Grazing pressure-induced shift in planktonic bacterial communities with the dominance of acIII-A1 actinobacterial lineage in soda pans

AbstractAstatic soda pans of the Pannonian Steppe are unique environments with respect to their multiple extreme physical and chemical characteristics (high daily water temperature fluctuation, high turbidity, alkaline pH, salinity, polyhumic organic carbon concentration, hypertrophic state and special ionic composition). However, little is known about the seasonal dynamics of the bacterial communities inhabiting these lakes and the role of environmental factors that have the main impact on their structure. Therefore, two soda pans were sampled monthly between April 2013 and July 2014 to reveal changes in the planktonic community. By late spring in both years, a sudden shift in the community structure was observed, the previous algae-associated bacterial communities had collapsed, resulting the highest ratio of actinobacteria within the bacterioplankton (89%, with the dominance of acIII-A1 lineage) ever reported in the literature. Before these peaks, an extremely high abundance (>10,000 individuum l−1) of microcrustaceans (Moina and Arctodiaptomus) was observed. OTU-based statistical approaches showed that in addition to algal blooms and water-level fluctuations, zooplankton densities had the strongest effect on the composition of bacterial communities. In these extreme environments, this implies a surprisingly strong, community-shaping top-down role of microcrustacean grazers.

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Grazing pressure-induced shift in planktonic bacterial communities with the dominance of acIII-A1 actinobacterial lineage in soda pans

Scientific Reports ◽

10.1038/s41598-020-76822-8 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Attila Szabó ◽

Kristóf Korponai ◽

Boglárka Somogyi ◽

Balázs Vajna ◽

Lajos Vörös ◽

...

Keyword(s):

Bacterial Communities ◽

Algal Blooms ◽

Ionic Composition ◽

Extreme Environments ◽

Grazing Pressure ◽

Water Level Fluctuations ◽

Organic Carbon Concentration ◽

High Turbidity ◽

Physical And Chemical

AbstractAstatic soda pans of the Pannonian Steppe are unique environments with respect to their multiple extreme physical and chemical characteristics (high daily water temperature fluctuation, high turbidity, alkaline pH, salinity, polyhumic organic carbon concentration, hypertrophic state and special ionic composition). However, little is known about the seasonal dynamics of the bacterial communities inhabiting these lakes and the role of environmental factors that have the main impact on their structure. Therefore, two soda pans were sampled monthly between April 2013 and July 2014 to reveal changes in the planktonic community. By late spring in both years, a sudden shift in the community structure was observed, the previous algae-associated bacterial communities had collapsed, resulting the highest ratio of Actinobacteria within the bacterioplankton (89%, with the dominance of acIII-A1 lineage) ever reported in the literature. Before these peaks, an extremely high abundance (> 10,000 individuum l−1) of microcrustaceans (Moina brachiata and Arctodiaptomus spinosus) was observed. OTU-based statistical approaches showed that in addition to algal blooms and water-level fluctuations, zooplankton densities had the strongest effect on the composition of bacterial communities. In these extreme environments, this implies a surprisingly strong, community-shaping top-down role of microcrustacean grazers.

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Limnology and Aquatic Microbial Ecology of Byers Peninsula: A Main Freshwater Biodiversity Hotspot in Maritime Antarctica

Diversity ◽

10.3390/d11100201 ◽

2019 ◽

Vol 11 (10) ◽

pp. 201 ◽

Cited By ~ 2

Author(s):

Carlos Rochera ◽

Antonio Camacho

Keyword(s):

Microbial Communities ◽

Microbial Ecology ◽

Strong Influence ◽

Extreme Environments ◽

Grazing Pressure ◽

Functional Ecology ◽

South Shetland Islands ◽

Freshwater Biodiversity ◽

High Level ◽

Physical And Chemical

Here we present a comprehensive review of the diversity revealed by research in limnology and microbial ecology conducted in Byers Peninsula (Livingston Island, South Shetland Islands, Antarctica) during the last two decades. The site constitutes one of the largest ice-free areas within the Antarctic Peninsula region. Since it has a high level of environmental protection, it is less human-impacted compared to other sites within the South Shetland archipelago. The main investigations in Byers Peninsula focused on the physical and chemical limnology of the lakes, ponds, rivers, and wetlands, as well as on the structure of their planktonic and benthic microbial communities, and on the functional ecology of the microbial food webs. Lakes and ponds in Byers range along a productivity gradient that extends from the less productive lakes located upland to the eutrophic coastal lakes. Their planktonic assemblages include viruses, bacteria, a metabolically diverse community of protists (i.e., autotrophs, heterotrophs, and mixotrophs), and a few metazooplankton species. Most of the studies conducted in the site demonstrate the strong influence of the physical environment (i.e., temperature, availability of light, and water) and nutrient availability in structuring these microbial communities. However, top-down biotic processes may occur in summer, when predation by zooplankton can exert a strong influence on the abundance of protists, including flagellates and ciliated protozoa. As a consequence, bacterioplankton could be partly released from the grazing pressure exerted by these protists, and proliferates fueled by external nutrient subsidies from the lake’s catchment. As summer temperatures in this region are slightly above the melting point of water, biotic processes, such as those related to the productivity of lakes during ice-free periods, could become even more relevant as warming induced by climate change progresses. The limnological research carried out at the site proves that Byers Peninsula deserves special attention in the framework of the research in extreme environments. Together with nearby sites, such as Signy Island, Byers Peninsula comprises a featuring element of the Maritime Antarctic region that represents a benchmark area relative to the global distribution and diversity of aquatic microorganisms.

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Microbial communities of soda lakes and pans in the Carpathian Basin: a review

Biologia Futura ◽

10.1007/s42977-020-00034-4 ◽

2020 ◽

Vol 71 (4) ◽

pp. 393-404 ◽

Cited By ~ 3

Author(s):

Tamás Felföldi

Keyword(s):

Bacterial Communities ◽

Current Knowledge ◽

Soda Lakes ◽

Grazing Pressure ◽

Carpathian Basin ◽

Nutrient Load ◽

Ecological Processes ◽

Microbial Groups ◽

Physical And Chemical ◽

External Nutrient

AbstractIn this review, I would like to summarize the current knowledge on the microbiology of soda lakes and pans of the Carpathian Basin. First, the characteristic physical and chemical features of these sites are described. Most of the microbiological information presented deals with prokaryotes and algae, but protists and viruses are also mentioned. Planktonic bacterial communities are dominated by members of the phyla Actinobacteria, Bacteroidetes and Proteobacteria; small-sized trebouxiophycean green algae and Synechococcus/Cyanobium picocyanobacteria are the most important components of phytoplankton. Based on the current knowledge, it seems that mainly temperature, salinity, turbidity and grazing pressure regulate community composition and the abundance of individual microbial groups, but the external nutrient load from birds also has a significant impact on the ecological processes.

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The role of abiotic and biotic environmental factors in shaping epiphyton on common reed in shallow, hydrologically transformed, temperate lakes

Knowledge and Management of Aquatic Ecosystems ◽

10.1051/kmae/2018005 ◽

2018 ◽

pp. 18 ◽

Cited By ~ 1

Author(s):

Magdalena Toporowska ◽

Jacek Rechulicz ◽

Małgorzata Adamczuk ◽

Michał Niedźwiecki

Keyword(s):

Environmental Parameters ◽

Eutrophic Lake ◽

Common Reed ◽

Grazing Pressure ◽

Biomass Composition ◽

Water Level Fluctuations ◽

Significant Variable ◽

Eutrophic Lakes ◽

Epiphytic Algae

Epiphytic algae are an important group of organisms involved in primary productivity, nutrient cycling, and energy transfer in littoral food webs. However, multifactorial studies conducted on epiphyton on the same substrate across a spectrum of environmental parameters are very limited. Here, we present first complex field study on the role of abiotic and biotic factors in shaping the species richness, diversity, abundance, and biomass composition of epiphyton on common reed in four shallow lakes with different trophic status, water and fish management, and the abundance and structure of potential algal grazers: littoral crustaceans and fish. The obtained results revealed that the algal taxa richness was the lowest in the hypertrophic lake and the highest in the meso-eutrophic lake. Epiphyton abundance (predominated by pennate diatoms) and biomass were found to be the highest in eutrophic water bodies. Biomass consisted primarily of diatoms, but we found the seasonal predominance of filamentous Chlorophyta (in the eutrophic lakes) and Chlorophyceae (in the meso-eutrophic lake). Redundancy analysis (RDA) showed that the frequency of water level fluctuations was the most significant variable in the composition of epiphyton. RDA also revealed the importance of grazing pressure of fish. Thus, in hydrologically transformed lakes, man-made factors may be of great relevance in the development of epiphytic algae.

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The Role of the Interaction between Fe(III) and Cell Surface in the Accumulation of 67Ga by Tumor Cells

Nuklearmedizin ◽

10.1055/s-0038-1629590 ◽

1991 ◽

Vol 30 (06) ◽

pp. 290-293 ◽

Cited By ~ 1

Author(s):

P. Maleki ◽

A. Martinezi ◽

M. C. Crone-Escanye ◽

J. Robert ◽

L. J. Anghileri

Keyword(s):

Cell Surface ◽

Tumor Cells ◽

Ionic Composition ◽

Iron Complex ◽

Iron Binding ◽

Complex Time ◽

Interaction Product ◽

Thermodynamic Constant ◽

Number Of Cells

The study of the interaction between complexed iron and tumor cells in the presence of 67Ga-citrate indicates that a phenomenon of iron-binding related to the thermodynamic constant of stability of the iron complex, and a hydrolysis (or anion penetration) of the interaction product determine the uptake of 67Ga. The effects of various parameters such as ionic composition of the medium, nature of the iron complex, time of incubation and number of cells are discussed.

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