensing alone do not allow for the spatial generalisation of the finest attributes (species distribution and types of seagrass beds), but staged stratified field sampling provides synoptic views of these attributes. Using three examples, we discuss how the hierarchical and spatial information generated from this framework's application can inform conservation and management objectives.

International audience | The diffusive gradient in thin film technique was recently adapted to organic compounds. The diffusional coefficient (D) is a key parameter needed to calculate the time-weighted average concentration. In this study, two methods are used for D measurement in two gels (agarose and polyacrylamide): the diffusion cell method (D-cell) and the slice stacking method (D-stack). Thus, D were discussed and compared for 112 organic compounds, including pesticides, hormones, and pharmaceuticals. D-stack tends to be higher than D-cell. It could be explained by the presence of a non-negligible diffusive boundary layer thickness in diffusion cell. Consequently, the use of sampling rates (R-S) should be more adequate to determine water concentration, for a given bulk flow velocity. D-stack also corresponds to the diffusion in gel only, allowing the determination of the maximal R-S, and would be considered as a reference value that can be adjusted to in situ conditions, by applying the appropriate DBL thickness. The range and variability of D values found in the literature and obtained in this work were discussed. Relationships between D and compound physicochemical properties (molecular mass, log Dow, polar surface area, van der Waals volume) were investigated. We did not find clear and robust correlation between D and any single physicochemical property, for the set of compounds tested.

Benthic exchanges of oxygen and nutrient at the sediment-water interface were investigated under light and dark conditions at 5 selected sites in a sub-tropical atoll. Mean oxygen fluxes were - 1316.5 ± 242.0 μmol m−2 h−1 and mean effluxes of oxygen under light conditions were 2231.7 ± 626.4 μmol m−2 h−1, presumably due to microphytobenthos present at the sediment-water interface. The consequences of this high related productivity was a systematic consumption of nutrients (DIN, PO4 and Si(OH)4) during almost all light incubations, contrasting with the effluxes of nutrients during dark incubations. Our results suggest that the sediments were net autotrophic and the oxygen balance in favor of microbenthic production when compared to community demand. Diurnal rates of gross benthic primary productivity were high (3423 ± 1192 μmol m−2 h−1) which emphasize the role of microphytobenthos in maintaining the oxygen reservoir in tropical lagoons.

International audience | The environmental situation concerning pollution by (eco)toxic and persistent trace elements in Kazakhstan has been investigated by analytical reviews of scientific studies published over the past 20 years reporting concentrations of 10 toxic trace elements (TTE) observed in soil, sediments or surface water. A database of 62 articles published in Kazakh, Russian or English covered the majority of the territory of the country for soil and water samples but to a lesser extent for sediments. Reported concentrations were summarized using statistical parameters, then spatialized and finally classified in contamination classes according to local legislation. This analysis revealed some hotspots of TTE in surface waters (Cd and Pb), soil (As) and sediments (Cd and As). Hotspots of less toxic Cu, Zn and Mn were also detected. Spatialization of results allowed localization of these hotspots close to industrial sites, such as smelters or mining and metallurgic combines. Others have been shown to be close to disused mining sites or landfills with municipal waste. Methodological improvements for further studies have been suggested, such as to integrate more West Kazakhstan or remote areas in sampling campaigns, but also to describe more exhaustively the used analytical methods and to be more attentive to the speciation of the analyzed form of the element. Finally, a management strategy to strengthen a sustainable food policy has been proposed: to reduce emissions by modernization of industrial facilities and better waste management, to organize land use depending on the contamination levels and to reduce the bioavailability of the toxic elements.