Long range gene flow beyond predictions from oceanographic transport in a tropical marine foundation species.

The transport of passively dispersed organisms across tropical margins remains poorly understood. Hypotheses of oceanographic transportation potential lack testing with large scale empirical data. To address this gap, we used the seagrass species, Halodule wrightii, which is unique in spanning the entire tropical Atlantic. We tested the hypothesis that genetic differentiation estimated across its large-scale biogeographic range can be predicted by simulated oceanographic transport. The alternative hypothesis posits that dispersal is independent of ocean currents, such as transport by grazers. We compared empirical genetic estimates and modelled predictions of dispersal along the distribution of H. wrightii. We genotyped eight microsatellite loci on 19 populations distributed across Atlantic Africa, Gulf of Mexico, Caribbean, Brazil and developed a biophysical model with high-resolution ocean currents. Genetic data revealed low gene flow and highest differentiation between (1) the Gulf of Mexico and two other regions: (2) Caribbean-Brazil and (3) Atlantic Africa. These two were more genetically similar despite separation by an ocean. The biophysical model indicated low or no probability of passive dispersal among populations and did not match the empirical genetic data. The results support the alternative hypothesis of a role for active dispersal vectors like grazers.

Plastic ingestion in aquatic birds in Portugal.

In modern society, plastic items have become indispensable. The rapid growth of plastic production has led to an increase in the concentration of plastic waste in the environment and, consequently, wildlife has been severely affected. As wide-ranging foragers and predators, aquatic birds are ideal sentinels for monitoring changes in their environment. Plastic found in stomach contents of stranded aquatic birds collected throughout Portugal was examined. Out of the 288 birds processed, 12.9% ingested plastics. Six of the 16 species assessed showed evidence of plastic ingestion. The Lesser Black-backed Gull (18.7%) had the highest incidence while, among those that did ingest plastics, the Northern Gannet (4.8%) had the lowest. User plastics were the most common type of plastic ingested, while microplastics and off/white-clear were the most common size and colour respectively of plastics found. This study sets a first multispecies baseline for incidence of plastic ingestion by aquatic birds in Portugal.

Isolation and characterization of nine microsatellite markers for the red alga Corallina officinalis.

We report the development of nine polymorphic microsatellite markers for Corallina officinalis (Linnaeus, 1758), a calcifying intertidal red alga and important ecosystem engineer spread along the North East Atlantic. Characterization and analysis of loci were made using 15 individuals of C. officinalis from populations in Iceland and the UK. The average number of alleles per locus was 3.78 (range 2-6) and mean of gene diversity was 0.58 (range 0.38-0.77). The set of microsatellites developed here will provide a useful molecular tool for population genetic and conservation studies.