Sandy beaches: state of the art of nematode ecology

Abstract

In this review, we summarize existing knowledge of the ecology of sandy-beach nematodes, in relation to spatial distribution, food webs, pollution and climate change. We attempt to discuss spatial scale patterns (macro-, meso-and microscale) according to their degree of importance in structuring sandy-beach nematode assemblages. This review will provide a substantial background on current knowledge of sandybeach nematodes, and can be used as a starting point to delineate further investigations in this field. Over decades, sandy beaches have been the scene of studies focusing on community and population ecology, both related to morphodynamic models. The combination of physical factors (e.g. grain size, tidal exposure) and biological interactions (e.g. trophic relationships) is responsible for the spatial distribution of nematodes. In other words, the physical factors are more important in structuring nematodes communities over large scale of distribution while biological interactions are largely important in finer-scale distributions. It has been accepted that biological interactions are assumed to be of minor importance because physical factors overshadow the biological interactions in sandy beach sediments; however, the most recent results from in-situ and ex-situ experimental investigations on behavior and biological factors on a microscale have shown promise for understanding the mechanisms underlying larger-scale patterns and processes. Besides nematodes are very promising organisms used to understand the effects of pollution and climate changes although these subjects are less studied in sandy beaches than distribution patterns.

Meiofauna at a tropical sandy beach in the SW Atlantic: the influence of seasonality on diversity

“…Overall, meiofaunal assemblage at Gramuté beach was mainly dominated by Crustacea and Annelida (46% and 28% of reads), with Nematoda representing only 12% of the meiofauna over the year. Nematodes often dominate meiofauna in benthic habitats, with high diversity in the full range of beach types ( Maria et al, 2016 ), for example representing 50–90% of the total individuals in medium to fine sandy sediments ( Coull, 1988 ; Giere, 2009 ; Merckx et al, 2009 ) but also showing high diversity in coarse sand beaches ( Gheskiere et al, 2005 ). However, crustaceans and nematodes become more representative during the winter (57% and 17% of sequence reads), while annelids are less (11% of sequence reads).…”

Nourished, Exposed Beaches Exhibit Altered Sediment Structure and Meiofaunal Communities

“…Although the roles of beach meiofauna in recycling nutrients and influencing beach bacterial populations have not been quantified extensively and examined under a range of conditions, several studies have demonstrated that meiofauna are a functionally important beach community component [ 19 ] and provide useful information for policy makers [ 68 ]. Unfortunately, changes to the physical environment of the beach, arising from anthropogenic activities [ 58 , 69 – 72 ] and responses to shoreline erosion, may be altering beach meiofaunal communities in ways that affect beach processes, before we fully understand those processes.…”

Un ensayo experimental sobre la ecofisiología del poliqueto intersticial <em>Polygordius eschaturus</em> (Annelida: Polygordiidae)

“…Temperature, salinity, light, gravity and oxygen tension gradients are known to play an essential role in conditioning the spatial distribution of intertidal species on sandy beaches (Jansson 1968a, Giere 2009, Maria et al 2016. Therefore, the aim of the present study was to test the effect of these factors on the survival and vertical distribution of P. eschaturus in laboratory conditions.…”