Interrelationships of bacteria, meiofauna and macrofauna in a Mediterranean sedimentary beach (Maremma Park, NW Italy)

Abstract

Collelungo beach (Maremma Park, NW Italy), was sampled quantitatively for macrofauna, meiofauna and bacteria in May 2003; several physicochemical variables and variables associated with food availability and sediment structure were also measured. Replicated samples were collected from three sites representing natural conditions, an erosion regime, and the influence of the Ombrone River, respectively, as well as from four stations each located in the surf and sublittoral zones. Both uni-and multivariate techniques were used to assess the benthic community structure and the associated environmental variables. Different diversity indices revealed no pattern; in contrast, multivariate techniques applied on the macrobenthic fauna and the polychaete taxocommunity distinguished between the sites located in natural and eroding conditions from the one located nearby the discharges of the Ombrone river. The community patterns deriving from meio-and macrofauna are clearly divergent. The overall benthic faunal community appears to be influenced by both groups of organisms. The patterns of the meio-and macrofaunal communities seem to be affected synergistically by a number of environmental variables, in accordance with the multicausal environmental severity hypothesis. Meiofaunal patterns are more often correlated with bacteria and the protein concentration than are macrofaunal patterns, indicating a potential utilization of bacteria as a food source by the meiofaunal organisms. Total bacterial numbers are associated with the macrofaunal pattern under the erosion regime, probably as a consequence of competition for food between macrofauna and meiofauna.

Meiobenthic communities in the shallow subtidal of three Italian Marine Protected Areas

“…This is supported by the results of the present study, where the meiofaunal assemblages in the three MPAs are very rich, and the dominant taxa are generally nematodes and copepods, followed by several other groups of variable importance. Our study shows that the density and relative abundance of meiofauna does not differ considerably from that previously shown in other Mediterranean studies (Rodriguez et al 2003;Gheskiere et al 2004Gheskiere et al , 2005aCovazzi-Harriague et al 2006;Moreno et al 2006;Papageorgiou et al 2007). On the other hand, the meiofaunal densities reported here were not comparable to those found in similar habitats of Ligurian Sea (Fabiano et al 2002(Fabiano et al , 2004Moreno et al 2005), where the low abundance of meiofauna was related to the low concentrations of organic matter and bacterial density representing the primary food sources.…”

Benthic communities along a littoral of the Central Adriatic Sea (Italy)

“…It is so evident that the benthic response to changes in environmental conditions (from climate changes to pollution events) can be better understood by taking into account the whole benthic size spectrum (Schwinghamer 1988;Danovaro 2000;Austen and Widdicombe 2006). Nevertheless, to our knowledge, data sets on bacteria, meiofauna and macrofauna have only sporadically been collected in a simultaneous manner in the Mediterranean (Albertelli et al 1999;Covazzi-Harriague et al 2006;Papageorgiou et al 2007) and never in the Adriatic Sea.…”

Influence of environmental factors and biogenic habitats on intertidal meiofauna

“…The marine intertidal zone is a perfect model to study the concurrence of different factors in shaping biodiversity; it is one of the most dynamic and challenging environments worldwide, but provides important ecosystem goods and services (Sarà et al, 2014). It represents a unique resource to explore hypotheses about patterns potentially driving organisms' distribution and diversity at different geographical scales (Hulings & Gray, 1976;Papageorgiou et al, 2007;Covazzi-Harriague et al, 2013;Sarà et al, 2014). Fluctuations in a wide array of physical forces, like wave exposure, tide amplitude and anthropogenic disturbance, are main determinants in driving the distribution of organisms (Papageorgiou et al, 2007, Helmuth, 2008, Covazzi-Harriague et al, 2013Sarà et al, 2014;Kroeker et al, 2016).…”

“…It represents a unique resource to explore hypotheses about patterns potentially driving organisms' distribution and diversity at different geographical scales (Hulings & Gray, 1976;Papageorgiou et al, 2007;Covazzi-Harriague et al, 2013;Sarà et al, 2014). Fluctuations in a wide array of physical forces, like wave exposure, tide amplitude and anthropogenic disturbance, are main determinants in driving the distribution of organisms (Papageorgiou et al, 2007, Helmuth, 2008, Covazzi-Harriague et al, 2013Sarà et al, 2014;Kroeker et al, 2016). These factors may covary, affecting the intertidal substrate, and the occurrence and the characteristics of habitat-forming species, which in turn influence (both directly and indirectly) food and shelter availability for other organisms (Gartner et al, 2013) and strengthen the effect on local diversity further.…”

“…Benedetti-Cecchi et al, 2001;Bulleri et al, 2002;Covazzi-Harriague & Albertelli, 2007;Defeo & McLachlan, 2013), while only scant research has focused on meiofauna (Giere, 2009), paying more attention to sandy beach systems (e.g. Rodríguez et al, 2003;Kotwicki et al, 2005;Papageorgiou et al, 2007;Covazzi-Harriague et al, 2013). Meiofauna comprise the organisms that are amongst the most abundant and diverse metazoans on Earth (Balsamo et al, 2010); they play a key role in the functioning of the food webs and sustain critical ecological processes (Danovaro & Fraschetti, 2002).…”