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Dr. Kuno Kasak
Department of Geography, University of Tartu, Tartu, Estonia

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0 Carbon Sequestration
0 Constructed Wetlands
0 Wetland Restoration
0 urban water management
0 Natural climate mitigation measures

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Constructed Wetlands
Carbon Sequestration
Wetland Restoration

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Data description paper
Published: 29 July 2021 in Earth System Science Data
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Methane (CH4) emissions from natural landscapes constitute roughly half of global CH4 contributions to the atmosphere, yet large uncertainties remain in the absolute magnitude and the seasonality of emission quantities and drivers. Eddy covariance (EC) measurements of CH4 flux are ideal for constraining ecosystem-scale CH4 emissions due to quasi-continuous and high-temporal-resolution CH4 flux measurements, coincident carbon dioxide, water, and energy flux measurements, lack of ecosystem disturbance, and increased availability of datasets over the last decade. Here, we (1) describe the newly published dataset, FLUXNET-CH4 Version 1.0, the first open-source global dataset of CH4 EC measurements (available at https://fluxnet.org/data/fluxnet-ch4-community-product/, last access: 7 April 2021). FLUXNET-CH4 includes half-hourly and daily gap-filled and non-gap-filled aggregated CH4 fluxes and meteorological data from 79 sites globally: 42 freshwater wetlands, 6 brackish and saline wetlands, 7 formerly drained ecosystems, 7 rice paddy sites, 2 lakes, and 15 uplands. Then, we (2) evaluate FLUXNET-CH4 representativeness for freshwater wetland coverage globally because the majority of sites in FLUXNET-CH4 Version 1.0 are freshwater wetlands which are a substantial source of total atmospheric CH4 emissions; and (3) we provide the first global estimates of the seasonal variability and seasonality predictors of freshwater wetland CH4 fluxes. Our representativeness analysis suggests that the freshwater wetland sites in the dataset cover global wetland bioclimatic attributes (encompassing energy, moisture, and vegetation-related parameters) in arctic, boreal, and temperate regions but only sparsely cover humid tropical regions. Seasonality metrics of wetland CH4 emissions vary considerably across latitudinal bands. In freshwater wetlands (except those between 20∘ S to 20∘ N) the spring onset of elevated CH4 emissions starts 3 d earlier, and the CH4 emission season lasts 4 d longer, for each degree Celsius increase in mean annual air temperature. On average, the spring onset of increasing CH4 emissions lags behind soil warming by 1 month, with very few sites experiencing increased CH4 emissions prior to the onset of soil warming. In contrast, roughly half of these sites experience the spring onset of rising CH4 emissions prior to the spring increase in gross primary productivity (GPP). The timing of peak summer CH4 emissions does not correlate with the timing for either peak summer temperature or peak GPP. Our results provide seasonality parameters for CH4 modeling and highlight seasonality metrics that cannot be predicted by temperature or GPP (i.e., seasonality of CH4 peak). FLUXNET-CH4 is a powerful new resource for diagnosing and understanding the role of terrestrial ecosystems and climate drivers in the global CH4 cycle, and future additions of sites in tropical ecosystems and site years of data collection will provide added value to this database. All seasonality parameters are available at https://doi.org/10.5281/zenodo.4672601 (Delwiche et al., 2021). Additionally, raw FLUXNET-CH4 data used to extract seasonality parameters can be downloaded from https://fluxnet.org/data/fluxnet-ch4-community-product/ (last access: 7 April 2021), and a complete list of the 79 individual site data DOIs is provided in Table 2 of this paper.

ACS Style

Kyle B. Delwiche; Sara Helen Knox; Avni Malhotra; Etienne Fluet-Chouinard; Gavin McNicol; Sarah Feron; Zutao Ouyang; Dario Papale; Carlo Trotta; Eleonora Canfora; You-Wei Cheah; Danielle Christianson; Ma. Carmelita R. Alberto; Pavel Alekseychik; Mika Aurela; Dennis Baldocchi; Sheel Bansal; David P. Billesbach; Gil Bohrer; Rosvel Bracho; Nina Buchmann; David I. Campbell; Gerardo Celis; Jiquan Chen; Weinan Chen; Housen Chu; Higo J. Dalmagro; Sigrid Dengel; Ankur R. Desai; Matteo Detto; Han Dolman; Elke Eichelmann; Eugenie Euskirchen; Daniela Famulari; Kathrin Fuchs; Mathias Goeckede; Sébastien Gogo; Mangaliso J. Gondwe; Jordan P. Goodrich; Pia Gottschalk; Scott L. Graham; Martin Heimann; Manuel Helbig; Carole Helfter; Kyle S. Hemes; Takashi Hirano; David Hollinger; Lukas Hörtnagl; Hiroki Iwata; Adrien Jacotot; Gerald Jurasinski; Minseok Kang; Kuno Kasak; John King; Janina Klatt; Franziska Koebsch; Ken W. Krauss; Derrick Y. F. Lai; Annalea Lohila; Ivan Mammarella; Luca Belelli Marchesini; Giovanni Manca; Jaclyn Hatala Matthes; Trofim Maximov; Lutz Merbold; Bhaskar Mitra; Timothy H. Morin; Eiko Nemitz; Mats B. Nilsson; Shuli Niu; Walter C. Oechel; Patricia Y. Oikawa; Keisuke Ono; Matthias Peichl; Olli Peltola; Michele L. Reba; Andrew D. Richardson; William Riley; Benjamin R. K. Runkle; Youngryel Ryu; Torsten Sachs; Ayaka Sakabe; Camilo Rey Sanchez; Edward A. Schuur; Karina V. R. Schäfer; Oliver Sonnentag; Jed P. Sparks; Ellen Stuart-Haëntjens; Cove Sturtevant; Ryan C. Sullivan; Daphne J. Szutu; Jonathan E. Thom; Margaret S. Torn; Eeva-Stiina Tuittila; Jessica Turner; Masahito Ueyama; Alex C. Valach; Rodrigo Vargas; Andrej Varlagin; Alma Vazquez-Lule; Joseph G. Verfaillie; Timo Vesala; George L. Vourlitis; Eric J. Ward; Christian Wille; Georg Wohlfahrt; Guan Xhuan Wong; Zhen Zhang; Donatella Zona; Lisamarie Windham-Myers; Benjamin Poulter; Robert B. Jackson. FLUXNET-CH4: a global, multi-ecosystem dataset and analysis of methane seasonality from freshwater wetlands. Earth System Science Data 2021, 13, 3607 -3689.

AMA Style

Kyle B. Delwiche, Sara Helen Knox, Avni Malhotra, Etienne Fluet-Chouinard, Gavin McNicol, Sarah Feron, Zutao Ouyang, Dario Papale, Carlo Trotta, Eleonora Canfora, You-Wei Cheah, Danielle Christianson, Ma. Carmelita R. Alberto, Pavel Alekseychik, Mika Aurela, Dennis Baldocchi, Sheel Bansal, David P. Billesbach, Gil Bohrer, Rosvel Bracho, Nina Buchmann, David I. Campbell, Gerardo Celis, Jiquan Chen, Weinan Chen, Housen Chu, Higo J. Dalmagro, Sigrid Dengel, Ankur R. Desai, Matteo Detto, Han Dolman, Elke Eichelmann, Eugenie Euskirchen, Daniela Famulari, Kathrin Fuchs, Mathias Goeckede, Sébastien Gogo, Mangaliso J. Gondwe, Jordan P. Goodrich, Pia Gottschalk, Scott L. Graham, Martin Heimann, Manuel Helbig, Carole Helfter, Kyle S. Hemes, Takashi Hirano, David Hollinger, Lukas Hörtnagl, Hiroki Iwata, Adrien Jacotot, Gerald Jurasinski, Minseok Kang, Kuno Kasak, John King, Janina Klatt, Franziska Koebsch, Ken W. Krauss, Derrick Y. F. Lai, Annalea Lohila, Ivan Mammarella, Luca Belelli Marchesini, Giovanni Manca, Jaclyn Hatala Matthes, Trofim Maximov, Lutz Merbold, Bhaskar Mitra, Timothy H. Morin, Eiko Nemitz, Mats B. Nilsson, Shuli Niu, Walter C. Oechel, Patricia Y. Oikawa, Keisuke Ono, Matthias Peichl, Olli Peltola, Michele L. Reba, Andrew D. Richardson, William Riley, Benjamin R. K. Runkle, Youngryel Ryu, Torsten Sachs, Ayaka Sakabe, Camilo Rey Sanchez, Edward A. Schuur, Karina V. R. Schäfer, Oliver Sonnentag, Jed P. Sparks, Ellen Stuart-Haëntjens, Cove Sturtevant, Ryan C. Sullivan, Daphne J. Szutu, Jonathan E. Thom, Margaret S. Torn, Eeva-Stiina Tuittila, Jessica Turner, Masahito Ueyama, Alex C. Valach, Rodrigo Vargas, Andrej Varlagin, Alma Vazquez-Lule, Joseph G. Verfaillie, Timo Vesala, George L. Vourlitis, Eric J. Ward, Christian Wille, Georg Wohlfahrt, Guan Xhuan Wong, Zhen Zhang, Donatella Zona, Lisamarie Windham-Myers, Benjamin Poulter, Robert B. Jackson. FLUXNET-CH4: a global, multi-ecosystem dataset and analysis of methane seasonality from freshwater wetlands. Earth System Science Data. 2021; 13 (7):3607-3689.

Chicago/Turabian Style

Kyle B. Delwiche; Sara Helen Knox; Avni Malhotra; Etienne Fluet-Chouinard; Gavin McNicol; Sarah Feron; Zutao Ouyang; Dario Papale; Carlo Trotta; Eleonora Canfora; You-Wei Cheah; Danielle Christianson; Ma. Carmelita R. Alberto; Pavel Alekseychik; Mika Aurela; Dennis Baldocchi; Sheel Bansal; David P. Billesbach; Gil Bohrer; Rosvel Bracho; Nina Buchmann; David I. Campbell; Gerardo Celis; Jiquan Chen; Weinan Chen; Housen Chu; Higo J. Dalmagro; Sigrid Dengel; Ankur R. Desai; Matteo Detto; Han Dolman; Elke Eichelmann; Eugenie Euskirchen; Daniela Famulari; Kathrin Fuchs; Mathias Goeckede; Sébastien Gogo; Mangaliso J. Gondwe; Jordan P. Goodrich; Pia Gottschalk; Scott L. Graham; Martin Heimann; Manuel Helbig; Carole Helfter; Kyle S. Hemes; Takashi Hirano; David Hollinger; Lukas Hörtnagl; Hiroki Iwata; Adrien Jacotot; Gerald Jurasinski; Minseok Kang; Kuno Kasak; John King; Janina Klatt; Franziska Koebsch; Ken W. Krauss; Derrick Y. F. Lai; Annalea Lohila; Ivan Mammarella; Luca Belelli Marchesini; Giovanni Manca; Jaclyn Hatala Matthes; Trofim Maximov; Lutz Merbold; Bhaskar Mitra; Timothy H. Morin; Eiko Nemitz; Mats B. Nilsson; Shuli Niu; Walter C. Oechel; Patricia Y. Oikawa; Keisuke Ono; Matthias Peichl; Olli Peltola; Michele L. Reba; Andrew D. Richardson; William Riley; Benjamin R. K. Runkle; Youngryel Ryu; Torsten Sachs; Ayaka Sakabe; Camilo Rey Sanchez; Edward A. Schuur; Karina V. R. Schäfer; Oliver Sonnentag; Jed P. Sparks; Ellen Stuart-Haëntjens; Cove Sturtevant; Ryan C. Sullivan; Daphne J. Szutu; Jonathan E. Thom; Margaret S. Torn; Eeva-Stiina Tuittila; Jessica Turner; Masahito Ueyama; Alex C. Valach; Rodrigo Vargas; Andrej Varlagin; Alma Vazquez-Lule; Joseph G. Verfaillie; Timo Vesala; George L. Vourlitis; Eric J. Ward; Christian Wille; Georg Wohlfahrt; Guan Xhuan Wong; Zhen Zhang; Donatella Zona; Lisamarie Windham-Myers; Benjamin Poulter; Robert B. Jackson. 2021. "FLUXNET-CH4: a global, multi-ecosystem dataset and analysis of methane seasonality from freshwater wetlands." Earth System Science Data 13, no. 7: 3607-3689.

Journal article
Published: 10 July 2021 in Agricultural and Forest Meteorology
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Time series of wetland methane fluxes measured by eddy covariance require gap-filling to estimate daily, seasonal, and annual emissions. Gap-filling methane fluxes is challenging because of high variability and complex responses to multiple drivers. To date, there is no widely established gap-filling standard for wetland methane fluxes, with regards both to the best model algorithms and predictors. This study synthesizes results of different gap-filling methods systematically applied at 17 wetland sites spanning boreal to tropical regions and including all major wetland classes and two rice paddies. Procedures are proposed for: 1) creating realistic artificial gap scenarios, 2) training and evaluating gap-filling models without overstating performance, and 3) predicting half-hourly methane fluxes and annual emissions with realistic uncertainty estimates. Performance is compared between a conventional method (marginal distribution sampling) and four machine learning algorithms. The conventional method achieved similar median performance as the machine learning models but was worse than the best machine learning models and relatively insensitive to predictor choices. Of the machine learning models, decision tree algorithms performed the best in cross-validation experiments, even with a baseline predictor set, and artificial neural networks showed comparable performance when using all predictors. Soil temperature was frequently the most important predictor whilst water table depth was important at sites with substantial water table fluctuations, highlighting the value of data on wetland soil conditions. Raw gap-filling uncertainties from the machine learning models were underestimated and we propose a method to calibrate uncertainties to observations. The python code for model development, evaluation, and uncertainty estimation is publicly available. This study outlines a modular and robust machine learning workflow and makes recommendations for, and evaluates an improved baseline of, methane gap-filling models that can be implemented in multi-site syntheses or standardized products from regional and global flux networks (e.g., FLUXNET).

ACS Style

Jeremy Irvin; Sharon Zhou; Gavin McNicol; Fred Lu; Vincent Liu; Etienne Fluet-Chouinard; Zutao Ouyang; Sara Helen Knox; Antje Lucas-Moffat; Carlo Trotta; Dario Papale; Domenico Vitale; Ivan Mammarella; Pavel Alekseychik; Mika Aurela; Anand Avati; Dennis Baldocchi; Sheel Bansal; Gil Bohrer; David I Campbell; Jiquan Chen; Housen Chu; Higo J Dalmagro; Kyle B Delwiche; Ankur R Desai; Eugenie Euskirchen; Sarah Feron; Mathias Goeckede; Martin Heimann; Manuel Helbig; Carole Helfter; Kyle S Hemes; Takashi Hirano; Hiroki Iwata; Gerald Jurasinski; Aram Kalhori; Andrew Kondrich; Derrick Yf Lai; Annalea Lohila; Avni Malhotra; Lutz Merbold; Bhaskar Mitra; Andrew Ng; Mats B Nilsson; Asko Noormets; Matthias Peichl; A. Camilo Rey-Sanchez; Andrew D Richardson; Benjamin Rk Runkle; Karina Vr Schäfer; Oliver Sonnentag; Ellen Stuart-Haëntjens; Cove Sturtevant; Masahito Ueyama; Alex C Valach; Rodrigo Vargas; George L Vourlitis; Eric J Ward; Guan Xhuan Wong; Donatella Zona; Ma. Carmelita R Alberto; David P Billesbach; Gerardo Celis; Han Dolman; Thomas Friborg; Kathrin Fuchs; Sébastien Gogo; Mangaliso J Gondwe; Jordan P Goodrich; Pia Gottschalk; Lukas Hörtnagl; Adrien Jacotot; Franziska Koebsch; Kuno Kasak; Regine Maier; Timothy H Morin; Eiko Nemitz; Walter C Oechel; Patricia Y Oikawa; Keisuke Ono; Torsten Sachs; Ayaka Sakabe; Edward A Schuur; Robert Shortt; Ryan C Sullivan; Daphne J Szutu; Eeva-Stiina Tuittila; Andrej Varlagin; Joeseph G Verfaillie; Christian Wille; Lisamarie Windham-Myers; Benjamin Poulter; Robert B Jackson. Gap-filling eddy covariance methane fluxes: Comparison of machine learning model predictions and uncertainties at FLUXNET-CH4 wetlands. Agricultural and Forest Meteorology 2021, 308-309, 108528 .

AMA Style

Jeremy Irvin, Sharon Zhou, Gavin McNicol, Fred Lu, Vincent Liu, Etienne Fluet-Chouinard, Zutao Ouyang, Sara Helen Knox, Antje Lucas-Moffat, Carlo Trotta, Dario Papale, Domenico Vitale, Ivan Mammarella, Pavel Alekseychik, Mika Aurela, Anand Avati, Dennis Baldocchi, Sheel Bansal, Gil Bohrer, David I Campbell, Jiquan Chen, Housen Chu, Higo J Dalmagro, Kyle B Delwiche, Ankur R Desai, Eugenie Euskirchen, Sarah Feron, Mathias Goeckede, Martin Heimann, Manuel Helbig, Carole Helfter, Kyle S Hemes, Takashi Hirano, Hiroki Iwata, Gerald Jurasinski, Aram Kalhori, Andrew Kondrich, Derrick Yf Lai, Annalea Lohila, Avni Malhotra, Lutz Merbold, Bhaskar Mitra, Andrew Ng, Mats B Nilsson, Asko Noormets, Matthias Peichl, A. Camilo Rey-Sanchez, Andrew D Richardson, Benjamin Rk Runkle, Karina Vr Schäfer, Oliver Sonnentag, Ellen Stuart-Haëntjens, Cove Sturtevant, Masahito Ueyama, Alex C Valach, Rodrigo Vargas, George L Vourlitis, Eric J Ward, Guan Xhuan Wong, Donatella Zona, Ma. Carmelita R Alberto, David P Billesbach, Gerardo Celis, Han Dolman, Thomas Friborg, Kathrin Fuchs, Sébastien Gogo, Mangaliso J Gondwe, Jordan P Goodrich, Pia Gottschalk, Lukas Hörtnagl, Adrien Jacotot, Franziska Koebsch, Kuno Kasak, Regine Maier, Timothy H Morin, Eiko Nemitz, Walter C Oechel, Patricia Y Oikawa, Keisuke Ono, Torsten Sachs, Ayaka Sakabe, Edward A Schuur, Robert Shortt, Ryan C Sullivan, Daphne J Szutu, Eeva-Stiina Tuittila, Andrej Varlagin, Joeseph G Verfaillie, Christian Wille, Lisamarie Windham-Myers, Benjamin Poulter, Robert B Jackson. Gap-filling eddy covariance methane fluxes: Comparison of machine learning model predictions and uncertainties at FLUXNET-CH4 wetlands. Agricultural and Forest Meteorology. 2021; 308-309 ():108528.

Chicago/Turabian Style

Jeremy Irvin; Sharon Zhou; Gavin McNicol; Fred Lu; Vincent Liu; Etienne Fluet-Chouinard; Zutao Ouyang; Sara Helen Knox; Antje Lucas-Moffat; Carlo Trotta; Dario Papale; Domenico Vitale; Ivan Mammarella; Pavel Alekseychik; Mika Aurela; Anand Avati; Dennis Baldocchi; Sheel Bansal; Gil Bohrer; David I Campbell; Jiquan Chen; Housen Chu; Higo J Dalmagro; Kyle B Delwiche; Ankur R Desai; Eugenie Euskirchen; Sarah Feron; Mathias Goeckede; Martin Heimann; Manuel Helbig; Carole Helfter; Kyle S Hemes; Takashi Hirano; Hiroki Iwata; Gerald Jurasinski; Aram Kalhori; Andrew Kondrich; Derrick Yf Lai; Annalea Lohila; Avni Malhotra; Lutz Merbold; Bhaskar Mitra; Andrew Ng; Mats B Nilsson; Asko Noormets; Matthias Peichl; A. Camilo Rey-Sanchez; Andrew D Richardson; Benjamin Rk Runkle; Karina Vr Schäfer; Oliver Sonnentag; Ellen Stuart-Haëntjens; Cove Sturtevant; Masahito Ueyama; Alex C Valach; Rodrigo Vargas; George L Vourlitis; Eric J Ward; Guan Xhuan Wong; Donatella Zona; Ma. Carmelita R Alberto; David P Billesbach; Gerardo Celis; Han Dolman; Thomas Friborg; Kathrin Fuchs; Sébastien Gogo; Mangaliso J Gondwe; Jordan P Goodrich; Pia Gottschalk; Lukas Hörtnagl; Adrien Jacotot; Franziska Koebsch; Kuno Kasak; Regine Maier; Timothy H Morin; Eiko Nemitz; Walter C Oechel; Patricia Y Oikawa; Keisuke Ono; Torsten Sachs; Ayaka Sakabe; Edward A Schuur; Robert Shortt; Ryan C Sullivan; Daphne J Szutu; Eeva-Stiina Tuittila; Andrej Varlagin; Joeseph G Verfaillie; Christian Wille; Lisamarie Windham-Myers; Benjamin Poulter; Robert B Jackson. 2021. "Gap-filling eddy covariance methane fluxes: Comparison of machine learning model predictions and uncertainties at FLUXNET-CH4 wetlands." Agricultural and Forest Meteorology 308-309, no. : 108528.

Preprint content
Published: 04 March 2021
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Treatment wetlands are widespread measures to reduce agricultural diffuse pollution. Systems that are often planted with emergent macrophytes such as Typha spp. and Phragmites spp. are efficient to reduce nutrients, particularly nitrogen and phosphorus compounds. While many experiments have been conducted to study the emission of carbon dioxide (CO2) and methane (CH4), little attention has been paid for the emission of nitrous oxide (N2O). Few studies have been shown that usually N2O emission from water saturated ecosystems such as wetlands is low to negligible. In Vända in-stream treatment wetland that was built in 2015 and located in southern Estonia, we carried out first long term N2O measurements using floating chambers. The total area of the wetland is roughly .5 ha; 12 boardwalks, each equipped with two sampling spots, were created. Samples were collected biweekly from March 2019 through January 2021. In each sampling campaign water table depth, water and air temperature, O2 concentration, oxygen reduction potential, pH and electrical conductivity were registered. Water samples for TN, NO3-N, NO2-N, TOC, TIC and TC were collected from inflow and outflow of the system in each sampling session and the average concentrations were 5.1 mg/L, 3.68 mg/L, <0.1 mg/L, 41.2 mg/L and 28.7, respectively. Our results showed a very high variability of N2O emission: the fluxes ranged from -4.5 ug m-2 h-1 to 2674.2 ug m-2 h-1 with mean emission of 97.3 ug m-2 h-1. Based on gas samples (n=687) we saw a strong correlation (R2 = -0.38, p<0.0001) between N2O emission and water depth. The average N2O emission from sections with the water table depth >15 cm was 45.9 ug m-2 h-1 while sections with water table depth <15 cm showed average emission of 648.3 ug m-2 h-1. The difference between these areas was more than 10 times. Water temperature that is often considered as the main driver had less effect to the N2O emission. For instance, at lower temperatures, when the emissions from deeper zones decreased, there was no temperature effect on emissions from shallow zones. We also saw that over the years the overall N2O emission followed clear seasonal dynamics and has a slight trend towards lower emissions. This can be related to the more intensive vegetation growth that has been increased from ~40% in 2019 to approximately 90% in 2020. Our study demonstrates that the design of the wetland is not only important for the water treatment, but it can also determine the magnitude of greenhouse gas emissions. We saw that even slight changes in water table depth can have a significant effect on the annual N2O emission. Thus, in-stream treatment wetlands that have water table depth at least 15 cm likely have remarkably lower N2O emissions without losing water treatment efficiency.

 

ACS Style

Kuno Kasak; Keit Kill; Evelyn Uuemaa; Ülo Mander. Design of the treatment wetland determines nitrous oxide emission. 2021, 1 .

AMA Style

Kuno Kasak, Keit Kill, Evelyn Uuemaa, Ülo Mander. Design of the treatment wetland determines nitrous oxide emission. . 2021; ():1.

Chicago/Turabian Style

Kuno Kasak; Keit Kill; Evelyn Uuemaa; Ülo Mander. 2021. "Design of the treatment wetland determines nitrous oxide emission." , no. : 1.

Preprint content
Published: 03 March 2021
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Restoring wetlands for climate mitigation purposes could provide an effective method to protect existing soil carbon stocks, as well as act as a negative emission technology by sequestering atmospheric carbon for 100-1000s of years. However, many peatlands have low productivity limiting carbon sequestration, while high productivity marshes often emit large amounts of methane. Studies on water level management to control methane emissions have shown differing results depending on wetland type, climate, as well as measurement method and duration. Here we show with multi-year flux measurements that water level changes were likely responsible for significantly reducing annual methane emissions. To assess management impacts on annual greenhouse gas budgets, continuous high frequency measurements of fluxes are needed, such as by eddy covariance. However, this method is less suited to monitor concurrent manipulation experiments to compare treatments.  We compared the impact of water level fluctuations by creating a second timeseries where water drawdown events were removed, which was then gap-filled by a random forest model trained only on measurements from periods when the water table was above the surface. These estimates were used to compare the annual budgets with the complete data and showed that annual methane emissions were up to 50% lower in years where water levels went sufficiently below the peat surface. This threshold was key, as only reductions in water depth above the surface were related to temporary increases in emissions. We further show that in some cases the drawdowns tipped the greenhouse gas budgets so that marshes were net greenhouse gas sinks, as long as the drawdown did not also reduce plant productivity through drought stress. In comparison, wetlands with average annual fluxes would require between approx. 50 and 200 years given current levels of net carbon uptake to offset high methane emissions and become cumulative greenhouse gas sinks. 

ACS Style

Alex Valach; Elke Eichelmann; Kyle Hemes; Kuno Kasak; Sara Knox; Patty Oikawa; Daphne Szutu; Joseph Verfaillie; Dennis Baldocchi. Managing hydrology can reduce methane emissions of high-emitting freshwater marshes by half making them present-day net greenhouse gas sinks. 2021, 1 .

AMA Style

Alex Valach, Elke Eichelmann, Kyle Hemes, Kuno Kasak, Sara Knox, Patty Oikawa, Daphne Szutu, Joseph Verfaillie, Dennis Baldocchi. Managing hydrology can reduce methane emissions of high-emitting freshwater marshes by half making them present-day net greenhouse gas sinks. . 2021; ():1.

Chicago/Turabian Style

Alex Valach; Elke Eichelmann; Kyle Hemes; Kuno Kasak; Sara Knox; Patty Oikawa; Daphne Szutu; Joseph Verfaillie; Dennis Baldocchi. 2021. "Managing hydrology can reduce methane emissions of high-emitting freshwater marshes by half making them present-day net greenhouse gas sinks." , no. : 1.

Preprint content
Published: 18 January 2021
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Methane (CH4) emissions from natural landscapes constitute roughly half of global CH4 contributions to the atmosphere, yet large uncertainties remain in the absolute magnitude and the seasonality of emission quantities and drivers. Eddy covariance (EC) measurements of CH4 flux are ideal for constraining ecosystem-scale CH4 emissions, including their seasonality, due to quasi-continuous and high temporal resolution of flux measurements, coincident measurements of carbon, water, and energy fluxes, lack of ecosystem disturbance, and increased availability of datasets over the last decade. Here, we 1) describe the newly published dataset, FLUXNET-CH4 Version 1.0, the first global dataset of CH4 EC measurements (available at https://fluxnet.org/data/fluxnet-ch4- community-product/). FLUXNET-CH4 includes half-hourly and daily gap-filled and non gap-filled aggregated CH4 fluxes and meteorological data from 79 sites globally: 42 freshwater wetlands, 6 brackish and saline wetlands, 7 formerly drained ecosystems, 7 rice paddy sites, 2 lakes, and 15 uplands. Then, we 2) evaluate FLUXNET-CH4 representativeness for freshwater wetland coverage globally, because the majority of sites in FLUXNET-CH4 Version 1.0 are freshwater wetlands and because freshwater wetlands are a substantial source of total atmospheric CH4 emissions; and 3) provide the first global estimates of the seasonal variability and seasonality predictors of freshwater wetland CH4 fluxes. Our representativeness analysis suggests that the freshwater wetland sites in the dataset cover global wetland bioclimatic attributes (encompassing energy, moisture, and vegetation-related parameters) in arctic, boreal, and temperate regions, but only sparsely cover humid tropical regions. Seasonality metrics of wetland CH4 emissions vary considerably across latitudinal bands. In freshwater wetlands (except those between 20° S to 20° N) the spring onset of elevated CH4 emissions starts three days earlier, and the CH4 emission season lasts 4 days longer, for each degree C increase in mean annual air temperature. On average, the onset of increasing CH4 emissions lags soil warming by one month, with very few sites experiencing increased CH4 emissions prior to the onset of soil warming. In contrast, roughly half of these sites experience the spring onset of rising CH4 emissions prior to the spring increase in gross primary productivity (GPP). The timing of peak summer CH4 emissions does not correlate with the timing for either peak summer temperature or peak GPP. Our results provide seasonality parameters for CH4 modeling, and highlight seasonality metrics that cannot be predicted by temperature or GPP (i.e., seasonality of CH4 peak). The FLUXNET-CH4 dataset provides an open-access resource for CH4 flux synthesis, has a range of applications, and is unique in that it includes coupled measurements of important CH4 drivers such as GPP and temperature. Although FLUXNET-CH4 could certainly be improved by adding more sites in tropical ecosystems and by increasing the number of site-years at existing sites, it is a powerful new resource for diagnosing and understanding the role of terrestrial ecosystems and climate drivers in the global CH4 cycle. All seasonality parameters are available at https://doi.org/10.5281/zenodo.4408468. Additionally, raw FLUXNET-CH4 data used to extract seasonality parameters can be downloaded from https://fluxnet.org/data/fluxnet-ch4-community-product/, and a complete list of the 79 individual site data DOIs is provided in Table 2 in the Data Availability section of this document.

ACS Style

Kyle B. Delwiche; Sara Helen Knox; Avni Malhotra; Etienne Fluet-Chouinard; Gavin McNicol; Sarah Feron; Zutao Ouyang; Dario Papale; Carlo Trotta; Eleonora Canfora; You-Wei Cheah; Danielle Christianson; M. Carmelita R. Alberto; Pavel Alekseychik; Mika Aurela; Dennis Baldocchi; Sheel Bansal; David P. Billesbach; Gil Bohrer; Rosvel Bracho; Nina Buchmann; David I. Campbell; Gerardo Celis; Jiquan Chen; Weinan Chen; Housen Chu; Higo J. Dalmagro; Sigrid Dengel; Ankur R. Desai; Matteo Detto; Han Dolman; Elke Eichelmann; Eugenie Euskirchen; Daniela Famulari; Thomas Friborg; Kathrin Fuchs; Mathias Goeckede; Sébastien Gogo; Mangaliso J. Gondwe; Jordan P. Goodrich; Pia Gottschalk; Scott L. Graham; Martin Heimann; Manuel Helbig; Carole Helfter; Kyle S. Hemes; Takashi Hirano; David Hollinger; Lukas Hörtnagl; Hiroki Iwata; Adrien Jacotot; Joachim Jansen; Gerald Jurasinski; Minseok Kang; Kuno Kasak; John King; Janina Klatt; Franziska Koebsch; Ken W. Krauss; Derrick Y. F. Lai; Ivan Mammarella; Giovanni Manca; Luca Belelli Marchesini; Jaclyn Hatala Matthes; Trofim Maximon; Lutz Merbold; Bhaskar Mitra; Timothy H. Morin; Eiko Nemitz; Mats B. Nilsson; Shuli Niu; Walter C. Oechel; Patricia Y. Oikawa; Keisuke Ono; Matthias Peichl; Olli Peltola; Michele L. Reba; Andrew D. Richardson; William Riley; Benjamin R. K. Runkle; Youngryel Ryu; Torsten Sachs; Ayaka Sakabe; Camilo Rey Sanchez; Edward A. Schuur; Karina V. R. Schäfer; Oliver Sonnentag; Jed P. Sparks; Ellen Stuart-Haëntjens; Cove Sturtevant; Ryan C. Sullivan; Daphne J. Szutu; Jonathan E. Thom; Margaret S. Torn; Eeva-Stiina Tuittila; Jessica Turner; Masahito Ueyama; Alex C. Valach; Rodrigo Vargas; Andrej Varlagin; Alma Vazquez-Lule; Joseph G. Verfaillie; Timo Vesala; George L. Vourlitis; Eric J. Ward; Christian Wille; Georg Wohlfahrt; Guan Xhuan Wong; Zhen Zhang; Donatella Zona; Lisamarie Windham-Myers; Benjamin Poulter; Robert B. Jackson. FLUXNET-CH4: A global, multi-ecosystem dataset and analysis of methane seasonality from freshwater wetlands. 2021, 2021, 1 -111.

AMA Style

Kyle B. Delwiche, Sara Helen Knox, Avni Malhotra, Etienne Fluet-Chouinard, Gavin McNicol, Sarah Feron, Zutao Ouyang, Dario Papale, Carlo Trotta, Eleonora Canfora, You-Wei Cheah, Danielle Christianson, M. Carmelita R. Alberto, Pavel Alekseychik, Mika Aurela, Dennis Baldocchi, Sheel Bansal, David P. Billesbach, Gil Bohrer, Rosvel Bracho, Nina Buchmann, David I. Campbell, Gerardo Celis, Jiquan Chen, Weinan Chen, Housen Chu, Higo J. Dalmagro, Sigrid Dengel, Ankur R. Desai, Matteo Detto, Han Dolman, Elke Eichelmann, Eugenie Euskirchen, Daniela Famulari, Thomas Friborg, Kathrin Fuchs, Mathias Goeckede, Sébastien Gogo, Mangaliso J. Gondwe, Jordan P. Goodrich, Pia Gottschalk, Scott L. Graham, Martin Heimann, Manuel Helbig, Carole Helfter, Kyle S. Hemes, Takashi Hirano, David Hollinger, Lukas Hörtnagl, Hiroki Iwata, Adrien Jacotot, Joachim Jansen, Gerald Jurasinski, Minseok Kang, Kuno Kasak, John King, Janina Klatt, Franziska Koebsch, Ken W. Krauss, Derrick Y. F. Lai, Ivan Mammarella, Giovanni Manca, Luca Belelli Marchesini, Jaclyn Hatala Matthes, Trofim Maximon, Lutz Merbold, Bhaskar Mitra, Timothy H. Morin, Eiko Nemitz, Mats B. Nilsson, Shuli Niu, Walter C. Oechel, Patricia Y. Oikawa, Keisuke Ono, Matthias Peichl, Olli Peltola, Michele L. Reba, Andrew D. Richardson, William Riley, Benjamin R. K. Runkle, Youngryel Ryu, Torsten Sachs, Ayaka Sakabe, Camilo Rey Sanchez, Edward A. Schuur, Karina V. R. Schäfer, Oliver Sonnentag, Jed P. Sparks, Ellen Stuart-Haëntjens, Cove Sturtevant, Ryan C. Sullivan, Daphne J. Szutu, Jonathan E. Thom, Margaret S. Torn, Eeva-Stiina Tuittila, Jessica Turner, Masahito Ueyama, Alex C. Valach, Rodrigo Vargas, Andrej Varlagin, Alma Vazquez-Lule, Joseph G. Verfaillie, Timo Vesala, George L. Vourlitis, Eric J. Ward, Christian Wille, Georg Wohlfahrt, Guan Xhuan Wong, Zhen Zhang, Donatella Zona, Lisamarie Windham-Myers, Benjamin Poulter, Robert B. Jackson. FLUXNET-CH4: A global, multi-ecosystem dataset and analysis of methane seasonality from freshwater wetlands. . 2021; 2021 ():1-111.

Chicago/Turabian Style

Kyle B. Delwiche; Sara Helen Knox; Avni Malhotra; Etienne Fluet-Chouinard; Gavin McNicol; Sarah Feron; Zutao Ouyang; Dario Papale; Carlo Trotta; Eleonora Canfora; You-Wei Cheah; Danielle Christianson; M. Carmelita R. Alberto; Pavel Alekseychik; Mika Aurela; Dennis Baldocchi; Sheel Bansal; David P. Billesbach; Gil Bohrer; Rosvel Bracho; Nina Buchmann; David I. Campbell; Gerardo Celis; Jiquan Chen; Weinan Chen; Housen Chu; Higo J. Dalmagro; Sigrid Dengel; Ankur R. Desai; Matteo Detto; Han Dolman; Elke Eichelmann; Eugenie Euskirchen; Daniela Famulari; Thomas Friborg; Kathrin Fuchs; Mathias Goeckede; Sébastien Gogo; Mangaliso J. Gondwe; Jordan P. Goodrich; Pia Gottschalk; Scott L. Graham; Martin Heimann; Manuel Helbig; Carole Helfter; Kyle S. Hemes; Takashi Hirano; David Hollinger; Lukas Hörtnagl; Hiroki Iwata; Adrien Jacotot; Joachim Jansen; Gerald Jurasinski; Minseok Kang; Kuno Kasak; John King; Janina Klatt; Franziska Koebsch; Ken W. Krauss; Derrick Y. F. Lai; Ivan Mammarella; Giovanni Manca; Luca Belelli Marchesini; Jaclyn Hatala Matthes; Trofim Maximon; Lutz Merbold; Bhaskar Mitra; Timothy H. Morin; Eiko Nemitz; Mats B. Nilsson; Shuli Niu; Walter C. Oechel; Patricia Y. Oikawa; Keisuke Ono; Matthias Peichl; Olli Peltola; Michele L. Reba; Andrew D. Richardson; William Riley; Benjamin R. K. Runkle; Youngryel Ryu; Torsten Sachs; Ayaka Sakabe; Camilo Rey Sanchez; Edward A. Schuur; Karina V. R. Schäfer; Oliver Sonnentag; Jed P. Sparks; Ellen Stuart-Haëntjens; Cove Sturtevant; Ryan C. Sullivan; Daphne J. Szutu; Jonathan E. Thom; Margaret S. Torn; Eeva-Stiina Tuittila; Jessica Turner; Masahito Ueyama; Alex C. Valach; Rodrigo Vargas; Andrej Varlagin; Alma Vazquez-Lule; Joseph G. Verfaillie; Timo Vesala; George L. Vourlitis; Eric J. Ward; Christian Wille; Georg Wohlfahrt; Guan Xhuan Wong; Zhen Zhang; Donatella Zona; Lisamarie Windham-Myers; Benjamin Poulter; Robert B. Jackson. 2021. "FLUXNET-CH4: A global, multi-ecosystem dataset and analysis of methane seasonality from freshwater wetlands." 2021, no. : 1-111.

Journal article
Published: 06 October 2020 in Ecological Engineering
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Constructed wetlands are used as an effective measure to improve water quality and reduce nutrient runoff from agriculture. However, their role as alternative breeding sites for different amphibian species is rarely explored. We studied amphibians' colonization and breeding success in two in-stream free surface water wetlands in intensively managed agricultural landscape in south-eastern Estonia. Additionally, the sedimentation pond and a nearby farm pond were observed. The observations started a year after the establishment of the constructed wetlands in 2015 and lasted for four years. In Vända constructed wetlands, breeding of five amphibian species were observed, all of which were common to the area: smooth newt (Lissotriton vulgaris L.), common toad (Bufo bufo L.), common frog (Rana temporaria L.), moor frog (Rana arvalis Nilsson) and pool frog (Pelophylax lessonae Camerano). Threatened species, such as the common spadefoot toad (Pelobates fuscus Wagler) or the northern crested newt (Triturus cristatus Laur.), also present in this region, were not found in the study sites. Unlike the sedimentation and farm ponds, constructed wetlands with their shallow rapidly warming water and absence of fish, provided breeding habitat for amphibians, especially for common frog and moor frog. In addition, chemical analyses of the water showed that nutrient concentration in the surface water was relatively low, which should not impair the reproduction of amphibians, at least in the short-term.

ACS Style

Riinu Rannap; Marta M. Kaart; Tanel Kaart; Keit Kill; Evelyn Uuemaa; Ülo Mander; Kuno Kasak. Constructed wetlands as potential breeding sites for amphibians in agricultural landscapes: A case study. Ecological Engineering 2020, 158, 106077 .

AMA Style

Riinu Rannap, Marta M. Kaart, Tanel Kaart, Keit Kill, Evelyn Uuemaa, Ülo Mander, Kuno Kasak. Constructed wetlands as potential breeding sites for amphibians in agricultural landscapes: A case study. Ecological Engineering. 2020; 158 ():106077.

Chicago/Turabian Style

Riinu Rannap; Marta M. Kaart; Tanel Kaart; Keit Kill; Evelyn Uuemaa; Ülo Mander; Kuno Kasak. 2020. "Constructed wetlands as potential breeding sites for amphibians in agricultural landscapes: A case study." Ecological Engineering 158, no. : 106077.

Journal article
Published: 03 August 2020 in Soil Systems
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Constructed wetland-microbial electrochemical snorkel (CW-MES) systems, which are short-circuited microbial fuel cells (MFC), have emerged as a novel tool for wastewater management, although the system mechanisms are insufficiently studied in process-based or environmental contexts. Based on quantitative polymerase chain reaction assays, we assessed the prevalence of different nitrogen removal processes for treating nitrate-rich waters with varying cathode materials (stainless steel, graphite felt, and copper) and sizes in the CW-MES systems and correlated them to the changes of N2O emissions. The nitrate and nitrite removal efficiencies were in range of 40% to 75% and over 98%, respectively. In response to the electrochemical manipulation, the abundances of most of the nitrogen-transforming microbial groups decreased in general. Graphite felt cathodes supported nitrifiers, but nirK-type denitrifiers were inhibited. Anaerobic ammonium oxidation (ANAMMOX) bacteria were less abundant in the electrochemically manipulated treatments compared to the controls. ANAMMOX and denitrification are the main nitrogen reducers in CW-MES systems. The treatments with 1:1 graphite felt, copper, plastic, and stainless-steel cathodes showed higher N2O emissions. nirS- and nosZI-type denitrifiers are mainly responsible for producing and reducing N2O emissions, respectively. Hence, electrochemical manipulation supported dissimilatory nitrate reduction to ammonium (DNRA) microbes may play a crucial role in producing N2O in CW-MES systems.

ACS Style

Sharvari S. Gadegaonkar; Timothé Philippon; Joanna M. Rogińska; Ülo Mander; Martin Maddison; Mathieu Etienne; Frédéric Barrière; Kuno Kasak; Rauno Lust; Mikk Espenberg. Effect of Cathode Material and Its Size on the Abundance of Nitrogen Removal Functional Genes in Microcosms of Integrated Bioelectrochemical-Wetland Systems. Soil Systems 2020, 4, 47 .

AMA Style

Sharvari S. Gadegaonkar, Timothé Philippon, Joanna M. Rogińska, Ülo Mander, Martin Maddison, Mathieu Etienne, Frédéric Barrière, Kuno Kasak, Rauno Lust, Mikk Espenberg. Effect of Cathode Material and Its Size on the Abundance of Nitrogen Removal Functional Genes in Microcosms of Integrated Bioelectrochemical-Wetland Systems. Soil Systems. 2020; 4 (3):47.

Chicago/Turabian Style

Sharvari S. Gadegaonkar; Timothé Philippon; Joanna M. Rogińska; Ülo Mander; Martin Maddison; Mathieu Etienne; Frédéric Barrière; Kuno Kasak; Rauno Lust; Mikk Espenberg. 2020. "Effect of Cathode Material and Its Size on the Abundance of Nitrogen Removal Functional Genes in Microcosms of Integrated Bioelectrochemical-Wetland Systems." Soil Systems 4, no. 3: 47.

Preprint content
Published: 23 March 2020
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Restoring degraded peat soils to wetlands can be an attractive and efficient measure with many benefits including carbon sequestration, water quality improvement, food and habitat for wildlife, flood control, and opportunities for recreation. Agricultural lands which are restored to wetlands will start rebuild soils and reverse land subsidence. Using eddy covariance towers in four wetlands that were restored in 1997, 2010, 2013 and 2016 in the Sacramento-San Joaquin Delta in California, we saw high carbon sequestration potentials and peat accumulation. Since soil restoration takes place gradually, it is important to specify the critical turning-points in the process of improving soil microbial community structure and nitrogen cycling. In August 2018, soil samples from four wetlands with different restoration ages in the Delta were collected for chemical and microbial analyses. The bacterial and archaeal 16S rRNA genes and functional genes involved in nitrogen cycling (nirS, nirK, nosZ-I, nosZ-II, bacterial and archaeal amoA, nifH, nrfA, and ANAMMOX-specific genes) in soils were determined using a quantitative PCR method. Soil chemical parameters such as C%, N%, Al, Mn, Fe and two different organic and inorganic P pools were analysed as well. Preliminary results indicate significant dissimilarities in the abundance of soil bacterial and archaeal communities, as well as nirS, nirK, nosZ, nifH, nrfA and archaeal amoA gene-possessing microbial communities in different wetlands. Data analysis showed several statistically significant relationships between target gene parameters and soil chemical parameters that were different when comparing the sites with the restoration age. It is clear, that the complexity of the relationships increases as the wetland gets older. For example, in younger wetlands the availability of C and N plays a crucial role in gene abundances while in the oldest wetland, the most important chemical parameters were different phosphorus forms. This might indicate that more than 20 years of C and N accumulation has led to the availability of phosphorus for N transformation now to be the main limiting factor. Another important finding was that the design criteria can also determine how the wetland acts in terms of nitrogen gas emissions. For example, one of the wetlands was designed with more varied bathymetry that includes many open channels and a fluctuating water table. We saw that the nifH gene-possessing microbes that are responsible for molecular N fixing are highly abundant in open water areas while at the same time this wetland has also the highest abundance of nir genes that control N2O production by denitrifiers. Our study demonstrates that the design of the wetland can have a significant impact on N-transforming processes, but most importantly at some age, restored wetlands become more similar to natural wetlands.

ACS Style

Kuno Kasak; Tyler Anthony; Alex Valach; Kyle Hemes; Keit Kill; Whendee Silver; Ülo Mander; Daphne Szutu; Joseph Verfaillie; Dennis Baldocchi. Variability of nitrogen-cycle microbial communities determined by the age of restored wetlands. 2020, 1 .

AMA Style

Kuno Kasak, Tyler Anthony, Alex Valach, Kyle Hemes, Keit Kill, Whendee Silver, Ülo Mander, Daphne Szutu, Joseph Verfaillie, Dennis Baldocchi. Variability of nitrogen-cycle microbial communities determined by the age of restored wetlands. . 2020; ():1.

Chicago/Turabian Style

Kuno Kasak; Tyler Anthony; Alex Valach; Kyle Hemes; Keit Kill; Whendee Silver; Ülo Mander; Daphne Szutu; Joseph Verfaillie; Dennis Baldocchi. 2020. "Variability of nitrogen-cycle microbial communities determined by the age of restored wetlands." , no. : 1.

Journal article
Published: 13 February 2020 in Water
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Assessments of groundwater aquifers made around the world show that in many cases, nitrate concentrations exceed the safe drinking water threshold. This study assessed how bioelectrochemical systems could be used to enhance nitrate removal from waters with low organic carbon concentrations. A two-chamber microbial electrosynthesis cell (MES) was constructed and operated for 45 days with inoculum that was taken from a municipal wastewater treatment plant. A study showed that MES can be used to enhance nitrate removal efficiency from 3.66% day−1 in a control reactor to 8.54% day−1 in the MES reactor, if a cathode is able to act as an electron donor for autotrophic denitrifying bacteria or there is reducing oxygen in a cathodic chamber to favor denitrification. In the MES, greenhouse gas emissions were also lower compared to the control. Nitrous oxide average fluxes were −639.59 and −9.15 µg N m−2 h−1 for the MES and control, respectively, and the average carbon dioxide fluxes were −5.28 and 43.80 mg C m−2 h−1, respectively. The current density correlated significantly with the dissolved oxygen concentration, indicating that it is essential to keep the dissolved oxygen concentration in the cathode chamber as low as possible, not only to suppress oxygen’s inhibiting effect on denitrification but also to achieve better power efficiency.

ACS Style

Rauno Lust; Jaak Nerut; Kuno Kasak; Ülo Mander. Enhancing Nitrate Removal from Waters with Low Organic Carbon Concentration Using a Bioelectrochemical System—A Pilot-Scale Study. Water 2020, 12, 516 .

AMA Style

Rauno Lust, Jaak Nerut, Kuno Kasak, Ülo Mander. Enhancing Nitrate Removal from Waters with Low Organic Carbon Concentration Using a Bioelectrochemical System—A Pilot-Scale Study. Water. 2020; 12 (2):516.

Chicago/Turabian Style

Rauno Lust; Jaak Nerut; Kuno Kasak; Ülo Mander. 2020. "Enhancing Nitrate Removal from Waters with Low Organic Carbon Concentration Using a Bioelectrochemical System—A Pilot-Scale Study." Water 12, no. 2: 516.

Journal article
Published: 27 January 2020 in Science of The Total Environment
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Constructed wetlands built for water treatment often need biomass harvesting to remove nutrients from the system. Usually harvesting is done during the peak growing season to maximize the amount of nutrients removed from the system. This, however, can create huge methane fluxes that escape from plant tissues to the atmosphere. We used manual chambers and eddy covariance measurements to analyze the increase in methane emissions due to the harvesting of two common wetland species, Typha spp. and Schoenoplectus spp., in two climatically different constructed wetlands in Estonia and California. In addition, we determined the biomass nutrient and carbon concentrations from harvested biomass. We found that harvesting during the summer season, e.g. June and August, resulted in a significant release of methane at both sites. At the California site, baseline median methane emissions were 217.6 nmol m−2 s−1, and harvesting resulted in increases to 395.4 nmol m−2 s−1 that decreased to baseline emission within three days. Footprint modeling demonstrated that the emission increases measured by eddy covariance were dominated by contributions from the cut area to the total footprint signal. At the Estonian site, harvesting resulted in methane increases of 15.9 nmol m−2 s−1 to 110.4 nmol m−2 s−1 in August. However, in September and October the emission was significantly lower. Plant biomass analyses showed clear temporal dynamics in terms of nutrient concentration, being highest in summer and lowest in winter. Our experiments indicate that the optimal time for aboveground biomass harvesting is at the end of the growing season before nutrient translocation to belowground plant structures begins coinciding with lowest methane emissions. Therefore, strategic planning of the harvest timing may help reduce greenhouse gas emissions from managed wetlands and thus improve their multi-faceted ecological benefit.

ACS Style

K. Kasak; Alex Valach; C. Rey-Sanchez; K. Kill; R. Shortt; J. Liu; I. Dronova; Ü. Mander; D. Szutu; J. Verfaillie; D.D. Baldocchi. Experimental harvesting of wetland plants to evaluate trade-offs between reducing methane emissions and removing nutrients accumulated to the biomass in constructed wetlands. Science of The Total Environment 2020, 715, 136960 .

AMA Style

K. Kasak, Alex Valach, C. Rey-Sanchez, K. Kill, R. Shortt, J. Liu, I. Dronova, Ü. Mander, D. Szutu, J. Verfaillie, D.D. Baldocchi. Experimental harvesting of wetland plants to evaluate trade-offs between reducing methane emissions and removing nutrients accumulated to the biomass in constructed wetlands. Science of The Total Environment. 2020; 715 ():136960.

Chicago/Turabian Style

K. Kasak; Alex Valach; C. Rey-Sanchez; K. Kill; R. Shortt; J. Liu; I. Dronova; Ü. Mander; D. Szutu; J. Verfaillie; D.D. Baldocchi. 2020. "Experimental harvesting of wetland plants to evaluate trade-offs between reducing methane emissions and removing nutrients accumulated to the biomass in constructed wetlands." Science of The Total Environment 715, no. : 136960.

Journal article
Published: 24 January 2019 in Agricultural and Forest Meteorology
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Restoring degraded peat soils presents an attractive, but largely untested, climate change mitigation approach. Drained peat soils used for agriculture can be large greenhouse gas sources. By restoring subsided peat soils to managed, impounded wetlands, significant agricultural emissions are avoided, and soil carbon can be sequestered and protected. Here, we synthesize 36 site-years of continuous carbon dioxide and methane flux data from a mesonetwork of eddy covariance towers in the Sacramento-San Joaquin Delta in California, USA to compute carbon and greenhouse gas budgets for drained agricultural land uses and compare these to restored deltaic wetlands. We found that restored wetlands effectively sequestered carbon and halted soil carbon loss associated with drained agricultural land uses. Depending on the age and disturbance regime of the restored wetland, many land use conversions from agriculture to restored wetland resulted in emission reductions over a 100-year timescale. With a simple model of radiative forcing and atmospheric lifetimes, we showed that restored wetlands do not begin to accrue greenhouse gas benefits until nearly a half century, and become net sinks from the atmosphere after a century. Due to substantial interannual variability and uncertainty about the multi-decadal successional trajectory of managed, restored wetlands, ongoing ecosystem flux measurements are critical for understanding the long-term impacts of wetland restoration for climate change mitigation.

ACS Style

Kyle S. Hemes; Samuel D. Chamberlain; Elke Eichelmann; Tyler Anthony; Alex Valach; Kuno Kasak; Daphne Szutu; Joe Verfaillie; Whendee L. Silver; Dennis D. Baldocchi. Assessing the carbon and climate benefit of restoring degraded agricultural peat soils to managed wetlands. Agricultural and Forest Meteorology 2019, 268, 202 -214.

AMA Style

Kyle S. Hemes, Samuel D. Chamberlain, Elke Eichelmann, Tyler Anthony, Alex Valach, Kuno Kasak, Daphne Szutu, Joe Verfaillie, Whendee L. Silver, Dennis D. Baldocchi. Assessing the carbon and climate benefit of restoring degraded agricultural peat soils to managed wetlands. Agricultural and Forest Meteorology. 2019; 268 ():202-214.

Chicago/Turabian Style

Kyle S. Hemes; Samuel D. Chamberlain; Elke Eichelmann; Tyler Anthony; Alex Valach; Kuno Kasak; Daphne Szutu; Joe Verfaillie; Whendee L. Silver; Dennis D. Baldocchi. 2019. "Assessing the carbon and climate benefit of restoring degraded agricultural peat soils to managed wetlands." Agricultural and Forest Meteorology 268, no. : 202-214.

Journal article
Published: 08 November 2018 in Water
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Diffuse agricultural pollution degrades water quality and is one of the main causes of eutrophication; therefore, it is important to reduce it. Constructed wetlands (CW) can be used as an effective measure for water quality improvement. There are two possible ways to establish surface flow CWs, in-stream and off-stream. We studied treatment efficiency of the in-stream free surface flow (FSW) Vända CW in southern Estonia from March 2017 until July 2018. The CW consists of two shallow-water parts planted with cattail (Typha latifolia). According to our analyses, the CW reduced total phosphorus (TP) and phosphate (PO4-P) by 20.5% and 16.3%, respectively, however, in summer, phosphorus removal was twice as high. We saw significant logarithmic correlation between flow rates and log TP and log PO4-P removal efficiency (rs = 0.53, rs = 0.63, p < 0.01 respectively). Yearly reduction of total organic carbon was 12.4% while total inorganic carbon increased by 9.7% due to groundwater seepage. Groundwater inflow also increased the concentration of total nitrogen in the outlet by 27.7% and nitrate concentration by 31.6%. In-stream FWS CWs are a promising measure to reduce diffuse pollution from agriculture; however, our experience and literature data prove that there are several factors that can influence CWs’ treatment efficiency.

ACS Style

Keit Kill; Jaan Pärn; Rauno Lust; Ülo Mander; Kuno Kasak. Treatment Efficiency of Diffuse Agricultural Pollution in a Constructed Wetland Impacted by Groundwater Seepage. Water 2018, 10, 1601 .

AMA Style

Keit Kill, Jaan Pärn, Rauno Lust, Ülo Mander, Kuno Kasak. Treatment Efficiency of Diffuse Agricultural Pollution in a Constructed Wetland Impacted by Groundwater Seepage. Water. 2018; 10 (11):1601.

Chicago/Turabian Style

Keit Kill; Jaan Pärn; Rauno Lust; Ülo Mander; Kuno Kasak. 2018. "Treatment Efficiency of Diffuse Agricultural Pollution in a Constructed Wetland Impacted by Groundwater Seepage." Water 10, no. 11: 1601.

Journal article
Published: 01 October 2018 in Science of The Total Environment
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Biochar has shown great potential as an amendment to improve soil quality and promote plant growth, as well as to adsorb pollutants from water. However, information about the effect of biochar on the wastewater treatment efficiency in horizontal subsurface flow (HSSF) constructed wetlands (CWs) is still scarce. In this study, we assessed the effect of biochar amendment on the purification efficiency of pretreated municipal wastewater in planted (Typha latifolia) experimental horizontal subsurface flow filters filled with lightweight expanded clay aggregates (LECA). The addition of wood-derived biochar (10% v/v) to LECA significantly increased plant biomass production and enhanced the wastewater treatment efficiency of the planted filters. Both the aboveground plant biomass and belowground plant biomass were higher (1.9- and 1.5-fold, respectively) in the filters of the LBP (LECA + biochar + plants) treatments compared to the LP (LECA + plants) filters. The water pH was significantly lower in the planted filters (LBP < LP < LB-LECA + biochar). The efficiencies of TN and TP removal from wastewater were highest in the LBP filters (20.0% and 22.5%, respectively), followed by the LP (13.7% and 16.2%, respectively) and LB (9.5% and 15.6%, respectively) filters. More N and P were incorporated into the plant biomass from wastewater in the presence of biochar in the filter medium. The study results confirm that biochar can be an advantageous supplement for planted HSSF CWs to enhance the treatment efficiency of these systems.

ACS Style

Kuno Kasak; Jaak Truu; Ivika Ostonen; Jürgen Sarjas; Kristjan Oopkaup; Päärn Paiste; Margit Kõiv-Vainik; Ülo Mander; Marika Truu. Biochar enhances plant growth and nutrient removal in horizontal subsurface flow constructed wetlands. Science of The Total Environment 2018, 639, 67 -74.

AMA Style

Kuno Kasak, Jaak Truu, Ivika Ostonen, Jürgen Sarjas, Kristjan Oopkaup, Päärn Paiste, Margit Kõiv-Vainik, Ülo Mander, Marika Truu. Biochar enhances plant growth and nutrient removal in horizontal subsurface flow constructed wetlands. Science of The Total Environment. 2018; 639 ():67-74.

Chicago/Turabian Style

Kuno Kasak; Jaak Truu; Ivika Ostonen; Jürgen Sarjas; Kristjan Oopkaup; Päärn Paiste; Margit Kõiv-Vainik; Ülo Mander; Marika Truu. 2018. "Biochar enhances plant growth and nutrient removal in horizontal subsurface flow constructed wetlands." Science of The Total Environment 639, no. : 67-74.

Journal article
Published: 01 August 2018 in Ecological Engineering
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Diffuse agricultural pollution, especially from intensively managed agricultural land is a major cause of eutrophication, therefore it is important to reduce the diffuse load to surface water. Constructed wetlands (CW) are an effective measure for improving water quality and reducing nutrient runoff from agriculture by using natural water treatment mechanisms. We studied treatment efficiency of an in-stream free surface flow (FSW) Vända CW in southern Estonia from 16th of March 2017 till 11th of January 2018. Vända CW has a catchment area of 2.2 km2 and of which approximately 62% is under intensive agricultural management. The CW consists of a sedimentation pond followed by two shallow water wetlands planted with cattail (Typha latifolia). Our analyses showed that the CW retained 17.5 kg phosphorus (P) ha−1 yr−1. During the warm period phosphate removal was up to 41.8% whereas annually it was only 14.4%. Phosphate removal efficiency showed strong negative correlation (R2 = 0.58, p < 0.001) with flow rate and therefore it can be seen that shorter retention time reduces significantly the overall P removal efficiency. The yearly reduction of total organic carbon was up to 3300 kg C ha−1 yr−1 while surprisingly the CW increased total nitrogen up to 1375 kg N ha−1 yr−1. The results demonstrate that the acclimatization period of newly established in-stream FWS CWs in northern countries can be relatively long and after two years of establishment we still cannot see satisfactory treatment processes, especially in nitrogen.

ACS Style

Kuno Kasak; Keit Kill; Jaan Pärn; Ülo Mander. Efficiency of a newly established in-stream constructed wetland treating diffuse agricultural pollution. Ecological Engineering 2018, 119, 1 -7.

AMA Style

Kuno Kasak, Keit Kill, Jaan Pärn, Ülo Mander. Efficiency of a newly established in-stream constructed wetland treating diffuse agricultural pollution. Ecological Engineering. 2018; 119 ():1-7.

Chicago/Turabian Style

Kuno Kasak; Keit Kill; Jaan Pärn; Ülo Mander. 2018. "Efficiency of a newly established in-stream constructed wetland treating diffuse agricultural pollution." Ecological Engineering 119, no. : 1-7.

Author correction
Published: 26 April 2018 in Nature Communications
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The original version of this Article contained an error in the first sentence of the Acknowledgements section, which incorrectly referred to the Estonian Research Council grant identifier as "PUTJD618". The correct version replaces the grant identifier with "PUTJD619". This has been corrected in both the PDF and HTML versions of the Article.

ACS Style

Jaan Pärn; Jos T. A. Verhoeven; Klaus Butterbach-Bahl; Nancy B. Dise; Sami Ullah; Anto Aasa; Sergey Egorov; Mikk Espenberg; Järvi Järveoja; Jyrki Jauhiainen; Kuno Kasak; Leif Klemedtsson; Ain Kull; Fatima Laggoun-Défarge; Elena D. Lapshina; Annalea Lohila; Krista Lõhmus; Martin Maddison; William J. Mitsch; Christoph Muller; Ülo Niinemets; Bruce Osborne; Taavi Pae; Jüri-Ott Salm; Fotis Sgouridis; Kristina Sohar; Kaido Soosaar; Kathryn Storey; Alar Teemusk; Moses M. Tenywa; Julien Tournebize; Jaak Truu; Gert Veber; Jorge A. Villa; Seint Sann Zaw; Ulo Mander. Author Correction: Nitrogen-rich organic soils under warm well-drained conditions are global nitrous oxide emission hotspots. Nature Communications 2018, 9, 1748 .

AMA Style

Jaan Pärn, Jos T. A. Verhoeven, Klaus Butterbach-Bahl, Nancy B. Dise, Sami Ullah, Anto Aasa, Sergey Egorov, Mikk Espenberg, Järvi Järveoja, Jyrki Jauhiainen, Kuno Kasak, Leif Klemedtsson, Ain Kull, Fatima Laggoun-Défarge, Elena D. Lapshina, Annalea Lohila, Krista Lõhmus, Martin Maddison, William J. Mitsch, Christoph Muller, Ülo Niinemets, Bruce Osborne, Taavi Pae, Jüri-Ott Salm, Fotis Sgouridis, Kristina Sohar, Kaido Soosaar, Kathryn Storey, Alar Teemusk, Moses M. Tenywa, Julien Tournebize, Jaak Truu, Gert Veber, Jorge A. Villa, Seint Sann Zaw, Ulo Mander. Author Correction: Nitrogen-rich organic soils under warm well-drained conditions are global nitrous oxide emission hotspots. Nature Communications. 2018; 9 (1):1748.

Chicago/Turabian Style

Jaan Pärn; Jos T. A. Verhoeven; Klaus Butterbach-Bahl; Nancy B. Dise; Sami Ullah; Anto Aasa; Sergey Egorov; Mikk Espenberg; Järvi Järveoja; Jyrki Jauhiainen; Kuno Kasak; Leif Klemedtsson; Ain Kull; Fatima Laggoun-Défarge; Elena D. Lapshina; Annalea Lohila; Krista Lõhmus; Martin Maddison; William J. Mitsch; Christoph Muller; Ülo Niinemets; Bruce Osborne; Taavi Pae; Jüri-Ott Salm; Fotis Sgouridis; Kristina Sohar; Kaido Soosaar; Kathryn Storey; Alar Teemusk; Moses M. Tenywa; Julien Tournebize; Jaak Truu; Gert Veber; Jorge A. Villa; Seint Sann Zaw; Ulo Mander. 2018. "Author Correction: Nitrogen-rich organic soils under warm well-drained conditions are global nitrous oxide emission hotspots." Nature Communications 9, no. 1: 1748.

Journal article
Published: 05 April 2018 in Land Use Policy
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Excess nutrients cause eutrophication of freshwaters all over the world. Decision-support tools are needed to assess nutrient discharges from catchments. This paper used a 28-year nutrient-discharge, hydroclimate and land-use history of small rural catchments to calibrate a simple nitrogen (N) and phosphorus (P) runoff model. The N and P runoffs declined following the post-Soviet collapse of agriculture, and stabilised at low output during the 1990s and early 2000s. Introduction of the European Union Common Agricultural Policy (CAP) re-intensified the agriculture and somewhat rebounded the N and P discharges. Thus, the history of the catchment represents a broad range of land-management systems. Our objective was to explain annual nutrient runoffs from small rural catchments by five factors: hydroclimate, soil type, land-use type, fertilisation and the autumn soil-nutrient stock. Our model independently predicted the eight-year mean N and P losses from a test set of small agricultural catchments in Estonia. This shows the impact of political decisions on agricultural contamination of waters. We can suggest our robust model as a decision-making tool for land-use management in small agricultural catchments.

ACS Style

Jaan Pärn; Hocine Henine; Kuno Kasak; Karin Kauer; Kristina Sohar; Julien Tournebize; Evelyn Uuemaa; Kristiina Välik; Ulo Mander. Nitrogen and phosphorus discharge from small agricultural catchments predicted from land use and hydroclimate. Land Use Policy 2018, 75, 260 -268.

AMA Style

Jaan Pärn, Hocine Henine, Kuno Kasak, Karin Kauer, Kristina Sohar, Julien Tournebize, Evelyn Uuemaa, Kristiina Välik, Ulo Mander. Nitrogen and phosphorus discharge from small agricultural catchments predicted from land use and hydroclimate. Land Use Policy. 2018; 75 ():260-268.

Chicago/Turabian Style

Jaan Pärn; Hocine Henine; Kuno Kasak; Karin Kauer; Kristina Sohar; Julien Tournebize; Evelyn Uuemaa; Kristiina Välik; Ulo Mander. 2018. "Nitrogen and phosphorus discharge from small agricultural catchments predicted from land use and hydroclimate." Land Use Policy 75, no. : 260-268.

Journal article
Published: 19 March 2018 in Nature Communications
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Nitrous oxide (N2O) is a powerful greenhouse gas and the main driver of stratospheric ozone depletion. Since soils are the largest source of N2O, predicting soil response to changes in climate or land use is central to understanding and managing N2O. Here we find that N2O flux can be predicted by models incorporating soil nitrate concentration (NO3−), water content and temperature using a global field survey of N2O emissions and potential driving factors across a wide range of organic soils. N2O emissions increase with NO3− and follow a bell-shaped distribution with water content. Combining the two functions explains 72% of N2O emission from all organic soils. Above 5 mg NO3−-N kg−1, either draining wet soils or irrigating well-drained soils increases N2O emission by orders of magnitude. As soil temperature together with NO3− explains 69% of N2O emission, tropical wetlands should be a priority for N2O management.

ACS Style

Jaan Pärn; Jos T. A. Verhoeven; Klaus Butterbach-Bahl; Nancy B. Dise; Sami Ullah; Anto Aasa; Sergey Egorov; Mikk Espenberg; Järvi Järveoja; Jyrki Jauhiainen; Kuno Kasak; Leif Klemedtsson; Ain Kull; Fatima Laggoun-Défarge; Elena Lapshina; Annalea Lohila; Krista Lõhmus; Martin Maddison; William J. Mitsch; Christoph Müller; Ülo Niinemets; Bruce Osborne; Taavi Pae; Jüri-Ott Salm; Fotis Sgouridis; Kristina Sohar; Kaido Soosaar; Kathryn Storey; Alar Teemusk; Moses M. Tenywa; Julien Tournebize; Jaak Truu; Gert Veber; Jorge A. Villa; Seint Sann Zaw; Ülo Mander. Nitrogen-rich organic soils under warm well-drained conditions are global nitrous oxide emission hotspots. Nature Communications 2018, 9, 1135 .

AMA Style

Jaan Pärn, Jos T. A. Verhoeven, Klaus Butterbach-Bahl, Nancy B. Dise, Sami Ullah, Anto Aasa, Sergey Egorov, Mikk Espenberg, Järvi Järveoja, Jyrki Jauhiainen, Kuno Kasak, Leif Klemedtsson, Ain Kull, Fatima Laggoun-Défarge, Elena Lapshina, Annalea Lohila, Krista Lõhmus, Martin Maddison, William J. Mitsch, Christoph Müller, Ülo Niinemets, Bruce Osborne, Taavi Pae, Jüri-Ott Salm, Fotis Sgouridis, Kristina Sohar, Kaido Soosaar, Kathryn Storey, Alar Teemusk, Moses M. Tenywa, Julien Tournebize, Jaak Truu, Gert Veber, Jorge A. Villa, Seint Sann Zaw, Ülo Mander. Nitrogen-rich organic soils under warm well-drained conditions are global nitrous oxide emission hotspots. Nature Communications. 2018; 9 (1):1135.

Chicago/Turabian Style

Jaan Pärn; Jos T. A. Verhoeven; Klaus Butterbach-Bahl; Nancy B. Dise; Sami Ullah; Anto Aasa; Sergey Egorov; Mikk Espenberg; Järvi Järveoja; Jyrki Jauhiainen; Kuno Kasak; Leif Klemedtsson; Ain Kull; Fatima Laggoun-Défarge; Elena Lapshina; Annalea Lohila; Krista Lõhmus; Martin Maddison; William J. Mitsch; Christoph Müller; Ülo Niinemets; Bruce Osborne; Taavi Pae; Jüri-Ott Salm; Fotis Sgouridis; Kristina Sohar; Kaido Soosaar; Kathryn Storey; Alar Teemusk; Moses M. Tenywa; Julien Tournebize; Jaak Truu; Gert Veber; Jorge A. Villa; Seint Sann Zaw; Ülo Mander. 2018. "Nitrogen-rich organic soils under warm well-drained conditions are global nitrous oxide emission hotspots." Nature Communications 9, no. 1: 1135.

Journal article
Published: 16 March 2018 in Scientific Reports
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Tropical peatlands, which play a crucial role in the maintenance of different ecosystem services, are increasingly drained for agriculture, forestry, peat extraction and human settlement purposes. The present study investigated the differences between natural and drained sites of a tropical peatland in the community structure of soil bacteria and archaea and their potential to perform nitrogen transformation processes. The results indicate significant dissimilarities in the structure of soil bacterial and archaeal communities as well as nirK, nirS, nosZ, nifH and archaeal amoA gene-possessing microbial communities. The reduced denitrification and N2-fixing potential was detected in the drained tropical peatland soil. In undisturbed peatland soil, the N2O emission was primarily related to nirS-type denitrifiers and dissimilatory nitrate reduction to ammonium, while the conversion of N2O to N2 was controlled by microbes possessing nosZ clade I genes. The denitrifying microbial community of the drained site differed significantly from the natural site community. The main reducers of N2O were microbes harbouring nosZ clade II genes in the drained site. Additionally, the importance of DNRA process as one of the controlling mechanisms of N2O fluxes in the natural peatlands of the tropics revealed from the results of the study.

ACS Style

Mikk Espenberg; Marika Truu; Ülo Mander; Kuno Kasak; Hiie Nõlvak; Teele Ligi; Kristjan Oopkaup; Martin Maddison; Jaak Truu. Differences in microbial community structure and nitrogen cycling in natural and drained tropical peatland soils. Scientific Reports 2018, 8, 1 -12.

AMA Style

Mikk Espenberg, Marika Truu, Ülo Mander, Kuno Kasak, Hiie Nõlvak, Teele Ligi, Kristjan Oopkaup, Martin Maddison, Jaak Truu. Differences in microbial community structure and nitrogen cycling in natural and drained tropical peatland soils. Scientific Reports. 2018; 8 (1):1-12.

Chicago/Turabian Style

Mikk Espenberg; Marika Truu; Ülo Mander; Kuno Kasak; Hiie Nõlvak; Teele Ligi; Kristjan Oopkaup; Martin Maddison; Jaak Truu. 2018. "Differences in microbial community structure and nitrogen cycling in natural and drained tropical peatland soils." Scientific Reports 8, no. 1: 1-12.

Journal article
Published: 10 August 2016 in Water, Air, & Soil Pollution
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Previous pilot-scale studies have shown outstanding levels of efficiency in phosphorus removal by using hydrated oil shale ash (HOSA) sediments in horizontal subsurface flow (HSSF) filters with low greenhouse gas emissions. However, no long-term full-scale experiment has been conducted using this material. From September 2013 to December 2015, two HSSF filters with different hydraulic loading regimes (NH1 with a stable loading regime and NH2 with a fluctuating regime), used to treat municipal wastewater, were analysed to estimate greenhouse gas (GHG) fluxes and to develop a treatment system with minimised GHG emissions. The fluxes of CO2, CH4 and N2O, as well as their emission factors were significantly lower when compared with studies where regular filter materials (sand, gravel, etc.) are in use. The fluctuating loading regime significantly increased CO2 and N2O fluxes (median values of −3.3 and 2.6 mg CO2−C m−2 h−1, and 5.7 and 8.6 μg N2O−N m−2 h−1 for NH1 and NH2 regimes, respectively), whereas no impact could be seen on CH4 emissions (median 93.3 and 95.6 μg CH4−C m−2 h−1, for NH1 and NH2, respectively). All GHG emissions were strongly affected by the chemical composition of the water entering into the system. The water purification efficiency of the system was satisfactory for most water quality parameters and excellent for phosphorus. Thus, the HOSA-filled filters have a good potential for municipal wastewater treatment with low GHG emission.

ACS Style

Kuno Kasak; Riho Mõtlep; Marika Truu; Jaak Truu; Margit Kõiv-Vainik; Mikk Espenberg; Päärn Paiste; Kalle Kirsimäe; Ülo Mander. Hydrated Oil Shale Ash Mitigates Greenhouse Gas Emissions from Horizontal Subsurface Flow Filters for Wastewater Treatment. Water, Air, & Soil Pollution 2016, 227, 1 -12.

AMA Style

Kuno Kasak, Riho Mõtlep, Marika Truu, Jaak Truu, Margit Kõiv-Vainik, Mikk Espenberg, Päärn Paiste, Kalle Kirsimäe, Ülo Mander. Hydrated Oil Shale Ash Mitigates Greenhouse Gas Emissions from Horizontal Subsurface Flow Filters for Wastewater Treatment. Water, Air, & Soil Pollution. 2016; 227 (9):1-12.

Chicago/Turabian Style

Kuno Kasak; Riho Mõtlep; Marika Truu; Jaak Truu; Margit Kõiv-Vainik; Mikk Espenberg; Päärn Paiste; Kalle Kirsimäe; Ülo Mander. 2016. "Hydrated Oil Shale Ash Mitigates Greenhouse Gas Emissions from Horizontal Subsurface Flow Filters for Wastewater Treatment." Water, Air, & Soil Pollution 227, no. 9: 1-12.

Journal article
Published: 01 April 2015 in Ecological Engineering
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ACS Style

Kuno Kasak; Ülo Mander; Jaak Truu; Marika Truu; Järvi Järveoja; Martin Maddison; Alar Teemusk. Alternative filter material removes phosphorus and mitigates greenhouse gas emission in horizontal subsurface flow filters for wastewater treatment. Ecological Engineering 2015, 77, 242 -249.

AMA Style

Kuno Kasak, Ülo Mander, Jaak Truu, Marika Truu, Järvi Järveoja, Martin Maddison, Alar Teemusk. Alternative filter material removes phosphorus and mitigates greenhouse gas emission in horizontal subsurface flow filters for wastewater treatment. Ecological Engineering. 2015; 77 ():242-249.

Chicago/Turabian Style

Kuno Kasak; Ülo Mander; Jaak Truu; Marika Truu; Järvi Järveoja; Martin Maddison; Alar Teemusk. 2015. "Alternative filter material removes phosphorus and mitigates greenhouse gas emission in horizontal subsurface flow filters for wastewater treatment." Ecological Engineering 77, no. : 242-249.