DNA barcodes of Antipode marine invertebrates in Bay of Biscay and Gulf of Lion ports suggest new biofouling challenges

Beware of oysters. Rapid advance of non-native species in tropical Pacific islands

Non-indigenous species can become a problem for the ecosystem health, especially when their distribution grows to the detriment of native species. In this moment, they can become invasive species. In marine ecosystems, the maritime transport is the principal gate and corridor for the movement of alien species. The genetic identification, using barcoding tools, of different oyster species in ports of the remote French Polynesia islands and atolls, showed a significant increase of exotic versus native oyster species between 2011 and 2018. This supports the spread of exotic species with the maritime traffic as the main cause. Moreover, the 11% of inaccurate identification at species level obtained in this study shows the need to complete the genetic databases.

An Overview of DNA-Based Applications for the Assessment of Benthic Macroinvertebrates Biodiversity in Mediterranean Aquatic Ecosystems

The loss of aquatic biodiversity is increasing at a rapid rate globally. There is a worldwide effort to protect, preserve and restore aquatic ecosystems. For efficient biodiversity monitoring and reliable management tools, comprehensive biodiversity data are required. The abundance and species diversity of benthic macroinvertebrates are commonly used as indicators of the aquatic ecosystem condition. Currently, macroinvertebrate species biodiversity assessment is based on morpho-taxonomy, which could be enhanced by recent advances in DNA-based tools for species identification. In particular, DNA metabarcoding has the potential to identify simultaneously many different taxa in a pool of species and to improve aquatic biomonitoring significantly, especially for indicator species. This review is focused on the current state of DNA-based aquatic biomonitoring using benthic macroinvertebrates in the Mediterranean region.

Stress resistance for unraveling potential biopollutants. Insights from ballast water community analysis through DNA

In marine settings, anthropogenic disturbances and climate change increase the rate of biological invasions. Predicting still undescribed invasive alien species (IAS) is needed for preparing timely management responses. We tested a strategy for discovering new potential IAS using DNA in a trans-equatorial expedition onboard RV Polarstern. During one-month travel, species inside ballast water experienced oxygen depletion, warming, darkness and ammonium stress. Many organisms died but several phytoplankton and zooplankton survivors resisted and were detected through a robust combination of individual sampling, DNA barcoding and metabarcoding, new in ballast water studies. Ammonium was identified as an important influential factor to explain diversity changes in phytoplankton and zooplankton. Some species reproduced until the end of the travel. These species tolerant to travel stress could be targeted as potential IAS and prioritized for designing control measures. Introducing resistance to travel stress in biosecurity risk analysis would be recommended.

Assessment of species gaps in DNA barcode libraries of non-indigenous species (NIS) occurring in European coastal regions

DNA metabarcoding has the capacity to bolster current biodiversity assessment techniques, including the early detection and monitoring of non-indigenous species (NIS). However, the success of this approach is greatly dependent on the availability, taxonomic coverage and reliability of reference sequences in genetic databases, whose deficiencies can potentially compromise species identifications at the taxonomic assignment step. In this study we assessed lacunae in availability of DNA sequence data from four barcodes (COI, 18S, rbcL and matK) for NIS occurring in European marine and coastal environments. NIS checklists were based on EASIN and AquaNIS databases. The highest coverage was found for COI for Animalia and rbcL for Plantae (up to 63%, for both) and 18S for Chromista (up to 51%), that greatly increased when only high impact species were taken into account (up to 82 to 89%). Results show that different markers have unbalanced representations in genetic databases, implying that the parallel use of more than one marker can act complimentarily and may greatly increase NIS identification rates through DNA-based tools. Furthermore, based on the COI marker, data for approximately 30% of the species had maximum intra-specific distances higher than 3%, suggesting that many NIS may have undescribed or cryptic diversity. Although completing the gaps in reference libraries is essential to make the most of the potential of the DNA-based tools, a careful compilation, verification and annotation of available sequences is fundamental to assemble large curated and reliable reference libraries that provide support for rigorous species identifications.

Monitoring of biofouling communities in a Portuguese port using a combined morphological and metabarcoding approach

Marine biofouling remains an unsolved problem with a serious economic impact on several marine associated industries and constitutes a major vector for the spread of non-indigenous species (NIS). The implementation of biofouling monitoring programs allows for better fouling management and also for the early identification of NIS. However, few monitoring studies have used recent methods, such as metabarcoding, that can significantly enhance the detection of those species. Here, we employed monthly monitoring of biofouling growth on stainless steel plates in the Atlantic Port of Leixões (Northern Portugal), over one year to test the effect of commercial anti-corrosion paint in the communities. Fouling organisms were identified by combining morpho-taxonomy identification with community DNA metabarcoding using multiple markers (16S rRNA, 18S rRNA, 23S rRNA, and COI genes). The dominant colonizers found at this location were hard foulers, namely barnacles and mussels, while other groups of organisms such as cnidarians, bryozoans, and ascidians were also abundant. Regarding the temporal dynamics of the fouling communities, there was a progressive increase in the colonization of cyanobacteria, green algae, and red algae during the sampled period with the replacement of less abundant groups. The tested anticorrosion paint demonstrated to have a significant prevention effect against the biofouling community resulting in a biomass reduction. Our study also reports, for the first time, 29 NIS in this port, substantiating the need for the implementation of recurring biofouling monitoring programs in ports and harbours.