Bioaccumulation and Toxicity of Organic Chemicals in Terrestrial Invertebrates

Terrestrial invertebrates are key components in ecosystems, with crucial roles in soil structure, functioning, and ecosystem services. The present chapter covers how terrestrial invertebrates are impacted by organic chemicals, focusing on up-to-date information regarding bioavailability, exposure routes and general concepts on bioaccumulation, toxicity, and existing models. Terrestrial invertebrates are exposed to organic chemicals through different routes, which are dependent on both the organismal traits and nature of exposure, including chemical properties and media characteristics. Bioaccumulation and toxicity data for several groups of organic chemicals are presented and discussed, attempting to cover plant protection products (herbicides, insecticides, fungicides, and molluscicides), veterinary and human pharmaceuticals, polycyclic aromatic compounds, polychlorinated biphenyls, flame retardants, and personal care products. Chemical mixtures are also discussed bearing in mind that chemicals appear simultaneously in the environment. The biomagnification of organic chemicals is considered in light of the consumption of terrestrial invertebrates as novel feed and food sources. This chapter highlights how science has contributed with data from the last 5 years, providing evidence on bioavailability, bioaccumulation, and toxicity derived from exposure to organic chemicals, including insights into the main challenges and shortcomings to extrapolate results to real exposure scenarios

Facteurs environnementaux impactant la diversité taxonomique, fonctionnelle et phylogénétique (composantes alpha, bêta et gamma) dans les communautés de poissons estuariens.

International audienceWe applied a diversity partitioning approach to identify the influence of multiple environmental factors on taxonomic, functional and phylogenetic diversity of estuarine fish assemblages at different spatial scales. Our aim was to determine (1) how variation in γ-diversity (estuary scale) is supported by changes in α- (local scale) and β-components (dissimilarity between these two scales) for the three diversity facets and (2) how these diversity measures are related to biogeographic, hydroclimatic, marine, estuarine and land cover conditions. Fish assemblages were sampled using standardized beam trawl surveys in 32 estuaries during spring and autumn (period 200

Les petits pélagiques dans l'estuaire de la Gironde : 30 ans de suivi d'abondance face à 30 ans de changements globaux

National audienceLes conséquences écologiques du changement global (changement climatique + pressions anthropiques) ont été montrées pour les communautés écologiques de l'estuaire de la Gironde dans plusieurs études récentes. La marinisation et le réchauffement de l'eau, principaux effets, entrainent de profondes modifications dans la structure et la dynamique des communautés ichtyologiques. Cependant, ces récentes études sur les poissons notamment, n'ont pas explicitement montré le lien entre les facteurs environnementaux et les réponses des communautés. Objectifs : caractériser explicitement les modifications de structure et de dynamique temporelle des poissons pélagiques et le lien avec les facteurs environnementaux

Toward a phenological mismatch in estuarine pelagic food web?

International audienceAlterations of species phenology in response to climate change are now unquestionable. Until now, most studies have reported precocious occurrence of life cycle events as a major phenological response. Desynchronizations of biotic interactions, in particular predator-prey relationships, are however assumed to strongly impact ecosystems' functioning, as formalized by the Match-Mismatch Hypothesis (MMH). Temporal synchronicity between juvenile fish and zooplankton in estuaries is therefore of essential interest since estuaries are major nursery grounds for many commercial fish species. The Gironde estuary (SW France) hassuffered significant alterations over the last three decades, including two Abrupt Ecosystem Shifts (AES), and three contrasted intershift periods. The main objective of this study was to depict modifications in fish and zooplankton phenology among inter-shift periods and discuss the potential effects of the resulting mismatches at a community scale. A flexible Bayesian method was used to estimate and compare yearly patterns of species abundance in the estuary among the three pre-defined periods. Results highlighted (1) an earlier peak of zooplankton production and entrance of fish species in the estuary and (2) a decrease inresidence time of both groups in the estuary. Such species-specific phenological changes led to changes in temporal overlap between juvenile fish and their zooplanktonic prey. This situation questions the efficiency and potentially the viability of nursery function of theGironde estuary, with potential implications for coastal marine fisheries of the Bay of Biscay

Quand il faut plus chaud les poissons sont-ils en retard à la cantine ?

International audienceImagine you are a young and hungry fish looking for food in an estuary (the part of a river where it meets the ocean). You need to grow big and strong before you migrate to the ocean, and depend on tiny floating creatures (plankton) for food. However, the occurrence of these tiny creatures in the estuary varies seasonally. Lucky for you, nature has synchronized both your time in the estuary and that of your prey, and you survive. This synchronization depends on many different factors, among them the temperature of the water. Now imagine someone turning up the heat (like we humans are doing by changing the climate). Could the rising water temperatures mess up the timing for you, the predator, and your prey? To answer this question we looked at climate related changes in the synchronization of predator and prey in the biggest estuary in Western Europe. And indeed, we found signs of temporal mismatches in its aquatic food web. We fear that the observed changes can put this important ecosystem and its role as a big fish nursery at risk.Imagine que tu sois un poisson jeune et affamé à la recherche de nourriture dans un estuaire (la partie d'une rivière où elle rencontre l'océan). Tu dois devenir grand et fort avant de nager vers l'océan, et tu dépends de minuscules animaux flottants : le plancton pour manger. Cependant, la présence de ces créatures dans l'estuaire varie selon les saisons. Heureusement pour toi, la nature a fait en sorte que tu sois dans l'estuaire en même temps que ton repas et donc tu survivras (on parle alors de synchronisation). Cette synchronisation dépend néanmoins de nombreux paramètres, comme la température de l'eau. Maintenant, imagine que quelqu'un fasse monter cette température (comme nous, les humains, en changeant le climat). Cette augmentation de la température peut-elle perturber ton calendrier et celui des animaux que tu manges (tes proies) ? Pour répondre à la question, nous avons examiné la synchronisation de plusieurs espèces de poissons (prédateurs) avec celle de leurs proies dans le plus grand estuaire d'Europe occidentale (La Gironde) et son lien avec le changement du climat. Et en effet, nous avons trouvé des signes de décalage au sein de la chaine alimentaire. Nous craignons que les changements observés ne mettent en péril la fonction de nourricerie de cet écosystème

Climatic facilitation of the colonization of an estuary by Acartia tonsa

International audienceGlobal change has become a major driving force of both terrestrial and marine systems. Located at the interface between these two realms, estuarine ecosystems are probably the place where both direct and indirect effects of human activities conspire together to affect biodiversity from phytoplankton to top predators. Among European estuarine systems, the Gironde is the largest estuary of Western Europe and many studies have provided evidence that it has been affected by a variety of anthropogenic stressors such as thermal and chemical pollution, physical alterations and exploitation, especially for maritime traffic. In such a context, species introduction is also a current major issue with the establishment of strong competitive species that could lead to ecosystem reorganization with potential decrease or even disappearance of native species. In the Gironde estuary, this hypothesis was proposed for the invasive shrimp species Palaemon macrodactylus as a decrease in the native species abundance was observed at the same time. Although species introduction often takes place via ballast water, the influence of climate-driven changes on the establishment of new species remains a key issue. The calanoid copepod Acartia tonsa, observed in the Gironde estuary for the first time in 1983, have since colonized most part of the estuary, reaching a level of abundance comparable to the dominant native species Eurytemora affinis. In this study, using both the concept of the ecological niche sensu Hutchinson (fundamental and realized niches) and statistical models, we reveal that the dynamics of the colonization of A. tonsa was facilitated by environmental conditions that have become closer to its environmental optimum with respect to temperature and salinity

Functional reorganization of marine fish nurseries under climate warming

WOS:00045602890002

Changes in the distribution of copepods in the Gironde estuary: A warming and marinisation consequence?

International audienceThe Gironde is the largest estuary of South-West Europe and is one of the best monitored estuarine systems in the world. This macrotidal estuary is characterized by a low biodiversity in both oligo- and mesohaline zones. Its zooplankton community is constituted by only five major species, three calanoid copepods (including one invasive species) and two mysids. Retrospective analyses have already documented a warming associated to a phenomenon of marinisation. Here, we investigate the influence of both marinisation and warming on the spatial distribution and the abundance of copepods (i.e. Eurytemora affinis, Acartia bifilosa and neritic species) in the Gironde estuary. We modelled the environmental envelope of the copepods as a function of salinity and temperature to demonstrate that the alteration of their longitudinal distribution in the estuary between 1975 and 2003 was the result of both changing temperature and salinity. Although the upstream movement of neritic species was mostly related to salinity, we show that the augmentation of both temperature and salinity was at the origin of the upstream progression of both A. bifilosa and E. affinis. These results suggest that the distribution of copepods can be affected by both anthropogenic forcing and climatic change, which modulate the physic-chemistry of the Gironde estuary