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During recent years plastics became one of the focuses of EU policy. A harmonisation and comparability of microplastics monitoring results across Europe is needed. The complexity of microplastic data makes it necessary to develop a specific, tailor-made database rather than adapting and modifying one of the existing databases. To meet this demand, we present a publicly accessible, flexible, and extendable structured relational database for particle-based microplastic data. The developed relational database is adaptive and meets the specific demands of microplastics, e.g., a large variety of sampling, processing and analytical methods, many types of plastics, and a very wide size spectrum ranging from micrometres to millimetres. In this paper we discuss the development of the database, data entry specifics, sample analysis methods, microplastics data manipulation and quality assurance, and database integration and accessibility. [ABSTRACT FROM AUTHOR]

Steep redoxclines form between oxic surface water and the stagnant, sulfidic hypolimnion in the eutrophied, brackish water Baltic Sea. Nitrification, denitrification, and anammox were measured at and below the redoxcline to quantify the role of water-column nitrogen processes in the overall magnitude of nitrogen removal in the Baltic Sea. Rates of nitrification were very high (up to 85 nmol N L-1 d-1) at the oxic-anoxic interface, but, surprisingly, nitrification was separated from the processes reducing nitrate to N2 (up to 810 nmol N L-1 d-1) by tens of meters in depth. N2 production was dominated by chemolithotrophic denitrification, with anammox playing only a negligible role, and limited to the water layers in which nitrite or nitrate coexisted with sulfide. The alternating oxygen concentrations in the basin induce irregular bursts of nitrogen removal. Nitrification takes place after mixing of ammonium-rich deep water with oxic water, and denitrification uses the formed nitrite and nitrate once anoxic conditions re-establish. Although removal rates can be high, conditions allowing such rates are likely short-lived. While the sedimentary denitrification rates at the shallower, oxic areas are lower, they are more constant in time, highlighting the need to avoid hypoxia, which would prevent sedimentary denitrification. [ABSTRACT FROM AUTHOR]

A correction to the article "Widespread Distribution of Proteorhodopsins in Freshwater and Brackish Ecosystems," by Nof Atamna-Ismaeel, Gazalah Sabehi, Itai Sharon that was published in the 2008 issue of the journal is presented

We determined the abundance and distribution of chemolithoautotrophic prokaryotes in the redoxcline in two basins (Gotland Deep, Landsort Deep) of the central Baltic Sea by combining dark CO2 fixation measurements with flow cytometric cell sorting. Maximum CO2 fixation rates were recorded in sulfidic waters about 20 m below the chemocline. Flow cytometric analyses of deoxyribonucleic acid (DNA)-stained bacterioplankton revealed the existence of at least five different prokaryotic clusters in water samples collected below the chemocline. Dark CO2 fixation in these clusters was determined by flow cytometric sorting after anoxic incubations with NaH14CO3 tracer. Two clusters, representing about 30% of total prokaryotes, were responsible for 65% to 100% of the total dark fixation. Calculated cell-specific CO2 fixation rates in the two basins ranged from 3.5 to 24.7 fg C cell-1 d-1 and suggested that these clusters are dominated by chemolithoautotrophic prokaryotes. Mean cell-specific fixation rates reached more than 10 fg C cell-1 d-1 in most cases, indicating relatively high growth rates (doubling times 1-2 d) of chemolithoautotrophic prokaryotes. Our results provide the first evidence of such high cell-specific CO2 uptake and abundance of chemolithoautotrophic prokaryotes in a pelagic marine environment. However, the identity of the organisms as well as the mechanisms fueling CO2 dark fixation in the anoxic zone remain unknown. [ABSTRACT FROM AUTHOR]

Summary: Microplastics in marine ecosystems are colonized by diverse prokaryotic and eukaryotic communities. How these communities and their functional profiles are shaped by the artificial surfaces remains broadly unknown. In order to close this knowledge gap, we set up an in situ experiment with pellets of the polyolefin polymer polyethylene (PE), the aromatic hydrocarbon polymer polystyrene (PS), and wooden beads along a coastal to estuarine gradient in the Baltic Sea, Germany. We used an integrated metagenomics/metaproteomics approach to evaluate the genomic potential as well as protein expression levels of aquatic plastic biofilms. Our results suggest that material properties had a minor influence on the plastic‐associated assemblages, as genomic and proteomic profiles of communities associated with the structurally different polymers PE and PS were highly similar, hence polymer‐unspecific. Instead, it seemed that these communities were shaped by biogeographic factors. Wood, on the other hand, induced the formation of substrate‐specific biofilms and served as nutrient source itself. Our study indicates that, while PE and PS microplastics may be relevant in the photic zone as opportunistic colonization grounds for phototrophic microorganisms, they appear not to be subject to biodegradation or serve as vectors for pathogenic microorganisms in marine habitats. [ABSTRACT FROM AUTHOR]

Determining microplastics in environmental samples quickly and reliably is a challenging task. With a largely automated combination of optical particle analysis, Fourier transform infrared (FT-IR), and Raman microscopy along with spectral database search, particle sizes, particle size distributions, and the type of polymer including particle color can be determined. We present a self-developed, open-source software package for realizing a particle analysis approach with both Raman and FT-IR microspectroscopy. Our software GEPARD (Gepard Enabled PARticle Detection) allows for acquiring an optical image, then detects particles and uses this information to steer the spectroscopic measurement. This ultimately results in a multitude of possibilities for efficiently reviewing, correcting, and reporting all obtained results. [ABSTRACT FROM AUTHOR]

The genome encodes the metabolic and functional capabilities of an organism and should be a major determinant of its ecological niche. Yet, it is unknown if the niche can be predicted directly from the genome. Here, we conduct metagenomic binning on 123 water samples spanning major environmental gradients of the Baltic Sea. The resulting 1961 metagenome-assembled genomes represent 352 species-level clusters that correspond to 1/3 of the metagenome sequences of the prokaryotic size-fraction. By using machine-learning, the placement of a genome cluster along various niche gradients (salinity level, depth, size-fraction) could be predicted based solely on its functional genes. The same approach predicted the genomes' placement in a virtual niche-space that captures the highest variation in distribution patterns. The predictions generally outperformed those inferred from phylogenetic information. Our study demonstrates a strong link between genome and ecological niche and provides a conceptual framework for predictive ecology based on genomic data. Alneberg et al. conduct metagenomics binning of water samples collected over major environmental gradients in the Baltic Sea. They use machine-learning to predict the placement of genome clusters along niche gradients based on the content of functional genes. [ABSTRACT FROM AUTHOR]

Abstract Microbial communities are the main drivers of biogeochemical cycling of multiple elements sustaining life in the ocean. The rapidity of their response to stressors and abrupt environmental changes implies that even fast and infrequent events can affect local transformations of organic matter and nutrients. Modern molecular techniques now allow for monitoring of microbial activities and functions in the environment through the analysis of genes and expressed genes contained in natural microbial assemblages. However, messenger RNA turnover in cells can be as short as 30 seconds and stability varies greatly between transcripts. Sampling of in situ communities involves an inevitable delay between the collection of seawater and the extraction of its RNA, leaving the bacterial communities plenty of time to alter their gene expression. The characteristics of microbial RNA turnover make time-series very difficult because samples need to be processed immediately to limit alterations to the metatranscriptomes. To address these challenges we designed an autonomous in situ fixation multi-sampler (AFISsys) for the reliable sampling of microbial metatranscriptomes at frequent intervals, for refined temporal resolution. To advance the development of this instrument, we examined the minimal seawater volume necessary for adequate coverage of community gene expression, and the suitability of phenol/ethanol fixation for immediate and long-term preservation of transcripts from a microbial community. We then evaluated the field eligibility of the instrument itself, with two case studies in a brackish system. AFISsys is able to collect, fix, and store water samples independently at a predefined temporal resolution. Phenol/ethanol fixation can conserve metatranscriptomes directly in the environment for up to a week, for later analysis in the laboratory. Thus, the AFISsys constitutes an invaluable tool for the integration of molecular functional analyses in environmental monitoring in brackish waters and in aquatic environments in general. Graphical abstract Image 1 Highlights • An autonomous water in situ fixation multi-sampler (AFISsys) has been designed. • AFISsys collects, fixes, stores water samples independently off-shore at high temporal resolution. • AFISsys conserves sensitive mRNA directly in the environment for up to a week. • Metatranscriptome analysis feasible with 250 mL of water volumes. • Integration of molecular functional analyses in environmental monitoring in aquatic environments feasible. [ABSTRACT FROM AUTHOR]

Nitrogen (N 2) fixation rates in the brackish Baltic Sea are among the highest per unit of area in the world. However, beyond the filamentous heterocyst-forming cyanobacteria, knowledge about the composition and distribution of N 2 -fixing microbes (diazotrophs) is limited. To address this, we investigated nitrogenase gene (nifH) composition and expression at coastal (<10 km offshore) and offshore (>10 km offshore) stations, at surface (avg. 1.8 m) and at depth (avg. 24 m) and in free-living (0.2–3.0 μm) and particle-associated size fractions (>3 μm). Surprisingly, nifH genes affiliated with Pseudanabaena and non-cyanobacterial diazotrophs (NCDs) dominated the composition whereas filamentous heterocyst-forming cyanobacteria accounted for almost 80% of the nifH transcripts. Salinity had a minor influence on the composition, but Aphanizomenon and Nodularia showed increased relative nifH gene expression at low and higher salinity, respectively. Pseudanabaena only accounted for up to 5% of the nifH transcripts and nifH gene expression by Candidatus Atelocyanobacterium thalassa (sublineage UCYN-A2) was mainly observed in the most saline western part of the Baltic. The only notable expression by NCDs (up to 15% of nifH transcripts at a given station) coincided with an upwelling event at the southern coast and was largely accounted for by a Pseudomonas -like nifH phylotype, recurrently found in the Baltic Sea. NCD relative abundances were dominant in coastal stations, presumably driven by sediment resuspension as evidenced by higher turbidity and DOC levels and the recovery of sediment diazotrophs in the pelagic zone. This study reveals the heterogeneity of the composition and activity of diazotrophs in the Baltic Sea, and underscores the need for future N 2 fixation studies that include coastal and offshore Baltic waters. [Display omitted] • Pseudanabaena and non-cyanobacteria dominate the nitrogenase (nifH) gene pool. • Heterocyst-forming cyanobacteria accounted for 80% of the nifH gene transcripts. • Coastal upwelling affected composition and activity of diazotrophs. • The composition and activity of diazotrophs in the Baltic Sea is heterogeneous. • Future N 2 fixation studies should include coastal and offshore Baltic waters. [ABSTRACT FROM AUTHOR]

Life on tidal coasts presents physiological major challenges for sessile species. Fluctuations in oxygen and temperature can affect bioenergetics and modulate metabolism and redox balance, but their combined effects are not well understood. We investigated the effects of intermittent hypoxia (12h/12h) in combination with different temperature regimes (normal (15 °C), elevated (30 °C) and fluctuating (15 °C water/30 °C air)) on the Pacific oyster Crassostrea (Magallana) gigas. Fluctuating temperature led to energetic costly metabolic rearrangements and accumulation of proteins in oyster tissues. Elevated temperature led to high (60%) mortality and oxidative damage in survivors. Normal temperature had no major negative effects but caused metabolic shifts. Our study shows high plasticity of oyster metabolism in response to oxygen and temperature fluctuations and indicates that metabolic adjustments to oxygen deficiency are strongly modulated by the ambient temperature. Co-exposure to constant elevated temperature and intermittent hypoxia demonstrates the limits of this adaptive metabolic plasticity. [Display omitted] • C. gigas was exposed to intermittent hypoxia at different temperature regimes. • Hypoxia & fluctuating temperature led to energetic costly metabolic shifts. • Hypoxia & fluctuating temperature present cues for metabolic suppression. • Tissue damage & high mortality was caused by hypoxia & constant elevated temperature. • Hypoxia & constant normal temperature led to metabolic shifts without costs. [ABSTRACT FROM AUTHOR]

In recent years, many studies on the analysis of microplastics (MP) in environmental samples have been published. These studies are hardly comparable due to different sampling, sample preparation, as well as identification and quantification techniques. Here, MP identification is one of the crucial pitfalls. Visual identification approaches using morphological criteria alone often lead to significant errors, being especially true for MP fibers. Reliable, chemical structure-based identification methods are indispensable. In this context, the frequently used vibrational spectroscopic techniques but also thermoanalytical methods are established. However, no critical comparison of these fundamentally different approaches has ever been carried out with regard to analyzing MP in environmental samples. In this blind study, we investigated 27 single MP particles and fibers of unknown material isolated from river sediments. Successively micro-attenuated total reflection Fourier transform infrared spectroscopy (μ-ATR-FTIR) and pyrolysis gas chromatography-mass spectrometry (py-GCMS) in combination with thermochemolysis were applied. Both methods differentiated between plastic vs. non-plastic in the same way in 26 cases, with 19 particles and fibers (22 after re-evaluation) identified as the same polymer type. To illustrate the different approaches and emphasize the complementarity of their information content, we exemplarily provide a detailed comparison of four particles and three fibers and a critical discussion of advantages and disadvantages of both methods. [ABSTRACT FROM AUTHOR]

Abstract: We report on methane enrichments that were observed during summer in the upper water column of the Gotland Basin, central Baltic Sea. In the eastern part of the basin, methane concentrations just below the thermocline varied between 15 nM and 77 nM, in contrast to the western part where no methane enrichments could be detected. Stable carbon isotope ratios of methane (δ13C‐CH4 of −67.6‰) indicated its in situ biogenic origin from CO2 reduction, which was supported by clonal sequences that clustered with Methanomicrobiaceae, a family of methanogenic Archaea. Incubation experiments with a Temora longicornis dominated seston fraction obtained from the relevant depth showed a positive correlation between seston concentration and methane production rates. Our results, in combination with previous literature outcomes, suggest that the methane enrichment in the eastern basin might be sustained by a diet‐consumer relationship between the dinoflagellate Dinophysis norvegica and the copepod T. longicornis. However, our mass balance indicates that a local methane production of 110 pmol L−1 d−1 was needed to maintain the methane enrichment, and that the estimated production rate from our incubation experiments of 0.3 pmol CH4 d−1 per adult T. longicornis (about 1 pmol L−1 d−1) was too low to maintain the methane enrichment by zooplankton associated methane production only. These calculations also showed that methane was consumed below the thermocline and not transported into the upper‐ocean, suggesting that other sources in the mixed layer in the range of 95 pmol L−1 d−1 are needed to maintain the observed methane air–sea flux. [ABSTRACT FROM AUTHOR]

Despite increasing concerns about microplastic (MP) pollution in aquatic ecosystems, there is insufficient knowledge on how MP affect fungal communities. In this study, we explored the diversity and community composition of fungi attached to polyethylene (PE) and polystyrene (PS) particles incubated in different aquatic systems in north-east Germany: the Baltic Sea, the River Warnow and a wastewater treatment plant. Based on next generation 18S rRNA gene sequencing, 347 different operational taxonomic units assigned to 81 fungal taxa were identified on PE and PS. The MP-associated communities were distinct from fungal communities in the surrounding water and on the natural substrate wood. They also differed significantly among sampling locations, pointing towards a substrate and location specific fungal colonization. Members of Chytridiomycota, Cryptomycota and Ascomycota dominated the fungal assemblages, suggesting that both parasitic and saprophytic fungi thrive in MP biofilms. Thus, considering the worldwide increasing accumulation of plastic particles as well as the substantial vector potential of MP, especially these fungal taxa might benefit from MP pollution in the aquatic environment with yet unknown impacts on their worldwide distribution, as well as biodiversity and food web dynamics at large. [ABSTRACT FROM AUTHOR]

The contamination of aquatic ecosystems with microplastics has recently been reported through many studies, and negative impacts on the aquatic biota have been described. For the chemical identification of microplastics, mainly Fourier transform infrared (FTIR) and Raman spectroscopy are used. But up to now, a critical comparison and validation of both spectroscopic methods with respect to microplastics analysis is missing. To close this knowledge gap, we investigated environmental samples by both Raman and FTIR spectroscopy. Firstly, particles and fibres >500 μm extracted from beach sediment samples were analysed by Raman and FTIR microspectroscopic single measurements. Our results illustrate that both methods are in principle suitable to identify microplastics from the environment. However, in some cases, especially for coloured particles, a combination of both spectroscopic methods is necessary for a complete and reliable characterisation of the chemical composition. Secondly, a marine sample containing particles <400 μm was investigated by Raman imaging and FTIR transmission imaging. The results were compared regarding number, size and type of detectable microplastics as well as spectra quality, measurement time and handling. We show that FTIR imaging leads to significant underestimation (about 35 %) of microplastics compared to Raman imaging, especially in the size range <20 μm. However, the measurement time of Raman imaging is considerably higher compared to FTIR imaging. In summary, we propose a further size division within the smaller microplastics fraction into 500-50 μm (rapid and reliable analysis by FTIR imaging) and into 50-1 μm (detailed and more time-consuming analysis by Raman imaging). [ABSTRACT FROM AUTHOR]

The presence of microplastics in aquatic ecosystems is a topical problem and leads to the need of appropriate and reliable analytical methods to distinctly identify and to quantify these particles in environmental samples. As an example transmission, Fourier transform infrared (FTIR) imaging can be used to analyze samples directly on filters without any visual presorting, when the environmental sample was afore extracted, purified, and filtered. However, this analytical approach is strongly restricted by the limited IR transparency of conventional filter materials. Within this study, we describe a novel silicon (Si) filter substrate produced by photolithographic microstructuring, which guarantees sufficient transparency for the broad mid-infrared region of 4000-600 cm. This filter type features holes with a diameter of 10 μm and exhibits adequate mechanical stability. Furthermore, it will be shown that our Si filter substrate allows a distinct identification of the most common microplastics, polyethylene (PE), and polypropylene (PP), in the characteristic fingerprint region (1400-600 cm). Moreover, using the Si filter substrate, a differentiation of microparticles of polyesters having quite similar chemical structure, like polyethylene terephthalate (PET) and polybutylene terephthalate (PBT), is now possible, which facilitates a visualization of their distribution within a microplastic sample by FTIR imaging. Finally, this Si filter can also be used as substrate for Raman microscopy-a second complementary spectroscopic technique-to identify microplastic samples. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Pelagic redoxclines of the central Baltic Sea are dominated by the epsilonproteobacterial group Sulfurimonas GD17, considered to be the major driver of chemolithoautotrophic denitrification in this habitat. Autecological investigations of a recently isolated representative of this environmental group, Sulfurimonas gotlandica str. GD1T, demonstrated that the bacterium grows best under sulfur-oxidizing, denitrifying conditions. However, in the presence of bicarbonate, this strain is able to use pyruvate as both an additional carbon source and an alternative electron donor. These observations suggested that the environmental group GD17 actively metabolizes organic substrates in situ. To examine this possibility, we used RNA-based stable isotope probing ( RNA- SIP) on a natural redoxcline community provided with 13C-labeled pyruvate. While in this experiment, we were able to identify putative heterotrophic microorganisms, the uptake of 13C-pyruvate in GD17 nucleic acids could not be established. To resolve these contradictory findings, combined incorporation experiments with 14C- and 13C-labeled pyruvate were carried out in cells of strain GD1T cultivated under chemolithoautotrophic conditions, which favor pyruvate uptake rather than oxidation. An analysis of the labeled biomolecules revealed that pyruvate was mostly incorporated in cellular components such as amino acids, whose synthesis requires only minimal transformation. Carbon transfer into nucleic acids was not observed, explaining the inability of RNA- SIP to detect pyruvate incorporation by strain GD1T and the environmental group GD17. Together, these findings suggest that by integrating organic compounds such as pyruvate into cellular components S. gotlandica GD1T is able to replenish chemolithoautotrophic growth and thus ensure its survival in nutrient-limited habitats such as marine pelagic redoxclines. [ABSTRACT FROM AUTHOR]

Knowledge on Actinobacteria rhodopsin gene ( actR) diversity and spatial distribution is scarce. The Baltic Sea is characterized by strong salinity gradients leading to the coexistence of marine and freshwater bacteria and hence is an ideal study area to elucidate the dispersion and phylogenetic affiliation of actR in dependence on salinity . ActR DGGE fingerprints in summer 2008 revealed between 3 and 19 distinct bands within a salinity range of 2.4-27 PSU. Environmental actR clone sequences were obtained from stations distributed along the whole salinity gradient. Overall, 20 different actR sequence groups (operational taxonomic units) were found, with up to 11 different ones per station. Phylogenetically, the actR sequences were predominantly (80%) affiliated with freshwater acI- Actinobacteria whose 16 S rRNA gene accounted for 2-33% of total 16 S rRNA genes in both the Bothnian Sea and central Baltic Sea. However, at salinities above 14 PSU, acI-16 S rRNA gene accounted for less than 1%. In contrast, the diversity of actR remained high. Changes in actR gene diversity were significantly correlated with salinity, oxygen, silica or abundance of Synechococcus sp. Our results demonstrate a wide distribution of freshwater actR along the Baltic Sea salinity gradient indicating that some freshwater Actinobacteria might have adapted to higher salinities. [ABSTRACT FROM AUTHOR]

The article lists the referees to the "FEMS Microbiology Ecology," 2007-2008 issue including Raeid Abed.

The abundance, vertical distribution, and diversity of aerobic anoxygenic phototrophic bacteria (AAP) were studied at four basins of the Baltic Sea. AAP were enumerated by infrared epifluorescence microscopy, and their diversity was analyzed by using pufM gene clone libraries. In addition, numbers of CFU containing the pufM gene were determined, and representative strains were isolated. Both approaches indicated that AAP reached maximal abundance in the euphotic zone. Maximal AAP abundance was 2.5 × 105 cells ml-1 (11% of total prokaryotes) or 1.0 × 10³ CFU ml-1 (9 to 10% of total CFU). Environmental pufM clone sequences were grouped into 11 operational taxonomic units phylogenetically related to cultivated members of the Alpha-, Beta-, and Gammaproteobacteria. In spite of varying pufM compositions, five clones were present in all libraries. Of these, Jannaschia-related clones were always found in relative abundances representing 25 to 30% of the total AAP clones. The abundances of the other clones varied. Clones potentially affiliated with typical freshwater Betaproteobacteria sequences were present at three Baltic Sea stations, whereas clones grouping with Loktanella represented 40% of the total cell numbers in the Gotland Basin. For three alphaproteobacterial clones, probable pufM phylogenetic relationships were supported by 16S rRNA gene analyses of Baltic AAP isolates, which showed nearly identical pufM sequences. Our data indicate that the studied AAP assemblages represented a mixture of marine and freshwater taxa, thus characterizing the Baltic Sea as a "melting pot" of abundant, polyphyletic aerobic photoheterotrophic bacteria. [ABSTRACT FROM AUTHOR]

Vibrio spp. are ubiquitous in aquatic environments. In temperate regions, including the Baltic Sea, these bacteria, which include facultative pathogenic species, proliferate during warm water periods and may thus pose a risk to human health. However, while present at relatively high abundances in the summer months, Vibrio spp. are rarely detected during cold water periods. Several potential winter reservoirs, such as fish and sediment, have been discussed, but the seeding sources that give rise to Vibrio during the summer months are unknown. In this study, we employed a combination of cultivation-independent genus-specific digital droplet PCR, Illumina 16S rRNA gene sequencing, culture-dependent determinations of colony-forming units (CFU) and genus-specific strain isolation to identify possible winter reservoirs of Vibrio spp. Using these techniques, we demonstrate that in the southern Baltic Sea especially fish can serve as a winter reservoir for distinct Vibrio assemblages, including facultative pathogenic V. vulnificus. Particularly the invasive species round goby (Neogobius melanostomus), with its potential to appear in high individual densities, has the capacity to carry a comparable Vibrio spp. cell number like water and sediment, while only accounting for 1/1000 of the spatial share in the overall coastal environment. Thus, by providing a winter reservoir for distinct Vibrio communities, coastal fish and, especially areas in which round goby densities are high, may be hot spots of pathogenic Vibrio species. [Display omitted] • Fish acts as Vibrio winter reservoir in the Baltic Sea. • Vibrio spp. often highest abundant in connection to invasive species round goby. • Quantitative Vibrio 16S rRNA gene ddPCR without Photobacterium falsification. [ABSTRACT FROM AUTHOR]

The bacterial genus Vibrio is widespread in aquatic systems and contains several pathogenic species. As pathogenic Vibrio infections in aquaculture systems have been documented, the release of untreated aquaculture wastewater could cause the release of high doses of the pathogens into the environment and thus to the replacement of naturally occurring Vibrio populations. Aquaculture is one of the main industries on the island of Hainan (southern China) and the risk of pathogenic Vibrio contamination of the environment and humans is accordingly high. In this study, we used Illumina 16S rRNA gene sequencing of water, sediment, seagrass and tissue samples obtained from aquaculture operations in this region and from adjoining coastal and riverine areas to examine the impact of aquaculture on Vibrio assemblages. The results indicated that the effects of aquaculture on Vibrio community structure and abundance depended on the particular system. Classical pond aquaculture decreased Vibrio diversity and significantly reduced the relative abundances of Vibrio 16S rRNA genes compared to coastal reference populations. Aquaculture systems continuously flushed with marine water had a Vibrio community structure and diversity similar to that of coastal populations but with elevated levels of Vibrio sequence reads. Despite the observed changes, there was no clear evidence that aquaculture facilities altered Vibrio composition or led to a measurable increase in the relative abundance of Vibrio genes in the environment. Image 1 • Aquaculture operation systems influence Vibrio spp. communities in the aquacultures. • Pond aquaculture lowers Vibrio diversity. • Continuous aquaculture systems increase Vibrio abundance. • Aquaculture had no detectable impact on environmental Vibrio populations. [ABSTRACT FROM AUTHOR]

The article presents acknowledgement to reviewers of the journal "Water" in 2018.