Marine Nematoda from Ajuruteua beach, Amazon Coast, Brazil

Abstract

RESUMOEste estudo objetiva preencher uma lacuna do conhecimento sobre nematodeos no Brasil, fornecendo a primeira lista de gêneros de uma praia arenosa amazônica brasileira (Ajuruteua, Pará). As amostras foram coletadas em junho de 2009 ao longo de quatro transectos perpendiculares à linha da praia ao longo do médio litoral (supra, médio e infra), usando um amostrador cilíndrico de 3.14 cm 2 , o qual foi enterrado até 10cm no sedimento. Um total de 17 famílias e 47 gêneros foi registrado. Entre as famílias Xyalidae foi a mais rica (11 gêneros) seguida por Chromadoridae (11 gêneros). Os táxons encontrados neste estudo são comuns em praias arenosas no mundo, tendo sido já registrados também na região costeira brasileira. Trochamus, Neotonchus e Metadasynemella foram registrados pela primeira vez em praias arenosas no Brasil. A maioria dos gêneros teve baixa frequência de ocorrência, sendo apenas Chromadorita, Paracanthonchus, Monoposthia, Metadesmolaimus, Bathylaimus, Daptonema e Trichotheristus comuns. PALAVRAS-CHAVES:Nematoda, Praia arenosa, Pará, Região Amazonica. ABSTRACTThis study aims to fill a gap in knowledge about nematodes in Brazil, providing the first list of nematodes genera from a Brazilian Amazon sandy beach (Ajuruteua, Pará). Samples were collected in June 2009 along four transects perpendicular to the beachline along the midlittoral (upper, middle and inferior), using a cylindrical sampler of 3.14 cm 2 which was buried to 10 cm depth in the sediment. A total of 17 families and 47 genera were recorded. Among families, Xyalidae was the richest (11 genera) followed by Chromadoridae (7 genera). The taxa found in this study are common on sandy beaches around the world have been also reported already for Brazilian coast. Trochamus, Neotonchus and Metadasynemella were recorded for the first time in sandy beaches of Brazil. Most genera had low frequency of occurrence with only Chromadorita, Paracanthonchus, Monoposthia, Metadesmolaimus, Bathylaimus, Daptonema and Trichotheristus being common.

Structure of meiofaunal communities in an urban tropical sandy beach in Pernambuco, Brazil

“…Fonseca et al (2014) stated that Theristus showed a broad distribution that was correlated with average grain size. The high abundance of Daptonema in this study agrees with what has been previously reported indicating that this genus is commonly an abundant nematofaunal taxa present in various environments, especially in sandy beaches (Pereira-Gomes de Melo et al 2013) with well-selected sands (Moreno et al 2008) or fine sand (Corbisier et al 2008).…”

“…Four trophic types were identified in both sampling periods, although selective deposit feeders constituted less than 2% of the meiofaunal community. In contrast, nonselective deposit feeders dominated the community followed by epistrate feeders, which agrees with what was reported by Pereira-Gomes de Melo et al (2013). The high representativeness of nonselective deposit feeders on Gaibu Beach agrees with what was reported by Alongi (1990), who stated that this group is dominant during warm months due to the elevated number of bacteria, protozoa, and microphytobenthos present.…”

“…Furthermore, anthropogenic impacts on the beach can also play important roles in determining the structure of meiofaunal communities, as nematode predators are quite sensitive to environmental disturbance (Bongers and Ferris 1999). ambientes, especialmente en playas arenosas (Pereira-Gomes de Melo et al 2013) con arenas bien seleccionadas (Moreno et al 2008) o arena fina (Corbisier et al 2008).…”

“…Se identificaron 4 tipos tróficos en ambos periodos de muestreo, aunque los alimentadores de depósitos selectivos constituyeron menos del 2% de la comunidad de meiofauna. En contraste, los alimentadores de depósito no selectivos dominaron la comunidad seguidos por los alimentadores de superficie, lo que concuerda con lo reportado por Pereira-Gomes de Melo et al (2013). La alta representatividad de los alimentadores de depósito no selectivos en la playa de Gaibu concuerda con lo reportado por Alongi (1990), quien afirmó que este grupo es dominante durante los meses cálidos debido la presencia elevada de bacterias, protozoos y microfitobentos.…”