ABSTRACT Functional traits, short life cycles, and the pivotal role in the ocean make copepod diversity a solid foundation for assessing the effect of global changes in marine food webs and ecosystem functioning. Climate change and extreme events, particularly El Niño, can affect coastal ecosystems. The Arvoredo Marine Biological Reserve (MPA), located in highly productive coastal waters of the Southern Brazilian Bight, presents complex climate and oceanographic conditions. This study investigates the influence of oceanographic processes and El Niño 2015-2016 on the copepod functional diversity from 2014 to 2016 in the Arvoredo MPA. Horizontal tows were performed using a WP2 net with a mesh size of 200 µm. The 41 species accounted for 19 functional entities and four functional groups. Our findings reveal that the seasonal intrusion of water masses influenced copepod functional diversity. During summer, the upwelling of South Atlantic Central Water increased nutrient availability and favored large herbivore-omnivores and carnivores. The Plata Plume Water enrichment during winter coincided with a decline in functional richness and abundance, leading to the predominance of the Oithona nana, a small-sized omnivore. Compensatory mechanisms were observed as functional equivalence and species composition shifts. Acartia lilljeborgii and Temora turbinata exhibited functional equivalence and compensated for each other in response to salinity changes associated with upwelling and El Niño. The copepod assemblage demonstrated the ability to maintain functional diversity despite changes in copepod abundance. However, the decline in functional diversity and abundance during the intense winter indicated potential disruption in trophic dynamics and ecosystem functioning. Maintaining balance and compensating for disturbances such as El Niño is crucial for marine food web resilience. The functional trait approach provided a comprehensive understanding of the copepod assemblage in Arvoredo MPA, contributing to a broader knowledge of the impact of oceanographic processes intensification. Monitoring functional diversity and abundance is crucial for evaluating the effects of copepod assemblage changes in ecosystem functionings. traits cycles functioning events ecosystems MPA , (MPA) Bight conditions 20152016 2015 2015-201 201 WP 20 µm 4 1 groups summer herbivoreomnivores herbivore omnivores carnivores nana smallsized small sized omnivore shifts However resilience intensification functionings (MPA 2015201 2015-20 2 201520 2015-2 20152 2015-

Abstract The Sally lightfoot crab, Grapsus grapsus (Linnaeus, 1758), is distributed along the Eastern Pacific coast and along the Western Atlantic coast, from the Gulf of Mexico to the Southwestern Atlantic. In Brazil, the only established populations are found on the Brazilian oceanic islands, although two previous records (1901 and 1966) reported the presence of individuals on the continental coast. Here, we report new records of the Sally lightfoot crab on the coast of the states of Espírito Santo and Rio Grande do Norte, southeastern and northeastern Brazil, respectively. We also discuss three main hypotheses that could explain occasional records (1901, 1966, 2005, and 2020) of single individuals on the mainland: rafting events associated with flotsam and debris carried by oceanic currents; hitchhiking on vessels and fishing boats navigating routes from the Brazilian oceanic islands to the mainland; and stochastic settlement through larval dispersal.

Abstract The sally lightfoot crab, Grapsus grapsus (Linnaeus, 1758), has been recorded from the oceanic islands off Brazil, as well as from the Caribbean, in coastal rocky shores in the Eastern Pacific, and in Galapagos. We report the first observation of G. grapsus in freshwater habitat, registered in a stream at Trindade Island, Brazil.