peer reviewed

Microsporidia parasites are commonly found in amphipods, where they are often asymptomatic, vertically-transmitted and have several effects on host sexuality and behaviour. As amphipods are often used as models in ecotoxicological studies, we investigated the effect of microsporidian infections on energy reserves and defence capacities of Gammarus roeseli under cadmium stress. Only females were infected by two microsporidia parasites: Dictyocoela roeselum or Dictyocoela muelleri. In physiological conditions, microsporidia had no major effect on energy reserves and defence capacities of G. roeseli, while under cadmium exposure, energy reserves and antioxidant defence were weaker in infected females. Moreover, higher malondialdehyde levels detected in infected females revealed that they suffered more cellular damages. Our results suggest that microsporidia may affect gammarid fitness in stressful conditions, when parasitic stress cannot be compensated by the host. Consequently, microsporidia parasites should be a factor necessary to take into account in ecotoxicology studies involving amphipods.

peer reviewed | Concentrations of organochlorine pesticides and stable isotope ratios of nitrogen and carbon were measured in a tropical freshwater ecosystem to evaluate the contamination level of biota and examine the bioaccumulation patterns of pollutants through the food web. Chemical analyses showed a general and heavy contamination of the entire food web. They revealed the strong accumulation of pollutants by juveniles of diadromous fishes and shrimps, as they re-enter the river. The role of ecological factors in the bioaccumulation of pesticides was evaluated. Whereas the most persistent pollutants (chlordecone and monohydro-chlordecone) were related to the organisms diet and habitat, bioaccumulation of b-HCH was only influenced by animal lipid content. The biomagnification potential of chlordecone through the food chain has been demonstrated. It highlighted the importance of trophic transfer in this compound bioaccumulation process. In contrast, bioconcentration by passive diffusion from water seemed to be the main exposure route of biota to b-HCH.

Concentrations of organochlorine pesticides and stable isotope ratios of nitrogen and carbon were measured in a tropical freshwater ecosystem to evaluate the contamination level of biota and examine the bioaccumulation patterns of pollutants through the food web. Chemical analyses showed a general and heavy contamination of the entire food web. They revealed the strong accumulation of pollutants by juveniles of diadromous fishes and shrimps, as they re-enter the river. The role of ecological factors in the bioaccumulation of pesticides was evaluated. Whereas the most persistent pollutants (chlordecone and monohydro-chlordecone) were related to the organisms diet and habitat, bioaccumulation of β-HCH was only influenced by animal lipid content. The biomagnification potential of chlordecone through the food chain has been demonstrated. It highlighted the importance of trophic transfer in this compound bioaccumulation process. In contrast, bioconcentration by passive diffusion from water seemed to be the main exposure route of biota to β-HCH.

Direction Régionale de l’Environnement de la Guadeloupe | Centre Interfacultaire de Recherches en Océanologie - MARE | Concentrations of organochlorine pesticides and stable isotope ratios of nitrogen and carbon weremeasured in a tropical freshwater ecosystem to evaluate the contamination level of biota and examinethe bioaccumulation patterns of pollutants through the food web. Chemical analyses showed a generaland heavy contamination of the entire food web. They revealed the strong accumulation of pollutants byjuveniles of diadromous fishes and shrimps, as they re-enter the river. The role of ecological factors in thebioaccumulation of pesticides was evaluated. Whereas the most persistent pollutants (chlordecone andmonohydro-chlordecone) were related to the organisms diet and habitat, bioaccumulation of b-HCH wasonly influenced by animal lipid content. The biomagnification potential of chlordecone through the foodchain has been demonstrated. It highlighted the importance of trophic transfer in this compound bioaccumulationprocess. In contrast, bioconcentration by passive diffusion from water seemed to be themain exposure route of biota to b-HCH. | Linked papers: Coat et al. 2009 and Lefrançois et al. 2010

International audience | Revegetation of abandoned aquaculture regions should be a priority for any integrated coastal zone management (ICZM). This paper examines the potential of a matchless time series of 20 very high spatial resolution (VHSR) optical satellite images acquired for mapping trends in the evolution of mangrove forests from 2001 to 2015 in an estuary fragmented into aquaculture ponds. Evolution of mangrove extent was quantified through robust multitemporal analysis based on supervised image classification. Results indicated that mangroves are expanding inside and outside ponds and over pond dykes. However, the yearly expansion rate of vegetation cover greatly varied between replanted ponds. Ground truthing showed that only Rhizophora species had been planted, whereas natural mangroves consist of Avicennia and Sonneratia species. In addition, the dense Rhizophora plantations present very low regeneration capabilities compared with natural mangroves. Time series of VHSR images provide comprehensive and intuitive level of information for the support of ICZM.

Revegetation of abandoned aquaculture regions should be a priority for any integrated coastal zone management (ICZM). This paper examines the potential of a matchless time series of 20 very high spatial resolution (VHSR) optical satellite images acquired for mapping trends in the evolution of mangrove forests from 2001 to 2015 in an estuary fragmented into aquaculture ponds. Evolution of mangrove extent was quantified through robust multitemporal analysis based on supervised image classification. Results indicated that mangroves are expanding inside and outside ponds and over pond dykes. However, the yearly expansion rate of vegetation cover greatly varied between replanted ponds. Ground truthing showed that only Rhizophora species had been planted, whereas natural mangroves consist of Avicennia and Sonneratia species. In addition, the dense Rhizophora plantations present very low regeneration capabilities compared with natural mangroves. Time series of VHSR images provide comprehensive and intuitive level of information for the support of ICZM.

Thiamethoxam (TMX) is a neonicotinoid insecticide that is widely used for seed treatment in a variety of crops. Farmland birds can be exposed to TMX by consuming treated seeds remaining on the soil surface due to either spills or failed implantation during sowing. In the environment, TMX can be metabolized into clothianidin (CLO), another neonicotinoid insecticide that is also toxic to birds. The goal of the present study was to evaluate the feasibility of a non-invasive approach consisting in the analysis of fecal samples to detect recent exposure of wild birds to TMX and CLO. To achieve this, 16 grayish baywings (Agelaioides badius) were exposed for 21 days to seeds coated with four different concentrations of TMX: 0 (control), 0.027 (low), 0.33 (medium), and 4.3 (high) g TMX/kg of seed. These concentrations are within the approved range for seed coating with TMX in typical crops of the Pampa Region in Argentina, where baywings are common. Seed consumption was monitored over 24 h and fecal samples were collected on day 1, 2, 3, 4, 7, and 21 of exposure. Finally, concentrations TMX and CLO were determined in collected feces through LC-MS/MS. Fecal concentrations of both TMX and CLO showed a significant dependence on the treatment dose (p = 0.006). Average concentrations of TMX and CLO were respectively 63, 689, and 2363 ng/g and 75, 735 and 2040 ng/g for low, medium and high dose groups. These results demonstrate that fecal analysis is a reliable non-invasive method for assessing recent bird exposure to TMX. The results also confirm that TMX is metabolized into CLO, and suggest a saturation of the metabolic pathway at high doses. This study supports the use of fecal analysis for pesticide exposure estimation in field monitoring studies of wild birds. | Instituto de Recursos Biológicos | Fil: Fernández-Vizcaíno, Elena. CSIC-UCLM-JCCM. Instituto de Investigación en Recursos Cinegéticos (IREC); España | Fil: Poliserpi, María Belén. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Recursos Biológicos; Argentina | Fil: Ortiz-Santaliestra, Manuel E. CSIC-UCLM-JCCM. Instituto de Investigación en Recursos Cinegéticos (IREC); España | Fil: Mougeot, Francois. CSIC-UCLM-JCCM. Instituto de Investigación en Recursos Cinegéticos (IREC); España | Fil: Mateo, Rafael. CSIC-UCLM-JCCM. Instituto de Investigación en Recursos Cinegéticos (IREC); España. CSIC. Institute for Environmental Assessment and Water Research (IDAEA); España | Fil: Camarero, Pablo R. CSIC-UCLM-JCCM. Instituto de Investigación en Recursos Cinegéticos (IREC); España | Fil: Brodeur, Julie C. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Recursos Biológicos; Argentina | Fil: Brodeur, Julie C. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Thiamethoxam (TMX) is a neonicotinoid insecticide that is widely used for seed treatment in a variety of crops. Farmland birds can be exposed to TMX by consuming treated seeds remaining on the soil surface due to either spills or failed implantation during sowing. In the environment, TMX can be metabolized into clothianidin (CLO), another neonicotinoid insecticide that is also toxic to birds. The goal of the present study was to evaluate the feasibility of a non-invasive approach consisting in the analysis of fecal samples to detect recent exposure of wild birds to TMX and CLO. To achieve this, 16 grayish baywings (Agelaioides badius) were exposed for 21 days to seeds coated with four different concentrations of TMX: 0 (control), 0.027 (low), 0.33 (medium), and 4.3 (high) g TMX/kg of seed. These concentrations are within the approved range for seed coating with TMX in typical crops of the Pampa Region in Argentina, where baywings are common. Seed consumption was monitored over 24 h and fecal samples were collected on day 1, 2, 3, 4, 7, and 21 of exposure. Finally, concentrations TMX and CLO were determined in collected feces through LC-MS/MS. Fecal concentrations of both TMX and CLO showed a significant dependence on the treatment dose (p = 0.006). Average concentrations of TMX and CLO were respectively 63, 689, and 2363 ng/g and 75, 735 and 2040 ng/g for low, medium and high dose groups. These results demonstrate that fecal analysis is a reliable non-invasive method for assessing recent bird exposure to TMX. The results also confirm that TMX is metabolized into CLO, and suggest a saturation of the metabolic pathway at high doses. This study supports the use of fecal analysis for pesticide exposure estimation in field monitoring studies of wild birds. | This work was made possible by the pre-doctoral stay grant funded by the Banco Santander Ibero-America Research Scholarships for the 2020–2021 call. Funding for this work was provided by the “Agencia Nacional de Promoción Científica y Técnica” (PICT-2021-0473) and the “Instituto Nacional de Tecnología Agropecuaria” (2023-PD-L03-I094). The first author acknowledges economic support from project BIOD22_00033_17_PPCB during the final revision stage of the manuscript. | Peer reviewed

Plastic pollution threatens many organisms around the world. In particular, the northern fulmar, Fulmarus glacialis, is known to ingest high quantities of plastics. Since data are sparse in the Eurasian Arctic, we investigated plastic burdens in the stomachs of fulmar fledglings from Kongsfjorden, Svalbard. Fifteen birds were collected and only particles larger than 1 mm were extracted, characterised and analysed with Fourier Transform InfraRed spectroscopy. All birds ingested plastic. In total, 683 plastic particles were found, with an average of 46 ± 40 SD items per bird. The most common shape, colour and polymer were hard fragment, white, and polyethylene, respectively. Microplastics ( 5 mm). This study confirms high numbers of ingested plastics in fulmar fledglings from Svalbard and suggests that fulmar fledglings may be suitable for temporal monitoring of plastic pollution, avoiding potential biases caused by age composition or breeding state. | publishedVersion

Plastic pollution threatens many organisms around the world. In particular, the northern fulmar, Fulmarus glacialis, is known to ingest high quantities of plastics. Since data are sparse in the Eurasian Arctic, we investigated plastic burdens in the stomachs of fulmar fledglings from Kongsfjorden, Svalbard. Fifteen birds were collected and only particles larger than 1 mm were extracted, characterised and analysed with Fourier Transform InfraRed spectroscopy. All birds ingested plastic. In total, 683 plastic particles were found, with an average of 46 ± 40 SD items per bird. The most common shape, colour and polymer were hard fragment, white, and polyethylene, respectively. Microplastics ( 5 mm). This study confirms high numbers of ingested plastics in fulmar fledglings from Svalbard and suggests that fulmar fledglings may be suitable for temporal monitoring of plastic pollution, avoiding potential biases caused by age composition or breeding state.