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Khan A, Ball BA. Soil microbial responses to simulated climate change across polar ecosystems. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 909:168556. [PMID: 37979872 DOI: 10.1016/j.scitotenv.2023.168556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2023] [Revised: 11/10/2023] [Accepted: 11/11/2023] [Indexed: 11/20/2023]
Abstract
The polar regions are among the most biologically constrained in the world, characterized by cold temperatures and reduced liquid water. These limitations make them among the most climate-sensitive regions on Earth. Despite the overwhelming constraints from low temperatures and resource availability, many polar ecosystems, including polar deserts and tundras across the Arctic and Antarctic host uniquely diverse microbial communities. Polar regions have warmed more rapidly than the global average, with continued warming predicted for the future, which will reduce constraints on soil microbial activity. This could alter polar carbon (C) cycles, increasing CO2 emissions into the atmosphere. The objective of this study was to determine how increased temperature and moisture availability impacts microbial respiration in polar regions, by focusing on a diversity of ecosystem types (polar desert vs. tundra) that are geographically distant across Antarctica and the Arctic. We found that polar desert soil microbes were co-limited by temperature and moisture, though C and nitrogen (N) mineralization were only stimulated at the coldest and driest of the two polar deserts. Only bacterial biomass was impacted at the less harsh of the polar deserts, suggesting microbial activity is limited by factors other than temperature and moisture. Of the tundra sites, only the Antarctic tundra was climate-sensitive, where increased temperature decreased C and N mineralization while water availability stimulated it. The greater availability of soil resources and vegetative biomass at the Arctic tundra site might lead to its lack of climate-sensitivity. Notably, while C and N dynamics were climate-sensitive at some of our polar sites, P availability was not impacted at any of them. Our results demonstrate that soil microbial processes in some polar ecosystems are more sensitive to changes in temperature and moisture than others, with implications for soil C and N storage that are not uniformly predictable across polar regions.
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Affiliation(s)
- Ana Khan
- School of Mathematical and Natural Sciences, Arizona State University at the West Campus, Glendale, AZ 85306, USA
| | - Becky A Ball
- School of Mathematical and Natural Sciences, Arizona State University at the West Campus, Glendale, AZ 85306, USA.
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2
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Chien SC, Krumins JA. Anthropogenic effects on global soil nitrogen pools. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 902:166238. [PMID: 37586519 DOI: 10.1016/j.scitotenv.2023.166238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 08/07/2023] [Accepted: 08/09/2023] [Indexed: 08/18/2023]
Abstract
The amount of nitrogen stored in terrestrial soils, its "nitrogen pool", moderates biogeochemical cycling affecting primary productivity, nitrogen pollution and even carbon budgets. The soil nitrogen pools and the transformation of nitrogen forms within them are heavily influenced by environmental factors including anthropogenic activities. However, our understanding of the global distribution of soil nitrogen with respect to anthropogenic activity and human land use remains unclear. We constructed a meta-analysis from a global sampling, in which we compare soil total nitrogen pools and the driving mechanisms affecting each pool across three major classifications of human land use: natural, agricultural, and urban. Although the size of the nitrogen pool can be similar across natural, agricultural and urban soils, the ecological and human associated drivers vary. Specifically, the drivers within agricultural and urban soils as opposed to natural soils are more complex and often decoupled from climatic and soil factors. This suggests that the nitrogen pools of those soils may be co-moderated by other factors not included in our analyses, like human activities. Our analysis supports the notion that agricultural soils act as a nitrogen source while urban soils as a nitrogen sink and informs a modern understanding of the fates and distributions of anthropogenic nitrogen in natural, agricultural, and urban soils.
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Affiliation(s)
- Shih-Chieh Chien
- Doctoral Program in Environmental Science and Management, Montclair State University, Montclair, NJ, 07043, USA.
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3
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Soil microbial community of urban green infrastructures in a polar city. Urban Ecosyst 2022. [DOI: 10.1007/s11252-022-01233-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Ortiz M, Bosch J, Coclet C, Johnson J, Lebre P, Salawu-Rotimi A, Vikram S, Makhalanyane T, Cowan D. Microbial Nitrogen Cycling in Antarctic Soils. Microorganisms 2020; 8:E1442. [PMID: 32967081 PMCID: PMC7564152 DOI: 10.3390/microorganisms8091442] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 09/02/2020] [Accepted: 09/03/2020] [Indexed: 01/19/2023] Open
Abstract
The Antarctic continent is widely considered to be one of the most hostile biological habitats on Earth. Despite extreme environmental conditions, the ice-free areas of the continent, which constitute some 0.44% of the total continental land area, harbour substantial and diverse communities of macro-organisms and especially microorganisms, particularly in the more "hospitable" maritime regions. In the more extreme non-maritime regions, exemplified by the McMurdo Dry Valleys of South Victoria Land, nutrient cycling and ecosystem servicing processes in soils are largely driven by microbial communities. Nitrogen turnover is a cornerstone of ecosystem servicing. In Antarctic continental soils, specifically those lacking macrophytes, cold-active free-living diazotrophic microorganisms, particularly Cyanobacteria, are keystone taxa. The diazotrophs are complemented by heterotrophic bacterial and archaeal taxa which show the genetic capacity to perform elements of the entire N cycle, including nitrification processes such as the anammox reaction. Here, we review the current literature on nitrogen cycling genes, taxa, processes and rates from studies of Antarctic soils. In particular, we highlight the current gaps in our knowledge of the scale and contribution of these processes in south polar soils as critical data to underpin viable predictions of how such processes may alter under the impacts of future climate change.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Don Cowan
- Centre for Microbial Ecology and Genomics, Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria 0002, South Africa; (M.O.); (J.B.); (C.C.); (J.J.); (P.L.); (A.S.-R.); (S.V.); (T.M.)
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Wang R, Sun Q, Wang Y, Zheng W, Yao L, Hu Y, Guo S. Contrasting responses of soil respiration and temperature sensitivity to land use types: Cropland vs. apple orchard on the Chinese Loess Plateau. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 621:425-433. [PMID: 29190565 DOI: 10.1016/j.scitotenv.2017.11.290] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Revised: 11/03/2017] [Accepted: 11/25/2017] [Indexed: 06/07/2023]
Abstract
Land use plays an essential role in regional carbon cycling, potentially influencing the exchange rates of CO2 flux between soil and the atmosphere in terrestrial ecosystems. Temperature sensitivity of soil respiration (Q10), as an efficient parameter to reflect the possible feedback between the global carbon cycle and climate change, has been extensively studied. However, very few reports have assessed the difference in temperature sensitivity of soil respiration under different land use types. In this study, a three-year field experiment was conducted in cropland (winter wheat, Triticum aestivum L.) and apple orchard (Malus domestica Borkh) on the semi-arid Loess Plateau from 2011 to 2013. Soil respiration (measured using Li-Cor 8100), bacterial community structure (represented by 16S rRNA), soil enzyme activities, and soil physicochemical properties of surface soil were monitored. The average annual soil respiration rate in the apple orchard was 12% greater than that in the cropland (2.01 vs. 1.80μmolm-2s-1), despite that the average Q10 values in the apple orchard was 15% lower than that in the cropland (ranging from 1.63 to 1.41). As to the differences among predominant phyla, Proteobacteria was 26% higher in the apple orchard than that in the cropland, whereas Actinobacteria and Acidobacteria were 18% and 36% lower in the apple orchard. The β-glucosidase and cellobiohydrolase activity were 15% (44.92 vs. 39.09nmolh-1g-1) and 22% greater (21.39 vs. 17.50nmolh-1g-1) in the apple orchard than that in the cropland. Compared to the cropland, the lower Q10 values in the apple orchard resulted from the variations of bacterial community structure and β-glucosidase and cellobiohydrolase activity. In addition, the lower C: N ratios in the apple orchard (6.50 vs. 8.40) possibly also contributed to its lower Q10 values. Our findings call for further studies to include the varying effects of land use types into consideration when applying Q10 values to predict the potential CO2 efflux feedbacks between terrestrial ecosystems and future climate scenarios.
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Affiliation(s)
- Rui Wang
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling, Shaanxi 712100, China; Collaborative Innovation Center of Water Security for Water Source Region of Mid-line of South-to-North Diversion Project of Henan Province, Nanyang Normal University, Nanyang, Henan 473061, China
| | - Qiqi Sun
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling, Shaanxi 712100, China; Collaborative Innovation Center of Water Security for Water Source Region of Mid-line of South-to-North Diversion Project of Henan Province, Nanyang Normal University, Nanyang, Henan 473061, China
| | - Ying Wang
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Wei Zheng
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Lunguang Yao
- Collaborative Innovation Center of Water Security for Water Source Region of Mid-line of South-to-North Diversion Project of Henan Province, Nanyang Normal University, Nanyang, Henan 473061, China
| | - Yaxian Hu
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling, Shaanxi 712100, China; Collaborative Innovation Center of Water Security for Water Source Region of Mid-line of South-to-North Diversion Project of Henan Province, Nanyang Normal University, Nanyang, Henan 473061, China
| | - Shengli Guo
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling, Shaanxi 712100, China; Collaborative Innovation Center of Water Security for Water Source Region of Mid-line of South-to-North Diversion Project of Henan Province, Nanyang Normal University, Nanyang, Henan 473061, China.
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Sun Q, Wang R, Hu Y, Yao L, Guo S. Spatial variations of soil respiration and temperature sensitivity along a steep slope of the semiarid Loess Plateau. PLoS One 2018; 13:e0195400. [PMID: 29624600 PMCID: PMC5889173 DOI: 10.1371/journal.pone.0195400] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 03/21/2018] [Indexed: 11/18/2022] Open
Abstract
The spatial heterogeneity of soil respiration and its temperature sensitivity pose a great challenge to accurately estimate the carbon flux in global carbon cycling, which has primarily been researched in flatlands versus hillslope ecosystems. On an eroded slope (35°) of the semiarid Loess Plateau, soil respiration, soil moisture and soil temperature were measured in situ at upper and lower slope positions in triplicate from 2014 until 2016, and the soil biochemical and microbial properties were determined. The results showed that soil respiration was significantly greater (by 44.2%) at the lower slope position (2.6 μmol m–2 s–1) than at the upper slope position, as were soil moisture, carbon, nitrogen fractions and root biomass. However, the temperature sensitivity was 13.2% greater at the upper slope position than at the lower slope position (P < 0.05). The soil fungal community changed from being Basidiomycota-dominant at the upper slope position to being Zygomycota-dominant at the lower slope position, corresponding with increased β-D-glucosidase activity at the upper slope position than at the lower slope position. We concluded that soil respiration was enhanced by the greater soil moisture, root biomass, carbon and nitrogen contents at the lower slope position than at the upper slope position. Moreover, the increased soil respiration and decreased temperature sensitivity at the lower slope position were partially due to copiotrophs replacing oligotrophs. Such spatial variations along slopes must be properly accounted for when estimating the carbon budget and feedback of future climate change on hillslope ecosystems.
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Affiliation(s)
- Qiqi Sun
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling, Shannxi, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Rui Wang
- College of Resources and Environment, Northwest A&F University, Yangling, Shannxi, China
| | - Yaxian Hu
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling, Shannxi, China
- College of Resources and Environment, Northwest A&F University, Yangling, Shannxi, China
| | - Lunguang Yao
- Collaborative Innovation Center of Water Security for Water Source Region of Mid-line of South-to-North Diversion Project of Henan Province, Nanyang Normal University, Nanyang, China
| | - Shengli Guo
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling, Shannxi, China
- College of Resources and Environment, Northwest A&F University, Yangling, Shannxi, China
- Collaborative Innovation Center of Water Security for Water Source Region of Mid-line of South-to-North Diversion Project of Henan Province, Nanyang Normal University, Nanyang, China
- * E-mail:
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Wang R, Sun Q, Wang Y, Liu Q, Du L, Zhao M, Gao X, Hu Y, Guo S. Temperature sensitivity of soil respiration: Synthetic effects of nitrogen and phosphorus fertilization on Chinese Loess Plateau. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 574:1665-1673. [PMID: 27614858 DOI: 10.1016/j.scitotenv.2016.09.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2016] [Revised: 08/29/2016] [Accepted: 09/01/2016] [Indexed: 06/06/2023]
Abstract
Nitrogen (N) and phosphorus (P) fertilization has the potential to alter soil respiration temperature sensitivity (Q10) by changing soil biochemical and crop physiological process. A four-year field experiment was conducted to determine how Q10 responded to these biochemical and physiological changes in rain-fed agro-ecosystems on the semi-arid Loess Plateau. Soil respiration, as well as biotic and abiotic factors were measured in winter wheat (Triticum aestivum L.), with three fertilization treatments: (no fertilization (CK), 160kgNhm-1 (N), and 160kgNha-1 with 39kgPha-1 (N+P). Mean annual soil respiration rate (calculated by averaging the four years) in the N treatment and N+P treatment was 18% and 48% higher than that in the CK treatment, respectively; and it was increased by 26% (14%-48%) in the N+P treatment as compared with that in the N treatment. The decrease of Q10 in the N and N+P treatments against the CK treatment was not stable for each year, ranging from 0.01 to 0.28. The maximum decrease of Q10 in the N and N+P treatments was 10% and 15% in 2014-2015, while in other years the decrease of Q10 was numerical but not significant. Soil microbial biomass carbon (SMBC) was increased by 10% and 50%, dissolved organic carbon (DOC) was increased by 6% and 21%, and photosynthesis rate was increased ranging from 6% to 33% with N and N+P fertilization. The relative abundance of Acidobacteria, Actinobacteria and Chloroflexi were significantly higher by 32.9%-54.1% in N addition soils (N and N+P) compared to CK treatment, whereas additional P application into soils increased the relative abundance of the family Micrococcaceae, Nocardioidaceae and Chitinophagaceae. Soil respiration was positively related to SMBC, DOC and photosynthesis rate (p<0.05). However, variation in Q10 may be related to the increase of soil mineral N content and variation of the relative abundance of soil microbial community in our study. Nitrogen and additional phosphorus fertilization regimes affect soil respiration and temperature sensitivity differently.
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Affiliation(s)
- Rui Wang
- College of Resources and Environment, Northwest A&F University, Yangling 712100, China; State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Qiqi Sun
- Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resource, Yangling 712100, China
| | - Ying Wang
- College of Resources and Environment, Northwest A&F University, Yangling 712100, China; State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling, Shaanxi 712100, China; Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resource, Yangling 712100, China
| | - Qingfang Liu
- College of Resources and Environment, Northwest A&F University, Yangling 712100, China
| | - Lanlan Du
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Man Zhao
- College of Resources and Environment, Northwest A&F University, Yangling 712100, China
| | - Xin Gao
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Yaxian Hu
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling, Shaanxi 712100, China; Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resource, Yangling 712100, China
| | - Shengli Guo
- College of Resources and Environment, Northwest A&F University, Yangling 712100, China; State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling, Shaanxi 712100, China; Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resource, Yangling 712100, China.
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Temperature Sensitivity of Soil Respiration to Nitrogen Fertilization: Varying Effects between Growing and Non-Growing Seasons. PLoS One 2016; 11:e0168599. [PMID: 27992576 PMCID: PMC5161502 DOI: 10.1371/journal.pone.0168599] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2016] [Accepted: 12/02/2016] [Indexed: 11/23/2022] Open
Abstract
Nitrogen (N) fertilization has a considerable effect on food production and carbon cycling in agro-ecosystems. However, the impacts of N fertilization rates on the temperature sensitivity of soil respiration (Q10) were controversial. Five N rates (N0, N45, N90, N135, and N180) were applied to a continuous winter wheat (Triticum aestivum L.) crop on the semi-arid Loess Plateau, and the in situ soil respiration was monitored during five consecutive years from 2008 to 2013. During the growing season, the mean soil respiration rates increased with increasing N fertilization rates, peaking at 1.53 μmol m−2s−1 in the N135 treatment. A similar dynamic pattern was observed during the non-growing season, yet on average with 7.3% greater soil respiration rates than the growing season. In general for all the N fertilization treatments, the mean Q10 value during the non-growing season was significantly greater than that during the growing season. As N fertilization rates increased, the Q10 values did not change significantly in the growing season but significantly decreased in the non-growing season. Overall, N fertilization markedly influenced soil respirations and Q10 values, in particular posing distinct effects on the Q10 values between the growing and non-growing seasons.
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Huang G, Cao YF, Wang B, Li Y. Effects of nitrogen addition on soil microbes and their implications for soil C emission in the Gurbantunggut Desert, center of the Eurasian Continent. THE SCIENCE OF THE TOTAL ENVIRONMENT 2015; 515-516:215-224. [PMID: 25686661 DOI: 10.1016/j.scitotenv.2015.01.054] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Revised: 01/18/2015] [Accepted: 01/18/2015] [Indexed: 06/04/2023]
Abstract
Nitrogen (N) deposition can influence carbon cycling of terrestrial ecosystems. However, a general recognition of how soil microorganisms respond to increasing N deposition is not yet reached. We explored soil microbial responses to two levels of N addition (2.5 and 5 gN m(-2) yr(-1)) in interplant soil and beneath shrubs of Haloxylon ammodendron and their consequences to soil respiration in the Gurbantunggut Desert, northwestern China from 2011 to 2013. Microbial biomass and respiration were significantly higher beneath H. ammodendron than in interplant soil. The responses of microbial biomass carbon (MBC) and microbial respiration (MR) showed opposite responses to N addition in interplant and beneath H. ammodendron. N addition slightly increased MBC and MR in interplant soil and decreased them beneath H. ammodendron, with a significant inhibition only in 2012. N addition had no impacts on the total microbial physiological activity, but N addition decreased the labile carbon substrate utilization beneath H. ammodendron when N addition level was high. Phospholipid fatty acid (PLFA) analysis showed that N addition did not alter the soil microbial community structure as evidenced by the similar ratios of fungal to bacterial PLFAs and gram-negative to gram-positive bacterial PLFAs. Microbial biomass and respiration showed close correlations with soil water content and dissolved carbon, and they were independent of soil inorganic nitrogen across three years. Our study suggests that N addition effects on soil microorganisms and carbon emission are dependent on the respiratory substrates and water availability in the desert ecosystem.
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Affiliation(s)
- Gang Huang
- State Key Lab of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, 818 South Beijing Road, Urumqi, Xinjiang 830011, China
| | - Yan Feng Cao
- State Key Lab of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, 818 South Beijing Road, Urumqi, Xinjiang 830011, China
| | - Bin Wang
- State Key Lab of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, 818 South Beijing Road, Urumqi, Xinjiang 830011, China
| | - Yan Li
- State Key Lab of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, 818 South Beijing Road, Urumqi, Xinjiang 830011, China.
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10
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Penguin activity influences soil biogeochemistry and soil respiration in rookeries on Ross Island, Antarctica. Polar Biol 2015. [DOI: 10.1007/s00300-015-1699-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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11
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Purcell AM, Mikucki JA, Achberger AM, Alekhina IA, Barbante C, Christner BC, Ghosh D, Michaud AB, Mitchell AC, Priscu JC, Scherer R, Skidmore ML, Vick-Majors TJ, the WISSARD Science Team. Microbial sulfur transformations in sediments from Subglacial Lake Whillans. Front Microbiol 2014; 5:594. [PMID: 25477865 PMCID: PMC4237127 DOI: 10.3389/fmicb.2014.00594] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Accepted: 10/21/2014] [Indexed: 11/13/2022] Open
Abstract
Diverse microbial assemblages inhabit subglacial aquatic environments. While few of these environments have been sampled, data reveal that subglacial organisms gain energy for growth from reduced minerals containing nitrogen, iron, and sulfur. Here we investigate the role of microbially mediated sulfur transformations in sediments from Subglacial Lake Whillans (SLW), Antarctica, by examining key genes involved in dissimilatory sulfur oxidation and reduction. The presence of sulfur transformation genes throughout the top 34 cm of SLW sediments changes with depth. SLW surficial sediments were dominated by genes related to known sulfur-oxidizing chemoautotrophs. Sequences encoding the adenosine-5'-phosphosulfate (APS) reductase gene, involved in both dissimilatory sulfate reduction and sulfur oxidation, were present in all samples and clustered into 16 distinct operational taxonomic units. The majority of APS reductase sequences (74%) clustered with known sulfur oxidizers including those within the "Sideroxydans" and Thiobacillus genera. Reverse-acting dissimilatory sulfite reductase (rDSR) and 16S rRNA gene sequences further support dominance of "Sideroxydans" and Thiobacillus phylotypes in the top 2 cm of SLW sediments. The SLW microbial community has the genetic potential for sulfate reduction which is supported by experimentally measured low rates (1.4 pmol cm(-3)d(-1)) of biologically mediated sulfate reduction and the presence of APS reductase and DSR gene sequences related to Desulfobacteraceae and Desulfotomaculum. Our results also infer the presence of sulfur oxidation, which can be a significant energetic pathway for chemosynthetic biosynthesis in SLW sediments. The water in SLW ultimately flows into the Ross Sea where intermediates from subglacial sulfur transformations can influence the flux of solutes to the Southern Ocean.
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Affiliation(s)
- Alicia M. Purcell
- Department of Microbiology, University of TennesseeKnoxville, TN, USA
| | - Jill A. Mikucki
- Department of Microbiology, University of TennesseeKnoxville, TN, USA
| | - Amanda M. Achberger
- Department of Biological Sciences, Louisiana State UniversityBaton Rouge, LA, USA
| | - Irina A. Alekhina
- Climate and Environmental Research Laboratory, Arctic and Antarctic Research Institute, St.Petersburg, Russia
| | - Carlo Barbante
- Institute for the Dynamics of Environmental Processes – Consiglio Nazionale delle Ricerche and Department of Environmental Sciences, Informatics and Statistics, Ca’ Foscari University of VeniceVenice, Italy
| | - Brent C. Christner
- Department of Biological Sciences, Louisiana State UniversityBaton Rouge, LA, USA
| | - Dhritiman Ghosh
- Department of Microbiology, University of TennesseeKnoxville, TN, USA
| | - Alexander B. Michaud
- Department of Land Resources and Environmental Sciences, Montana State UniversityBozeman, MT, USA
| | | | - John C. Priscu
- Department of Land Resources and Environmental Sciences, Montana State UniversityBozeman, MT, USA
| | - Reed Scherer
- Department of Geological and Environmental Sciences, Northern Illinois UniversityDeKalb, IL, USA
| | - Mark L. Skidmore
- Department of Earth Sciences, Montana State UniversityBozeman, MT, USA
| | - Trista J. Vick-Majors
- Department of Land Resources and Environmental Sciences, Montana State UniversityBozeman, MT, USA
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