Journal articles: 'Microbial resuspension'

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Wu, Miao, Ming Zhang, Wei Ding, Lin Lan, Zhilin Liu, Lingzhan Miao, and Jun Hou. "Microbial Carbon Metabolic Functions in Sediments Influenced by Resuspension Event." Water 13, no. 1 (December 23, 2020): 7. http://dx.doi.org/10.3390/w13010007.

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Microorganisms in sediments are an important part of the aquatic ecosystem, and their functional activities are sensitive to external environmental pressure. Shallow lakes are characterized by frequent sediment resuspension events, leading to large amounts of nutrients being released. However, information about the potential impacts of sediment resuspension events on the functional activities of microbial communities is limited. In this study, the responses of microbial carbon metabolism in sediments under different wind–wave disturbance were analyzed by BIOLOG ECO microplates. The results showed that under four disturbance conditions (wind speeds of 0, 1.60, 3.62, and 14.10 m/s), the total carbon metabolism function of the sediment microbial community (represented as average well-color development, AWCD) remained unchanged (p > 0.05), and the final total AWCD value stabilized at about 1.70. However, compared with the control group, some specific carbon sources (e.g., amines and carboxylic acids) showed significant changes (p < 0.05). We found that short-term (8 h) resuspension events did not affect the total carbon metabolism of sediment microbial communities, while it affected the microbial utilization ability of some specific types of carbon sources. For example, we found that the microbial utilization capacity of polymers in the 14.10 m/s group was the best. This study provides a new insight into the carbon cycle process of shallow lake sediments that resuspension events will affect the carbon cycle process of sediments.

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Pusceddu, Antonio, Carla Fiordelmondo, and Roberto Danovaro. "Sediment Resuspension Effects on the Benthic Microbial Loop in Experimental Microcosms." Microbial Ecology 50, no. 4 (November 2005): 602–13. http://dx.doi.org/10.1007/s00248-005-5051-6.

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Garstecki, T., S. A. Wickham, and H. Arndt. "Effects of Experimental Sediment Resuspension on a Coastal Planktonic Microbial Food Web." Estuarine, Coastal and Shelf Science 55, no. 5 (November 2002): 751–62. http://dx.doi.org/10.1006/ecss.2001.0937.

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Stocker, M. D., J. G. Rodriguez-Valentín, Y. A. Pachepsky, and D. R. Shelton. "Spatial and temporal variation of fecal indicator organisms in two creeks in Beltsville, Maryland." Water Quality Research Journal 51, no. 2 (April 8, 2016): 167–79. http://dx.doi.org/10.2166/wqrjc.2016.044.

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Evaluation of microbial water quality is commonly based on monitoring populations of fecal indicator organisms (FIO) such as Escherichia coli (EC) and enterococci (ENT). The occurrence of elevated FIO concentrations in surface waters after storm events is well documented and has been attributed to runoff and sediment resuspension. The reasons for FIO concentration variation under baseflow conditions are less clear. The objective of this study was to quantify the variability of EC and ENT in two small streams running through agricultural land use areas. FIO concentrations were measured at upstream and downstream locations under baseflow conditions. Concentrations were not significantly different along cross-sections of the streams. Diurnal concentration trends were observed at each of the sampling locations. Significant differences in concentrations between upstream and downstream locations were noted for both creeks during baseflow periods when no runoff or sediment resuspension occurred. A hypothetical explanation is that indicator organisms are released from sediments during baseflow conditions due to the effect of groundwater influx into streams or due to the motility of indicator organisms. If confirmed, this hypothesis may affect our understanding of the role of sediments in the microbial quality of surface waters.

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Luongo, Julia C., and Shelly L. Miller. "Ultraviolet germicidal coil cleaning: Decreased surface microbial loading and resuspension of cell clusters." Building and Environment 105 (August 2016): 50–55. http://dx.doi.org/10.1016/j.buildenv.2016.05.024.

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David, Valérie, Hans Hartmann, Alexandre Barnett, Martine Bréret, Hélène Montanié, Francis Orvain, and Christine Dupuy. "Impact of biofilm resuspension on mesozooplankton in a shallow coastal ecosystem characterized by a bare intertidal mudflat." Journal of the Marine Biological Association of the United Kingdom 96, no. 6 (April 29, 2016): 1319–29. http://dx.doi.org/10.1017/s0025315416000552.

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A prey–predator experimental setup was conducted in a shallow coastal ecosystem characterized by a bare intertidal mudflat to test if benthic biofilm resuspension causing microalgae inputs and carbon export toward nanoflagellates would favour the highest planktonic trophic level (i.e. mesozooplankton) when nutrient concentrations are high in the water column. Mesozooplankton predation and somatic production were studied by comparing the evolution of the prey assemblage (diversity and abundances) in the presence and absence of these predators during 24 h experiments. The results were then statistically analysed according to the cross-calculation method. Biofilm resuspension caused (i) a direct input of benthic microorganisms that had changed prey structure in term of diversity and/or size and (ii) a differential growth ability between prey taxa. Both reasons implied a bottom-up control on both micro- and mesozooplankton. The carbon export toward heterotrophic nanoflagellates favoured pelagic ciliate growth while mesozooplankton benefited from largest diatoms with high growth rates, both benthic and R-strategist pelagic species. Even if these microbial and herbivorous pathways are controlled by benthic inputs, they seemed to be totally disconnected since ciliates represented only a small part of mesozooplankton diet. The sensitivity of mesozooplankton production appeared species-dependent with the most tolerant taxa dominating the zooplankton assemblages. This suggests a role of the intensities and the frequencies of biofilm resuspension on the spatio-temporal structuring of mesozooplankton in macrotidal coastal ecosystems.

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Cabrol, Léa, Marianne Quéméneur, and Benjamin Misson. "Inhibitory effects of sodium azide on microbial growth in experimental resuspension of marine sediment." Journal of Microbiological Methods 133 (February 2017): 62–65. http://dx.doi.org/10.1016/j.mimet.2016.12.021.

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Dadi, Tallent, Katrin Wendt-Potthoff, and Matthias Koschorreck. "Sediment resuspension effects on dissolved organic carbon fluxes and microbial metabolic potentials in reservoirs." Aquatic Sciences 79, no. 3 (April 28, 2017): 749–64. http://dx.doi.org/10.1007/s00027-017-0533-4.

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Prest, Emmanuelle I., Peter G. Schaap, Michael D. Besmer, and Frederik Hammes. "Dynamic Hydraulics in a Drinking Water Distribution System Influence Suspended Particles and Turbidity, But Not Microbiology." Water 13, no. 1 (January 5, 2021): 109. http://dx.doi.org/10.3390/w13010109.

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Spatial and short-term temporal changes in water quality as a result of water age and fluctuating hydraulic conditions were investigated in a drinking water distribution system. Online measurements of total and intracellular adenosine tri-phosphate (ATP), total and intact cell concentrations measured with flow cytometry (FCM), turbidity, and particle counts were performed over five weeks at five subsequent locations of the distribution system. The high number of parallel FCM and ATP measurements revealed the combined effect of water age and final disinfection on spatial changes in microbiology in the system. The results underlined that regular daily dynamics in flow velocities are normal and inevitable in drinking water distribution systems, and significantly impact particle counts and turbidity. However, hydraulic conditions had no detectable impact on the concentration of suspended microbial cells. A weak correlation between flow velocity and ATP concentrations suggests incidental resuspension of particle-bound bacteria, presumably caused by either biofilm detachment or resuspension from sediment when flow velocities increase. The highly dynamic hydraulic conditions highlight the value of online monitoring tools for the meaningful description of short-term dynamics (day-scale) in drinking water distribution systems.

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Otten, Jerko, and Herman J. Gons. "Aerobic decomposition of settled algae in a laboratory system: The impact of resuspension on microbial activity." SIL Proceedings, 1922-2010 24, no. 2 (March 1991): 734–37. http://dx.doi.org/10.1080/03680770.1989.11898839.

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Gardner, Wayne S., Brian J. Eadie, Joann F. Chandler, Christopher C. Parrish, and John M. Malczyk. "Mass Flux and "Nutritional Composition" of settling Epilimnetic Particles in Lake Michigan." Canadian Journal of Fisheries and Aquatic Sciences 46, no. 7 (July 1, 1989): 1118–24. http://dx.doi.org/10.1139/f89-145.

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A series of sediment-trap samples, collected at a 30-m depth in southeastern Lake Michigan, was analyzed to evaluate the seasonal flux and nutritional value of settling epilimnetic particles as potential food for benthic organisms. Flux was highest in the spring (due in part to resuspension), lowest in the summer during stratification, and intermediate during autumn months. Organic content of the particles ranged from 10% ash free dry weight (AFDW) in March through May samples to 17–19% in July–August samples. During the summer, microbial degradation of organic materials occurred in the trap bottles without added preservative, as evidenced by less AFDW in nonpreserved trap bottles than in similar chloroform-preserved bottles. The percentage of AFDW occuring as lipid ranged from 3.5% in April–May up to 14% during May through August. Dominant lipid classes were hydrocarbons, polar lipids including phospholipids and chlorophyll a, and free fatty acids. The ratio of n-alkane C-17 (algal indicator) to n-alkane C-29 (terrestrial or resuspension indicator) and the ratio of biogenic silica to AFDW in preserved samples both reached a maximum in May, shortly before lipid content peaked in the benthic amphipod, Pontoporeia hoyi. This observation agrees with the hypothesis that P. hoyi receives much of its nutrition from the spring algal bloom.

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Sloth, Niels Peter, Bo Riemann, Lars Peter Nielsen, and T. Blackburn. "Resilience of Pelagic and Benthic Microbial Communities to Sediment Resuspension in a Coastal Ecosystem, Knebel Vig, Denmark." Estuarine, Coastal and Shelf Science 42, no. 4 (April 1996): 405–15. http://dx.doi.org/10.1006/ecss.1996.0027.

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Garstecki, T., and SA Wickham. "Effects of resuspension and mixing on population dynamics and trophic interactions in a model benthic microbial food web." Aquatic Microbial Ecology 25 (2001): 281–92. http://dx.doi.org/10.3354/ame025281.

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Ritzrau, Will, and Gerhard Graf. "Increase of microbial biomass in the benthic turbidity zone of Kiel Bight after resuspension by a storm event." Limnology and Oceanography 37, no. 5 (July 1992): 1081–86. http://dx.doi.org/10.4319/lo.1992.37.5.1081.

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Heiskanen, Anna-Stiina, and Juha-Markku Lepp�nen. "Estimation of export production in the coastal Baltic Sea: effect of resuspension and microbial decomposition on sedimentation measurements." Hydrobiologia 316, no. 3 (December 1995): 211–24. http://dx.doi.org/10.1007/bf00017438.

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Mussared, Amanda, Rolando Fabris, Jan Vreeburg, Jenny Jelbart, and Mary Drikas. "The origin and risks associated with loose deposits in a drinking water distribution system." Water Supply 19, no. 1 (April 19, 2018): 291–302. http://dx.doi.org/10.2166/ws.2018.073.

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Abstract Sediment accumulates in distribution systems over time, and can potentially result in dirty water events. The primary origin of these particles in most networks has not been examined. Controlled sediment resuspension (flushing) events were performed at 10 sites in a drinking water distribution system and repeated six months later to observe redeposition. Different patterns of sediment deposition observed are suspected to be related to particle origin. A large proportion of pipe sediment resuspended during the first flushing event was composed of iron, most likely arising from corrosion of distribution system infrastructure. This sediment appears to play a role in sheltering microbial cells from secondary disinfection. In this study, a source of particles was identified that may provide an alternate explanation for the presence of iron deposits in systems not dominated by iron pipework.

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Srivastava, Atul, Kenji Kikuchi, and Takuji Ishikawa. "Non-biodegradable objects may boost microbial growth in water bodies by harnessing bubbles." Royal Society Open Science 8, no. 9 (September 2021): 210646. http://dx.doi.org/10.1098/rsos.210646.

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Given the ubiquity of bubbles and non-biodegradable wastes in aqueous environments, their transport through bubbles should be widely extant in water bodies. In this study, we investigate the effect of bubble-induced waste transport on microbial growth by using yeasts as model microbes and a silicone rubber object as model waste. Noteworthily, this object repeatedly rises and sinks in fluid through fluctuations in bubble-acquired buoyant forces produced by cyclic nucleation, growth and release of bubbles from object's surface. The rise–sink movement of the object gives rise to a strong bulk mixing and an enhanced resuspension of cells from the floor. Such spatially dynamic contaminant inside a nutrient-rich medium also leads to an increment in the total microbe concentration in the fluid. The enhanced concentration is caused by strong nutrient mixing generated by the object's movement which increases the nutrient supply to growing microbes and thereby, prolonging their growth phases. We confirm these findings through a theoretical model for cell concentration and nutrient distribution in fluid medium. The model is based on the continuum hypothesis and it uses the general conservation law which takes an advection–diffusion growth form. We conclude the study with the demonstration of bubble-induced digging of objects from model sand.

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Cruaud, Perrine, Adrien Vigneron, Caetano C. Dorea, Manuel J. Rodriguez, and Steve J. Charette. "Rapid Changes in Microbial Community Structures along a Meandering River." Microorganisms 8, no. 11 (October 22, 2020): 1631. http://dx.doi.org/10.3390/microorganisms8111631.

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Streams and rivers convey freshwater from lands to the oceans, transporting various organic particles, minerals, and living organisms. Microbial communities are key components of freshwater food webs and take up, utilize, and transform this material. However, there are still important gaps in our understanding of the dynamic of these organisms along the river channels. Using high-throughput 16S and 18S rRNA gene sequencing and quantitative PCR on a 11-km long transect of the Saint-Charles River (Quebec, CA), starting from its main source, the Saint-Charles Lake, we show that bacterial and protist community structures in the river drifted quickly but progressively downstream of its source. The dominant Operational Taxonomic Units (OTUs) of the lake, notably related to Cyanobacteria, decreased in proportions, whereas relative proportions of other OTUs, such as a Pseudarcicella OTU, increased along the river course, becoming quickly predominant in the river system. Both prokaryotic and protist communities changed along the river transect, suggesting a strong impact of the shift from a stratified lake ecosystem to a continuously mixed river environment. This might reflect the cumulative effects of the increasing water turbulence, fluctuations of physicochemical conditions, differential predation pressure in the river, especially in the lake outlet by benthic filter feeders, or the relocation of microorganisms, through flocculation, sedimentation, resuspension, or inoculation from the watershed. Our study reveals that the transit of water in a river system can greatly impact both bacterial and micro-eukaryotic community composition, even over a short distance, and, potentially, the transformation of materials in the water column.

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Trubl, Gareth, Natalie Solonenko, Lauren Chittick, Sergei A. Solonenko, Virginia I. Rich, and Matthew B. Sullivan. "Optimization of viral resuspension methods for carbon-rich soils along a permafrost thaw gradient." PeerJ 4 (May 17, 2016): e1999. http://dx.doi.org/10.7717/peerj.1999.

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Permafrost stores approximately 50% of global soil carbon (C) in a frozen form; it is thawing rapidly under climate change, and little is known about viral communities in these soils or their roles in C cycling. In permafrost soils, microorganisms contribute significantly to C cycling, and characterizing them has recently been shown to improve prediction of ecosystem function. In other ecosystems, viruses have broad ecosystem and community impacts ranging from host cell mortality and organic matter cycling to horizontal gene transfer and reprogramming of core microbial metabolisms. Here we developed an optimized protocol to extract viruses from three types of high organic-matter peatland soils across a permafrost thaw gradient (palsa, moss-dominated bog, and sedge-dominated fen). Three separate experiments were used to evaluate the impact of chemical buffers, physical dispersion, storage conditions, and concentration and purification methods on viral yields. The most successful protocol, amended potassium citrate buffer with bead-beating or vortexing and BSA, yielded on average as much as 2-fold more virus-like particles (VLPs) g−1of soil than other methods tested. All method combinations yielded VLPs g−1of soil on the 108order of magnitude across all three soil types. The different storage and concentration methods did not yield significantly more VLPs g−1of soil among the soil types. This research provides much-needed guidelines for resuspending viruses from soils, specifically carbon-rich soils, paving the way for incorporating viruses into soil ecology studies.

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Förstner, U., W. Ahlf, and W. Calmano. "Sediment Quality Objectives and Criteria Development in Germany." Water Science and Technology 28, no. 8-9 (October 1, 1993): 307–16. http://dx.doi.org/10.2166/wst.1993.0629.

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New objectives regarding the improvement of water quality as well as problems with the resuspension and land deposition of dredged materials require a standardized assessment of sediment quality. Numerical approaches are based on the accumulation, pore water concentrations, solid/liquid partition and elution properties of contaminants; these non-biological schemes can be extended and completed by additional biological criteria. Specific biological approaches have been combined with chemical surveys (for example Sediment Quality Triad). In Germany, numerical criteria are based on the background approach. Biological criteria approaches include bioassays on sediment, porewater and elutriates; recent developments are directed towards microbial solid phase bioassays. Special emphasis is placed on the characteristics of the mineral and organic solid substrate, in particular, buffer capacity against pH-depression; these components should be classified on the basis of the carbonate and sulfide inventories.

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Layglon, Nicolas, Benjamin Misson, Nicolas Gallois, Sébastien D'Onofrio, Véronique Lenoble, Stéphane Mounier, Dario Omanović, and Cédric Garnier. "Negligible microbial heterotrophic quantitative contribution onto trace metals remobilization during marine sediment resuspension - insights from a Mediterranean urbanized bay." Marine Chemistry 234 (August 2021): 103981. http://dx.doi.org/10.1016/j.marchem.2021.103981.

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Zhou, Xia, Stephen J. Bent, Maria G. Schneider, Catherine C. Davis, Mohammed R. Islam, and Larry J. Forney. "Characterization of vaginal microbial communities in adult healthy women using cultivation-independent methods." Microbiology 150, no. 8 (August 1, 2004): 2565–73. http://dx.doi.org/10.1099/mic.0.26905-0.

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The normal microbial flora of the vagina plays an important role in preventing genital and urinary tract infections in women. Thus an accurate understanding of the composition and ecology of the ecosystem is important to understanding the aetiology of these diseases. Common wisdom is that lactobacilli dominate the normal vaginal microflora of post-pubertal women. However, this conclusion is based on methods that require cultivation of microbial populations; an approach that is known to yield a biased and incomplete assessment of microbial community structure. In this study cultivation-independent methods were used to analyse samples collected from the mid-vagina of five normal healthy Caucasian women between the ages of 28 and 44. Total microbial community DNA was isolated following resuspension of microbial cells from vaginal swabs. To identify the constituent numerically dominant populations in each community 16S rRNA gene libraries were prepared following PCR amplification using the 8f and 926r primers. From each library, the DNA sequences of approximately 200 16S rRNA clones were determined and subjected to phylogenetic analyses. The diversity and kinds of organisms that comprise the vaginal microbial community varied among women. Species of Lactobacillus appeared to dominate the communities in four of the five women. However, the community of one woman was dominated by Atopobium sp., whereas a second woman had appreciable numbers of Megasphaera sp., Atopobium sp. and Leptotrichia sp., none of which have previously been shown to be common members of the vaginal ecosystem. Of the women whose communities were dominated by lactobacilli, there were two distinct clusters, each of which consisted of a single species. One class consisted of two women with genetically divergent clones that were related to Lactobacillus crispatus, whereas the second group of two women had clones of Lactobacillus iners that were highly related to a single phylotype. These surprising results suggest that culture-independent methods can provide new insights into the diversity of bacterial species found in the human vagina, and this information could prove to be pivotal in understanding risk factors for various infectious diseases.

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Pembrey, Richard S., Kevin C. Marshall, and René P. Schneider. "Cell Surface Analysis Techniques: What Do Cell Preparation Protocols Do to Cell Surface Properties?" Applied and Environmental Microbiology 65, no. 7 (July 1, 1999): 2877–94. http://dx.doi.org/10.1128/aem.65.7.2877-2894.1999.

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ABSTRACT Cell surface analysis often requires manipulation of cells prior to examination. The most commonly employed procedures are centrifugation at different speeds, changes of media during washing or final resuspension, desiccation (either air drying for contact angle measurements or freeze-drying for sensitive spectroscopic analysis, such as X-ray photoelectron spectroscopy), and contact with hydrocarbon (hydrophobicity assays). The effects of these procedures on electrophoretic mobility, adhesion to solid substrata, affinity to a number of Sepharose columns, structural integrity, and cell viability were systematically investigated for a range of model organisms, including carbon- and nitrogen-limited Psychrobacter sp. strain SW8 (glycocalyx-bearing cells), Escherichia coli(gram-negative cells without a glycocalyx), and Staphylococcus epidermidis (gram-positive cells without a glycocalyx). All of the cell manipulation procedures severely modified the physicochemical properties of cells, but with each procedure some organisms were more susceptible than others. Considerable disruption of cell surfaces occurred when organisms were placed in contact with a hydrocarbon (hexadecane). The majority of cells became nonculturable after air drying and freeze-drying. Centrifugation at a high speed (15,000 × g) modified many cell surface parameters significantly, although cell viability was considerably affected only in E. coli. The type of washing or resuspension medium had a strong influence on the values of cell surface parameters, particularly when high-salt solutions were compared with low-salt buffers. The values for parameters obtained with different methods that allegedly measure similar cell surface properties did not correlate for most cells. These results demonstrate that the methods used to prepare cells for cell surface analysis need to be critically investigated for each microorganism so that the final results obtained reflect the nature of the in situ microbial cell surface as closely as possible. There is an urgent need for new, reliable, nondestructive, minimally manipulative cell surface analysis techniques that can be used in situ.

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Wang, Changhui, and Yuansheng Pei. "Effects of light, microbial activity, and sediment resuspension on the phosphorus immobilization capability of drinking water treatment residuals in lake sediment." Environmental Science and Pollution Research 20, no. 12 (June 8, 2013): 8900–8908. http://dx.doi.org/10.1007/s11356-013-1865-9.

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Rouquet, V., F. Homer, J. M. Brignon, P. Bonne, and J. Cavard. "Source and occurrence of Giardia and Cryptosporidium in Paris rivers." Water Science and Technology 41, no. 7 (April 1, 2000): 79–86. http://dx.doi.org/10.2166/wst.2000.0118.

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This paper presents an investigation of the variability of concentrations of Giardia cyst and Cryptosporidium oocyst in two main rivers of Ile-de-France: the Seine (upstream from Paris) and its largest tributary: the Marne. The first goal of this study was to examine risk of presence of Cryptosporidium and Giardia at the drinking water treatment plants' intakes at high concentrations. A second goal was to study the relationship between parasite concentrations and a variety of more easily measured water quality parameters (microbial or physicochemical) which could be used as risk indicators. Two aspects were particularly addressed: the influence of upstream waste water discharges, and the influence of rain fall and river floods on parasite concentrations. Preliminary results of an ongoing study are also presented: they show possible influence of non-point sources on parasite concentrations. Overall results show that parasite sedimentation in rivers is high, urban run-off and resuspension of particles could be at certain times the main factors responsible for peak pathogen levels in raw water.

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Abia, Akebe Luther King, Eunice Ubomba-Jaswa, Bettina Genthe, and Maggy Ndombo Benteke Momba. "Quantitative microbial risk assessment (QMRA) shows increased public health risk associated with exposure to river water under conditions of riverbed sediment resuspension." Science of The Total Environment 566-567 (October 2016): 1143–51. http://dx.doi.org/10.1016/j.scitotenv.2016.05.155.

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Veillette, Marc, Luke D. Knibbs, Ariane Pelletier, Remi Charlebois, Pascale Blais Lecours, Congrong He, Lidia Morawska, and Caroline Duchaine. "Microbial Contents of Vacuum Cleaner Bag Dust and Emitted Bioaerosols and Their Implications for Human Exposure Indoors." Applied and Environmental Microbiology 79, no. 20 (August 9, 2013): 6331–36. http://dx.doi.org/10.1128/aem.01583-13.

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ABSTRACTVacuum cleaners can release large concentrations of particles, both in their exhaust air and from resuspension of settled dust. However, the size, variability, and microbial diversity of these emissions are unknown, despite evidence to suggest they may contribute to allergic responses and infection transmission indoors. This study aimed to evaluate bioaerosol emission from various vacuum cleaners. We sampled the air in an experimental flow tunnel where vacuum cleaners were run, and their airborne emissions were sampled with closed-face cassettes. Dust samples were also collected from the dust bag. Total bacteria, total archaea,Penicillium/Aspergillus, and totalClostridiumcluster 1 were quantified with specific quantitative PCR protocols, and emission rates were calculated.Clostridium botulinumand antibiotic resistance genes were detected in each sample using endpoint PCR. Bacterial diversity was also analyzed using denaturing gradient gel electrophoresis (DGGE), image analysis, and band sequencing. We demonstrated that emission of bacteria and molds (Penicillium/Aspergillus) can reach values as high as 1E5 cell equivalents/min and that those emissions are not related to each other. The bag dust bacterial and mold content was also consistent across the vacuums we assessed, reaching up to 1E7 bacterial or mold cell equivalents/g. Antibiotic resistance genes were detected in several samples. No archaea orC. botulinumwas detected in any air samples. Diversity analyses showed that most bacteria are from human sources, in keeping with other recent results. These results highlight the potential capability of vacuum cleaners to disseminate appreciable quantities of molds and human-associated bacteria indoors and their role as a source of exposure to bioaerosols.

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McAuliffe, T. F., R. J. Lukatelich, A. J. McComb, and S. Qiu. "Nitrate applications to control phosphorus release from sediments of a shallow eutrophic estuary: an experimental evaluation." Marine and Freshwater Research 49, no. 6 (1998): 463. http://dx.doi.org/10.1071/mf97116.

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Effects of nitrate on phosphate release from sediments of a eutrophic estuary were investigated under laboratory conditions, using reconstituted sediment–water cores. Application of nitrate (5–100 mg L-1 NO3-N) increased redox potential near the sediment–water interface from –200 mV to about 200 mV during 25 days of incubation. The effective concentration of nitrate differed between sediments, reflecting differences in sediment properties, particularly bioavailable carbon. Reduced phosphate after nitrate application is attributed mainly to: (1) increased iron (III) binding near the sediment–water interface; and (2) increased dissolved oxygen in the water column due to lowered oxygen demand, with increased oxidation of ferrous iron and substances binding soluble reactive phosphate. High nitrate concentrations (50 and 100 mg L-1 NO3-N) did not persist through a 155-day incubation, suggesting that without carbon limitation added nitrate will eventually be consumed by microbial activity, and increased phosphate release may occur. Nitrate application directly into the surface sediment increased nitrate consumption, and so was less effective than application to the water column. Frequent resuspension increased dissolved oxygen concentration, so reduced nitrate consumption and lowered concentration of soluble reactive phosphate.

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North, R. L., N. H. Khan, M. Ahsan, C. Prestie, D. R. Korber, J. R. Lawrence, and J. J. Hudson. "Relationship between water quality parameters and bacterial indicators in a large prairie reservoir: Lake Diefenbaker, Saskatchewan, Canada." Canadian Journal of Microbiology 60, no. 4 (April 2014): 243–49. http://dx.doi.org/10.1139/cjm-2013-0694.

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Lake Diefenbaker (LD) is a large reservoir on the South Saskatchewan River used for agricultural irrigation, drinking water, and recreation. Our objectives were to determine the distribution and abundance of bacterial indicators in embayments and the main channel of LD and to relate these to environmental factors. Total coliforms (TCs), fecal coliforms (FCs), and fecal indicator bacteria (i.e., Escherichia coli) were measured concurrently with water quality parameters. Although TCs, FCs, and E. coli were present in LD, they rarely exceeded the TC and FC Canadian Council of Ministers of the Environment (CCME) water quality standards for agricultural use (1000 colony-forming units (CFU) per 100 mL and 100 CFU per 100 mL, respectively). The correlation between the bacterial indicators in the sediments and the water column indicates that higher embayment abundances may be related to sediment loading and (or) resuspension events in these frequently mixed embayments. With higher water temperatures and water levels, as well as higher microbial activity, CCME bacterial limits may be exceeded. The greatest contributor to bacterial indicator abundance was water temperature. We predict that water quality standards will be exceeded more frequently with climate warming.

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Wu, Qinglong L., Yuwei Chen, Kuidong Xu, Zhengwen Liu, and Martin W. Hahn. "Intra-habitat heterogeneity of microbial food web structure under the regime of eutrophication and sediment resuspension in the large subtropical shallow Lake Taihu, China." Hydrobiologia 581, no. 1 (May 2007): 241–54. http://dx.doi.org/10.1007/s10750-006-0500-x.

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Rosales, Stephanie M., Christopher Sinigalliano, Maribeth Gidley, Paul R. Jones, and Lewis J. Gramer. "Oceanographic habitat and the coral microbiomes of urban-impacted reefs." PeerJ 7 (September 10, 2019): e7552. http://dx.doi.org/10.7717/peerj.7552.

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Coral reefs are in decline worldwide. In response to this habitat loss, there are efforts to grow, outplant, and restore corals in many regions. The physical oceanographic habitat of corals—such as sea temperature, waves, ocean currents, and available light—is spatially heterogeneous. We therefore hypothesize that outplant location may affect microbiomes, and ultimately, coral health and restoration success. We evaluated the influence of the physical oceanographic habitat on microbes in wild Porites astreoides and Siderastrea siderea. Tissue samples were collected at four Florida reefs in March, June, and September of 2015. We estimated oceanographic conditions from moored instruments, diver observations, remote sensing data, and numerical models. We analyzed microbiomes using amplicon 16S rRNA high-throughput sequencing data. We found microbial alpha-diversity negatively correlated with in situ sea temperature (which represented both the annual cycle and upwelling), as well as modeled alongshore currents, in situ sea-level, and modeled tide. Microbial beta-diversity correlated positively with significant wave height and alongshore currents from models, remotely-sensed relative turbidity, and in situ temperature. We found that archaea from the order Marine Group II decrease with increases in significant wave height, suggesting that this taxon may be influenced by waves. Also, during times of high wave activity, the relative abundance of bacteria from the order Flavobacteriales increases, which may be due to resuspension and cross-shelf transport of sediments. We also found that bacteria from the order SAR86 increase in relative abundance with increased temperature, which suggests that this taxon may play a role in the coral microbiome during periods of higher temperature. Overall, we find that physical oceanographic variability correlates with the structure of these coral microbiomes in ways that could be significant to coral health.

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Haffert, Laura, Matthias Haeckel, Henko de Stigter, and Felix Janssen. "Assessing the temporal scale of deep-sea mining impacts on sediment biogeochemistry." Biogeosciences 17, no. 10 (May 26, 2020): 2767–89. http://dx.doi.org/10.5194/bg-17-2767-2020.

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Abstract. Deep-sea mining for polymetallic nodules is expected to have severe environmental impacts because not only nodules but also benthic fauna and the upper reactive sediment layer are removed through the mining operation and blanketed by resettling material from the suspended sediment plume. This study aims to provide a holistic assessment of the biogeochemical recovery after a disturbance event by applying prognostic simulations based on an updated diagenetic background model and validated against novel data on microbiological processes. It was found that the recovery strongly depends on the impact type; complete removal of the reactive surface sediment reduces benthic release of nutrients over centuries, while geochemical processes after resuspension and mixing of the surface sediment are near the pre-impact state 1 year after the disturbance. Furthermore, the geochemical impact in the DISturbance and reCOLonization (DISCOL) experiment area would be mitigated to some degree by a clay-bound Fe(II)-reaction layer, impeding the downward diffusion of oxygen, thus stabilizing the redox zonation of the sediment during transient post-impact recovery. The interdisciplinary (geochemical, numerical and biological) approach highlights the closely linked nature of benthic ecosystem functions, e.g. through bioturbation, microbial biomass and nutrient fluxes, which is also of great importance for the system recovery. It is, however, important to note that the nodule ecosystem may never recover to the pre-impact state without the essential hard substrate and will instead be dominated by different faunal communities, functions and services.

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Passow, Uta, and Edward B. Overton. "The Complexity of Spills: The Fate of the Deepwater Horizon Oil." Annual Review of Marine Science 13, no. 1 (January 3, 2021): 109–36. http://dx.doi.org/10.1146/annurev-marine-032320-095153.

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The Deepwater Horizon oil spill was the largest, longest-lasting, and deepest oil accident to date in US waters. As oil and natural gas jetted from release points at 1,500-m depth in the northern Gulf of Mexico, entrainment of the surrounding ocean water into a buoyant plume, rich in soluble hydrocarbons and dispersed microdroplets of oil, created a deep (1,000-m) intrusion layer. Larger droplets of liquid oil rose to the surface, forming a slick of mostly insoluble, hydrocarbon-type compounds. A variety of physical, chemical, and biological mechanisms helped to transform, remove, and redisperse the oil and gas that was released. Biodegradation removed up to 60% of the oil in the intrusion layer but was less efficient in the surface slick, due to nutrient limitation. Photochemical processes altered up to 50% (by mass) of the floating oil. The surface oil expression changed daily due to wind and currents, whereas the intrusion layer flowed southwestward. A portion of the weathered surface oil stranded along shorelines. Oil from both surface and intrusion layers were deposited onto the seafloor via sinking marine oil snow. The biodegradation rates of stranded or sedimented oil were low, with resuspension and redistribution transiently increasing biodegradation. The subsequent research efforts increased our understanding of the fate of spilled oil immensely, with novel insights focusing on the importance of photooxidation, the microbial communities driving biodegradation, and the formation of marine oil snow that transports oil to the seafloor.

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Carelli, Thiago Gonçalves, and Leonardo Borghi. "Caracterização de Microfácies Sedimentares em Folhelhos da Formação Ponta Grossa (Devoniano) na Borda Leste da Bacia do Paraná." Anuário do Instituto de Geociências 34, no. 2 (January 1, 2011): 84–104. http://dx.doi.org/10.11137/2011_2_84-104.

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This study aims a microfacies characterization of outcropping shales in the Eastern border of Paraná Basin (34 samples) representing a transgressive system tract (lower Jaguariaíva Member, 20 samples) and a highstand system tract (upper São Domingos Member, 14 samples) of the Ponta Grossa Formation, inserted in a 3rd order depositional sequence cycle (megasequence), and their interpretation in terms of sedimentary processes and paleoenvironments. The study is based on petrographic microscopy, aided by XRD (clay mineralogy) and geochemical (TOC) data. The microfacies analysis took into consideration the mineralogy, microtexture, microfabric, microstructure (physical and biogenic), microfossils, particulate organic content, stratal variation, and colour in plugues and thin sections. Results point out 9 microfacies, 2 of them typical of the TST (M1 and M2) and 7 of the HST (M3 to M9). The microfacies from the TST show in general a chaotic microfabric (in part resulted from a higher bioturbation index), and a fine sand and silt rich composition (except one, associated to the 3rd order MFS); whereas the HST are silt and clay rich, and show a fairly oriented microfabric, and better preserved physical structures. Bottom wave reworking followed by biogenic activity (bioturbation) in proximal offshore paleoenvironmets are responsible for the best reservoir sedimentological characteristics of the microfacies M1 (associated to the TST) among all of them. Distal hyperpycnal flows, decantation from bottom wave resuspension plumes, microbial mats development, and low biogenic activity in prodelta/offshore paleoenvironments are responsible for best sedimentological sealing characteristics of the microfacies M3-M9 (associated to the HST).

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Graczyk, Thaddeus K., Deirdre Sunderland, Leena Tamang, Timothy M. Shields, Frances E. Lucy, and Patrick N. Breysse. "Quantitative Evaluation of the Impact of Bather Density on Levels of Human-Virulent Microsporidian Spores in Recreational Water." Applied and Environmental Microbiology 73, no. 13 (May 4, 2007): 4095–99. http://dx.doi.org/10.1128/aem.00365-07.

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ABSTRACT Microsporidial gastroenteritis, a serious disease of immunocompromised people, can have a waterborne etiology. During summer months, samples of recreational bathing waters were tested weekly for human-virulent microsporidian spores and water quality parameters in association with high and low bather numbers during weekends and weekdays, respectively. Enterocytozoon bieneusi spores were detected in 59% of weekend (n = 27) and 30% of weekday (n = 33) samples, and Encephalitozoon intestinalis spores were concomitant in a single weekend sample; the overall prevalence was 43%. The numbers of bathers, water turbidity levels, prevalences of spore-positive samples, and concentrations of spores were significantly higher for weekend than for weekday samples; P values were <0.001, <0.04, <0.03, and <0.04, respectively. Water turbidity and the concentration of waterborne spores were significantly correlated with bather density, with P values of <0.001 and <0.01, respectively. As all water samples were collected on days deemed acceptable for bathing by fecal bacterial standards, this study reinforces the scientific doubt about the reliability of bacterial indicators in predicting human waterborne pathogens. The study provides evidence that bathing in public waters can result in exposure to potentially viable microsporidian spores and that body contact recreation in potable water can play a role in the epidemiology of microsporidiosis. The study indicates that resuspension of bottom sediments by bathers resulted in elevated turbidity values and implies that the microbial load from both sediments and bathers can act as nonpoint sources for the contamination of recreational waters with Enterocytozoon bieneusi spores. Both these mechanisms can be considered for implementation in predictive models for contamination with microsporidian spores.

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MATTA, LEANN LERIE, and EVANGELYN C. ALOCILJA. "Carbohydrate Ligands on Magnetic Nanoparticles for Centrifuge-Free Extraction of Pathogenic Contaminants in Pasteurized Milk." Journal of Food Protection 81, no. 12 (November 19, 2018): 1941–49. http://dx.doi.org/10.4315/0362-028x.jfp-18-040.

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ABSTRACT Rapid detection of bacterial contamination in the food supply chain is critically important for food safety monitoring. Reliable extraction and concentration of bacteria from complex matrices is required to achieve high detection sensitivity, especially in situations of low contamination and infective dose. Carbohydrate ligands that attach to microbial cell–surface epitopes are promising economical and biocompatible substitutes for cell-targeting ligands and antibodies. Two different carbohydrate ligands immobilized onto magnetic nanoparticles (MNPs) were easily suspended in liquid food (milk) and allowed expedient extraction of microbes within minutes, without the need for centrifugation or loss in capture capacity. In this pilot study, 25-mL samples of undiluted milk were spiked with 5 mg of MNPs and artificially contaminated with bacteria at 3 to 5 log CFU/mL. MNPs and bacteria formed MNP-cell complexes, which were rapidly separated from the milk matrix with a simple magnet to allow supernatant removal. MNP-cell complexes were then concentrated by resuspension in 1 mL of fresh milk and plated per Bacteriological Analytical Manual procedures. Capture was carried out in vitamin D, 2% reduced fat, and fat-free milk spiked with Salmonella Enteritidis, Escherichia coli O157:H7, and Bacillus cereus for a combined total of 18 experiments (three replicates each). An additional eight experiments were conducted to investigate the effect of competitive bacteria on capture. All experiments were carried out over several months to account for environmental variations. Capture efficiency, on a log basis, for all combinations of milk and bacteria was 73 to 90%. Long-term exposure of the MNPs to milk did not markedly affect capture efficiency. These carbohydrate-functionalized MNPs have potential as nonspecific receptors for rapid extraction of bacteria from complex liquids, opening the door to discovery of biocompatible ligands that can reliably target pathogens in our food.

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Rapp, Insa, Christian Schlosser, Jan-Lukas Menzel Barraqueta, Bernhard Wenzel, Jan Lüdke, Jan Scholten, Beat Gasser, et al. "Controls on redox-sensitive trace metals in the Mauritanian oxygen minimum zone." Biogeosciences 16, no. 21 (November 5, 2019): 4157–82. http://dx.doi.org/10.5194/bg-16-4157-2019.

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Abstract. The availability of the micronutrient iron (Fe) in surface waters determines primary production, N2 fixation, and microbial community structure in large parts of the world's ocean, and thus it plays an important role in ocean carbon and nitrogen cycles. Eastern boundary upwelling systems and the connected oxygen minimum zones (OMZs) are typically associated with elevated concentrations of redox-sensitive trace metals (e.g., Fe, manganese (Mn), and cobalt (Co)), with shelf sediments typically forming a key source. Over the last 5 decades, an expansion and intensification of OMZs has been observed and this trend is likely to proceed. However, it is unclear how trace-metal (TM) distributions and transport are influenced by decreasing oxygen (O2) concentrations. Here we present dissolved (d; <0.2 µm) and leachable particulate (Lp; >0.2 µm) TM data collected at seven stations along a 50 km transect in the Mauritanian shelf region. We observed enhanced concentrations of Fe, Co, and Mn corresponding with low O2 concentrations (<50 µmol kg−1), which were decoupled from major nutrients and nutrient-like and scavenged TMs (cadmium (Cd), lead (Pb), nickel (Ni), and copper (Cu)). Additionally, data from repeated station occupations indicated a direct link between dissolved and leachable particulate Fe, Co, Mn, and O2. An observed dFe (dissolved iron) decrease from 10 to 5 nmol L−1 coincided with an O2 increase from 30 to 50 µmol kg−1 and with a concomitant decrease in turbidity. The changes in Fe (Co and Mn) were likely driven by variations in their release from sediment pore water, facilitated by lower O2 concentrations and longer residence time of the water mass on the shelf. Variations in organic matter remineralization and lithogenic inputs (atmospheric deposition or sediment resuspension; assessed using Al as indicator for lithogenic inputs) only played a minor role in redox-sensitive TM variability. Vertical dFe fluxes from O2-depleted subsurface-to-surface waters (0.08–13.5 µmol m−2 d−1) driven by turbulent mixing and vertical advection were an order of magnitude larger than atmospheric deposition fluxes (0.63–1.43 µmol m−2 d−1; estimated using dAl inventories in the surface mixed layer) in the continental slope and shelf region. Benthic fluxes are therefore the dominant dFe supply to surface waters on the continental margins of the Mauritanian upwelling region. Overall, our results indicated that the projected future decrease in O2 concentrations in OMZs may result in increases in Fe, Mn, and Co concentrations.

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Crawford, Ian, Martin W. Gallagher, Keith N. Bower, Thomas W. Choularton, Michael J. Flynn, Simon Ruske, Constantino Listowski, et al. "Real-time detection of airborne fluorescent bioparticles in Antarctica." Atmospheric Chemistry and Physics 17, no. 23 (December 1, 2017): 14291–307. http://dx.doi.org/10.5194/acp-17-14291-2017.

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Abstract. We demonstrate, for the first time, continuous real-time observations of airborne bio-fluorescent aerosols recorded at the British Antarctic Survey's Halley VI Research Station, located on the Brunt Ice Shelf close to the Weddell Sea coast (lat 75°34′59′′ S, long 26°10′0′′ W) during Antarctic summer, 2015. As part of the NERC MAC (Microphysics of Antarctic Clouds) aircraft aerosol cloud interaction project, observations with a real-time ultraviolet-light-induced fluorescence (UV-LIF) spectrometer were conducted to quantify airborne biological containing particle concentrations along with dust particles as a function of wind speed and direction over a 3-week period. Significant, intermittent enhancements of both non- and bio-fluorescent particles were observed to varying degrees in very specific wind directions and during strong wind events. Analysis of the particle UV-induced emission spectra, particle sizes and shapes recorded during these events suggest the majority of particles were likely a subset of dust with weak fluorescence emission responses. A minor fraction, however, were likely primary biological particles that were very strongly fluorescent, with a subset identified as likely being pollen based on comparison with laboratory data obtained using the same instrument. A strong correlation of bio-fluorescent particles with wind speed was observed in some, but not all, periods. Interestingly, the fraction of fluorescent particles to total particle concentration also increased significantly with wind speed during these events. The enhancement in concentrations of these particles could be interpreted as due to resuspension from the local ice surface but more likely due to emissions from distal sources within Antarctica as well as intercontinental transport. Likely distal sources identified by back trajectory analyses and dispersion modelling were the coastal ice margin zones in Halley Bay consisting of bird colonies with likely associated high bacterial activity together with contributions from exposed ice margin bacterial colonies but also long-range transport from the southern coasts of Argentina and Chile. Dispersion modelling also demonstrated emissions from shipping lanes, and therefore marine anthropogenic sources cannot be ruled out. Average total concentrations of total fluorescent aerosols were found to be 1.9 ± 2.6 L−1 over a 3-week period crossing over from November into December, but peak concentrations during intermittent enhancement events could be up to several tens per litre. While this short pilot study is not intended to be generally representative of Antarctic aerosol, it demonstrates the usefulness of the UV-LIF measurement technique for quantification of airborne bioaerosol concentrations and to understand their dispersion. The potential importance for microbial colonisation of Antarctica is highlighted.

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Williamson, S. J., L. A. Houchin, L. McDaniel, and J. H. Paul. "Seasonal Variation in Lysogeny as Depicted by Prophage Induction in Tampa Bay, Florida." Applied and Environmental Microbiology 68, no. 9 (September 2002): 4307–14. http://dx.doi.org/10.1128/aem.68.9.4307-4314.2002.

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ABSTRACT A seasonal study of the distribution of lysogenic bacteria in Tampa Bay, Florida, was conducted over a 13-month period. Biweekly water samples were collected and either were left unaltered or had the viral population reduced by filtration (pore size, 0.2 μm) and resuspension in filtered (pore size, 0.2 μm) water. Virus-reduced and unaltered samples were then treated by adding mitomycin C (0.5 μg ml−1) to induce prophage or were left untreated. In order to test the hypothesis that prophage induction was phosphate limited, additional induction experiments were performed in the presence and absence of phosphate. Induction was assessed as an increase in viral direct counts, relative to those obtained in controls, as detected by epifluorescence microscopy. Induction of prophage was observed in 5 of 25 (20%) unaltered samples which were obtained during or after the month of February, paralleling the results from a previous seasonal study. Induction of prophage was observed in 9 of 25 (36%) of the virus-reduced samples, primarily those obtained in the winter months, which was not observed in a prior seasonal study (P. K. Cochran and J. H. Paul, Appl. Environ. Microbiol. 64:2308-2312, 1998). Induction was noted in the months of lowest bacterial and primary production, suggesting that lysogeny was favored under conditions of poor host growth. Phosphate addition enabled prophage induction in two of nine (22%) experiments. These results indicate that prophage induction may occasionally be phosphate limited or respond to increases in phosphate concentration, suggesting that phosphate concentration may modulate the lysogenic response of natural populations.

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Cui, Linlin, Courtney K. Harris, and Danielle R. N. Tarpley. "Formation of Oil-Particle-Aggregates: Numerical Model Formulation and Calibration." Frontiers in Marine Science 8 (May 13, 2021). http://dx.doi.org/10.3389/fmars.2021.629476.

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When oil spills occur in turbid waters, the oil droplets and mineral grains can combine to form oil-particle aggregates (OPAs). The formation of OPAs impacts the vertical transport of both the oil and the mineral grains; especially increasing deposition of oil to the seabed. Though the coastal oceans can be very turbid, to date, few numerical ocean models have accounted for aggregation processes that form OPAs. However, interactions between oil and mineral aggregates may be represented using techniques developed to account for sediment aggregation. As part of Consortium for Simulation of Oil Microbial Interactions in the Ocean (CSOMIO), we modified an existing, population dynamics-based sediment flocculation model to develop OPAMOD, a module that accounts for the formation of OPAs. A zero-dimensional model using OPAMOD is shown to be capable of reproducing the size distribution of aggregates from existing laboratory experimental results. Also using the zero-dimensional model, sensitivity tests were performed on two model parameters, the fractal dimension and collision efficiency. Results showed that fractal dimension played a role in the OPA size distribution by influencing the effective particle density, which modified the number concentration of flocs for a given mass concentration. However, the modeled particle characteristics and oil sequestration were relatively insensitive to collision efficiency. To explore OPA formation for an outer continental shelf site, two simulations were conducted using a one-dimensional (vertical) implementation of the model. One scenario had high sediment concentration near the seabed to mimic storm-induced resuspension. The other scenario represented river plume sediment delivery by having high sediment concentration in surface waters. Results showed that OPA formation was sensitive to the vertical distribution of suspended sediment, with the river plume scenario creating more OPA, and sequestering more oil within OPA than the storm resuspension scenario. OPAMOD was developed within the Coupled Ocean-Atmosphere-Wave-and-Sediment Transport (COAWST) modeling system, therefore the methods and parameterizations from this study are transferrable to a three-dimensional coupled oil-sediment-microbial model developed by CSOMIO within the COAWST framework.

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Zouch, Hana, Léa Cabrol, Sandrine Chifflet, Marc Tedetti, Fatma Karray, Hatem Zaghden, Sami Sayadi, and Marianne Quéméneur. "Effect of Acidic Industrial Effluent Release on Microbial Diversity and Trace Metal Dynamics During Resuspension of Coastal Sediment." Frontiers in Microbiology 9 (December 14, 2018). http://dx.doi.org/10.3389/fmicb.2018.03103.

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Lloyd, Karen G., Jordan T. Bird, Joy Buongiorno, Emily Deas, Richard Kevorkian, Talor Noordhoek, Jacob Rosalsky, and Taylor Roy. "Evidence for a Growth Zone for Deep-Subsurface Microbial Clades in Near-Surface Anoxic Sediments." Applied and Environmental Microbiology 86, no. 19 (July 24, 2020). http://dx.doi.org/10.1128/aem.00877-20.

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ABSTRACT Global marine sediments harbor a large and highly diverse microbial biosphere, but the mechanism by which this biosphere is established during sediment burial is largely unknown. During burial in marine sediments, concentrations of easily metabolized organic compounds and total microbial cell abundance decrease. However, it is unknown whether some microbial clades increase with depth. We show total population increases in 38 microbial families over 3 cm of sediment depth in the upper 7.5 cm of White Oak River (WOR) estuary sediments. Clades that increased with depth were more often associated with one or more of the following: anaerobes, uncultured, or common in deep marine sediments relative to those that decreased. Maximum doubling times (in situ steady-state growth rates could be faster to balance cell decay) were estimated as 2 to 25 years by combining sedimentation rate with either quantitative PCR (qPCR) or the product of the fraction read abundance of 16S rRNA genes and total cell counts (FRAxC). Doubling times were within an order of magnitude of each other in two adjacent cores, as well as in two laboratory enrichments of Cape Lookout Bight (CLB), NC, sediments (average difference of 28% ± 19%). qPCR and FRAxC in sediment cores and laboratory enrichments produced similar doubling times for key deep subsurface uncultured clades Bathyarchaeota (8.7 ± 1.9 years) and Thermoprofundales/MBG-D (4.1 ± 0.7 years). We conclude that common deep subsurface microbial clades experience a narrow zone of growth in shallow sediments, offering an opportunity for selection of long-term subsistence traits after resuspension events. IMPORTANCE Many studies show that the uncultured microbes that dominate global marine sediments do not actually increase in population size as they are buried in marine sediments; rather, they exist in a sort of prolonged torpor for thousands of years. This is because, although studies have shown biomass turnover in these clades, no evidence has ever been found that deeper sediments have larger populations for specific clades than shallower layers. We discovered that they actually do increase population sizes during burial, but only in the upper few centimeters. This suggests that marine sediments may be a vast repository of mostly nongrowing microbes with a thin and relatively rapid area of cell abundance increase in the upper 10 cm, offering a chance for subsurface organisms to undergo natural selection.

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Voss, Maren, Eero Asmala, Ines Bartl, Jacob Carstensen, Daniel J. Conley, Joachim W. Dippner, Christoph Humborg, et al. "Origin and fate of dissolved organic matter in four shallow Baltic Sea estuaries." Biogeochemistry, October 15, 2020. http://dx.doi.org/10.1007/s10533-020-00703-5.

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Abstract Coastal waters have strong gradients in dissolved organic matter (DOM) quantity and characteristics, originating from terrestrial inputs and autochthonous production. Enclosed seas with high freshwater input therefore experience high DOM concentrations and gradients from freshwater sources to more saline waters. The brackish Baltic Sea experiences such salinity gradients from east to west and from river mouths to the open sea. Furthermore, the catchment areas of the Baltic Sea are very diverse and vary from sparsely populated northern areas to densely populated southern zones. Coastal systems vary from enclosed or open bays, estuaries, fjords, archipelagos and lagoons where the residence time of DOM at these sites varies and may control the extent to which organic matter is biologically, chemically or physically modified or simply diluted with transport off-shore. Data of DOM with simultaneous measurements of dissolved organic (DO) nitrogen (N), carbon (C) and phosphorus (P) across a range of contrasting coastal systems are scarce. Here we present data from the Roskilde Fjord, Vistula and Öre estuaries and Curonian Lagoon; four coastal systems with large differences in salinity, nutrient concentrations, freshwater inflow and catchment characteristics. The C:N:P ratios of DOM of our data, despite high variability, show site specific significant differences resulting largely from differences residence time. Microbial processes seemed to have minor effects, and only in spring did uptake of DON in the Vistula and Öre estuaries take place and not at the other sites or seasons. Resuspension from sediments impacts bottom waters and the entire shallow water column in the Curonian Lagoon. Finally, our data combined with published data show that land use in the catchments seems to impact the DOC:DON and DOC:DOP ratios of the tributaries most.

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Melnik, R. N., N. S. Klyushentseva, and N. V. Melnik. "Development and manufacture of erythrocyte pullorosis diagnosticum for the diagnosis of avian pullorosis typhoid." Veterinaria i kormlenie, no. 1 (February 2021). http://dx.doi.org/10.30917/att-vk-1814-9588-2021-1-11.

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The article is devoted to the problems of diagnostics of poultry typhoid fever and the development of a technology for the manufacture of diagnosticum against this disease. A method of making erythrocyte diagnosticum for the diagnosis of poultry typhoid fever is shown, including obtaining the bacterial mass of Salmonella pullorum-gallinarum, isolating the antigenic fraction from it by treating the bacterial mass with a surfactant with the addition of soda or alkali in distilled water at 93-96 °C, followed by sensitization of formalinized erythrocytes, their purification and obtaining the target product in the form of 10% suspension, characterized in that 1-1.5% aqueous solution of Desmol is used as a surfactant to isolate the antigenic fraction, taken in a final weight concentration of 0, 1-0.3%, and the sensitization of formalinized erythrocytes is carried out in the presence of the sodium salt of chitosan succinate taken in a final weight concentration of 0.5-1.5%. In the industrial production of the diagnosticum at the initial stage, the bacterial suspension was necessarily mixed and the optical concentration was measured photometrically. The concentration of the surfactant solution was adjusted to 25 ml of microbial cells in 1 ml. At the second stage, antigen-sensitin was obtained and stored at 4 ° C. Sheep erythrocytes were used for sensitization. At the third stage, 20% formalized ram erythrocytes were obtained. Formalized erythrocytes were washed five times until the supernatant was completely cleared and sensitized. At the fourth stage, 300-500 ml was added to 1 liter of erythrocyte suspension for sensitization. sensitin and kept in a water bath at a temperature of 600С. At the fifth stage, the sensitized erythrocytes were washed to remove residual sensitin not associated with erythrocytes. Obtaining highly effective erythrocyte diagnostics for the diagnosis of avian pullorosis typhoid is an urgent problem. We have produced, improved and optimized the technology of industrial production of erythrocyte pullor antigen from the Salmonella pullorum-gallinarum strain for the diagnosis of avian pullorosis-typhus. We have theoretically substantiated and tested in production conditions a new method of resuspension, extraction, clarification of the bacterial mass. Used surfactants (surfactants) to obtain sensitin.

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Journal articles on the topic 'Microbial resuspension'

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