Nanoplankton assemblages in maritime Antarctic lakes: characterisation and molecular fingerprinting comparison

Unrein, Fernando; Izaguirre, Irina; Massana, Ramón; Balagué, Vanessa; Gasol, Josep M.

doi:10.3354/ame040269

Cited by 34 publications

(29 citation statements)

References 71 publications

(92 reference statements)

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“…was negatively related to nutrient concentration, suggesting also a preference for nutrient-poor waters. Even though this genus was sporadically found growing well in experiments with nutrient enrichments (Lagus et al 2004), most records of Pseudopedinella in marine and freshwater environments correspond to nutrient-poor waters (Rosén 1981, Hearing 1984, De Hoyos et al 1998, Olrik 1998, Hobbie et al 2000, Unrein et al 2005, Gerea et al 2013. In contrast to our results, some long-term investigations carried out in the Baltic Sea found a positive relationship between the abundance of Pseudopedinella spp.…”

Section: Discussioncontrasting

confidence: 97%

“…Most of them are shallow and of glacial origin. Extensive information about all sampled lakes, including the main abiotic variables, is available in several studies (Izaguirre et al 1998, Unrein et al 2005, Callieri et al 2007, Schiaffino et al 2011, Gerea 2013, Saad et al 2013. Table S2 in the Supplement at www.int-res.com/ articles/ suppl/ a076 p219 _ supp.…”

Section: Study Sitementioning

confidence: 99%

“…In particular, Pseudopedinella sp. were detected in some oligotrophic Antarctic lakes using molecular fingerprinting and microscopic techniques (Unrein et al 2005). In the present investigation, we studied 54 water bodies located along a latitudinal gradient from North Patagonia to the Antarctic Peninsula covering a wide variety of lake types.…”

Section: Introductionmentioning

confidence: 99%

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Presence, abundance and bacterivory of the mixotrophic algae Pseudopedinella (Dictyochophyceae) in freshwater environments

Gerea¹,

Saad²,

Izaguirre³

et al. 2016

Aquat. Microb. Ecol.

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Section: Discussioncontrasting

confidence: 97%

Section: Study Sitementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Presence, abundance and bacterivory of the mixotrophic algae Pseudopedinella (Dictyochophyceae) in freshwater environments

Gerea¹,

Saad²,

Izaguirre³

et al. 2016

Aquat. Microb. Ecol.

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“…The upper zone was over-represented by OTUs for Pedinellales (silicoflagellate algae) that co-varied with chloroplasts (Figures 2 and 3). Pedinellales have only been detected in Antarctic lakes from molecular studies (Unrein et al, 2005;Lauro et al, 2011), including Organic Lake , and light microscopy studies of Antarctic Peninsula freshwater lakes reported 5-8-mm diameter cells resembling Pseudopedinella (Unrein et al, 2005). It is possible that in Organic Lake, small (0.8-0.1 mm) free-living members or chloroplast-containing cyst forms (Thomsen, 1988) exist.…”

Section: -30-mm Fraction Community Compositionmentioning

confidence: 99%

Metagenomic insights into strategies of carbon conservation and unusual sulfur biogeochemistry in a hypersaline Antarctic lake

et al. 2013

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Organic Lake is a shallow, marine-derived hypersaline lake in the Vestfold Hills, Antarctica that has the highest reported concentration of dimethylsulfide (DMS) in a natural body of water. To determine the composition and functional potential of the microbial community and learn about the unusual sulfur chemistry in Organic Lake, shotgun metagenomics was performed on size-fractionated samples collected along a depth profile. Eucaryal phytoflagellates were the main photosynthetic organisms. Bacteria were dominated by the globally distributed heterotrophic taxa Marinobacter, Roseovarius and Psychroflexus. The dominance of heterotrophic degradation, coupled with low fixation potential, indicates possible net carbon loss. However, abundant marker genes for aerobic anoxygenic phototrophy, sulfur oxidation, rhodopsins and CO oxidation were also linked to the dominant heterotrophic bacteria, and indicate the use of photo-and lithoheterotrophy as mechanisms for conserving organic carbon. Similarly, a high genetic potential for the recycling of nitrogen compounds likely functions to retain fixed nitrogen in the lake. Dimethylsulfoniopropionate (DMSP) lyase genes were abundant, indicating that DMSP is a significant carbon and energy source. Unlike marine environments, DMSP demethylases were less abundant, indicating that DMSP cleavage is the likely source of high DMS concentration. DMSP cleavage, carbon mixotrophy (photoheterotrophy and lithoheterotrophy) and nitrogen remineralization by dominant Organic Lake bacteria are potentially important adaptations to nutrient constraints. In particular, carbon mixotrophy relieves the extent of carbon oxidation for energy production, allowing more carbon to be used for biosynthetic processes. The study sheds light on how the microbial community has adapted to this unique Antarctic lake environment.

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“…Jungblut et al 2005) and surveys of the surface pigment composition, for example in east Antarctic lakes , which revealed that lake water depth (and lake ice dynamics and light climate related variables such as turbidity), salinity and nutrient concentration are the most important environmental variables structuring the microbial communities. However, it is still unclear which factors influence the taxonomic composition of those microorganisms that are difficult to identify to species level by microscopy, such as the Cyanobacteria and green algae (Vincent 2000, Taton et al 2003, Unrein et al 2005. These data are urgently needed; however, because these organisms (particularly Cyanobacteria) not only constitute the bulk of the biomass in most Antarctic lakes (Broady 1996), but also include a large number of endemics (e.g.…”

mentioning

confidence: 99%

Structuring effects of climate-related environmental factors on Antarctic microbial mat communities

Verleyen

Sabbe²,

Hodgson³

et al. 2010

Aquat. Microb. Ecol.

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Both ground-based and satellite data show that parts of Antarctica have entered a period of rapid climate change, which already affects the functioning and productivity of limnetic ecosystems. To predict the consequences of future climate anomalies for lacustrine microbial communities, we not only need better baseline information on their biodiversity but also on the climaterelated environmental factors structuring these communities. Here we applied denaturing gradient gel electrophoresis (DGGE) of the small subunit ribosomal DNA (SSU rDNA) to assess the genetic composition and distribution of Cyanobacteria and eukaryotes in 37 benthic microbial mat samples from east Antarctic lakes. The lakes were selected to span a wide range of environmental gradients governed by differences in lake morphology and chemical limnology across 5 ice-free oases. Sequence analysis of selected DGGE bands revealed a high degree of potential endemism among the Cyanobacteria (mainly represented by Oscillatoriales and Nostocales), and the presence of a variety of protists (alveolates, stramenopiles and green algae), fungi, tardigrades and nematodes, which corroborates previous microscopy-based observations. Variation partitioning analyses revealed that the microbial mat community structure is largely regulated by both geographical and local environmental factors of which salinity (and related variables), lake water depth and nutrient concentrations are of major importance. These 3 groups of environmental variables have previously been shown to change drastically in Antarctica in response to climate change. Together, these results have obvious consequences for predicting the trajectory of biodiversity under changing climate conditions and call for the continued assessment of the biodiversity of these unique ecosystems.KEY WORDS: Antarctica · Climate change · Lake · Microbial mats · DGGE Resale or republication not permitted without written consent of the publisherAquat Microb Ecol 59: [11][12][13][14][15][16][17][18][19][20][21][22][23][24] 2010 showing a rapid net cooling trend, such as the McMurdo Dry Valleys, where temperatures dropped by 0.7°C per decade between 1986 and 2000 (Doran et al. 2002). In east Antarctica, many regions are similarly experiencing marked changes in their weather, including increased wind speeds (Gillett & Thompson 2003) and changing patterns of snow and ice accumulation .The recent temperature and climate anomalies have also had impacts on both terrestrial and marine ecosystems in the Antarctic (Walther et al. 2002). Experiments measuring the ecological changes occurring at inland nunataks, dry valleys and coastal ice-free areas, have likened these ecosystems to 'canaries in a coalmine' and 'natural experiments' with which to identify biological responses to changing climate variables that are applicable on a wider (global) scale (see Convey 2001, Robinson et al. 2003, Lyons et al. 2006 for reviews). Already lacustrine ecosystems in some icefree regions have been shown to respond quickly to air t...

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Nanoplankton assemblages in maritime Antarctic lakes: characterisation and molecular fingerprinting comparison

Cited by 34 publications

References 71 publications

Presence, abundance and bacterivory of the mixotrophic algae Pseudopedinella (Dictyochophyceae) in freshwater environments

Presence, abundance and bacterivory of the mixotrophic algae Pseudopedinella (Dictyochophyceae) in freshwater environments

Metagenomic insights into strategies of carbon conservation and unusual sulfur biogeochemistry in a hypersaline Antarctic lake

Structuring effects of climate-related environmental factors on Antarctic microbial mat communities

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