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Changes in marine communities in response to elevated CO2 have been reported but information on how representatives of the benthic lower trophic levels will be impacted remains scarce. A laboratory experiment was conducted to evaluate the impact of different climate change scenarios on a coral reef meiofauna community. Samples of the meiofauna community were collected from the coral reef subtidal zone of Serrambi beach (Ipojuca, Pernambuco, Brazil), using artificial substrate units. The units were exposed to control treatments and to three climate change scenarios, and collected after 15 and 29 d. Important changes in the meiofauna community structure were observed after 15 d of exposure. The major meiofauna groups exhibited divergent responses to the various scenarios. Although polychaetes were negatively affected after 29 d in the most severe scenario (Scenario III), harpacticoid copepods were negatively affected in Scenarios II and III after 15 and 29 d. Harpacticoid nauplii were strongly and negatively affected in all scenarios. In contrast, Nematoda exhibited higher densities in all scenarios. To the best of our knowledge, this community-based study was the first to observe how meiofauna organisms from a coral reef environment react to the synergetic effects of reductions in seawater pH and increased temperature.

Coastal environments are trampled by humans worldwide; however, there are few studies that evaluate the effect of trampling on the meiofauna of hard substrates, and none on meiofauna of reef environments. We investigated the effects of trampling due to tourism on the meiofauna of reef formations on the northeastern coast of Brazil. Samples were taken from five paired stations located in two areas on the reef: an area protected since 2004, and an area open to tourist visits. Trampling caused important changes in the meiofaunal assemblage. The densities of the total meiofauna and of the commonest groups were negatively affected in the trampled area. Among the major groups, Polychaeta proved to be very sensitive to this disturbance. The meiofauna groups showed different response patterns to trampling depending on the species of algae trampled. Reductions in animal densities were partly attributed to the loss of turf biomass and associated sand caused by trampling, and partly to the direct effect of people stepping on the animals. Considering the importance of meiofauna in the food web as well as its biodiversity, these results highlight the possible negative effects of human trampling on the ecological and economic "services" that coral reefs provide.

The coral reefs of Porto de Galinhas Beach (Pernambuco, Brazil, Northeast region) are among the most important tourist destinations in the country. However, this ecosystem is being increasingly threatened by impacts related to tourism. A first list of the Harpacticoida species found in the phytal of these reefs is provided here. The total of 1501 individuals analyzed included 42 species belonging to 13 families and 32 genera. The dominant species were Parastenhelia spinosa, Amphiascoides sp., Robertsonia knoxi, Ameira parvula, Paralaophonte congenera congenera and Amphiascopsis cinctus. First records for the Brazilian coast include the subspecies Nitocra affinis californica and nine species: Nannomesochra arupinensis, Cletodes aff. pseudodissimilisoris, Esola lobata, Paralaophonte congenera (sensu Yeatman 1962), Sarsamphiascus parvus (sensu Rouch 1962), Rhyncholagena littoralis, Stenhelia gibba, Alteutha roeae and Xouthous purpurocinctus. The high diversity and the isocommunity hypothesis are discussed.