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Does Climate Warming Stimulate or Inhibit Soil Protist Communities? A Test on Testate Amoebae in High-Arctic Tundra with Free-Air Temperature Increase.

https://arctichealth.org/en/permalink/ahliterature99233
Source
Protist. 2010 Aug 12;
Publication Type
Article
Date
Aug-12-2010
Author
Andrey N Tsyganov
Ivan Nijs
Louis Beyens
Author Affiliation
Research group Polar Ecology, Limnology and Geomorphology, Department of Biology, University of Antwerp, Universiteitsplein 1, B-2610 Antwerp (Wilrijk), Belgium.
Source
Protist. 2010 Aug 12;
Date
Aug-12-2010
Language
English
Publication Type
Article
Abstract
Soil testate amoebae assemblages in a grassland area at Zackenberg (Northeast Greenland) were subjected to simulated climate-warming during the growing season using the Free-Air Temperature Increase technique. Samples were collected in upper (0 - 3cm) and deeper (3 - 6cm) soil horizons. Mean temperature elevations at 2.5 and 7.5 cm depth were 2.58 +/- SD 1.11 and 2.13+/-SD 0.77 degrees C, respectively, and did not differ significantly. Soil moisture in the top 11cm was not affected by the warming. During the manipulation, the densities of living amoebae and empty shells were higher in the experimental plots but only in the upper layer. Possibly, testate amoebae in the deeper layer were limited by other factors, suggesting that warming enhances the carrying capacity only in favourable conditions. Species richness, on the other hand, was only increased in the deeper horizon. Warming did not change the percentage of individuals belonging to small-sized species in any of the living assemblages, contrary to our expectation that those species would quickly increase their density. However, in the empty shell assemblages, the proportion of small-sized individuals in the experimental plots was higher in both layers, indicating a rapid, transient increase in small amoebae before the first sampling date. Changes in successional state of testate amoebae assemblages in response to future climate change might thus be ephemeral, whereas alterations in density and species richness might be more sustained.
PubMed ID
20708962 View in PubMed
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Testate amoeba transfer function performance along localised hydrological gradients.

https://arctichealth.org/en/permalink/ahliterature278132
Source
Eur J Protistol. 2016 Sep;55(Pt B):141-151
Publication Type
Article
Date
Sep-2016
Author
Andrey N Tsyganov
Olga A Mityaeva
Yuri A Mazei
Richard J Payne
Source
Eur J Protistol. 2016 Sep;55(Pt B):141-151
Date
Sep-2016
Language
English
Publication Type
Article
Keywords
Amoeba - physiology
Classification
Groundwater - analysis - parasitology
Hydrology - methods
Reproducibility of Results
Russia
Soil - parasitology
Wetlands
Abstract
Testate amoeba transfer functions are widely used for reconstruction of palaeo-hydrological regime in peatlands. However, the limitations of this approach have become apparent with increasing attention to validation and assessing sources of uncertainty. This paper investigates effects of peatland type and sampling depth on the performance of a transfer function using an independent test-set from four Sphagnum-dominated sites in European Russia (Penza Region). We focus on transfer function performance along localised hydrological gradients, which is a useful analogue for predictive ability through time. The performance of the transfer function with the independent test-set was generally weaker than for the leave-one-out or bootstrap cross-validations. However, the transfer function was robust for the reconstruction of relative changes in water-table depth, provided the presence of good modern analogues and overlap in water-table depth ranges. When applied to subsurface samples, the performance of the transfer function was reduced due to selective decomposition, the presence of deep-dwelling taxa or vertical transfer of shells. Our results stress the importance of thorough testing of transfer functions, and highlight the role of taphonomic processes in determining results. Further studies of stratification, taxonomy and taphonomy of testate amoebae will be needed to improve the robustness of transfer function output.
PubMed ID
26776269 View in PubMed
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What is the optimum sample size for the study of peatland testate amoeba assemblages?

https://arctichealth.org/en/permalink/ahliterature287614
Source
Eur J Protistol. 2017 Oct;61(Pt A):85-91
Publication Type
Article
Date
Oct-2017
Author
Yuri A Mazei
Andrey N Tsyganov
Anton S Esaulov
Alexander Yu Tychkov
Richard J Payne
Source
Eur J Protistol. 2017 Oct;61(Pt A):85-91
Date
Oct-2017
Language
English
Publication Type
Article
Keywords
Amoeba - physiology
Biodiversity
Ecology - methods
Russia
Sample Size
Sphagnopsida - parasitology
Wetlands
Abstract
Testate amoebae are widely used in ecological and palaeoecological studies of peatlands, particularly as indicators of surface wetness. To ensure data are robust and comparable it is important to consider methodological factors which may affect results. One significant question which has not been directly addressed in previous studies is how sample size (expressed here as number of Sphagnum stems) affects data quality. In three contrasting locations in a Russian peatland we extracted samples of differing size, analysed testate amoebae and calculated a number of widely-used indices: species richness, Simpson diversity, compositional dissimilarity from the largest sample and transfer function predictions of water table depth. We found that there was a trend for larger samples to contain more species across the range of commonly-used sample sizes in ecological studies. Smaller samples sometimes failed to produce counts of testate amoebae often considered minimally adequate. It seems likely that analyses based on samples of different sizes may not produce consistent data. Decisions about sample size need to reflect trade-offs between logistics, data quality, spatial resolution and the disturbance involved in sample extraction. For most common ecological applications we suggest that samples of more than eight Sphagnum stems are likely to be desirable.
PubMed ID
28992522 View in PubMed
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Additive partitioning of testate amoeba species diversity across habitat hierarchy within the pristine southern taiga landscape (Pechora-Ilych Biosphere Reserve, Russia).

https://arctichealth.org/en/permalink/ahliterature262104
Source
Eur J Protistol. 2015 Feb;51(1):42-54
Publication Type
Article
Date
Feb-2015
Author
Andrey N Tsyganov
Alexander A Komarov
Edward A D Mitchell
Satoshi Shimano
Olga V Smirnova
Alexey A Aleynikov
Yuri A Mazei
Source
Eur J Protistol. 2015 Feb;51(1):42-54
Date
Feb-2015
Language
English
Publication Type
Article
Keywords
Amoeba - classification - physiology
Biodiversity
Russia
Soil - parasitology
Taiga
Abstract
In order to better understand the distribution patterns of terrestrial eukaryotic microbes and the factors governing them, we studied the diversity partitioning of soil testate amoebae across levels of spatially nested habitat hierarchy in the largest European old-growth dark coniferous forest (Pechora-Ilych Biosphere Reserve; Komi Republic, Russia). The variation in testate amoeba species richness and assemblage structure was analysed in 87 samples from six biotopes in six vegetation types using an additive partitioning procedure and principal component analyses. The 80 taxa recorded represent the highest value of species richness for soil testate amoebae reported for taiga soils so far. Our results indicate that testate amoeba assemblages were highly aggregated at all levels and were mostly controlled by environmental factors rather than dispersal processes. The variation in species diversity of testate amoebae increased from the lowest to the highest hierarchical level. We conclude that, similarly to macroscopic organisms, testate amoeba species richness and community structure are primarily controlled by environmental conditions within the landscape and suggest that metacommunity dynamics of free-living microorganisms are driven by species sorting and/or mass effect processes.
PubMed ID
25553551 View in PubMed
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Ecological and environmental transition across the forested-to-open bog ecotone in a west Siberian peatland.

https://arctichealth.org/en/permalink/ahliterature294337
Source
Sci Total Environ. 2017 Dec 31; 607-608:816-828
Publication Type
Journal Article
Date
Dec-31-2017
Author
Joshua L Ratcliffe
Angela Creevy
Roxane Andersen
Evgeny Zarov
Paul P J Gaffney
Mark A Taggart
Yuri Mazei
Andrey N Tsyganov
James G Rowson
Elena D Lapshina
Richard J Payne
Author Affiliation
Environmental Research Institute, North Highland College, University of the Highlands and Islands, Castle Street, Thurso, Caithness KW14 7JD, Scotland, United Kingdom; Science & Engineering, University of Waikato, Private Bag 3105, Hamilton 3240, New Zealand. Electronic address: jlr34@students.waikato.ac.nz.
Source
Sci Total Environ. 2017 Dec 31; 607-608:816-828
Date
Dec-31-2017
Language
English
Publication Type
Journal Article
Keywords
Carbon Sequestration
Climate change
Ecology
Forests
Siberia
Trees
Wetlands
Abstract
Climate change may cause increasing tree cover in boreal peatlands, and the impacts of this encroachment will be noted first at forested-to-open bog ecotones. We investigate key metrics of ecosystem function in five such ecotones at a peatland complex in Western Siberia. Stratigraphic analysis of three cores from one of these transects shows that the ecotone has been dynamic over time with evidence for recent expansion of forested peatland. We observed that the two alternative states for northern boreal peatlands (forested/open) clearly support distinct plant and microbial communities. These in turn drive and respond to a number of feedback mechanisms. This has led to steep ecological gradients across the ecotones. Tree cover was associated with lower water tables and pH, along with higher bulk density, aquatic carbon concentrations, and electrical conductivity. We propose that the conditions found in the forested peatland of Western Siberia make the carbon sink more vulnerable to warmer and drier conditions.
PubMed ID
28711843 View in PubMed
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