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Deng D, Pan Y, Liu G, Liu W, Ma L. Seeking the hotspots of nitrogen removal: A comparison of sediment denitrification rate and denitrifier abundance among wetland types with different hydrological conditions. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 737:140253. [PMID: 32783851 DOI: 10.1016/j.scitotenv.2020.140253] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 04/27/2020] [Accepted: 06/14/2020] [Indexed: 06/11/2023]
Abstract
Wetlands play a vital role in removing nitrogen (N) from aquatic environments via the denitrification process, which is regulated by multiple environmental and biological factors. Until now, the mechanisms by which environmental factors and microbial abundance regulate denitrification rates in wetlands under different hydrological conditions remain poorly understood. Here, we investigated sediment potential denitrification rate (PDR) and unamended denitrification rate (UDR), and quantified denitrifier abundance (nirS, nirK, and nosZ genes) in 36 stream, river, pond, and ditch wetland sites along the Dan River, a nitrogen-rich river in central China. The result indicated that ditches had the highest denitrification rates and denitrifier abundance. Both PDR and UDR showed strong seasonality, and were observed to be negatively correlated with water velocity in streams and rivers. Moreover, denitrification rates were significantly related to denitrifier abundance and many water quality parameters and sediment properties. Interestingly, PDR and UDR were generally positively associated with N and carbon (C) availability in streams and rivers, but such correlations were not found in ponds and ditches. Using a scaling analysis, we found that environmental parameters, including Reynolds number, sediment total C ratio, and interstitial space, coupled with relative nirS gene abundance could predict the hotspots of denitrification rates in wetlands with varying hydrologic regimes. Our findings highlight that hydrological conditions, especially water velocity and hydrologic pulsing, play a nonnegligible role in determining N biogeochemical processes in wetlands.
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Affiliation(s)
- Danli Deng
- CAS Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan 430074, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yongtai Pan
- Research Center for Ecology and Environment of Qinghai-Tibetan Plateau, Tibet University, Lhasa 850000, China
| | - Guihua Liu
- CAS Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan 430074, China; Center of Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Wuhan 430074, China; Hubei Key Laboratory of Wetland Evolution & Ecological Restoration, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan 430074, China
| | - Wenzhi Liu
- CAS Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan 430074, China; Center of Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Wuhan 430074, China; Hubei Key Laboratory of Wetland Evolution & Ecological Restoration, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan 430074, China.
| | - Lin Ma
- CAS Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan 430074, China; Hubei Key Laboratory of Wetland Evolution & Ecological Restoration, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan 430074, China.
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Ishtiaq KS, Abdul-Aziz OI. Ecological parameter reductions, environmental regimes, and characteristic process diagram of carbon dioxide fluxes in coastal salt marshes. Sci Rep 2020; 10:15732. [PMID: 32978413 PMCID: PMC7519661 DOI: 10.1038/s41598-020-72066-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Accepted: 08/25/2020] [Indexed: 11/11/2022] Open
Abstract
We investigated the ecological parameter reductions (termed "similitudes") and characteristic patterns of the net uptake fluxes of carbon dioxide (CO2) in coastal salt marshes using dimensional analysis method from fluid mechanics and hydraulic engineering. Data collected during May-October, 2013 from four salt marshes in Waquoit Bay and adjacent estuary, Massachusetts, USA were utilized to evaluate the theoretically-derived dimensionless flux and various ecological driver numbers. Two meaningful dimensionless groups were discovered as the light use efficiency number (LUE = CO2 normalized by photosynthetically active radiation) and the biogeochemical number (combination of soil temperature, porewater salinity, and atmospheric pressure). A semi-logarithmic plot of the dimensionless numbers indicated the emergence of a characteristic diagram represented by three distinct LUE regimes (high, transitional, and low). The high regime corresponded to the most favorable (high temperature and low salinity) condition for CO2 uptake, whereas the low regime represented an unfavorable condition (low temperature and high salinity). The analysis identified two environmental thresholds (soil temperature ~ 17 °C and salinity ~ 30 ppt), which dictated the regime transitions of CO2 uptake. The process diagram and critical thresholds provide important insights into the CO2 uptake potential of coastal wetlands in response to changes in key environmental drivers.
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Affiliation(s)
- Khandker S Ishtiaq
- West Virginia University, P.O. Box 6103, Morgantown, WV, 26506-6103, USA
| | - Omar I Abdul-Aziz
- West Virginia University, P.O. Box 6103, Morgantown, WV, 26506-6103, USA.
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Tomasek AA, Hondzo M, Kozarek JL, Staley C, Wang P, Lurndahl N, Sadowsky MJ. Intermittent flooding of organic‐rich soil promotes the formation of denitrification hot moments and hot spots. Ecosphere 2019. [DOI: 10.1002/ecs2.2549] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Affiliation(s)
- Abigail A. Tomasek
- St. Anthony Falls Laboratory University of Minnesota Minneapolis Minnesota 55455 USA
- Department of Civil, Environmental, and Geo‐Engineering University of Minnesota Minneapolis Minnesota 55455 USA
| | - Miki Hondzo
- St. Anthony Falls Laboratory University of Minnesota Minneapolis Minnesota 55455 USA
- Department of Civil, Environmental, and Geo‐Engineering University of Minnesota Minneapolis Minnesota 55455 USA
| | - Jessica L. Kozarek
- St. Anthony Falls Laboratory University of Minnesota Minneapolis Minnesota 55455 USA
| | - Christopher Staley
- BioTechnology Institute University of Minnesota St. Paul Minnesota 55108 USA
| | - Ping Wang
- BioTechnology Institute University of Minnesota St. Paul Minnesota 55108 USA
| | - Nicole Lurndahl
- Water Resources Science University of Minnesota St. Paul Minnesota 55108 USA
| | - Michael J. Sadowsky
- BioTechnology Institute University of Minnesota St. Paul Minnesota 55108 USA
- Water Resources Science University of Minnesota St. Paul Minnesota 55108 USA
- Department of Soil, Water, and Climate University of Minnesota St. Paul Minnesota 55108 USA
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Tomasek A, Staley C, Wang P, Kaiser T, Lurndahl N, Kozarek JL, Hondzo M, Sadowsky MJ. Increased Denitrification Rates Associated with Shifts in Prokaryotic Community Composition Caused by Varying Hydrologic Connectivity. Front Microbiol 2017; 8:2304. [PMID: 29213260 PMCID: PMC5702768 DOI: 10.3389/fmicb.2017.02304] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2017] [Accepted: 11/08/2017] [Indexed: 12/22/2022] Open
Abstract
While modern developments in agriculture have allowed for increases in crop yields and rapid human population growth, they have also drastically altered biogeochemical cycles, including the biotransformation of nitrogen. Denitrification is a critical process performed by bacteria and fungi that removes nitrate in surface waters, thereby serving as a potential natural remediation strategy. We previously reported that constant inundation resulted in a coupling of denitrification gene abundances with denitrification rates in sediments, but these relationships were not maintained in periodically-inundated or non-inundated environments. In this study, we utilized Illumina next-generation sequencing to further evaluate how the microbial community responds to these hydrologic regimes and how this community is related to denitrification rates at three sites along a creek in an agricultural watershed over 2 years. The hydrologic connectivity of the sampling location had a significantly greater influence on the denitrification rate (P = 0.010), denitrification gene abundances (P < 0.001), and the prokaryotic community (P < 0.001), than did other spatiotemporal factors (e.g., creek sample site or sample month) within the same year. However, annual variability among denitrification rates was also observed (P < 0.001). Furthermore, the denitrification rate was significantly positively correlated with water nitrate concentration (Spearman's ρ = 0.56, P < 0.0001), denitrification gene abundances (ρ = 0.23-0.47, P ≤ 0.006), and the abundances of members of the families Burkholderiaceae, Anaerolinaceae, Microbacteriaceae, Acidimicrobineae incertae sedis, Cytophagaceae, and Hyphomicrobiaceae (ρ = 0.17-0.25, P ≤ 0.041). Prokaryotic community composition accounted for the least amount of variation in denitrification rates (22%), while the collective influence of spatiotemporal factors and gene abundances accounted for 37%, with 40% of the variation related to interactions among all parameters. Results of this study suggest that the hydrologic connectivity at each location had a greater effect on the prokaryotic community than did spatiotemporal differences, where inundation is associated with shifts favoring increased denitrification potential. We further establish that while complex interactions among the prokaryotic community influence denitrification, the link between hydrologic connectivity, microbial community composition, and genetic potential for biogeochemical cycling is a promising avenue to explore hydrologic remediation strategies such as periodic flooding.
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Affiliation(s)
- Abigail Tomasek
- St. Anthony Falls Laboratory, University of Minnesota, Minneapolis, MN, United States.,Department of Civil, Environmental, and Geo-Engineering, University of Minnesota, Minneapolis, MN, United States
| | - Christopher Staley
- BioTechnology Institute, University of Minnesota, St. Paul, MN, United States
| | - Ping Wang
- BioTechnology Institute, University of Minnesota, St. Paul, MN, United States
| | - Thomas Kaiser
- BioTechnology Institute, University of Minnesota, St. Paul, MN, United States
| | - Nicole Lurndahl
- Water Resources Science, University of Minnesota, St. Paul, MN, United States
| | - Jessica L Kozarek
- St. Anthony Falls Laboratory, University of Minnesota, Minneapolis, MN, United States
| | - Miki Hondzo
- St. Anthony Falls Laboratory, University of Minnesota, Minneapolis, MN, United States.,Department of Civil, Environmental, and Geo-Engineering, University of Minnesota, Minneapolis, MN, United States
| | - Michael J Sadowsky
- BioTechnology Institute, University of Minnesota, St. Paul, MN, United States.,Department of Soil, Water, and Climate, University of Minnesota, St. Paul, MN, United States
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