Effects of seasonal fluctuation of amazon river discharge on the spatial and temporal changes of meiofauna and nematodes in the amazonian coast

Evaluation of freshwater benthic communities: a case study in an urban

“…This influence was observed not only in the present study in a hyporheic environment, but also in studies carried out in estuarine environments in Brazil, such as in Porto de Galinhas City, Pernambuco State, by Maranhão (2003), and in the Biological Reserve of Lago Piratuba, Amapá State, by Venekey, Melo and Rosa Filho (2019), in which factors such as resuspension and hydrodynamics affected the pattern of the vertical distribution of the studied organisms.…”

Patterns of spatial and temporal distribution of the macrobenthic fauna on an estuarine macrotidal sandy beach on the Amazon coast (Brazil)

“…Changes in beach morphodynamics are related to variations in wave and tide regime, sediment availability and characteristics, beach morphology, and coastal configuration (Masselink & Pattiaratchi, 2001; Masselink & Short, 1993; Taaouati et al., 2011; Wright et al., 1985). The environmental conditions on the Amazonian coast are very dynamic and temporally variable, as a response to its semidiurnal macro‐tides, large freshwater riverine inputs, and strong seasonal changes in rainfall (followed by high changes in salinity) and wave and wind regime (Souza‐Filho et al., 2009; Venekey et al., 2019). Previous studies about Amazonian beaches have shown cyclical modifications in beach morphology, with erosion processes dominating during the rainy months (associated with high fluvial discharge and strong tidal currents) and accretive processes during the dry season (Alves & El‐Robrini, 2006; Nascimento & Pereira, 2016; Pereira et al., 2013).…”

“…Seasonally, higher density and species richness were found in the dry season, a characteristic that has been widely reported in Amazonian coastal areas (Aviz et al., 2019; Beasley et al., 2010; Braga et al., 2013; Rosa Filho et al., 2009; Santos & Aviz, 2018; Silva et al., 2011). In contrast to sandy beaches from temperate regions, where changes in the structure of benthic communities are predominantly caused by modifications in temperature and photoperiod (Neves et al., 2008), salinity is primarily responsible for temporal variations in density and richness in the Amazon coastal zone (Baia et al., 2021; Rosa Filho et al., 2009; Venekey et al., 2019). High pluviosity sharply reduces salinity, leading to the restriction or exclusion of species that are exclusively marine or poorly adapted to low salinity (Kinne, 1971).…”

“…In this area, the macrotidal regime, the large amount of sediments carried by rivers to the coast and the high hydrodynamics in shallow waters favor the occurrence of ocean beaches with different sediment types, morphology, and exposure to waves (Klein & Short, 2016; Rosa Filho et al., 2011). The Amazonian coast has a number of unique features, including high volumes of river discharge and intense dry and rainy seasons, which contribute to marked fluctuations in the water salinity and hydrodynamics in coastal environments throughout the year (Pereira et al., 2016; Rosa Filho et al., 2018; Souza‐Filho et al., 2009; Venekey et al., 2019).…”

Macrobenthic community of an estuarine tidal flat on the Amazon coast: spatial variations and presence of polychaetes tubes

“…The Amazon coastal region is dominated by tidal flat systems that extend for almost 480 km (Kjerfve & Lacerda, 1993), and are influenced by unique conditions, such as macrotidal regime (> 4 m), high river discharge, and rainfall regime, the latter characterized by two contrasting periods, which lead to marked salinity variation (Dittmar & Lara, 2001;Souza-Filho et al, 2009;Pereira et al, 2012). Under such conditions, the intertidal benthic macrofauna of the soft-bottom habitats is known for its remarkable spatial and seasonal variations (Rosa-Filho et al, 2018;Venekey et al, 2019;Danin et al, 2020;Baia et al, 2021).…”