Leachates of weathering plastics from an urban sandy beach: Toxicity to sea urchin fertilization and early development

Plastic leachates have chemical and biological implications for marine environments. This study experimentally evaluated acute effects of weathering plastic leachates (0, 25, 50, 75 and 100 %) on fertilization and early development of the sea urchin Lytechinus variegatus. Fertilization, embryonic and larval development were drastically inhibited (~75 %) when gametes were exposed to intermediate and high leachate concentrations or delayed when exposed to the lowest concentration. Fertilization and first cleavage stages were highly affected by exposure to intermediate and high leachate concentrations. None of the cells incubated at concentrations from 50 % reached blastula stage, suggesting that embryonic development was the most sensitive stage. Abnormalities in embryos and larvae were observed in all leachate treatments. Chemical analysis detected high concentration of bisphenol A, which may induce these observed effects. Our results highlight the potential threats of plastic pollution to sea urchin populations, which may severely affect the structure and functioning of coastal ecosystems.

Composition and distribution of Darwinulidae (Crustacea, Ostracoda) in the alluvial valley of the upper Paraná River, Brazil

The occurrence and abundance of darwinulid ostracods, as well as environmental factors influencing these patterns, were investigated in the alluvial valley of the upper Paraná River. Ostracods were sampled from several substrates, like littoral sediments and pleuston, which included several aquatic macrophytes species, from 31 localities (lentic and lotic) belonging to different riverine systems. Eight darwinulid species were found, representing all genera from this family. Alicenula serricaudata, Vestalenula pagliolii, and Penthesilenula brasiliensis were the most common species. Cluster analysis based on the composition and abundance of darwinulid communities revealed the presence of five associations. Darwinula stevensoni, Vestalenula botocuda, and Penthesilenula aotearoa were almost exclusive to lotic environments. A Mantel multiple test showed that the occurrence and distribution of darwinulid ostracods were significantly related to types of habitat and systems, but not to abiotic variables. It thus seems that the hydrodynamic fluctuations of these environments are probably more important to darwinulid distribution than the limnological characteristics.