Browsing by Author "Labrenz, Matthias"

Now showing 1 - 3 of 3
  • Thumbnail Image
    Item
    Assessment of Subsampling Strategies in Microspectroscopy of Environmental Microplastic Samples
    (Lausanne : Frontiers Media, 2021) Brandt, Josef; Fischer, Franziska; Kanaki, Elisavet; Enders, Kristina; Labrenz, Matthias; Fischer, Dieter
    The analysis of environmental occurrence of microplastic (MP) particles has gained notable attention within the past decade. An effective risk assessment of MP litter requires elucidating sources of MP particles, their pathways of distribution and, ultimately, sinks. Therefore, sampling has to be done in high frequency, both spatially and temporally, resulting in a high number of samples to analyze. Microspectroscopy techniques, such as FTIR imaging or Raman particle measurements allow an accurate analysis of MP particles regarding their chemical classification and size. However, these methods are time-consuming, which gives motivation to establish subsampling protocols that require measuring less particles, while still obtaining reliable results. The challenge regarding the subsampling of environmental MP samples lies in the heterogeneity of MP types and the relatively low numbers of target particles. Herein, we present a comprehensive assessment of different proposed subsampling methods on a selection of real-world samples from different environmental compartments. The methods are analyzed and compared with respect to resulting MP count errors, which eventually allows giving recommendations for staying within acceptable error margins. Our results are based on measurements with Raman microspectroscopy, but are applicable to any other analysis technique. We show that the subsampling-errors are mainly due to statistical counting errors (i.e., extrapolation from low numbers) and only in edge cases additionally impacted by inhomogeneous distribution of particles on the filters. Keeping the subsampling-errors low can mainly be realized by increasing the fraction of MP particles in the samples.
  • Thumbnail Image
    Item
    Cross-Hemisphere Study Reveals Geographically Ubiquitous, Plastic-Specific Bacteria Emerging from the Rare and Unexplored Biosphere
    (Washington, DC : American Society for Microbiology, 2021) Scales, Brittan S.; Cable, Rachel N.; Duhaime, Melissa B.; Gerdts, Gunnar; Fischer, Franziska; Fischer, Dieter; Mothes, Stephanie; Hintzki, Lisa; Moldaenke, Lynn; Ruwe, Matthias; Kalinowski, Jörn; Kreikemeyer, Bernd; Pedrotti, Maria-Luiza; Gorsky, Gaby; Elineau, Amanda; Labrenz, Matthias; Oberbeckmann, Sonja; Campbell, Barbara J.
    While it is now appreciated that the millions of tons of plastic pollution travelling through marine systems carry complex communities of microorganisms, it is still unknown to what extent these biofilm communities are specific to the plastic or selected by the surrounding ecosystem. To address this, we characterized and compared the microbial communities of microplastic particles, nonplastic (natural and wax) particles, and the surrounding waters from three marine ecosystems (the Baltic, Sargasso and Mediterranean seas) using high-throughput 16S rRNA gene sequencing. We found that biofilm communities on microplastic and nonplastic particles were highly similar to one another across this broad geographical range. The similar temperature and salinity profiles of the Sargasso and Mediterranean seas, compared to the Baltic Sea, were reflected in the biofilm communities. We identified plastic-specific operational taxonomic units (OTUs) that were not detected on nonplastic particles or in the surrounding waters. Twenty-six of the plastic-specific OTUs were geographically ubiquitous across all sampled locations. These geographically ubiquitous plastic-specific OTUs were mostly low-abundance members of their biofilm communities and often represented uncultured members of marine ecosystems. These results demonstrate the potential for plastics to be a reservoir of rare and understudied microbes, thus warranting further investigations into the dynamics and role of these microbes in marine ecosystems.
  • Thumbnail Image
    Item
    Tracing microplastics in aquatic environments based on sediment analogies
    ([London] : Macmillan Publishers Limited, part of Springer Nature, 2019) Enders, Kristina; Käppler, Andrea; Biniasch, Oliver; Feldens, Peter; Stollberg, Nicole; Lange, Xaver; Fischer, Dieter; Eichhorn, Klaus-Jochen; Pollehne, Falk; Oberbeckmann, Sonja; Labrenz, Matthias
    Microplastics (MP) data collection from the aquatic environment is a challenging endeavour that sets apparent limitations to regional and global MP quantification. Expensive data collection causes small sample sizes and oftentimes existing data sets are compared without accounting for natural variability due to hydrodynamic processes governing the distribution of particles. In Warnow estuarine sediments (Germany) we found significant correlations between high-density polymer size fractions (≥500 µm) and sediment grain size. Among potential predictor variables (source and environmental terms) sediment grain size was the critical proxy for MP abundance. The MP sediment relationship can be explained by the force necessary to start particle transport: at the same level of fluid motion, transported sediment grains and MP particles are offset in size by one to two orders of magnitude. Determining grain-size corrected MP abundances by fractionated granulometric normalisation is recommended as a basis for future MP projections and identification of sinks and sources.