DataSheet_1_Extraction efficiency of different microplastic polymers from deep-sea sediments and their quantitative relevance.pdf

An increasing number of methods for extracting microplastic particles from marine sediments have been published but without evaluating the extraction efficiency. Furthermore, while most of the procedures developed have been applied to sandy sediments from shallow water habitats, specific and standardized procedures for deep-water sediments (> 200 meters deep) are limited. In this study, we describe a specific protocol for extracting microplastics (2- 1000 µm) from deep-sea sediments and for quantifying and identifying them. We also assessed its extraction efficiency, which resulted in a high recovery (on average ca. 60%, and up to 80%) particularly, for polyethylene, polypropylene, and polystyrene. This method can be applied to all fine-grained/muddy sediments and allows the extraction of even the smallest fraction of microplastics (<20 µm), which are expected to have the most severe effects on marine biodiversity and ecosystem functioning and ultimately also have implications for human health.</p

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

<div><p>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.</p></div

Results of PERMANOVA testing for differences in meiofaunal abundance, biomass, richness of taxa and assemblages composition among habitats across regions and among regions across habitats.

<p>Results of the pairwise tests among levels of the relevant factors are also reported. DF = degrees of freedom; MS = mean squares; Pseudo-F = F statistic; P = probability level; *** = P<0.001; ** = P<0.01; ns: not significant. Car = Caribbean Sea; Red = Red Sea; Cel = Celebes Sea; M = mangrove; R = reef; S = seagrass; na = not applicable.</p

Comparison between DNA concentrations obtained by different DNA extraction procedures from free-living and cultured nematodes.

<p>Upper panel: comparison of DNA concentrations obtained using NaOH and QIAGEN kit extraction procedures from cultured nematodes (i.e. <i>Plectus</i> sp., <i>Diplolaimelloides oschei</i> and <i>Pellioditis marina</i>). Lower panel: comparison of DNA concentrations obtained using NaOH procedure, QIAGEN and MoBio kits from coastal and deep-sea nematodes. Mean (n = 5) and standard deviations are shown. The MoBio kit has not been used on cultured nematodes since they were not extracted from the sediment.</p

Relative proportion of OCTUs belonging to different nematode species within the nematode assemblage (10 individuals) collected in the NW Mediterranean Sea.

<p>Reported are the relative contribution of the different nematode genera obtained at 97% and 99% clustering thresholds using the OCTUPUS pipeline and AmpliconNoise plus Mothur programs. The contributions are calculated from non-chimeric OCTUs representing forward sequencing reads from 18S rRNA gene.</p

Ecosystem functioning as prokaryotic heterotrophic production (µgC g

<p>^−<b>1</b><b> d</b>^−<b>1</b><b>) in seagrass, mangrove and reef habitats of the Caribbean, Red and Celebes Seas.</b></p

Eukaryotic taxa identified by metagenetic analysis of the nematode assemblage (100 individuals) collected in the Central Mediterranean Sea.

<p>Reported are the relative contribution of eukaryotic taxa obtained at 97% and 99% clustering thresholds using the OCTUPUS pipeline and AmpliconNoise plus Mothur programs. The contributions are calculated from non-chimeric Operational Clustered Taxonomic Units (OCTUs) representing forward sequencing reads from 18S rRNA gene. The contributions of the most important components (expressed as percentages) are reported.</p

Results of PERMANOVA testing for differences in nematode biodiversity, as nematode Species Richness, ES(51), Pielou’s evenness and index of trophic diversity (ITD), and nematode assemblage composition among habitats across regions and among regions across habitats.

<p>Results of the pairwise tests among levels of the relevant factors are also reported. df = degrees of freedom; MS = mean squares; Pseudo-F = F statistic; *** = P<0.001; ** = P<0.01; * = P<0.05; ns: not significant. Car = Caribbean Sea; Red = Red Sea; Cel = Celebes Sea; M = mangrove; R = reef; S = seagrass.</p

Relationship between biodiversity and ecosystem functioning.

<p>Illustrated are the relationships between: A) richness of meiofaunal taxa and prokaryotic heterotrophic production (µgC g⁻¹ d⁻¹); nematode diversity as ES(51) and prokaryotic heterotrophic production (µgC g⁻¹ d⁻¹); B) richness of meiofaunal taxa and prokaryotic heterotrophic production in different habitat types. Reported are R² values. P<0.01 for all linear regressions. Error bars indicate standard deviations among replicates (n = 3).</p

Effects of biodiversity, measured as richness of meiofaunal taxa and nematode expected species number ES(51), on ecosystem functioning, as prokaryotic heterotrophic production before and after the removal of the covariables’ effect: longitude, sediment biopolymeric organic C content and the protein to carbohydrate ratio.

<p>In the regression analyses, all tests were based on Euclidean distances calculated among observations from untransformed data, using all data from different regions and habitats. The following abbreviations are used: R² = regression coefficient, SS = sum of squares, Pseudo-F = statistic F; P = probability level (*** = P<0.001; * = P<0.05).</p