Distribution patterns of meiofauna on a tropical macrotidal sandy beach, with special focus on nematodes (Caixa d’Água, Amazon Coast, Brazil)

Abstract

Baia et al.: Meiofauna and nematodes on a macrotidal beach 1 Distribution patterns of meiofauna on a tropical macrotidal sandy beach, with special focus on nematodes (Caixa d'Água, Amazon Coast, Brazil) Spatial distribution patterns (both horizontal and vertical) of meiofauna, with special focus on nematodes, on a tropical macrotidal beach across different climatic periods were analyzed in this study. Samplings were carried out at five stations in the intertidal zone in June (rainy season) and December (dry season), 2011. At each station, three samples were taken using a corer with 3cm diameter, which was thrust 10cm into the substrate and stratified in 0-2, 2-5, and 5-10cm. Meiofauna was comprised of 16 groups and Nematoda was the dominant. Meiofauna density during rainy season was higher at the central intertidal station and during dry season it was lower near the high tide mark, followed by an increasing trend towards the low tide mark. Meiofauna was more concentrated in the upper sediment layer during rainy season. However, during dry season, the highest density occurred in the lower sediment layer at both stations near the high tide mark. Nematoda association was comprised of 72 genera, with Daptonema and Theristus (both from the family Xyalidae) as the dominant ones in most stations and strata. The genera richness and diversity increased towards the low tide mark, with lower richness in the upper stratum at most stations. Non-selective deposit-feeders predominated during rainy season, while at dry season there was an alternation of dominance between non-selective deposit-feeders and epistrate feeders. Significant differences were found in the meiofauna community, as well as in the Nematoda association in regard to the months, stations, and sediment layers. The distribution patterns of interstitial organisms found in this study, in part, follow what is already known for microtidal beaches but other differential aspects were observed even if compared to environments of macrotidal beaches in temperate regions.

Spatial and temporal variations of the subtidal meiobenthic community of the central coast of Venezuela

“…In most studies, the dominant group is nematodes (Giere, 2009;Baia & Venekey, 2019). However, foraminifera were the dominant group in this study.…”

“…The density values estimated in this study were eight times above those reported by Soltwedel (2000) for tropical areas, which, according to Coull (1999), are in the order of 1,000 ind/10 cm 2 in soft marine sediments. This is evidenced when comparing the densities obtained in depths of the Venezuelan territorial sea, in which the density of meiobenthos was between 13-153 ind/10 cm 2 (Woods & Tietjen, 1985), the central zone of the Great Barrier Reef in Australia (26 m deep) with 220-1,010 ind/10 cm 2 (Hansen et al 1987), southeastern Costa Rica (5 m deep) with 99-575 ind/10 cm 2 (Guzmán et al 1987), Rocks Atoll in northeast Brazil (2.5 m deep) with 278-4,165 ind/10 cm 2 (Netto et al 2003), Bay Lagoon in Jamaica (<10 m deep) with 327.7-5,518.9 ind/10 cm 2 (Edwards, 2009), Cienfuegos Bay in Cuba (9 m deep) with 780.02 ± 772 ind/10 cm 2 (Armenteros et al 2009), intertidal zones in Suriname and French Guiana (<1 m deep) with 1,760-4,400 ind/10 cm 2 (Dupuy et al 2015), and tropical beaches in Brazil (<6 m deep) with 288-2,553 ind/10 cm 2 (Baia & Venekey, 2019). These differences could be the result of different depths, temperatures, and other environmental conditions.…”

“…Other variables that influence the composition and distribution of meiobenthos are salinity, water movement, sediment characteristics, food quality and availability, predation, dispersal, biogenic structures, and biological disturbance (Edwards 2009;Giere, 2009;Baia & Venekey, 2019). However, Alfonso & López (2006) found that changes in the structure and composition of the meiofaunal communities were related to stochastic events such as storm drains, tropical storms, and hurricanes.…”

Microbial communities in sandy beaches from the three domains of life differ by microhabitat and intertidal location

“…For example, macrofaunal diversity tends to increase with lower intertidal elevations (Armonies & Reise, 2000; Degraer et al, 1999), whereas meiofaunal diversity is often at its maximum in the middle of the intertidal zone, which is consistent with the intermediate disturbance hypothesis (Armonies & Reise, 2000; Gheskiere et al, 2004; Gingold et al, 2010). These patterns, however, are affected by beach geomorphology, chemistry, seasonality and other local variations (Baia & Venekey, 2019; Degraer et al, 2003; Gheskiere et al, 2005; Hua et al, 2016; Kotwicki et al, 2005; Maria et al, 2013).…”

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

“…Despite its singular environmental characteristics and high economic (Santos et al., 2021) and ecological importance, the benthic fauna of these sandy beaches has been poorly studied, including its diversity and ecology. In general, studies have suggested that there is a vertical zonation of the benthic fauna and have argued that the presence and number of zones vary according to the morphodynamic state, being influenced by seasonal changes of environmental characteristics such as rainfall, wind, and wave regimes (Baia & Venekey, 2019; Gomes & Rosa Filho, 2009; Rosa Filho et al., 2009). Therefore, this study aimed to characterize the spatial distribution pattern of macrobenthic communities from an Amazonian macrotidal sandy beach and their seasonal changes (rainy season and dry season).…”