Macrobenthic community structure in tropical estuaries: the effect of sieve mesh-size and sampling depth on estimated abundance, biomass and composition

Abstract

Macrobenthic data from estuaries along the Pernambuco coast in north-eastern Brazil were analysed to evaluate the effect of sieve mesh size (1.0 mm × 0.5 mm) and sampling depth (0–10 cm × 0–20 cm) on the description of infaunal communities, in an attempt to discuss standardized sampling procedures for different ecological studies objectives in these ecosystems. In general, the difference in sieve retention was less evident for biomass but was important for abundance: the 1.0 mm sieve retained only 27% of total individuals but 77% of total biomass. Regarding sampling depth, the 0–10 cm layer contained most individuals (94%) but contributed just 64% of the overall biomass. Although no strong differences in community structure were observed at most sites with the use of different sieves, the correlations among community dissimilarity using different meshes with environmental parameters (organic matter, total-N and microphytobenthos) indicated that the use of the 0.5 mm sieve will allow a better evaluation of the status of these estuaries. The results also highlight the importance of taking the vertical distribution of tropical macrofauna into account for quantitative estimates: for taxa composition and abundance the top layer is clearly essential, whereas for biomass the deeper layers should also be considered.

Is meiofauna community structure in Artificial Substrate Units a good tool to assess anthropogenic impact in estuaries?

“…This could be related to a higher proportion of 'temporary meiofauna' (Watzin, 1983), such as juveniles of macrobenthic polychaetes. Valença and Santos (2013) described a higher dominance of annelids, particularly polychaetes, on macrofaunal assemblages from Pernambuco estuarine sediments. In general, copepods were shown in the literature as good swimmers and earlier colonizers of artificial substrates (e.g., Atilla and Fleeger, 2000;Gwyther and Fairweather, 2002;Mirto and Danovaro, 2004;Mascart et al, 2015).…”

“…In addition, there are historical discharges of mercury, chlorine and acid waters from sugarcane (Medeiros et al, 2001). More characteristics and summary of the main disturbance sources in these areas are resumed in Valença and Santos (2013).…”

Distribution and origin of sedimentary organic matter in an eutrophic estuary: Pina Sound – NE Brazil

“…~ 2.7 m) facilitate wastewater dilution, leading to oxic conditions in sediment. According to Valença & Santos (2013), there is a high density of macrobenthic fauna (up to 40,000 individuals m -2 ) in surface sediments of the lower sound, which is additional evidence for predominantly local oxic conditions. Diagenesis of labile OM was evaluated using Pheop/Chl a ratio (Rasiq et al 2016).…”

Benthic macrofaunal assemblage in seagrass-mangrove complex and adjacent ecosystems of Punang-Sari Estuary, Lawas, Sarawak, Malaysia

“…Malaysian seagrassmangrove complex comprises plethora of macrofauna species. Macrofauna is the most widely studied benthic organisms, which are retained on 0.5 mm or 1.0 mm mesh sieve (Valenca and Santos 2013). They reside beneath the sediment surface in burrows and tubes.…”