Aquatic worms: relevant model organisms to investigate pollution of microplastics throughout the freshwater-marine continuum.

Plastic pollution has become a global and emergency concern. Degradation processes of plastic macrowaste, either at the millimetre- and micrometre-size scales (microplastics, MP) or a nanometre one (nanoplastic, NP), is now well documented in all environmental compartments. It is hence necessary to study the environmental dynamic of MNP (micro(nano)plastic) on aquatic macrofauna considering their dispersion in different compartments. In this context, worms, having a large habitat in natural environments (soil, sediment, water) represent a relevant model organism for MNP investigations. In aquatic systems, worms could be used to compare MNP contamination between freshwater and seawater. The aim of this review was to discuss the relevance of using worms as model species for investigating MNP pollution in freshwater, estuarine, and marine systems. In this context, studies conducted in the field and in laboratory, using diverse classes of aquatic worms (polychaete and clitellate, i.e. oligochaete and hirudinea) to assess plastic contamination, were analysed. In addition, the reliability between laboratory exposure conditions and the investigation in the field was discussed. Finally, in a context of plastic use regulation, based on the literature, some recommendations about model species, environmental relevance, and experimental needs related to MNP are given for future studies.

Is there a link between acetylcholinesterase, behaviour and density populations of the ragworm Hediste diversicolor?

The main objective of the present study was to explore the potential link between acetylcholinesterase (AChE) activity and burrowing behaviour of the ragworm Hediste diversicolor, which may have consequences at higher levels of biological organisation. Two complementary studies were conducted. AChE activity, at the sub-individual level, and behavioural responses, at the individual level, were evaluated in worms from the Loire estuary (France), whereas density and biomass of H. diversicolor were determined at the population level. A Spearman positive correlation between both biomarkers (AChE and burrowing) suggested that inhibition of AChE activity was linked to behaviour impairments. At the population level, lower AChE and behaviour activities were detected in worms corresponding to lower population density and biomass. These results provide direct empirical field evidence demonstrating the sensitivity of behaviour of H. diversicolor as a biomonitor of estuarine health status assessment.

A new species of Flabelligeridae (Annelida), Trophoniella radesiensis n. sp., from Tunisia.

The family Flabelligeridae was previously represented in Tunisia by four genera including four species: Bradabyssa villosa (Rathke, 1843), Therochaeta flabellata (M. Sars in G.O. Sars, 1872), Pherusa plumosa (Müller, 1776), and Piromis eruca (Claparède, 1869). In this paper we report a fifth genus, Trophoniella, for the first time in Tunisia. The specimens were collected in Radés Station, Gulf of Tunis (Central Mediterranean) and belong to a new species, namely Trophoniella radesiensis n. sp., which is characterized by having: (1) a very smooth tunic, body covered dorsally, ventrally, and laterally by sediment grains (except in the posterior region), and (2) well-developed parapodia showing short neurohooks from chaetiger 6 to 19 and anchylosed neurohooks from chaetiger 20. Based on the 16S, the new species belongs to a low supported Piromis/Trophoniella clade and shows a 16.1% of genetic distance from Trophoniella hephaistos Jimi Fujiwara, 2016, the single known species of the genus sequenced to date. [Zoobank lsid: urn:lsid:zoobank.org:act:D7C85C70-87FF-4AF4-8599-A8462B3FB8B1].

From biomarkers to population responses in Nereis diversicolor: assessment of stress in estuarine ecosystems.

Suborganismal responses to toxicants can be sensitive tools to assess marine pollution, but their ecological significance is a matter of debate. Among these biomarkers, those linked to reproduction are most probably related to populational effects. To test this hypothesis, Nereis diversicolor were collected in the multipolluted Seine estuary and the comparatively clean Authie estuary (France). Energy reserves were higher in Authie worms, suggesting a better physiological status. The number of oocytes per female was higher for the polychaetes from the Authie, but it was related to the size of animals, which was higher at this site. Densities of worms were depleted in the Seine compared to those in Authie. Demographic structure of the Seine population was also altered. The concomitant changes in energy reserves, egg production, and population structure and density suggest that the effects on biomarkers and at the population level are related.

How false is Nereis falsa (Annelida, Phyllodocida, Nereididae)? / ¿Qué tan falsa es Nereis falsa (Annelida, Phyllodocida, Nereididae)?

Abstract: There are many taxonomic problems in polychaete species names and solving confusing or inadequate taxonomic procedures is both time-demanding and extremely important. Our objective in this contribution was to analyse what is the current taxonomic situation for Nereis falsa de Quatrefages, 1866; it was based upon Nereis pulsatoria? Rathke, 1837 from the Black Sea, and it is currently regarded as having a very wide distribution. The species has been collected from different benthic substrates and even can be found on floating objects or marine turtles. Nereis falsa has been recorded from the Mediterranean Sea, the Eastern Atlantic along Africa, the Western Atlantic (Gulf of Mexico, Caribbean Sea, Brazil), and the Indian Ocean. However, despite the fact N. falsa was proposed as a species from the Black Sea, it has not yet been found there. How can we explain that a species is able to attain a very wide distribution and yet be missing from its type locality? After a careful study of previous publications and with our understanding of the systematics of nereidid polychaetes, we clarify the current situation by examining several related species and pointed out some nomenclatural issues. Our analysis indicates there is more than one species included under the same name, and in this contribution we propose some means to promote discussion and actions, and suggest some basic research for solving this issue. Rev. Biol. Trop. 65 (3): 847-857. Epub 2017 September 01.

Resumen: Entre los nombres de especies de poliquetos hay muchos problemas taxonómicos y resolver los procedimientos taxonómicos confusos o inadecuados consume mucho tiempo y es muy importante. Nuestro objetivo en esta contribución es analizar cuál es la situación para Nereis falsa de Quatrefages, 1866; fue basada en Nereis pulsatoria? Rathke, 1837 del Mar Negro, y se considera como una especie de amplia distribución. La especie se ha recolectado en diferentes sustratos bénticos e incluso puede hallarse en objetos flotantes o sobre tortugas marinas. Nereis falsa se ha registrado del Mar Mediterráneo, en el Atlántico oriental a lo largo del África, en el Atlántico occidental (Golfo de México, Mar Caribe, Brasil), y en el Índico. Sin embargo, a pesar de haber sido propuesta para una especie del Mar Negro no se ha vuelto a encontrar en el mismo. ¿Cómo conjugar que una especie pueda alcanzar una vasta distribución y faltar en su localidad tipo? Después de un estudio cuidadoso de las publicaciones sobre el tema y con nuestra comprensión de la sistemática de los poliquetos neréididos, clarificamos la situación prevalente al examinar varias especies relacionadas e indicamos algunas cuestiones nomenclaturales. Nuestro análisis indica que hay más de una especie bajo el mismo nombre y en esta contribución, nos enfocamos al problema, proponemos algunas formas para promover la discusión y la acción, y sugerimos algunas actividades de investigación para resolver el problema.