Shape your career: Opportunities for Early Career Members in 2022 and the experience of applying for an ERS fellowship

In this article, we present the @EuroRespSoc opportunities for ECMs (@EarlyCareerERS) in the upcoming year and describe the experience of applying for an ERS Fellowship, with the key steps and challenges identified.info:eu-repo/semantics/publishedVersio

Diversity of plantonic fish larvae along a latitudinal gradient in the Eastern Atlantic Ocean estimated through DNA barcodes

Mid-trophic pelagic fish are essential components of marine ecosystems because they represent the link between plankton and higher predators. Moreover, they are the basis of the most important fisheries resources; for example, in African waters. In this study, we have sampled pelagic fish larvae in the Eastern Atlantic Ocean along a latitudinal gradient between 37°N and 2°S. We have employed Bongo nets for plankton sampling and sorted visually fish and fish larvae. Using the cytochrome oxidase I gene (COI) as a DNA barcode, we have identified 44 OTUs down to species level that correspond to 14 families, with Myctophidae being the most abundant. A few species were cosmopolitan and others latitude-specific, as was expected. The latitudinal pattern of diversity did not exhibit a temperate-tropical cline; instead, it was likely correlated with environmental conditions with a decline in low-oxygen zones. Importantly, gaps and inconsistencies in reference DNA databases impeded accurate identification to the species level of 49% of the individuals. Fish sampled from tropical latitudes and some orders, such as Perciformes, Myctophiformes and Stomiiformes, were largely unidentified due to incomplete references. Some larvae were identified based on morphology and COI analysis for comparing time and costs employed from each methodology. These results suggest the need of reinforcing DNA barcoding reference datasets of Atlantic bathypelagic tropical fish that, as main prey of top predators, are crucial for ecosystem-based management of fisheries resources

Rate of biological invasions is lower in coastal marine protected areas

Marine biological invasions threaten biodiversity worldwide. Here we explore how Marine Protected areas, by reducing human use of the coast, confer resilience against the introduction of non-indigenous species (NIS), using two very different Pacific islands as case studies for developing and testing mathematical models. We quantified NIS vectors and promoters on Vancouver (Canada) and Moorea (French Polynesia) islands, sampled and barcoded NIS, and tested models at different spatial scales with different types of interaction among vectors and between marine protection and NIS frequency. In our results NIS were negatively correlated with the dimension of the protected areas and the intensity of the protection. Small to medium geographical scale protection seemed to be efficient against NIS introductions. The likely benefit of MPAs was by exclusion of aquaculture, principally in Canada. These results emphasize the importance of marine protected areas for biodiversity conservation, and suggest that small or medium protected zones would confer efficient protection against NIS introduction

Microplastics pollution in genetically connected populations of Holothuria forskali from south Bay of Biscay

IntroductioSea cucumbers are increasingly demanded as seafood in different cultures around the world. Holothurians could be potentially exploited in southern Bay of Biscay (Iberian Cantabrian coast) where they are not fished yet. Recent studies show relatively high pollution by emerging pollutants like microplastics (MPs) in the region; perhaps the exposure of holothurians to those MPs may put them at risk.Material and methodsHere we analysed 60 samples of Holothuria forskali taken from the west and east of the Cape Peñas transition zone in different seasons. MPs were quantified from body wall tissue, and mitochondrial DNA sequences (16S and COI genes) were employed to determine population connectivity and infer replenishment capacity.ResultsMuch higher MPs content in holothurian tissue than in water and sediments confirmed bioconcentration in this species. Significant differences between sampling locations were found, holothurian pollution being consistent with the occurrence of MPs sources like rivers, fishing ports and aquaculture. Genetic connectivity and no signals of diversity reduction in the most polluted samples suggest population replenishment capacity in H. forskali in the studied region. Results for a few samples of H. mammata from the same sampling points confirmed a higher MPs pollution at the west of Cape Peñas.DiscussionAccording to these exploratory results, sea cucumbers seem to accumulate MPs especially in the western Cantabrian Sea. Further studies are recommended to understand the possible MPs threat for these holothurian species

Novel tools for early detection of a global aquatic invasive, the zebra mussel Dreissena polymorpha

1. This study presents a species-specific DNA-based marker for detection of the zebra mussel Dreissena polymorpha, recognized as one of the worst invasive species worldwide. 2. The marker was developed in silico and experimentally tested on environmental samples. Gel and capillary electrophoreses for visualization of the PCR products were compared. 3. Marker specificity and sensitivity were assessed in vitro by cross-amplifications and serial dilutions, respectively. The method allows detecting at least 0.7 ng of Dreissena DNA per μL and cross-species amplification was not found in any case. 4. Next-generation sequencing (NGS) metabarcoding (PCR amplification and massive sequencing of a DNA barcode) was used as an independent method for verifying presence of Dreissena DNA molecules in environmental plankton samples collected from the south-eastern Baltic Sea. 5. The consistency between NGS results reporting presence of Dreissena and positive PCR amplification of the marker from the plankton samples confirmed the efficacy of this highly reproducible, fast, cheap and technically easy method

DNA barcoding for assessment of exotic molluscs associated with maritime ports in northern Iberia

Ports are gateways for aquatic invasions. New arrivals from maritime traffic and disturbed environmental conditions can promote the settlement of exotic species. Molluscs fall into the most prevalent group of invasive species and can have a tremendous impact on aquatic ecosystems. Here we have investigated exotic molluscs in three ports with different intensities of maritime traffic in the Cantabrian Sea. DNA barcodes were employed to identify the species using BLASTn and BOLD IDS assignment. Deep morphological analysis using diagnostic criteria confirmed BLAST species assignation based on COI and 16S rRNA genes. Results confirmed the usefulness of DNA barcoding for detecting exotic species that are visually similar to native species. Three exotic bivalves were identified: Ostrea stentina (dwarf oyster), the highly invasive Crassostrea gigas (Pacific oyster) and Xenostrobus securis (pygmy mussel). This is the first record of O. stentina in the Bay of Biscay and the second of X. securis in the Cantabrian Sea. Furthermore, we report on the presence of the cryptogenic mussel Mytilaster minimus in the central Cantabrian Sea. These exotic species might have been overlooked due to their phenotypic similarity with co-occurring oyster and mussel species. This study illustrates how combining morphological and DNA taxonomic analysis can help in port and marina biosecurity surveys