Dataset Information

Diversity, abundance, and potential activity of nitrifying and nitrate-reducing microbial assemblages in a subglacial ecosystem.

ABSTRACT: Subglacial sediments sampled from beneath Robertson Glacier (RG), Alberta, Canada, were shown to harbor diverse assemblages of potential nitrifiers, nitrate reducers, and diazotrophs, as assessed by amoA, narG, and nifH gene biomarker diversity. Although archaeal amoA genes were detected, they were less abundant and less diverse than bacterial amoA, suggesting that bacteria are the predominant nitrifiers in RG sediments. Maximum nitrification and nitrate reduction rates in microcosms incubated at 4°C were 280 and 18.5 nmol of N per g of dry weight sediment per day, respectively, indicating the potential for these processes to occur in situ. Geochemical analyses of subglacial sediment pore waters and bulk subglacial meltwaters revealed low concentrations of inorganic and organic nitrogen compounds. These data, when coupled with a C/N atomic ratio of dissolved organic matter in subglacial pore waters of ~210, indicate that the sediment communities are N limited. This may reflect the combined biological activities of organic N mineralization, nitrification, and nitrate reduction. Despite evidence of N limitation and the detection of nifH, we were unable to detect biological nitrogen fixation activity in subglacial sediments. Collectively, the results presented here suggest a role for nitrification and nitrate reduction in sustaining microbial life in subglacial environments. Considering that ice currently covers 11% of the terrestrial landmass and has covered significantly greater portions of Earth at times in the past, the demonstration of nitrification and nitrate reduction in subglacial environments furthers our understanding of the potential for these environments to contribute to global biogeochemical cycles on glacial-interglacial timescales.

SUBMITTER: Boyd ES

PROVIDER: S-EPMC3147365 | biostudies-literature | 2011 Jul

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Diversity, abundance, and potential activity of nitrifying and nitrate-reducing microbial assemblages in a subglacial ecosystem.

Boyd Eric S ES Lange Rachel K RK Mitchell Andrew C AC Havig Jeff R JR Hamilton Trinity L TL Lafrenière Melissa J MJ Shock Everett L EL Peters John W JW Skidmore Mark M

Applied and environmental microbiology 20110527 14

Subglacial sediments sampled from beneath Robertson Glacier (RG), Alberta, Canada, were shown to harbor diverse assemblages of potential nitrifiers, nitrate reducers, and diazotrophs, as assessed by amoA, narG, and nifH gene biomarker diversity. Although archaeal amoA genes were detected, they were less abundant and less diverse than bacterial amoA, suggesting that bacteria are the predominant nitrifiers in RG sediments. Maximum nitrification and nitrate reduction rates in microcosms incubated a ...[more]

PMID: 21622799

Similar Datasets

Project description:In soil, the link between microbial diversity and carbon transformations is challenged by the concept of functional redundancy. Here, we hypothesized that functional redundancy may decrease with increasing carbon source recalcitrance and that coupling of diversity with C cycling may change accordingly. We manipulated microbial diversity to examine how diversity decrease affects the decomposition of easily degradable (i.e., allochthonous plant residues) versus recalcitrant (i.e., autochthonous organic matter) C sources. We found that a decrease in microbial diversity (i) affected the decomposition of both autochthonous and allochthonous carbon sources, thereby reducing global CO2 emission by up to 40%, and (ii) shaped the source of CO2 emission toward preferential decomposition of most degradable C sources. Our results also revealed that the significance of the diversity effect increases with nutrient availability. Altogether, these findings show that C cycling in soil may be more vulnerable to microbial diversity changes than expected from previous studies, particularly in ecosystems exposed to nutrient inputs. Thus, concern about the preservation of microbial diversity may be highly relevant in the current global-change context assumed to impact soil biodiversity and the pulse inputs of plant residues and rhizodeposits into the soil.IMPORTANCE With hundreds of thousands of taxa per gram of soil, microbial diversity dominates soil biodiversity. While numerous studies have established that microbial communities respond rapidly to environmental changes, the relationship between microbial diversity and soil functioning remains controversial. Using a well-controlled laboratory approach, we provide empirical evidence that microbial diversity may be of high significance for organic matter decomposition, a major process on which rely many of the ecosystem services provided by the soil ecosystem. These new findings should be taken into account in future studies aimed at understanding and predicting the functional consequences of changes in microbial diversity on soil ecosystem services and carbon storage in soil.

Project description:Carbon capture, utilization, and storage (CCUS) is an important component in many national net-zero strategies, and ensuring that CO2 can be safely and economically stored in geological systems is critical. Recent discoveries have shown that microbial processes (e.g., methanogenesis) can modify fluid composition and fluid dynamics within the storage reservoir. Oil reservoirs are under high pressure, but the influence of pressure on the petroleum microbial community has been previously overlooked. To better understand microbial community dynamics in deep oil reservoirs, we designed an experiment to examine the effect of high pressure (12 megapascals [MPa], 60 °C) on nitrate-reducing, sulfate-reducing, and methanogenic enrichment cultures. Cultures were exposed to these conditions for 90 d and compared with a control exposed to atmospheric pressure (0.1 MPa, 60 °C). The degradation characteristic oil compounds were confirmed by thin-layer analysis of oil SARA (saturates, aromatics, resins, and asphaltenes) family component rods. We found that the asphaltene component in crude oil was biodegraded under high pressure, but the concentration of asphaltenes increased under atmospheric pressure. Gas chromatography analyses of saturates showed that short-chain saturates (C8-C12) were biodegraded under high and atmospheric pressure, especially in the methanogenic enrichment culture under high pressure (the ratio of change was -81%), resulting in an increased relative abundance of medium- and long-chain saturates. In the nitrate-reducing and sulfate-reducing enrichment cultures, long-chain saturates (C22-C32) were biodegraded in cultures exposed to high-pressure and anaerobic conditions, with a ratio of change of -8.0% and -2.3%, respectively. However, the relative proportion of long-chain saturates (C22-C32) increased under atmospheric pressure. Gas Chromatography Mass Spectrometry analyses of aromatics showed that several naphthalene series compounds (naphthalene, C1-naphthalene, and C2-naphthalene) were biodegraded in the sulfate-reducing enrichment under both atmospheric pressure and high pressure. Our study has discerned the linkages between the biodegradation characteristics of crude oil and pressures, which is important for the future application of bioenergy with CCUS (bio-CCUS).

Dataset Information

Diversity, abundance, and potential activity of nitrifying and nitrate-reducing microbial assemblages in a subglacial ecosystem.

Publications

Diversity, abundance, and potential activity of nitrifying and nitrate-reducing microbial assemblages in a subglacial ecosystem.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets