Spatial and temporal variations of meiofaunal communities from the western sector of the Gulf of Batabanó, Cuba: III. Vertical distribution

Abstract

Abstract:The vertical distribution of meiofauna within subtidal sediments was studied in four stations pertaining to mangrove or muddy flats habitats. In 2003, replicated samples were taken in dry (February) and wet (July) seasons at the Bacunagua Inlet, southwestern coast of Cuba. The abundance and number of meiofaunal taxa exhibited a vertical gradient possibly due to changes in the concentrations of oxygen and hydrogen sulphide, rather than food availability along this gradient. Nematodes are capable of distributing themselves throughout the whole sediment column due to their ability to tolerate reducing conditions; however depletion of communities along depth was evident. Their presence in deeper sediments (6 -10 cm) suggests that certain species are adequately adapted to spend their entire life cycle in these harsh environments (where soluble tannins and decomposing organic matter predominate). Copepods showed a strong limitation to vertical distribution (concentrating in the top 2 cm), possibly in response to a sharp vertical decline in oxygenation within these organically enriched sediments. Rev. Biol. Trop. 56 (3): 1127-1134. Epub 2008 September 30.Key words: meiofauna, vertical distribution, Caribbean Sea, mangroves, muddy flats.The communities of meiofauna from soft bottom habitats show notable patchiness in their temporal and spatial distribution (Hodda 1990, Soetaert et al. 1995. In comparison to other benthic assemblages (e.g. macrofauna, macroalgae, stony corals, sponges), meiofauna have a well defined three dimensional distribution based on adaptations of their species to occupy the spaces within sediments up to several centimetres in depth (Soetaert et al. 1994). The vertical distribution depends on particular ecological processes (e.g. oxygenation of pore water, interstitial circulation, concentration of H 2 S), still poorly understood (Steyaert et al. 1999). In comparison to temperate habitats, the ecology of meiofauna in tropical areas still needs to be widely explored, particularly the vertical distribution.Mangroves are subtidal or intertidal tropical ecosystems characterized by high primary production and where the presence of vascular plants affects notably the associated assemblages of fauna. Research on meiofauna in mangrove ecosystems has been carried out in several places around the world, and insights on the effects of mangrove litter (Alongi 1987), disturbance by macrofauna (Olafsson and Ndaro 1997), spatial distribution (Hodda 1990, Armenteros et al. 2006 and seasonality (Hodda and Nicholas 1986) exist. The vertical distribution of meiofauna within tropical mangrove sediments and the factors that affect it are poorly studied; only two surveys (Ansari et al. 1980, Somerfield et al. 1998 have been published concerning this topic. Muddy flats are common habitats in shallow waters, particularly in semi/close estuaries (e.g. bays and coastal lagoons) or in the mouth of rivers and creeks. In tropical muddy flats, meiofaunal surveys concerning spatial and temporal distribution (Dittman 200...

Effect of sediment on meiofauna and Nematoda structure in different freshwater Amazon environments under the influence of mesotides

“…This pattern was expected, since several studies have shown the dominance of Nematoda in estuaries or beaches characterized by fine sediments (Ansari and Parulekar, 1993; Gomes and Rosa Filho, 2009; Baia and Venekey, 2019), while Copepoda (in their adult or larval form) are more common organisms in environments characterized by coarse sediments, such as reflective beaches with high-energy hydrodynamics (McLachlan, 1977; Martins et al ., 2015). This pattern occurs due to the high concentration of oxygen in sediments with coarser grains, and this is an ideal condition for Copepoda as they are highly sensitive to interstitial depletion of oxygen (McLachlan and Brown, 2006; Armenteros et al ., 2008). Additionally, Du et al .…”

“…On the other hand, the highest densities in muddy environments occurred in the upper layers. The same pattern was observed in several meiofauna studies conducted in tidal flats with muddy sediments, whether they were in marine, estuarine (Armenteros et al ., 2008) or freshwater environments (Reinicke, 2000). In freshwater tidal flats, environmental conditions are similar to those of marine muddy flats, at least in terms of grain size composition, temperature and oxygen availability (Reinicke, 2000).…”

“…These studies associate this trend towards decreasing meiofauna density from the upper layers to the lower layers to the higher vertical gradient in physical and chemical sediment properties. In fine sediments, oxygen penetration is limited to the few first centimetres of sediment (0–2 cm) and the concentration of hydrogen sulphide (H 2 S), a gas that causes damaging effects on the fauna, also increases with increased depth (Armenteros et al ., 2008). The presence of this gas becomes evident by the darkening of the sediment, a fact that was observed in loco in the sediment samples of deeper layers (4–6 to 8–10 cm) of the tidal flats studied.…”

“…In other words, in muddy A, a wide array of biotic and abiotic factors (thiobiotic capacity, predation, presence of mucus or biofilm and sediment permeability), whether they were occasional or not, might have contributed with the occurrence of several meiofauna groups also in the lower layers (Giere, 2009). Regarding the relative participation of meiofauna groups along the layers, Nematoda dominated all layers in all zones of both muddy environments, thus confirming the high ability of these organisms to tolerate reduced oxygenation conditions within the sediment, as they might even complete their entire life cycle in the presence of hydrogen sulphide (Heip et al ., 1985; Armenteros et al ., 2008).…”

Trends in Mangrove meiobenthic studies in India: an overview

“…Studies of meiofauna in the mangrove have been conducted in India (e.g., Krishnamurthy, Sultan Ali, Jeyaseelan, 1984;Ansari, Sreepada, Matondka, Parulekar, 1993;Kondalarao, 1983;Sarma, Wilsanand, 1994;Thilagavathi, Das, Saravanakumar, Raja, 2011), Australia (Hodda, Nicholas, 1985;Alongi, 1987aAlongi, , b, c, 1988Alongi, , 1990Alongi, Christoffersen, 1992;Abdullah, Lee, 2017), South Africa, Kenya and associated area (Dye, 1983a, b;Ólafsson, 1995;Ólafsson, Carlström, Ndaro, 2000;Mutua, 2013), Malaysia (Sasekumar, 1994;Somerfield, 1998;Gee, Somerfield, 1997), America (Hopper, Fell, Cefalu, 1973;Fell, Cefalu, Masters, Tallman, 1975), Caribbean islands (Armenteros et al, 2006) etc.…”