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Microbial community composition of transiently wetted Antarctic Dry Valley soils.

Niederberger TD, Sohm JA, Gunderson TE, Parker AE, Tirindelli J, Capone DG, Carpenter EJ, Cary SC - Front Microbiol (2015)

Bottom Line: Soil water content decreased to below ~3% in the arid soils.Community fingerprinting-based principle component analyses revealed that bacterial communities formed distinct clusters specific to arid and wet soils; however, eukaryotic communities that clustered together did not have similar soil moisture content nor did they group together based on sampling location.Results indicate that the repeated wetting of hyporheic zones has a profound impact on the bacterial and eukaryotic communities inhabiting in these areas.

View Article: PubMed Central - PubMed

Affiliation: College of Marine and Earth Sciences, University of Delaware Lewes, DE, USA.

ABSTRACT
During the summer months, wet (hyporheic) soils associated with ephemeral streams and lake edges in the Antarctic Dry Valleys (DVs) become hotspots of biological activity and are hypothesized to be an important source of carbon and nitrogen for arid DV soils. Recent research in the DV has focused on the geochemistry and microbial ecology of lakes and arid soils, with substantially less information being available on hyporheic soils. Here, we determined the unique properties of hyporheic microbial communities, resolved their relationship to environmental parameters and compared them to archetypal arid DV soils. Generally, pH increased and chlorophyll a concentrations decreased along transects from wet to arid soils (9.0 to ~7.0 for pH and ~0.8 to ~5 μg/cm(3) for chlorophyll a, respectively). Soil water content decreased to below ~3% in the arid soils. Community fingerprinting-based principle component analyses revealed that bacterial communities formed distinct clusters specific to arid and wet soils; however, eukaryotic communities that clustered together did not have similar soil moisture content nor did they group together based on sampling location. Collectively, rRNA pyrosequencing indicated a considerably higher abundance of Cyanobacteria in wet soils and a higher abundance of Acidobacterial, Actinobacterial, Deinococcus/Thermus, Bacteroidetes, Firmicutes, Gemmatimonadetes, Nitrospira, and Planctomycetes in arid soils. The two most significant differences at the genus level were Gillisia signatures present in arid soils and chloroplast signatures related to Streptophyta that were common in wet soils. Fungal dominance was observed in arid soils and Viridiplantae were more common in wet soils. This research represents an in-depth characterization of microbial communities inhabiting wet DV soils. Results indicate that the repeated wetting of hyporheic zones has a profound impact on the bacterial and eukaryotic communities inhabiting in these areas.

No MeSH data available.


Related in: MedlinePlus

Principal component analyses of T-RFLP fingerprints from both bacterial (A) and eukaryotic (B) communities (MS1-1 not included in plots).
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Figure 2: Principal component analyses of T-RFLP fingerprints from both bacterial (A) and eukaryotic (B) communities (MS1-1 not included in plots).

Mentions: Principle component analyses of bacterial T-RFLP fingerprints revealed that the arid soils (0–5% water moisture) formed a tight cluster grouping at 40% similarity (Figure 2A). Whereas, in general, the wetter sites (>5% moisture content) formed two major clusters grouping at 40% similarity, with one cluster comprised of sites located in Miers Valley (i.e., stream and lake systems) and a second cluster consisting of transects located in both the northern (NP and BL) and southern sites (Hidden Valley). In contrast to the bacterial profiles, high spatial variability was observed for the eukaryotic T-RFLP-based PCA profiles (Figure 2B). BEST analysis showed that only a small amount of community structure could be attributed to the environmental parameters measured, bacterial community structure best correlated to distance from water source, pH and NH4 (ϱ = 0.214), and the eukaryote community to distance from water source, pH and % moisture (ϱ = 0.202).


Microbial community composition of transiently wetted Antarctic Dry Valley soils.

Niederberger TD, Sohm JA, Gunderson TE, Parker AE, Tirindelli J, Capone DG, Carpenter EJ, Cary SC - Front Microbiol (2015)

Principal component analyses of T-RFLP fingerprints from both bacterial (A) and eukaryotic (B) communities (MS1-1 not included in plots).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4309182&req=5

Figure 2: Principal component analyses of T-RFLP fingerprints from both bacterial (A) and eukaryotic (B) communities (MS1-1 not included in plots).
Mentions: Principle component analyses of bacterial T-RFLP fingerprints revealed that the arid soils (0–5% water moisture) formed a tight cluster grouping at 40% similarity (Figure 2A). Whereas, in general, the wetter sites (>5% moisture content) formed two major clusters grouping at 40% similarity, with one cluster comprised of sites located in Miers Valley (i.e., stream and lake systems) and a second cluster consisting of transects located in both the northern (NP and BL) and southern sites (Hidden Valley). In contrast to the bacterial profiles, high spatial variability was observed for the eukaryotic T-RFLP-based PCA profiles (Figure 2B). BEST analysis showed that only a small amount of community structure could be attributed to the environmental parameters measured, bacterial community structure best correlated to distance from water source, pH and NH4 (ϱ = 0.214), and the eukaryote community to distance from water source, pH and % moisture (ϱ = 0.202).

Bottom Line: Soil water content decreased to below ~3% in the arid soils.Community fingerprinting-based principle component analyses revealed that bacterial communities formed distinct clusters specific to arid and wet soils; however, eukaryotic communities that clustered together did not have similar soil moisture content nor did they group together based on sampling location.Results indicate that the repeated wetting of hyporheic zones has a profound impact on the bacterial and eukaryotic communities inhabiting in these areas.

View Article: PubMed Central - PubMed

Affiliation: College of Marine and Earth Sciences, University of Delaware Lewes, DE, USA.

ABSTRACT
During the summer months, wet (hyporheic) soils associated with ephemeral streams and lake edges in the Antarctic Dry Valleys (DVs) become hotspots of biological activity and are hypothesized to be an important source of carbon and nitrogen for arid DV soils. Recent research in the DV has focused on the geochemistry and microbial ecology of lakes and arid soils, with substantially less information being available on hyporheic soils. Here, we determined the unique properties of hyporheic microbial communities, resolved their relationship to environmental parameters and compared them to archetypal arid DV soils. Generally, pH increased and chlorophyll a concentrations decreased along transects from wet to arid soils (9.0 to ~7.0 for pH and ~0.8 to ~5 μg/cm(3) for chlorophyll a, respectively). Soil water content decreased to below ~3% in the arid soils. Community fingerprinting-based principle component analyses revealed that bacterial communities formed distinct clusters specific to arid and wet soils; however, eukaryotic communities that clustered together did not have similar soil moisture content nor did they group together based on sampling location. Collectively, rRNA pyrosequencing indicated a considerably higher abundance of Cyanobacteria in wet soils and a higher abundance of Acidobacterial, Actinobacterial, Deinococcus/Thermus, Bacteroidetes, Firmicutes, Gemmatimonadetes, Nitrospira, and Planctomycetes in arid soils. The two most significant differences at the genus level were Gillisia signatures present in arid soils and chloroplast signatures related to Streptophyta that were common in wet soils. Fungal dominance was observed in arid soils and Viridiplantae were more common in wet soils. This research represents an in-depth characterization of microbial communities inhabiting wet DV soils. Results indicate that the repeated wetting of hyporheic zones has a profound impact on the bacterial and eukaryotic communities inhabiting in these areas.

No MeSH data available.


Related in: MedlinePlus