Effects of wave exposure on the abundance and composition of amphipod and tanaidacean assemblages inhabiting intertidal coralline algae

Abstract

Peracarid crustaceans are an important component of the vagile fauna associated with coralline algal beds, which often characterize the infralittoral fringe of tropical rocky shores. Among other variables affecting faunal assemblages, sedimentation, food supply and oxygen concentration within mats or turfs of coralline algae may greatly depend on the exposure to waves. In this study, peracarid assemblages were compared at replicated rocky shores within different levels of wave exposure, along a coastline in south-eastern Brazil. Overall amphipod diversity (11 species) was much higher than tanaidacean diversity (two species). Correlation analyses did not support any biological interactions between amphipods and tanaidaceans. Habitat complexity, while apparently limiting amphipod populations, did not affect tanaidaceans at a local scale. Amphipod abundance, not assemblage structure, was positively affected by wave exposure, probably improving oxygen concentration levels and renewal of food resources. Rather than abundance, which remains fairly stable, exposure to waves determined species identity in tanaidaceans, with Zeuxo coralensis found at exposed shores and Leptochelia aff. dubia found at sheltered shores, except for two L. aff. dubia individuals found at one of the exposed sites. Differences in the supply of sediment and the ability of these species in manipulating grains for tube building may explain such a striking pattern.

Sustainable Harvesting of the Ecosystem Engineer Corallina officinalis for Biomaterials

“…When sediment was elevated in the harvested plots, in comparison with the unharvested, there was a marked increase in abundance of Tanais dulongii in comparison with the previous year. Female T. dulongii build their tubes from sediment at the base of C. officinalis fronds (Johnson and Attramadal, 1982) and the increase in T. dulongii on the harvested samples in the year after harvest may relate to the increased amount of sediment available in the plots, as suggested by Bueno et al (2016) in Brazil. The amount of sediment in coralline algal turfs is positively correlated with the richness and abundance of gastropods (Kelaher et al, 2001;Kelaher and Castilla, 2005), and nematodes are generally found at higher densities in turf algae and sediment (Gibbons and Griffiths, 1986).…”

Peracarid Assemblages in a Human-Disturbed Location from South-Western Mediterranean Sea: Role of Surface Orientation and Phytal Structure of the Habitat

“…Sampling was conducted in August 2015, coinciding with highest phytal development and faunal population densities in the western Mediterranean (Urra et al 2013) and aiming to minimize the influence of seasonal trends (Bueno et al 2016). Ten samples were collected by scraping off a 100 cm 2 square area of rocky bottom immediately below water surface; similarly sized sample areas has proved to be representative for studies on peracarid populations from other locations (Bueno et al 2016).…”

“…Sampling was conducted in August 2015, coinciding with highest phytal development and faunal population densities in the western Mediterranean (Urra et al 2013) and aiming to minimize the influence of seasonal trends (Bueno et al 2016). Ten samples were collected by scraping off a 100 cm 2 square area of rocky bottom immediately below water surface; similarly sized sample areas has proved to be representative for studies on peracarid populations from other locations (Bueno et al 2016). In order to evaluate the role of orientation on peracarid population, half of the samples (site 1: samples Vill-1 to Vill-5) were collected from the sea wall located on the southern side of the cove and the rest link analyses were conducted.…”

Hydrodynamic Interactions Between Macroalgae and Their Epibionts

“…Little is known about effects of habitat type on the water motion experienced by organisms living on flexible macroalgae and seagrasses. Although there have been many reports of greater diversity (Norton, 1973;Fenwick, 1976;Schultze et al, 1990;Bueno et al, 2016) and higher abundance (Peteiro and Freire, 2013) of epibionts on macrophytes in habitats protected from fast ambient flow, there are other cases where epibiont abundance is higher in habitats exposed to rapid, turbulent water motion (Seed and O'Connor, 1981). The shallow coastal marine habitats where macrophytes live, from wave-swept rocky shores to protected estuaries, are exposed to turbulent currents and waves.…”