International audience | Benthic fluxes refer to the exchange rates of nutrients and other compounds between the water column and the sediment bed in aquatic ecosystems. Their quantification contributes to our understanding of aquatic ecosystem functioning. Near-bed hydrodynamics plays an important role at the sediment-water interface, especially in shallow lakes, but it is poorly considered by traditional measuring techniques of flux quantification, such as sediment incubations. Thus, alternative sampling techniques are needed to characterize key benthic fluxes under in-situ hydrodynamic conditions. This study aimed to evaluate the performance of two promising methods: relaxed eddy accumulation (REA) and mass transfer coefficient (MTC). We applied them in a hyper-eutrophic shallow lake to measure the fluxes of ammonium, phosphate, iron, and manganese ions. For the first time, REA revealed hourly nutrient flux variations, indicating a strong lake biogeochemical dynamics at short time-scales. Daily average fluxes are of similar orders of magnitude for REA and MTC for ammonium (24 and 42 mmol m2 d-1), manganese (1.0 and 0.8), and iron (0.8 and 0.7) ions. They are one order of magnitude higher than fluxes estimated from sediment incubations, due to the difficulty in reproducing in-situ oxygen and hydrodynamic conditions in the laboratory. Although the accuracy of both techniques needs to be improved, the results revealed their potential: REA follows the short-term biogeochemical dynamics of sediments, while MTC could be widely used for lake monitoring because of its simpler implementation.

International audience | Benthic fluxes refer to the exchange rates of nutrients and other compounds between the water column and the sediment bed in aquatic ecosystems. Their quantification contributes to our understanding of aquatic ecosystem functioning. Near-bed hydrodynamics plays an important role at the sediment-water interface, especially in shallow lakes, but it is poorly considered by traditional measuring techniques of flux quantification, such as sediment incubations. Thus, alternative sampling techniques are needed to characterize key benthic fluxes under in-situ hydrodynamic conditions. This study aimed to evaluate the performance of two promising methods: relaxed eddy accumulation (REA) and mass transfer coefficient (MTC). We applied them in a hyper-eutrophic shallow lake to measure the fluxes of ammonium, phosphate, iron, and manganese ions. For the first time, REA revealed hourly nutrient flux variations, indicating a strong lake biogeochemical dynamics at short time-scales. Daily average fluxes are of similar orders of magnitude for REA and MTC for ammonium (24 and 42 mmol m2 d-1), manganese (1.0 and 0.8), and iron (0.8 and 0.7) ions. They are one order of magnitude higher than fluxes estimated from sediment incubations, due to the difficulty in reproducing in-situ oxygen and hydrodynamic conditions in the laboratory. Although the accuracy of both techniques needs to be improved, the results revealed their potential: REA follows the short-term biogeochemical dynamics of sediments, while MTC could be widely used for lake monitoring because of its simpler implementation.

National audience

Correction to: Editorial trend: adverse outcome pathway (AOP) and computational strategy — towards new perspectives in ecotoxicology (Environmental Science and Pollution Research, (2023), 31, 5, (6587-6596), 10.1007/s11356-023-30647-w) : 10.1007/s11356-025-36073-4 | International audience | The adverse outcome pathway (AOP) has been conceptualized in 2010 as an analytical construct to describe a sequential chain of causal links between key events, from a molecular initiating event leading to an adverse outcome (AO), considering several levels of biological organization. An AOP aims to identify and organize available knowledge about toxic effects of chemicals and drugs, either in ecotoxicology or toxicology, and it can be helpful in both basic and applied research and serve as a decision-making tool in support of regulatory risk assessment. The AOP concept has evolved since its introduction, and recent research in toxicology, based on integrative systems biology and artificial intelligence, gave it a new dimension. This innovative in silico strategy can help to decipher mechanisms of action and AOP and offers new perspectives in AOP development. However, to date, this strategy has not yet been applied to ecotoxicology. In this context, the main objective of this short article is to discuss the relevance and feasibility of transferring this strategy to ecotoxicology. One of the challenges to be discussed is the level of organisation that is relevant to address for the AO (population/community). This strategy also offers many advantages that could be fruitful in ecotoxicology and overcome the lack of time, such as the rapid identification of data available at a time t, or the identification of “data gaps”. Finally, this article proposes a step forward with suggested priority topics in ecotoxicology that could benefit from this strategy.

International audience | Polychlorinated biphenyls (PCBs) are persistent organic pollutants in the environment that are responsible for many adverse health effects. Bioremediation appears to be a healthy and cost-effective alternative for remediating PCB-contaminated environments. While some microbial species have been observed to be capable of transforming PCBs, only two different microbial pathways (rdh and bph pathways) have been described to be involved in PCB transformations. Ligninolytic enzymes have been observed or are under suspicion in some microbial PCB transformations. However, the role of these promising PCB-transforming enzymes, which are produced by fungi and some aerobic bacteria, is still unclear. The present review describes their role by identifying microbial PCB-transforming species and their reported ligninolytic enzymes whether proven or suspected to be involved in PCB transformations. There are several lines of evidence that ligninolytic enzymes are responsible for PCB transformations such as (1) the ability of purified laccases from Myceliophthora thermophila, Pycnoporus cinnabarinus, Trametes versicolor, Cladosporium sp, and Coprinus cumatus to transform hydroxy-PCBs; (2) the increased production of laccases and peroxidases by many fungi in the presence of PCBs; and (3) the enhanced PCB transformation by Pseudomonas stutzeri and Sinorhizobium meliloti NM after the addition of ligninolytic enzyme enhancers. However, if the involvement of ligninolytic enzymes in PCB transformation is clearly demonstrated in some fungal species, it does not seem to be implicated in all microbial species suggesting other still unknown metabolic pathways involved in PCB transformation and different from the bph and rdh pathways. Therefore, PCB transformation may involve several metabolic pathways, some involving ligninolytic enzymes, bph or rdh genes, and some still unknown, depending on the microbial species. In addition, current knowledge does not fully clarify the role of ligninolytic enzymes in PCB oxidation and dechlorination. Therefore, further studies focusing on purified ligninolytic enzymes are needed to clearly elucidate their role in PCB transformation.

International audience | The proliferation of wireless and other telecommunications equipment brought about by technological advances in the communication industry has substantially increased the radiofrequency radiation levels in the environment. The emphasis is, therefore, placed on investigating the potential impacts of radiofrequency radiation on biota. In this work, the impact of 2850 MHz electromagnetic field radiation (EMF-r) on early development, photosynthetic pigments, and the metabolic profile of two Brassica oleracea L. cultivars (red and green cabbage) was studied. On a daily basis for seven days, seedlings were exposed to homogeneous EMF-r for one, two, and four hours, and observations were carried out at 0-h, 1-h, and 24-h following the final dose. Irrespective of the duration of harvest, exposure to EMF-r resulted in a dose-dependent reduction in both root (from 6.3 cm to 4.0 cm in red; 6.1 cm to 3.8 cm in green) and shoot lengths (from 5.3 cm to 3.1 cm in red; 5.1 cm to 3.1 cm in green), as well as a decrease in biomass (from 2.9 mg to similar to 1.1 mg in red; 2.5 to 0.9 mg in green) of the seedlings when compared to control samples. Likewise, the chlorophyll (from 6.09 to similar to 4.94 mg g(-1) d.wt in red; 7.37 to 6.05 mg g(-1) d.wt. in green) and carotenoid (from 1.49 to 1.19 mg g(-1) d.wt. in red; 1.14 to 0.51 mg g(-1) d.wt. in green) contents of both cultivars decreased significantly when compared to the control. Additionally, the contents of phenolic (28.99-45.52 mg GAE g(-1) in red; 25.49-33.76 mg GAE g(-1) in green), flavonoid (21.7-31.8 mg QE g(-1) in red; 12.1-19.0 mg QE g(-1) in green), and anthocyanin (28.8-43.6 mg per 100 g d.wt. in red; 1.1-2.6 mg per 100 g d.wt. in green) in both red and green cabbage increased with exposure duration. EMF-r produced oxidative stress in the exposed samples of both cabbage cultivars, as demonstrated by dose-dependent increases in the total antioxidant activity (1.33-2.58 mM AAE in red; 1.29-2.22 mM AAE in green), DPPH activity (12.96-78.33% in red; 9.62-67.73% in green), H2O2 content (20.0-77.15 nM g(-1) f.wt. in red; 14.28-64.29 nM g(-1) f.wt. in green), and MDA content (0.20-0.61 nM g(-1) f.wt. in red; 0.18-0.51 nM g(-1) f.wt. in green) compared to their control counterparts. The activity of antioxidant enzymes, i.e., superoxide dismutases (3.83-8.10 EU mg(-1) protein in red; 4.19-7.35 EU mg(-1) protein in green), catalases (1.81-7.44 EU mg(-1) protein in red; 1.04-6.24 EU mg(-1) protein in green), and guaiacol peroxidases (14.37-47.85 EU mg(-1) protein in red; 12.30-42.79 EU mg(-1) protein in green), increased significantly compared to their control counterparts. The number of polyphenols in unexposed and EMF-r exposed samples of red cabbage was significantly different. The study concludes that exposure to 2850 MHz EMF-r affects the early development of cabbage seedlings, modifies their photosynthetic pigments, alters polyphenol content, and impairs their oxidative metabolism.

International audience

International audience

Correction to: Editorial trend: adverse outcome pathway (AOP) and computational strategy — towards new perspectives in ecotoxicology (Environmental Science and Pollution Research, (2023), 31, 5, (6587-6596), 10.1007/s11356-023-30647-w) : 10.1007/s11356-025-36073-4 | International audience | The adverse outcome pathway (AOP) has been conceptualized in 2010 as an analytical construct to describe a sequential chain of causal links between key events, from a molecular initiating event leading to an adverse outcome (AO), considering several levels of biological organization. An AOP aims to identify and organize available knowledge about toxic effects of chemicals and drugs, either in ecotoxicology or toxicology, and it can be helpful in both basic and applied research and serve as a decision-making tool in support of regulatory risk assessment. The AOP concept has evolved since its introduction, and recent research in toxicology, based on integrative systems biology and artificial intelligence, gave it a new dimension. This innovative in silico strategy can help to decipher mechanisms of action and AOP and offers new perspectives in AOP development. However, to date, this strategy has not yet been applied to ecotoxicology. In this context, the main objective of this short article is to discuss the relevance and feasibility of transferring this strategy to ecotoxicology. One of the challenges to be discussed is the level of organisation that is relevant to address for the AO (population/community). This strategy also offers many advantages that could be fruitful in ecotoxicology and overcome the lack of time, such as the rapid identification of data available at a time t, or the identification of “data gaps”. Finally, this article proposes a step forward with suggested priority topics in ecotoxicology that could benefit from this strategy.