Relationships between Meiofaunal Biodiversity and Prokaryotic Heterotrophic Production in Different Tropical Habitats and Oceanic Regions

Abstract

Tropical marine ecosystems are among the most diverse of the world oceans, so that assessing the linkages between biodiversity and ecosystem functions (BEF) is a crucial step to predict consequences of biodiversity loss. Most BEF studies in marine ecosystems have been carried out on macrobenthic diversity, whereas the influence of the meiofauna on ecosystem functioning has received much less attention. We compared meiofaunal and nematode biodiversity and prokaryotic heterotrophic production across seagrass, mangrove and reef sediments in the Caribbean, Celebes and Red Seas. For all variables we report the presence of differences among habitats within the same region, and among regions within the same habitat. In all regions, the richness of meiofaunal taxa in reef and seagrass sediments is higher than in mangrove sediments. The sediments of the Celebes Sea show the highest meiofaunal biodiversity. The composition of meiofaunal assemblages varies significantly among habitats in the same region. The nematode beta diversity among habitats within the same region is higher than the beta diversity among regions. Although one site per habitat was considered in each region, these results suggest that the composition of meiofaunal assemblages varies primarily among biogeographic regions, whereas the composition of nematode assemblages varies more considerably among habitats. Meiofauna and nematode biodiversity and prokaryotic heterotrophic production, even after the removal of covariate effects linked with longitude and the quantity and nutritional quality of organic matter, are positively and linearly linked both across regions and within each habitat type. Our results confirm that meiofauna and nematode biodiversity may influence benthic prokaryotic activity, which, in turn, implies that diversity loss could have negative impacts on ecosystem functioning in these systems.

Marine biodiversity and ecosystem function relationships: The potential for practical monitoring applications

“…This was in contrast to the positive relationships detected by Danovaro et al (2008b) and Pusceddu et al (2014) within higher diversity meiofaunal assemblages, suggesting a breakdown of the exponential BEF relationship at high levels of diversity, which may be due to increased competition or greater functional redundancy (Leduc et al, 2013). …”

“…, using prokaryotic diversity (through molecular fingerprinting analysis), observed several positive relationships including one with organic matter decomposition rates. The diversity of free-living nematodes and other meiofaunal species was also found to generally relate positively with rates of organic matter degradation (Danovaro et al, 2008;Pusceddu et al, 2014; but in contrast see Leduc et al, 2013 for null relationships).…”

Characteristics of meiofauna in extreme marine ecosystems: a review

“…Nematodes withstand these extreme conditions particularly well, occasionally with high standing stocks, but with reduced diversity (Pusceddu et al 2014). Several authors have observed that a few genera typically dominate mangrove communities, whereas most genera are quite rare (e.g.…”

Is the meiofauna a good indicator for climate change and anthropogenic impacts?

“…They play an important role in benthic food webs, not only as consumers (feeding on detritus, diatoms and algae, and preying on other small metazoans; Pergent et al 1994;Duarte and Cebrian 1996;Gee and Somerfield 1997;Mateo and Romero 1997;Gwyther 2003;Torres-Pratts and Schizas 2007;Mascart et al 2013Mascart et al , 2015, but also as producers (being a food source for macrofauna and fish; Gerlach 1978; Lebreton et al 2011;Vinagre et al 2012;Carpentier et al 2014). The abundance, diversity, distribution and functional properties of meiofauna can be affected by several abiotic factors, including temperature, salinity, hydrodynamic and sedimentary processes, sediment grain size, oxygenation level and food availability (Ingels et al 2011;Lizhe et al 2012;Ngo et al 2013;Zeppilli et al 2013;Górska et al 2014;Pusceddu et al 2014b), and also, by biotic factors such as predation and competition (Tita et al 2000;Danovaro et al 2007;Nascimento et al 2011;Braeckman et al 2013;Boldina et al 2014). Meiofauna are characterised by a high sensitivity to environmental changes due to their short generation time and the lack of pelagic larval dispersion for the dominant meiofaunal groups (Bongers and Ferris 1999).…”