Different bulk and active bacterial communities in cryoconite from the margin and interior of the <scp>G</scp>reenland ice sheet

Stibal, Marek; Schostag, Morten; Cameron, Karen A.; Hansen, Lars Hestbjerg; Chandler, David; Wadham, Jemma L.; Jacobsen, Carsten Suhr

doi:10.1111/1758-2229.12246

Cited by 79 publications

(78 citation statements)

References 51 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…High abundance of cyanobacteria has been already observed in polar and alpine cryoconite (Segawa et al, 2014;Stibal et al, 2014), whereas low abundance was reported on Rotmoosferner Glacier (Tirol, Austria; Edwards et al, 2013). Consistently, coverage of psbD (photosystem II P680 reaction center D2 protein gene) was (mean ± s.e.)…”

mentioning

confidence: 60%

Light-dependent microbial metabolisms drive carbon fluxes on glacier surfaces

et al. 2016

View full text Add to dashboard Cite

Biological processes on glacier surfaces affect glacier reflectance, influence surface energy budget and glacier response to climate warming, and determine glacier carbon exchange with the atmosphere. Currently, carbon balance of supraglacial environment is assessed as the balance between the activity of oxygenic phototrophs and the respiration rate of heterotrophic organisms. Here we present a metagenomic analysis of tiny wind-blown supraglacial sediment (cryoconite) from Baltoro (Pakistani Karakoram) and Forni (Italian Alps) glaciers, providing evidence for the occurrence in these environments of different and previously neglected metabolic pathways. Indeed, we observed high abundance of heterotrophic anoxygenic phototrophs, suggesting that light might directly supplement the energy demand of some bacterial strains allowing them to use as carbon source organic molecules, which otherwise would be respired. Furthermore, data suggest that CO 2 could be produced also by microbiologically mediated oxidation of CO, which may be produced by photodegradation of organic matter. The ISME Journal Climate change is determining a global cryosphere shrinkage and mountain glacier environments are declining (IPPC, 2014). The consequent loss of biodiversity is yet to be fully assessed, particularly the loss of functional biodiversity in extreme environments (Stibal et al., 2012;Boetius et al., 2015). Cryoconite holes, that is, small depressions on glacier surfaces whose formation is because of windborne debris (cryoconite), are the most biologically active environments on glaciers (Boetius et al., 2015).We used whole-metagenomic sequencing to investigate the main functions of six cryoconite holes from Forni (Italian Alps) and six from Baltoro (Pakistani Karakoram) glaciers. We focused on carbon and energy metabolisms by comparing the total coverage of marker genes for photosynthesis, use of inorganic and organic compounds as energy source and autotrophy/heterotrophy. We also used metagenomic sequences for the taxonomic attribution of microorganisms carrying specific metabolic genes Table S4 reports the marker genes whose coverage (mean number per base of reads mapping the genes) was used to infer the abundance of each metabolism. Supplementary Table S5 and Figure 1 report their normalized coverages. Finally, we measured chemical/physical parameters of cryoconite holes and oxygen consumption rates on the days of sampling, both under light and dark conditions (Supplementary Table S3 and Supplementary Figure S2). The main hypothesis tested was whether oxygenic phototrophy and organotrophic respiration represent the only significant metabolisms affecting carbon balance on glacier surface, as currently conceived, or other microbial processes could contribute to it.On the basis of 16S rRNA gene sequencing, Cyanobacteria represented 22 and 3% of the microbial community on Forni and Baltoro, respectively (Supplementary Figure S3). High abundance of cyanobacteria has been already observed in polar and alpine cryoconite (Segawa et al....

show abstract

mentioning

confidence: 60%

Light-dependent microbial metabolisms drive carbon fluxes on glacier surfaces

et al. 2016

View full text Add to dashboard Cite

show abstract

“…The contribution of these microbes to supraglacial carbon fluxes has been estimated over various spatial scales (Hodson et al, 2007;Cook et al, 2012;Chandler et al, 2015). To date, spatial variability in the relative abundances of the various cryoconite microbes (Stibal et al, 2012b(Stibal et al, , 2015Vonnahme et al, 2015) and their carbon cycling potential (Anesio et al, 2009) have only been examined at macroscales. Moreover, cryoconite hole studies have almost exclusively been based on assumptions of steadystate equilibrium-independent of time-focussed on cylindrical holes and thereby decouple cryoconite ecology from changes in cryoconite hole shape and size.…”

Section: Cryoconite Hole Morphologymentioning

confidence: 99%

Biocryomorphology: Integrating Microbial Processes with Ice Surface Hydrology, Topography, and Roughness

2015

View full text Add to dashboard Cite

“…Despite some limitations, it is possible to differentiate between metabolically active and dormant microorganisms by coupling reverse-transcribed rRNA analysis with rRNA gene analysis (18). The approach of integrating 16S rRNA and rRNA genes has previously been used to investigate differences in bulk and potentially active bacterial communities in a variety of environments, including glaciated systems (19), permafrost (20), the oceanic coast (21), and a healthy spruce mountain forest (22); however, to our knowledge, no study has explored the interplay between bulk and potentially active terrestrial microbes in beetlekilled forests.…”

mentioning

confidence: 99%

Rare Taxa Maintain Microbial Diversity and Contribute to Terrestrial Community Dynamics throughout Bark Beetle Infestation

Mikkelson

Bokman

Sharp

2016

Appl Environ Microbiol

View full text Add to dashboard Cite

A global phenomenon of increasing bark beetle-induced tree mortality has heightened concerns regarding ecosystem response and biogeochemical implications. Here, we explore microbial dynamics under lodgepole pines through the analysis of bulk (16S rRNA gene) and potentially active (16S rRNA) communities to understand the terrestrial ecosystem responses that are associated with this form of large-scale tree mortality. We found that the relative abundances of bulk and potentially active taxa were correlated across taxonomic levels, but at lower levels, cladal differences became more apparent. Despite this correlation, there was a strong differentiation of community composition between bulk and potentially active taxa, with further clustering associated with the stages of tree mortality. Surprisingly, community clustering as a function of tree phase had limited correlation to soil water content and total nitrogen concentrations, which were the only two measured edaphic parameters to differ in association with tree phase. Bacterial clustering is more readily explained by the observed decrease in the abundance of active, rare microorganisms after tree death in conjunction with stable alpha diversity measurements. This enables the rare fraction of the terrestrial microbial community to maintain metabolic diversity by transitioning between metabolically active and dormant states during this ecosystem disturbance and contributes disproportionately to community dynamics and archived metabolic capabilities. These results suggest that analyzing bulk and potentially active communities after beetle infestation may be a more sensitive indicator of disruption than measuring local edaphic parameters. IMPORTANCEForests around the world are experiencing unprecedented mortality due to insect infestations that are fueled in part by a changing climate. While aboveground processes have been explored, changes at the terrestrial interface that are relevant to microbial biogeochemical cycling remain largely unknown. In this study, we investigated the changing bulk and potentially active microbial communities beneath healthy and beetle-killed trees. We found that, even though few edaphic parameters were altered from beetle infestation, the rare microbes were more likely to be active and fluctuate between dormancy and metabolic activity. This indicates that rare as opposed to abundant taxa contribute disproportionately to microbial community dynamics and presumably biogeochemical cycling within these types of perturbed ecosystems.

show abstract

Different bulk and active bacterial communities in cryoconite from the margin and interior of the Greenland ice sheet

Cited by 79 publications

References 51 publications

Light-dependent microbial metabolisms drive carbon fluxes on glacier surfaces

Light-dependent microbial metabolisms drive carbon fluxes on glacier surfaces

Biocryomorphology: Integrating Microbial Processes with Ice Surface Hydrology, Topography, and Roughness

Rare Taxa Maintain Microbial Diversity and Contribute to Terrestrial Community Dynamics throughout Bark Beetle Infestation

Contact Info

Product

Resources

About