Search Results (3)

Non-indigenous species represent a significant threat to marine biodiversity, and accurate taxonomic identification is critical for effective management. This study revisits the long-standing record of the Australian sea anemone Oulactis muscosa in Argentina, which has been cited in numerous studies for nearly 50 years. We conducted a comprehensive taxonomic revision of specimens from Mar del Plata, Argentina, using both morphological and molecular analyses. Our findings reveal a persistent taxonomic error: the specimens belong to a different species. Detailed morphological comparisons and genetic sequencing of mitochondrial and nuclear markers re-identified the specimens as Anthopleura correae. This species is native to Brazil and is distributed from Ceará to Santa Catarina. This represents the first record of an Anthopleura species in Argentina, extending its known distribution. Genetic analyses confirmed the re-identification, showing no significant divergence between the Argentine and Brazilian specimens, while revealing notable differences from O. muscosa. We highlight the importance of rigorous taxonomic approaches integrating both morphological and molecular data to prevent misidentifications, which is particularly crucial when identifying potential invasive species. This study clarifies the taxonomic status of a regionally distributed species and contributes to the accurate inventory of sea anemones in Argentina. Full article

Mangrove forests are important in providing habitats for complex communities of terrestrial and marine fauna. Moreover, they are recognized as highly productive ecosystems in providing nutrients to mangrove food webs or exporting them to nearby coastal waters. In the present study, stable isotopes of carbon and nitrogen were applied to examine the changes in the diets of benthic invertebrate communities following mangrove restoration. The isotope signature of invertebrate tissues varied among the forest ages and locations and ranged from 3.7 ± 1.0 to 13.9 ± 1.1‰ and −26.6 ± 0.5 to −15.0 ± 0.4‰ for δ¹⁵N and δ¹³C, respectively. The results showed that the food source assimilation of macro-invertebrates is slightly altered from a mixture of benthic microalgae and marine phytoplankton in the mudflat to a combination of benthic microalgae and sediment organic matter in the Sonneratia caseolaris and the Kandelia obovata forests. Therefore, the diets of macro-invertebrates varied following forest ages and the position of the forest in the intertidal zone. These insights from the present study are useful for the effective conservation and restoration of mangrove forests in Vietnam and worldwide. Full article

Evaluating the degree of metal exposure and bioaccumulation in estuarine organisms is important for understanding the fate of metals in estuarine food webs. We investigated the bioaccumulation of Hg, methylmercury (MeHg), Cd, Se, Pb, and As in common intertidal organisms across a watershed urbanization gradient of coastal marsh sites in New England to relate metal exposure and bioaccumulation in fauna to both chemical and ecological factors. In sediments, we measured metal and metalloid concentrations, total organic carbon (TOC) and SEM-AVS (Simultaneously extracted metal-acid volatile sulfides). In five different functional feeding groups of biota, we measured metal concentrations and delta ¹⁵N and delta ¹³C signatures. Concentrations of Hg and Se in biota for all sites were always greater than sediment concentrations whereas Pb in biota was always lower. There were positive relationships between biota Hg concentrations and sediment concentrations, and between biota MeHg concentrations and both pelagic feeding mode and trophic level. Bioavailability of all metals measured as SEM-AVS or Benthic-Sediment Accumulation Factor was lower in more contaminated sites, likely due to biogeochemical factors related to higher levels of sulfides and organic carbon in the sediments. Our study demonstrates that for most metals and metalloids, bioaccumulation is metal specific and not directly related to sediment concentrations or measures of bioavailability such as AVS-SEM. Full article