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.

Resumo -As interações que ocorrem entre a água superficial (rios e lagos) e água subterrânea envolvem uma série de processos que devem ser explorados no intuito de entender suas interligações, já que a taxa de recarga e a qualidade da água subterrânea dependem fortemente das características dessa interface. A zona de intercâmbio, conhecida por zona hiporreica é formada por uma camada subsuperficial de sedimentos entre o leito do rio e o aquífero, e suas características favorecem o estabelecimento de algumas espécies, destacando-se a meiofauna. Alguns processos biológicos responsáveis pela modificação da qualidade da água de recarga envolvem esses organismos. Um estudo sobre a comunidade da meiofauna hiporreica foi realizado em três pontos do rio Beberibe, Olinda -PE. A meiofauna esteve composta por um total de 4965 indivíduos, distribuídos em oito taxa, onde 97% dos organismos foram representados pelos rotíferas, nemátodas e anelídeos. A densidade média total variou entre 1446,3 indivíduos/ 10 cm 2 no verão e 12,1 indivíduos/ 10 cm 2 no inverno. A estrutura da comunidade foi correlacionada às variáveis: inverno, verão e granulometria dos sedimentos e o conjunto desses fatores refletiu-se nas características da meiofauna hiporreica do trecho estudado do rio Beberibe-PE. Tanto no verão como no inverno, os pontos onde as densidades de grupos foram mais significativas, foram as dominadas pelas frações arenosas. Palavras-chave:Interação água subterrânea -água superficial. Meiofauna hiporreica. Qualidade da água de recarga.Abstract -The interactions that occur between surface water (rivers and lakes) and groundwater involve a number of processes that should be explored in order to understand their interconnections, since the rate of recharge and groundwater quality strongly depend on the characteristics of this interface. The area of interconnection, known as hyporheic zone is formed by a subsurface layer of sediment from the river bed and the aquifer, and its characteristics favor the establishment of some species, highlighting the meiofauna. Some biological processes responsible for modifying the recharge water quality involve those bodies. A study on hyporheic meiofauna community was performed at three points of Beberibe river, Olinda -PE. The meiofauna was composed of a total of 4965 individuals, distributed in eight taxa where 97% of organizations were represented by rotíferas, nematodes and annelids. The average total density varied between individuals 1446.3 / 10 cm 2 in the summer and 12.1 individuals / 10 cm 2 in winter. The community structure was correlated to the variables: winter, summer and grain size of the sediment and the combination of these factors were reflected in characteristics of hyporheic zone of Beberibe river -PE. Both in summer and in winter, the points where the densities groups were more significant were dominated by sandy fractions.

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