scholarly journals Microbial community composition and abundance after millennia of submarine permafrost warming

2019 ◽  
Author(s):  
Julia Mitzscherling ◽  
Fabian Horn ◽  
Maria Winterfeld ◽  
Linda Mahler ◽  
Jens Kallmeyer ◽  
...  
Keyword(s):  
Microbial Community ◽  
Community Composition ◽  
Pore Water ◽  
Negative Correlation ◽  
Microbial Community Composition ◽  
Microbial Abundance ◽  
Bacterial Gene ◽  
Gene Abundance ◽  
Permafrost Warming

Abstract. Warming of the Arctic led to an increase of permafrost temperatures by about 0.3 °C during the last decade. Permafrost warming is associated with increasing sediment water content, permeability and diffusivity and could on the long-term alter microbial community composition and abundance even before permafrost thaws. We studied the long-term effect (up to 2500 years) of submarine permafrost warming on microbial communities along an onshore-offshore transect on the Siberian Arctic Shelf displaying a natural temperature gradient of more than 10 °C. We analysed the in-situ development of bacterial abundance and community composition through total cell counts (TCC), quantitative PCR of bacterial gene abundance and amplicon sequencing, and correlated the microbial community data with temperature, pore water chemistry and sediment physicochemical parameters. On time-scales of centuries, permafrost warming coincided with an overall decreasing microbial abundance while millennia after warming microbial abundance was similar to cold onshore permafrost and DOC content was least. Based on correlation analysis TCC unlike bacterial gene abundance showed a significant rank-based negative correlation with increasing temperature while both TCC and bacterial gene copy numbers showed a negative correlation with salinity. Bacterial community composition correlated only weakly with temperature but strongly with pore-water stable isotope signatures and depth, while it showed no correlation with salinity. Microbial community composition showed substantial spatial variation and an overall dominance of Actinobacteria, Chloroflexi, Firmicutes, Gemmatimonadetes and Proteobacteria which are amongst the microbial taxa that were found to be active in other frozen permafrost environments as well. We suggest that, millennia after permafrost warming by over 10 °C, microbial community composition and abundance show some indications for proliferation but mainly reflect the sedimentation history and paleo-environment and not a direct effect through warming.

scholarly journals Microbial community composition and abundance after millennia of submarine permafrost warming

2019 ◽  
Vol 16 (19) ◽  
pp. 3941-3958 ◽  
Author(s):  
Julia Mitzscherling ◽  
Fabian Horn ◽  
Maria Winterfeld ◽  
Linda Mahler ◽  
Jens Kallmeyer ◽  
...  
Keyword(s):  
Microbial Community ◽  
Bacterial Community ◽  
Community Composition ◽  
Pore Water ◽  
Negative Correlation ◽  
Microbial Community Composition ◽  
Microbial Abundance ◽  
Bacterial Gene ◽  
Permafrost Warming

Abstract. Warming of the Arctic led to an increase in permafrost temperatures by about 0.3 ∘C during the last decade. Permafrost warming is associated with increasing sediment water content, permeability, and diffusivity and could in the long term alter microbial community composition and abundance even before permafrost thaws. We studied the long-term effect (up to 2500 years) of submarine permafrost warming on microbial communities along an onshore–offshore transect on the Siberian Arctic Shelf displaying a natural temperature gradient of more than 10 ∘C. We analysed the in situ development of bacterial abundance and community composition through total cell counts (TCCs), quantitative PCR of bacterial gene abundance, and amplicon sequencing and correlated the microbial community data with temperature, pore water chemistry, and sediment physicochemical parameters. On timescales of centuries, permafrost warming coincided with an overall decreasing microbial abundance, whereas millennia after warming microbial abundance was similar to cold onshore permafrost. In addition, the dissolved organic carbon content of all cores was lowest in submarine permafrost after millennial-scale warming. Based on correlation analysis, TCC, unlike bacterial gene abundance, showed a significant rank-based negative correlation with increasing temperature, while bacterial gene copy numbers showed a strong negative correlation with salinity. Bacterial community composition correlated only weakly with temperature but strongly with the pore water stable isotopes δ18O and δD, as well as with depth. The bacterial community showed substantial spatial variation and an overall dominance of Actinobacteria, Chloroflexi, Firmicutes, Gemmatimonadetes, and Proteobacteria, which are amongst the microbial taxa that were also found to be active in other frozen permafrost environments. We suggest that, millennia after permafrost warming by over 10 ∘C, microbial community composition and abundance show some indications for proliferation but mainly reflect the sedimentation history and paleoenvironment and not a direct effect through warming.

Organic matter additions to soil and effects on microbially mediated carbon cycling

2020 ◽  
Author(s):  
Rachel hasler ◽  
Mark pawlett ◽  
Jim harris ◽  
Helen bostock ◽  
Marc redmile-gordon
Keyword(s):  
Organic Matter ◽  
Microbial Community ◽  
Carbon Cycling ◽  
Community Composition ◽  
Soil Microbial Community ◽  
Microbial Community Composition ◽  
Soil Microbial ◽  
Horse Manure ◽  
Soil Microbial Community Composition

<p>The type of soil organic amendment selected can have profound implications for carbon cycling processes in soils. Understanding the link between this choice and its effect on the soil microbiome will improve our understanding of the capacity of these materials to improve carbon sequestration and cycling dynamics. Understanding and facilitating the lifestyle strategies of microorganisms processing organic matter is essential to improving our understanding of the terrestrial carbon cycle. This research focuses on utilising organic amendments to alter the indigenous soil microbial community composition and function to improve the capacity of the soil to cycle and store carbon in horticultural soils.  The effects of annual application of various organic fertilisers (peat, bracken, bark, horse manure, garden compost) in a long-term (10year) field experiment were explored. Sampling was completed pre and post application of organic matter within one season (following 10 years of applications) to identify which organic amendment was more effective in producing benefits to plants through improved soil organic matter and which amendments provide the greatest legacy effect on carbon cycling. The response of the soil microbial community composition (phospholipid fatty acid analysis) and carbon functional cycling dynamics (respiration using MicroResp™) were determined with a view to improving our understanding of the interaction between the materials applied and microbial processes. PCA of the MicroResp™ data identified that all treatments had a different functional profile compared to the control[PM1]  with peat being significantly different from all other treatments. Horse manure and bark differed significantly within a single growing season; prior and post organic matter addition in spring 2019.  Microbial biomass measurements for garden compost and horse manure were significantly higher following organic matter addition compared to all other treatments and the control[PM2] .  All treatments had a significant effect [PM3] on hot water extractable carbon and total carbon. Peat had a significantly different effect[PM4] , when compared to other treatments, on the soil PLFA profile and bark application significantly increased [PM5] the neutral lipid (NLFA) biomarker 16:1ω5.  Bark and horse manure application both significantly increased PLFA fungal biomarker 18:2ω6,9. No significant differences were found between the fungal/bacterial ratios of the organic matter additions prior to being added to the soil. These findings show that altering the resources available to the soil microbial community has a significant impact on soil microbial community composition and microbially mediated carbon cycling functionality. Increasing our understanding of how soil functions are altered by land management decisions will enable better informed predictions of the long-term benefits of organic matter applications on carbon sequestration and cycling dynamics.</p>

scholarly journals Soil Microbial Community Based on PLFA Profiles in an Age Sequence of Pomegranate Plantation in the Middle Yellow River Floodplain

Diversity ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 408
Author(s):  
Shilin Wang ◽  
Xinyu Yan ◽  
Dong Wang ◽  
Imran Ahammad Siddique ◽  
Ji Chen ◽  
...  
Keyword(s):  
Microbial Community ◽  
Community Composition ◽  
Soil Microbial Community ◽  
Yellow River ◽  
Microbial Community Composition ◽  
Stand Age ◽  
Soil Microbial ◽  
Age Sequence ◽  
Soil Microbial Community Composition

Pomegranate (Punica granatum L.) is one of the most important fruit trees in semi-arid land. Previous studies were primarily focused on soil microbial community composition under different pomegranate plantation managements. However, soil microbial community composition under long-term pomegranate plantation has rarely been studied. We investigated pomegranate plantation along with an age sequence (i.e., 1, 3, 5, and 10 years after pomegranate plantation; abbreviated by P1, P3, P5, P10, respectively) in the Middle Yellow River floodplain. Our objectives were to address (1) variations of soil physicochemical properties and (2) changes in soil microbial community composition and the influential factors. The results demonstrated that the soil water content of pomegranate plantation decreased with the increase of pomegranate plantation stand age. Specifically, dissolved organic carbon, ammonium, and available phosphorus increased significantly with stand age both at 0–10- and 10–20-cm soil depths. The P10 had the highest microbial phospholipid fatty acid (PLFA) profiles, including fungi, bacteria, Gram-positive bacteria, Gram-negative bacteria, and arbuscular mycorrhizal fungi. The ratio of fungal PLFAs to bacterial PLFAs increased and the ratio of Gram-positive to Gram-negative bacterial PLFAs decreased along the pomegranate plantation stand age. Dissolved organic carbon was the most important influential factor among the studied variables, which explained 42.2% variation of soil microbial community. In summary, the long-term plantation of pomegranate elevated soil microbial biomass and altered microbial community composition.

scholarly journals Microbial Community Stratification Linked to Utilization of Carbohydrates and Phosphorus Limitation in a Boreal Peatland at Marcell Experimental Forest, Minnesota, USA

2014 ◽  
Vol 80 (11) ◽  
pp. 3518-3530 ◽  
Author(s):  
Xueju Lin ◽  
Malak M. Tfaily ◽  
J. Megan Steinweg ◽  
Patrick Chanton ◽  
Kaitlin Esson ◽  
...  
Keyword(s):  
Microbial Community ◽  
Microbial Communities ◽  
Community Composition ◽  
Hot Spot ◽  
Microbial Community Composition ◽  
Phosphorus Limitation ◽  
Rrna Gene ◽  
Content Type ◽  
Gene Abundance ◽  
P Limitation

ABSTRACTThis study investigated the abundance, distribution, and composition of microbial communities at the watershed scale in a boreal peatland within the Marcell Experimental Forest (MEF), Minnesota, USA. Through a close coupling of next-generation sequencing, biogeochemistry, and advanced analytical chemistry, a biogeochemical hot spot was revealed in the mesotelm (30- to 50-cm depth) as a pronounced shift in microbial community composition in parallel with elevated peat decomposition. The relative abundance ofAcidobacteriaand theSyntrophobacteraceae, including known hydrocarbon-utilizing genera, was positively correlated with carbohydrate and organic acid content, showing a maximum in the mesotelm. The abundance ofArchaea(primarily crenarchaeal groups 1.1c and 1.3) increased with depth, reaching up to 60% of total small-subunit (SSU) rRNA gene sequences in the deep peat below the 75-cm depth. Stable isotope geochemistry and potential rates of methane production paralleled vertical changes in methanogen community composition to indicate a predominance of acetoclastic methanogenesis mediated by theMethanosarcinalesin the mesotelm, while hydrogen-utilizing methanogens predominated in the deeper catotelm. RNA-derived pyrosequence libraries corroborated DNA sequence data to indicate that the above-mentioned microbial groups are metabolically active in the mid-depth zone. Fungi showed a maximum in rRNA gene abundance above the 30-cm depth, which comprised only an average of 0.1% of total bacterial and archaeal rRNA gene abundance, indicating prokaryotic dominance. Ratios of C to P enzyme activities approached 0.5 at the acrotelm and catotelm, indicating phosphorus limitation. In contrast, P limitation pressure appeared to be relieved in the mesotelm, likely due to P solubilization by microbial production of organic acids and C-P lyases. Based on path analysis and the modeling of community spatial turnover, we hypothesize that P limitation outweighs N limitation at MEF, and microbial communities are structured by the dominant shrub,Chamaedaphne calyculata, which may act as a carbon source for major consumers in the peatland.

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