Spatiotemporal variation of the bacterioplankton community in the German Bight: from estuarine to offshore regions

Marine microbial biogeography has been studied intensively; however few studies address community variation across temporal and spatial scales simultaneously so far. Here we present a yearlong study investigating the dynamics of the free-living and particle-attached bacterioplankton community across a 100 km transect in the German Bight reaching from the Elbe estuary towards the open North Sea. Community composition was assessed using automated ribosomal intergenic spacer analysis and linked to environmental parameters applying multivariate statistical techniques. Results suggest that the spatial variation of the bacterioplankton community is defined by hydrographic current conditions, which separate the inner German Bight from the open North Sea and lead to pronounced differences in the coastal and offshore bacterioplankton community. However this spatial variation is overwhelmed by a strong temporal variation which is triggered by temperature as the main driving force throughout the whole transect. Variation in the free-living community was predominantly driven by temperature, whereas the particle-attached community exhibited stronger spatial variation patterns

Impacts of a reduction of seawater pH mimicking ocean acidification impacts on assemblage, structure and diversity of marine fungal communities

Increases in atmospheric carbon dioxide (CO2) change ocean chemistry, as dissolved CO2 leads to a reduction in the seawater pH. Many marine taxa have been shown to be affected by ocean acidification, while information on marine fungi is lacking. Here, we analyze the effect of pH on mycoplankton communities. The pH of microcosms was adjusted to a value mimicking the predicted ocean acidification in the near future. Fungal communities were analyzed using a double-marker gene approach, allowing a more detailed analysis of their response using 454 pyrosequencing. Mycoplankton communities in microcosms with in situ and adjusted water pH values differed significantly in terms of structure and diversity. The differences were mainly based on abundance shifts among the dominant taxa rather than the exclusion of fungal groups. A sensitivity to lower pH values was reported for several groups across the fungal kingdom and was not phylogenetically conserved. Some of the fungal species that dominated the communities of microcosms with a lower pH were known pathogenic fungi. With the increasing awareness of the significant role fungi play in marine systems, including performing a diverse range of symbiotic activities, our results highlight the importance of including fungi in further research projects studying and modeling biotic responses to the predicted ocean acidification

Characterizing the multidimensionality of microplastics across environmental compartments

Understanding the multidimensionality of microplastics is essential for a realistic assessment of the risks these particles pose to the environment and human health. Here, we capture size, shape, area, polymer, volume and mass characteristics of >60 000 individual microplastic particles as continuous distributions. Particles originate from samples taken from different aquatic compartments, including surface water and sediments from the marine and freshwater environment, waste water effluents, and freshwater organisms. Data were obtained using state-of-the-art FTIR- imaging, using the same automated imaging post-processing software. We introduce a workflow with two quality criteria that assure minimum data quality loss due to volumetric and filter area subsampling. We find that probability density functions (PDFs) for particle length follow power law distributions, with median slopes ranging from 2.2 for marine surface water to 3.1 for biota samples, and that these slopes were compartment-specific. Polymer-specific PDFs for particle length demonstrated significant differences in slopes among polymers, hinting at polymer specific sources, removal or fragmentation processes. Furthermore, we provide PDFs for particle width, width to length ratio, area, specific surface area, volume and mass distributions and propose how these can represent the full diversity of toxicologically relevant dose metrics required for the assessment of microplastic risks

Toward the systematic identification of microplastics in the environment: evaluation of a new independent software tool (siMPle) for spectroscopic analysis

Microplastics (MP) are ubiquitous within the environment, but the analysis of this contaminant is currently quite diverse, and a number of analytical methods are available. The comparability of results is hindered as even for a single analytical method such as Fourier transform infrared spectroscopy (FT-IR) the different instruments currently available do not allow a harmonized analysis. To overcome this limitation, a new free of charge software tool, allowing the systematic identification of MP in the environment (siMPle) was developed. This software tool allows a rapid and harmonized analysis of MP across FT-IR systems from different manufacturers (Bruker Hyperion 3000, Agilent Cary 620/670, PerkinElmer Spotlight 400, Thermo Fischer Scientific Nicolet iN10). Using the same database and the automated analysis pipeline (AAP) in siMPle, MP were identified in samples that were analyzed with instruments with different detector systems and optical resolutions, the results of which are discussed

Comparison of two rapid automated analysis tools for large FTIR microplastic datasets

AbstractOne of the biggest issues in microplastic (MP, plastic items  &lt;5 mm) research is the lack of standardisation and harmonisation in all fields, reaching from sampling methodology to sample purification, analytical methods and data analysis. This hampers comparability as well as reproducibility among studies. Concerning chemical analysis of MPs, Fourier-transform infrared (FTIR) spectroscocopy is one of the most powerful tools. Here, focal plane array (FPA) based micro-FTIR (µFTIR) imaging allows for rapid measurement and identification without manual preselection of putative MP and therefore enables large sample throughputs with high spatial resolution. The resulting huge datasets necessitate automated algorithms for data analysis in a reasonable time frame. Although solutions are available, little is known about the comparability or the level of reliability of their output. For the first time, within our study, we compare two well-established and frequently applied data analysis algorithms in regard to results in abundance, polymer composition and size distributions of MP (11–500 µm) derived from selected environmental water samples: (a) the siMPle analysis tool (systematic identification of MicroPlastics in the environment) in combination with MPAPP (MicroPlastic Automated Particle/fibre analysis Pipeline) and (b) the BPF (Bayreuth Particle Finder). The results of our comparison show an overall good accordance but also indicate discrepancies concerning certain polymer types/clusters as well as the smallest MP size classes. Our study further demonstrates that a detailed comparison of MP algorithms is an essential prerequisite for a better comparability of MP data.</jats:p

Population analysis of Vibrio parahaemolyticus originating from different geographical regions demonstrates a high genetic diversity

Vibrio parahaemolyticus is frequently isolated from environmental and seafood samples and associated with gastroenteritis outbreakes in American, European, Asian and African countries. To distinguish between different lineages of V. parahaemolyticus various genotyping techniques have been used, incl. multilocus sequence typing (MLST). Even though some studies have already applied MLST analysis to characterize V. parahaemolyticus strain sets, these studies have been restricted to specific geographical areas (e.g. U.S. coast, Thailand and Peru), have focused exclusively on pandemic or non-pandemic pathogenic isolates or have been based on a limited strain number. To generate a global picture of V. parahaemolyticus genotype distribution, a collection of 130 environmental and seafood related V. parahaemolyticus isolates of different geographical origins (Sri Lanka, Ecuador, North Sea and Baltic Sea as well as German retail) was subjected to MLST analysis after modification of gyrB and recA PCRs. The V. parahaemolyticus population was composed of 82 unique Sequence Types (STs), of which 68 (82.9%) were new to the pubMLST database. After translating the in-frame nucleotide sequences into amino acid sequences, less diversity was detectable: a total of 31 different peptide Sequence Types (pSTs) with 19 (61.3%) new pSTs were generated from the analyzed isolates. Most STs did not show a global dissemination, but some were supra-regionally distributed and clusters of STs were dependent on geographical origin. On peptide level no general clustering of strains from specific geographical regions was observed, thereby the most common pSTs were found on all continents (Asia, South America and Europe) and rare pSTs were restricted to distinct countries or even geographical regions. One lineage of pSTs associated only with strains from North and Baltic Sea strains was identified. Our study reveals a high genetic diversity in the analyzed V. parahaemolyticus strain set as well as for geographical strain subsets, with a high proportion of newly discovered alleles and STs. Differences between the subsets were identified. Our data support the postulated population structure of V. parahaemolyticus which follows the 'epidemic' model of clonal expansion. Application of peptide based AA-MLST allowed the identification of reliable relationships between strains

Identifying microplastics in North Sea waters - A matter of extraction and detection

In times of a rising plastic production the occurrence of microplastics (< 5 mm in size) in the marine environment has been identified as an emerging topic of global concern. Microplastics are omnipresent in our environment, hardly degradable and are easily ingested by a wide range of organisms throughout all trophic levels. However, the extent of this microplastic pollution as well as the resulting impacts on the marine environment remains largely unknown. Therefore, standardized and reliable methods to securely detect microplastics are urgently needed. The conclusive identification requires a successful extraction from different, complex environmental matrices. Thus we developed a highly promising procedure to successfully analyze also small microplastics (11-500 µm) isolated from surface water samples. This procedure includes the usage of an enzymatic-oxidative purification in newly developed semi-enclosed filtration units (microplastic reactors). This is followed by a state-of-the-art analysis via micro Fourier transform infrared (µFTIR) spectroscopy. The aim of this work is to contribute to the field of microplastic research by applying innovative analysis techniques as well as generating solid and comparable data. These provide information on quantities, polymer and size composition as well as spatial distribution of microplastics in North Sea surface waters. First results show that microplastics are present in the North Sea exhibiting a variety of polymer types, dominated by rubbers and polyethylene. Concerning the size, the vast majority of the detected microplastic particles is less than 75 µm in length

One-year impact of bariatric surgery on left ventricular mechanics: results from the prospective FatWest study

Aims Patients with severe obesity are predisposed to left ventricular (LV) hypertrophy, increased myocardial oxygen demand, and impaired myocardial mechanics. Bariatric surgery leads to rapid weight loss and improves cardiovascular risk profile. The present prospective study assesses whether LV wall mechanics improve 1 year after bariatric surgery. Methods and results Ninety-four severely obese patients [43 ± 10 years, 71% women, body mass index (BMI) 41.8 ± 4.9 kg/m2, 57% with hypertension] underwent echocardiography before, 6 months and 1 year after gastric bypass surgery in the FatWest (Bariatric Surgery on the West Coast of Norway) study. We assessed LV mechanics by midwall shortening (MWS) and global longitudinal strain (GLS), LV power/mass as 0.222 × cardiac output × mean blood pressure (BP)/LV mass, and myocardial oxygen demand as the LV mass-wall stress-heart rate product. Surgery induced a significant reduction in BMI, heart rate, and BP (P < 0.001). Prevalence of LV hypertrophy fell from 35% to 19% 1 year after surgery (P < 0.001). The absolute value of GLS improved by—4.6% (i.e. 29% increase in GLS) while LV ejection fraction, MWS, and LV power/mass remained unchanged. In multivariate regression analyses, 1 year improvement in GLS was predicted by lower preoperative GLS, larger mean BP, and BMI reduction (all P < 0.05). Low 1-year MWS was associated with female sex, preoperative hypertension, and higher 1-year LV relative wall thickness and myocardial oxygen demand (all P < 0.001). Conclusion In severely obese patients, LV longitudinal function is largely recovered one year after bariatric surgery due to reduced afterload. LV midwall mechanics does not improve, particularly in women and patients with persistent LV geometric abnormalities.publishedVersio

Recurrent patterns of microdiversity in a temperate coastal marine environment

© The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in The ISME Journal 12 (2018): 237–252, doi:10.1038/ismej.2017.165.Temperate coastal marine environments are replete with complex biotic and abiotic interactions that are amplified during spring and summer phytoplankton blooms. During these events, heterotrophic bacterioplankton respond to successional releases of dissolved organic matter as algal cells are lysed. Annual seasonal shifts in the community composition of free-living bacterioplankton follow broadly predictable patterns, but whether similar communities respond each year to bloom disturbance events remains unknown owing to a lack of data sets, employing high-frequency sampling over multiple years. We capture the fine-scale microdiversity of these events with weekly sampling using a high-resolution method to discriminate 16S ribosomal RNA gene amplicons that are >99% identical. Furthermore, we used 2 complete years of data to facilitate identification of recurrent sub-networks of co-varying microbes. We demonstrate that despite inter-annual variation in phytoplankton blooms and despite the dynamism of a coastal–oceanic transition zone, patterns of microdiversity are recurrent during both bloom and non-bloom conditions. Sub-networks of co-occurring microbes identified reveal that correlation structures between community members appear quite stable in a seasonally driven response to oligotrophic and eutrophic conditions.PLB is supported by the European Research Council Advanced Investigator grant ABYSS 294757 to Antje Boetius. AF-G is supported by the European Union’s Horizon 2020 research and innovation program (Blue Growth: Unlocking the potential of Seas and Oceans) under grant agreement no. (634486) (project acronym INMARE). This study was funded by the Max Planck Society. Further support by the Department of Energy Joint Genome Institute (CSP COGITO) and DFG (FOR2406) is acknowledged by HT (TE 813/2-1) and RA (Am 73/9-1)