scholarly journals Mycoplankton Biome Structure and Assemblage Processes Differ Along a Transect From the Elbe River Down to the River Plume and the Adjacent Marine Waters

2021 ◽  
Vol 12 ◽  
Author(s):  
Yanyan Yang ◽  
Stefanos Banos ◽  
Gunnar Gerdts ◽  
Antje Wichels ◽  
Marlis Reich

Rivers are transport systems and supply adjacent ecosystems with nutrients. They also serve human well-being, for example as a source of food. Microorganism biodiversity is an important parameter for the ecological balance of river ecosystems. Despite the knowledge that fungi are key players in freshwater nutrient cycling and food webs, data on planktonic fungi of streams with higher stream order are scarce. This study aims to fill this knowledge gap by a fungi-specific 18S ribosomal RNA (rRNA) gene tag sequencing approach, investigating mycoplankton diversity in the Elbe River along a transect from shallow freshwater, to the estuary and river plume down to the adjacent marine waters (sections of seventh stream order number). Using multivariate analyses and the quantitative process estimates (QPEs) method, questions (i) of how mycoplankton communities as part of the river continuum change along the transect, (ii) what factors, spatial and environmental, play a role, and (iii) what assembly processes, such as selection or dispersion, operate along the transect, were addressed. The partitioning of mycoplankton communities into three significant distant biomes was mainly driven by local environmental conditions that were partly under spatial control. The assembly processes underlying the biomes also differed significantly. Thus, variable selection dominated the upstream sections, while undominated processes like ecological drift dominated the sections close to the river mouth and beyond. Dispersal played a minor role. The results suggest that the ecological versatility of the mycoplankton communities changes along the transect as response, for example, to a drastic change from an autotrophic to a heterotrophic system caused by an abrupt increase in the river depth. Furthermore, a significant salinity-dependent occurrence of diverse basal fungal groups was observed, with no clade found exclusively in marine waters. These results provide an important framework to help understand patterns of riverine mycoplankton communities and serve as basis for a further in-depth work so that fungi, as an important ecological organism group, can be integrated into models of, e.g., usage-balance considerations of rivers.

2021 ◽  
Author(s):  
Jonas Kruse ◽  
Hannes Laermanns ◽  
Friederike Stock ◽  
Corinna Foeldi ◽  
Dirk Schaefer ◽  
...  

<p>Accumulation of microplastics (MPs) in aquatic environments is an issue of emerging concern. After research initially focused on marine systems, more and more studies have been published investigating the abundance of MPs in freshwater environments in recent years.</p><p>The objective of our research is to examine, whether the Mulde river represents an input pathway for MP particles to the Elbe discharge system. Our hypothesis is that the chemical industries located in the catchment area of the Mulde act as a discharge source of primary MPs which are subsequently transported downstream towards the Elbe. Accordingly, there should be more (primary) MPs just downstream of the river mouth, compared to upstream. Therefore, 2 sediment samples and 18 water samples from the Elbe river upstream and downstream the Mulde confluence were taken and analysed on their MP contents.</p><p>To extract MPs, sample preparation requires various steps including drying, size-fractionation, reduction of organic matter and density separation. The gained fractions are then filtered through glass microfibres paper using a vacuum pump. The dried filters are photographed and examined for MPs under a digital microscope. Representative particles are picked and measured. Finally, we determine their polymer type by pyrolysis or µFTIR.</p><p>A key result is that both, sediment and water samples, show a substantial increase in primary MPs (especially spheres) just downstream the mouth of the Mulde. Regarding the sampling technique of water samples, we observe differences in the amount and shape of MP particles between filter cascades and filter nets.</p>


2021 ◽  
Vol 9 ◽  
Author(s):  
Hannes Laermanns ◽  
Georg Reifferscheid ◽  
Jonas Kruse ◽  
Corinna Földi ◽  
Georg Dierkes ◽  
...  

Accumulation of microplastics in aquatic environments is an issue of emerging concern. Initially, research focused on marine systems. However, recent studies also investigate the abundance of microplastics in freshwater environments. Rivers connect terrestrial with marine ecosystems and contribute a considerable share of macro- and microplastics to the oceans. A previous study found a large amount of micro-spheres in Dessau downstream the river mouth of the Mulde. Therefore, the objective of this research was to examine whether the Mulde river with its highly industrialized catchment contributes to the microplastic pollution of the Elbe. Sediment (Van Veen grab sampler) and water samples (filter cascade with the smallest mesh size 50 μm and nets with the smallest mesh size 150 μm) were taken from the Elbe river up- and downstream the confluence with the Mulde. After extensive sample preparation, we examined the samples under a digital microscope and determined polymer types by pyrolysis Gas Chromatography/Mass Spectrometry (pyr-GC-MS). The amount of primary microplastics increased in sediment and water samples just downstream the confluence. Those microplastics originate probably from the Mulde. We measured larger amounts and different shapes of microplastics in filter cascades that have a smaller mesh size compared to the nets.


1999 ◽  
Vol 51 (2-3) ◽  
pp. 293-312 ◽  
Author(s):  
U. Brockmann ◽  
K. Viehweger ◽  
T. Raabe ◽  
S. Rick ◽  
H. -J. Rick ◽  
...  

2021 ◽  
Vol 9 (6) ◽  
pp. 1307
Author(s):  
Sebastian Böttger ◽  
Silke Zechel-Gran ◽  
Daniel Schmermund ◽  
Philipp Streckbein ◽  
Jan-Falco Wilbrand ◽  
...  

Severe odontogenic abscesses are regularly caused by bacteria of the physiological oral microbiome. However, the culture of these bacteria is often prone to errors and sometimes does not result in any bacterial growth. Furthermore, various authors found completely different bacterial spectra in odontogenic abscesses. Experimental 16S rRNA gene next-generation sequencing analysis was used to identify the microbiome of the saliva and the pus in patients with a severe odontogenic infection. The microbiome of the saliva and the pus was determined for 50 patients with a severe odontogenic abscess. Perimandibular and submandibular abscesses were the most commonly observed diseases at 15 (30%) patients each. Polymicrobial infections were observed in 48 (96%) cases, while the picture of a mono-infection only occurred twice (4%). On average, 31.44 (±12.09) bacterial genera were detected in the pus and 41.32 (±9.00) in the saliva. In most cases, a predominantly anaerobic bacterial spectrum was found in the pus, while saliva showed a similar oral microbiome to healthy individuals. In the majority of cases, odontogenic infections are polymicrobial. Our results indicate that these are mainly caused by anaerobic bacterial strains and that aerobic and facultative anaerobe bacteria seem to play a more minor role than previously described by other authors. The 16S rRNA gene analysis detects significantly more bacteria than conventional methods and molecular methods should therefore become a part of routine diagnostics in medical microbiology.


AMB Express ◽  
2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Shenzheng Zeng ◽  
Sukontorn Khoruamkid ◽  
Warinphorn Kongpakdee ◽  
Dongdong Wei ◽  
Lingfei Yu ◽  
...  

Abstract The Pacific white shrimp, with the largest production in shrimp industry, has suffered from multiple severe viral and bacterial diseases, which calls for a more reliable and environmentally friendly system to promote shrimp culture. The “Aquamimicry system”, mimicking the nature of aquatic ecosystems for the well-being of aquatic animals, has effectively increased shrimp production and been adapted in many countries. However, the microbial communities in the shrimp intestine and surrounding environment that act as an essential component in Aquamimicry remain largely unknown. In this study, the microbial composition and diversity alteration in shrimp intestine, surrounding water and sediment at different culture stages were investigated by high throughput sequencing of 16S rRNA gene, obtaining 13,562 operational taxonomic units (OTUs). Results showed that the microbial communities in shrimp intestine and surrounding environment were significantly distinct from each other, and 23 distinguished taxa for each habitat were further characterized. The microbial communities differed significantly at different culture stages, confirmed by a great number of OTUs dramatically altered during the culture period. A small part of these altered OTUs were shared between shrimp intestine and surrounding environment, suggesting that the microbial alteration of intestine was not consistent with that of water and sediment. Regarding the high production of Aquamimicry farm used as a case in this study, the dissimilarity between intestinal and surrounding microbiota might be considered as a potential indicator for healthy status of shrimp farming, which provided hints on the appropriate culture practices to improve shrimp production.


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