Water masses’ bacterial community structure and microbial activities in the Ross Sea, Antarctica

2010 ◽  
Vol 22 (4) ◽  
pp. 361-370 ◽  
Author(s):  
Mauro Celussi ◽  
Andrea Bergamasco ◽  
Bruno Cataletto ◽  
Serena Fonda Umani ◽  
Paola Del Negro
Keyword(s):  
Community Structure ◽  
Bacterial Community ◽  
Deep Water ◽  
Bacterial Community Structure ◽  
Sea Water ◽  
Ross Sea ◽  
Water Masses ◽  
Shelf Water ◽  
Microbial Activities ◽  
Ice Shelf

AbstractDuring the summer 2005/06, an oceanographic cruise was carried out in the Ross Sea, from Cape Adare, through the Terra Nova Bay polynya to the eastern edge of the Ross Ice Shelf. We analysed microbial activities (prokaryotic carbon production, protease, phosphatase, beta-glucosidase and lipase activity) and bacterial community structure (using Denaturing Gradient Gel Electrophoresis - DGGE) in order to establish if differences in bacterioplankton assemblages and their metabolic requirements occur within the five Ross Sea water masses: Antarctic Surface Waters (AASW), High Salinity Shelf Water (HSSW), Ice Shelf Water (ISW), Antarctic Bottom Water (AABW), Circumpolar Deep Water (CDW). Differences in activities were found between the highly active AASW and all the other water bodies. A Principal Component Analysis highlighted two main gradients: in the Cape Adare area (AASWn, CDW and AABW) higher phosphatase, lipase and glycolytic activities, increasing towards the surface, were identified, whereas in the southern sector of the basin [AASWs and (m)HSSW] higher leucine uptake and polypeptide degradation characterized the second gradient. DGGE fingerprinting showed for the first time that different water masses harboured diverse bacterial communities, highlighting the high specificity of deep water assemblages.Alpha- andGammaproteobacteriarepresented the main phylogenetic groupings in all samples and no substantial difference in the phylogenetic composition of assemblages was found between different water masses.

scholarly journals Climatology and decadal variability of the Ross Sea shelf waters

2011 ◽  
Vol 2 (1) ◽  
pp. 55
Author(s):  
A. Russo ◽  
A. Bergamasco ◽  
S. Carniel ◽  
L. Grieco ◽  
M. Sclavo ◽  
...  
Keyword(s):  
Thermohaline Circulation ◽  
Decadal Variability ◽  
Ross Sea ◽  
World Ocean ◽  
Austral Summer ◽  
Water Masses ◽  
Shelf Water ◽  
Ice Shelf ◽  
Basal Melting ◽  
Ross Sea Shelf

The World Ocean Database 2001 data located in the Ross Sea (named WOD01 and containing data in this region since 1928) are merged with recent data collected by the Italian expeditions (CLIMA dataset) in the period November 1994-February 2004 in the same area. From this extended dataset, austral summer climatologies of the main Ross Sea subsurface, intermediate and bottom water masses: High Salinity Shelf Water (HSSW), Low Salinity Shelf Water (LSSW), Ice Shelf Water (ISW) and Modified Circumpolar Deep Water (MCDW) have been drawn. The comparison between the WOD01_1994 climatologies (a subset of the WOD01 dataset until April 1994) and the CLIMA ones for the period 1994/95-2003/04 showed significant changes occurred during the decade. The freshening of the Ross Sea shelf waters which occurred during the period 1960-2000, was confirmed by our analysis in all the main water masses, even though with a spatially varying intensity. Relevant variations were found for the MCDW masses, which appeared to reduce their presence and to deepen; this can be ascribed to the very limited freshening of the MCDW core, which allowed an increased density with respect to the surrounding waters. Variations in the MCDW properties and extension could have relevant consequences, e.g. a decreased Ross Ice Shelf basal melting or a reduced supply of nutrients, and may also be indicative of a reduced thermohaline circulation within the Ross Sea. Shelf Waters (SW) having neutral density γn > 28.7 Kg m-3, which contribute to form the densest Antarctic Bottom Waters (AABW), showed a large volumetric decrease in the 1994/95-2003/04 decade, most likely as a consequence of the SW freshening.

Temporally invariable bacterial community structure in the Arabian Sea oxygen minimum zone

2014 ◽  
Vol 73 (1) ◽  
pp. 51-67 ◽  
Author(s):  
A Jain ◽  
M Bandekar ◽  
J Gomes ◽  
D Shenoy ◽  
RM Meena ◽  
...  
Keyword(s):  
Community Structure ◽  
Bacterial Community ◽  
Bacterial Community Structure ◽  
Arabian Sea ◽  
Oxygen Minimum Zone ◽  
Minimum Zone ◽  
Oxygen Minimum

scholarly journals The root endophytic bacterial community of Ricinus communis L. resembles the seeds community more than the rhizosphere bacteria independent of soil water content

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Stephanie E. Hereira-Pacheco ◽  
Yendi E. Navarro-Noya ◽  
Luc Dendooven
Keyword(s):  
Community Structure ◽  
Bacterial Community ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Plant Development ◽  
Bacterial Community Structure ◽  
Ricinus Communis ◽  
Ricinus Communis L ◽  
Endophytic Bacterial Community

AbstractRhizosphere and root endophytic bacteria are crucial for plant development, but the question remains if their composition is similar and how environmental conditions, such as water content, affect their resemblance. Ricinus communis L., a highly drought resistant plant, was used to study how varying soil water content affected the bacterial community in uncultivated, non-rhizosphere and rhizosphere soil, and in its roots. Additionally, the bacterial community structure was determined in the seeds of R. communis at the onset of the experiment. Plants were cultivated in soil at three different watering regimes, i.e. 50% water holding capacity (WHC) or adjusted to 50% WHC every two weeks or every month. Reducing the soil water content strongly reduced plant and root dry biomass and plant development, but had little effect on the bacterial community structure. The bacterial community structure was affected significantly by cultivation of R. communis and showed large variations over time. After 6 months, the root endophytic bacterial community resembled that in the seeds more than in the rhizosphere. It was found that water content had only a limited effect on the bacterial community structure and the different bacterial groups, but R. communis affected the bacterial community profoundly.

scholarly journals Bacterial community structure alterations within the colorectal cancer gut microbiome

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Mark Loftus ◽  
Sayf Al-Deen Hassouneh ◽  
Shibu Yooseph
Keyword(s):  
Colorectal Cancer ◽  
Community Structure ◽  
Bacterial Community ◽  
Gut Microbiome ◽  
Late Stage ◽  
Bacterial Community Structure ◽  
Whole Genome ◽  
Human Gut ◽  
Fecal Samples ◽  
Human Gut Microbiome

Abstract Background Colorectal cancer is a leading cause of cancer-related deaths worldwide. The human gut microbiome has become an active area of research for understanding the initiation, progression, and treatment of colorectal cancer. Despite multiple studies having found significant alterations in the carriage of specific bacteria within the gut microbiome of colorectal cancer patients, no single bacterium has been unequivocally connected to all cases. Whether alterations in species carriages are the cause or outcome of cancer formation is still unclear, but what is clear is that focus should be placed on understanding changes to the bacterial community structure within the cancer-associated gut microbiome. Results By applying a novel set of analyses on 252 previously published whole-genome shotgun sequenced fecal samples from healthy and late-stage colorectal cancer subjects, we identify taxonomic, functional, and structural changes within the cancer-associated human gut microbiome. Bacterial association networks constructed from these data exhibited widespread differences in the underlying bacterial community structure between healthy and colorectal cancer associated gut microbiomes. Within the cancer-associated ecosystem, bacterial species were found to form associations with other species that are taxonomically and functionally dissimilar to themselves, as well as form modules functionally geared towards potential changes in the tumor-associated ecosystem. Bacterial community profiling of these samples revealed a significant increase in species diversity within the cancer-associated gut microbiome, and an elevated relative abundance of species classified as originating from the oral microbiome including, but not limited to, Fusobacterium nucleatum, Peptostreptococcus stomatis, Gemella morbillorum, and Parvimonas micra. Differential abundance analyses of community functional capabilities revealed an elevation in functions linked to virulence factors and peptide degradation, and a reduction in functions involved in amino-acid biosynthesis within the colorectal cancer gut microbiome. Conclusions We utilize whole-genome shotgun sequenced fecal samples provided from a large cohort of late-stage colorectal cancer and healthy subjects to identify a number of potentially important taxonomic, functional, and structural alterations occurring within the colorectal cancer associated gut microbiome. Our analyses indicate that the cancer-associated ecosystem influences bacterial partner selection in the native microbiota, and we highlight specific oral bacteria and their associations as potentially relevant towards aiding tumor progression.

Soil remediation approach and bacterial community structure in a long-term contaminated soil by a mining spill (Aznalcóllar, Spain)

2021 ◽  
Vol 777 ◽  
pp. 145128
Author(s):  
M. Paniagua-López ◽  
M. Vela-Cano ◽  
D. Correa-Galeote ◽  
F. Martín-Peinado ◽  
F.J. Martínez Garzón ◽  
...  
Keyword(s):  
Community Structure ◽  
Bacterial Community ◽  
Soil Remediation ◽  
Contaminated Soil ◽  
Bacterial Community Structure
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