Abstract
Eutrophication of natural water bodies is moderated by transformation of nitrate (NO3−) in riparian wetlands, which serve as filters of infiltrating drain water from upland agricultural areas. The present study comprised field observations, laboratory experiments and metagenomic studies to describe NO3− removing transformation pathways and interactions with the cycling of iron (Fe) in a temperate riparian wetland soil profile down to 1 m depth. Water samples from piezometers showed a distinct plume of NO3− in the subsurface soil where agricultural drain water was infiltrating. However, within a distance of few meters in the water flow direction, NO3− was depleted from the percolating water. Sampling and analyses of soil from the active zone of the biogeochemical NO3− removal showed that denitrifying enzyme activity was ~ tenfold higher in the upper 0–25 cm than in the lower 25–100 cm. Yet, net transformation of NO3− was substantial also at 25–100 cm when assayed with relatively undisturbed soil samples and by 15N tracer techniques in soil slurries. Transformation pathways of dissimilatory nitrate reduction to ammonium and anaerobic ammonium oxidation were identified, but were quantitatively minor as compared to denitrification. Heterotrophic denitrification and denitrification mediated by oxidation of ferrous iron, Fe(II), were identified as important processes in the wetland soil. The latter was substantiated by geochemical observations, by rates of NO3− depletion in slurry incubations with added FeCl2, and by identification of microorganisms with known capacity of NO3− reduction coupled to Fe(II) oxidation (Acidovorax sp.). The transformation pathway of iron-mediated NO3− reduction could involve biotic and abiotic reactions, and N2O, which is a potent greenhouse gas, was a major product of the process. It remains to be seen under field conditions if N2O emission hotspots are linked to specific sites of dynamic NO3− reduction coupled to Fe(II) oxidation.
Similar content being viewed by others
Data availability
Water chemistry data are available from the IGB Freshwater Research and Environmental Database (https://fred.igb-berlin.de/data/package/516, study site Fensholt, ID 136). Metagenomic sequence data has been deposited at MG-RAST under the ID mgm4881181.3 (Peat_soil_Metagenome). Static link = https://www.mg-rast.org/linkin.cgi?metagenome=mgm4881181.3.
References
Audet J et al (2014) Nitrous oxide fluxes in undisturbed riparian wetlands located in agricultural catchments: emission, uptake and controlling factors. Soil Biol Biochem 68:291–299. https://doi.org/10.1016/j.soilbio.2013.10.011
Audet J, Elsgaard L, Kjaergaard C, Larsen SE, Hoffmann CC (2013) Greenhouse gas emissions from a Danish riparian wetland before and after restoration. Ecol Eng 57:70–182. https://doi.org/10.1016/j.ecoleng.2013.04.021
Bankevich A et al (2012) SPAdes: a new genome assembly algorithm and its applications to single-cell sequencing. J Comput Biol 19:455–477. https://doi.org/10.1089/cmb.2012.0021
Bolger AM, Lohse M, Usadel B (2014) Trimmomatic: a flexible trimmer for Illumina sequence data. Bioinformatics 30:2114–2120. https://doi.org/10.1093/bioinformatics/btu170
Bryce C et al (2018) Microbial anaerobic Fe(II) oxidation: ecology, mechanisms and environmental implications. Environ Microbiol 20:3462–3483. https://doi.org/10.1111/1462-2920.14328
Butler IB, Schoonen MAA, Rickard DT (1994) Removal of dissolved oxygen from water: a comparison of four common techniques. Talanta 41:211–215. https://doi.org/10.1016/0039-9140(94)80110-X
Cao B et al (2011) Complete genome sequence of Pusillimonas sp. T7-7, a cold-tolerant diesel oil-degrading bacterium isolated from the Bohai Sea in China. J Bacteriol 193:4021–4022. https://doi.org/10.1128/JB.05242-11
Carlson HK, Clark IC, Blazewicz SJ, Iavarone AT, Coates JD (2013) Fe(II) oxidation is an innate capability of nitrate-reducing bacteria that involves abiotic and biotic reactions. J Bacteriol 195:3260. https://doi.org/10.1128/JB.00058-13
Caskey WH, Tiedje JM (1979) Evidence for clostridia as agents of dissimilatory reduction of nitrate to ammonium in soils. Soil Sci Soc Am J 43:931–936. https://doi.org/10.2136/sssaj1979.03615995004300050023x
Chakraborty A, Roden EE, Schieber J, Picardal F (2011) Enhanced growth of Acidovorax sp. strain 2AN during nitrate-dependent Fe(II) oxidation in batch and continuous-flow systems. Appl Environ Microbiol 77:8548. https://doi.org/10.1128/AEM.06214-11
Chan Y-K, Barraquio WL, Knowles R (1994) N2-fixing pseudomonads and related soil bacteria. FEMS Microbiol Rev 13:95–117. https://doi.org/10.1111/j.1574-6976.1994.tb00037.x
Chen S, Ding B, Qin Y, Chen Z, Li Z (2020) Nitrogen loss through anaerobic ammonium oxidation mediated by Mn(IV)-oxide reduction from agricultural drainage ditches into Jiuli River, Taihu Lake Basin. Sci Total Environ 700:134512. https://doi.org/10.1016/j.scitotenv.2019.134512
Collins MD et al (1994) The phylogeny of the genus Clostridium: proposal of five new genera and eleven new species combinations. Int J Syst Evol Microbiol 44:812–826. https://doi.org/10.1099/00207713-44-4-812
Comer-Warner SA et al (2020) Seasonal variability of sediment controls of nitrogen cycling in an agricultural stream. Biogeochemistry 148:31–48. https://doi.org/10.1007/s10533-020-00644-z
Dalsgaard T, Bak F (1992) Effect of acetylene on nitrous oxide reduction and sulfide oxidation in batch and gradient cultures of Thiobacillus denitrificans. Appl Environ Microbiol 58:1601–1608
Dalsgaard T, De Brabandere L, Hall POJ (2013) Denitrification in the water column of the central Baltic Sea. Geochim Cosmochim Acta 106:247–260. https://doi.org/10.1016/j.gca.2012.12.038
Dalsgaard T, Canfield DE, Petersen J, Thamdrup B, Acuna-Gonzalez J (2003) N2 production by the anammox reaction in the anoxic water column of Golfo Dulce, Costa Rica. Nature 422:606–608. https://doi.org/10.1038/nature01526
Devol AH (2003) Solution to a marine mystery. Nature 422:575–576. https://doi.org/10.1038/422575a
Ding B, Li Z, Qin Y (2017) Nitrogen loss from anaerobic ammonium oxidation coupled to Iron(III) reduction in a riparian zone. Environ Pollut 231:379–386. https://doi.org/10.1016/j.envpol.2017.08.027
Gao D, Wang X, Liang H, Wei Q, Dou Y, Li L (2018) Anaerobic ammonia oxidizing bacteria: ecological distribution, metabolism, and microbial interactions. Front Environ Sci Eng 12:10. https://doi.org/10.1007/s11783-018-1035-x
Gardner LM, White JR (2010) Denitrification enzyme activity as an indicator of nitrate movement through a diversion wetland. Soil Sci Soc Am J 74:1037–1047. https://doi.org/10.2136/sssaj2008.0354
Gayer KH, Wootner L (1956) The hydrolysis of ferrous chloride at 25°. J Am Chem Soc 78:3944–3946. https://doi.org/10.1021/ja01597a021
Gregory SV, Swanson FJ, McKee WA, Cummins KW (1991) An ecosystem perspective of riparian zones. Bioscience 41:540–551. https://doi.org/10.2307/1311607
Groffman P, Gold A, Simmons R (1992) Nitrate dynamics in riparian forests: microbial studies. J Environ Qual 21:666–671. https://doi.org/10.2134/jeq1992.00472425002100040021x
Groffman PM, Howard G, Gold AJ, Nelson WM (1996) Microbial nitrate processing in shallow groundwater in a riparian forest. J Environ Qual 25:1309–1316. https://doi.org/10.2134/jeq1996.00472425002500060020x
Hansen LB (1993) Anaerob metanoxidation i marint sediment. M.Sc. Thesis, Aarhus University
HELCOM (2016) Special report No 03. Combating eutrophication in the Baltic Sea: Further and more effective action needed. European Union, European Court of Auditors, Luxembourg. https://doi.org/10.2865/098206
Hansen JW, Thamdrup B, Jørgensen BB (2000) Anoxic incubation of sediment in gas-tight plastic bags: a method for biogeochemical process studies. Mar Ecol Prog Ser 208:273–282. https://doi.org/10.3354/meps208273
Hansen B, Thorling L, Schullehner J, Termansen M, Dalgaard T (2017) Groundwater nitrate response to sustainable nitrogen management. Sci Rep 7:8566. https://doi.org/10.1038/s41598-017-07147-2
Hardison AK, Algar CK, Giblin AE, Rich JJ (2015) Influence of organic carbon and nitrate loading on partitioning between dissimilatory nitrate reduction to ammonium (DNRA) and N2 production. Geochim Cosmochim Acta 164:146–160. https://doi.org/10.1016/j.gca.2015.04.049
Hill AR (1996) Nitrate removal in stream riparian zones. J Environ Qual 25:743–755
Hill AR (2019) Groundwater nitrate removal in riparian buffer zones: a review of research progress in the past 20 years. Biogeochemistry 143:347–369. https://doi.org/10.1007/s10533-019-00566-5
Hill AR, Cardaci M (2004) Denitrification and organic carbon availability in riparian wetland soils and subsurface sediments. Soil Sci Soc Am J 68:320–325. https://doi.org/10.2136/sssaj2004.3200
Hoffmann CC, Baattrup-Pedersen A (2007) Re-establishing freshwater wetlands in Denmark. Ecol Eng 30:157–166. https://doi.org/10.1016/j.ecoleng.2006.09.022
Howarth R, Chan F, Conley DJ, Garnier J, Doney SC, Marino R, Billen G (2011) Coupled biogeochemical cycles: eutrophication and hypoxia in temperate estuaries and coastal marine ecosystems. Front Ecol Environ 9:18–26. https://doi.org/10.1890/100008
Humbert S, Zopfi J, Tarnawski S-E (2012) Abundance of anammox bacteria in different wetland soils. Environ Microbiol Rep 4:484–490. https://doi.org/10.1111/j.1758-2229.2012.00347.x
Hungate RE (1969) A roll tube method for cultivation of strict anaerobes. In: Norris JR, Ribbons DW (eds) Methods in microbiology. Academic Press, New York, pp 117–1323
Hyatt D, Chen G-L, Locascio PF, Land ML, Larimer FW, Hauser LJ (2010) Prodigal: prokaryotic gene recognition and translation initiation site identification. BMC Bioinform 11:119. https://doi.org/10.1186/1471-2105-11-119
Højberg AL et al (2015) National kvælstofmodel. Oplandsmodel til belastning og virkemidler. Geological Survey of Denmark and Greenland, Copenhagen, Denmark
Høyer AS, Jørgensen F, Foged N, He X, Christiansen AV (2015) Three-dimensional geological modelling of AEM resistivity data: a comparison of three methods. J Appl Geophys 115:65–78. https://doi.org/10.1016/j.jappgeo.2015.02.005
Jones LC, Peters B, Lezama Pacheco JS, Casciotti KL, Fendorf S (2015) Stable isotopes and iron oxide mineral products as markers of chemodenitrification. Environ Sci Technol 49:3444–3452. https://doi.org/10.1021/es504862x
Keith SM, MacFarlane GT, Herbert RA (1982) Dissimilatory nitrate reduction by a strain of Clostridium butyricum isolated from estuarine sediments. Arch Microbiol 132:62–66. https://doi.org/10.1007/bf00690819
Klueglein N, Kappler A (2013) Abiotic oxidation of Fe(II) by reactive nitrogen species in cultures of the nitrate-reducing Fe(II) oxidizer Acidovorax sp. BoFeN1-questioning the existence of enzymatic Fe(II) oxidation. Geobiology 11:180–190. https://doi.org/10.1111/gbi.12019
Knight V, Blakemore R (1998) Reduction of diverse electron acceptors by Aeromonas hydrophila. Arch Microbiol 169:239–248. https://doi.org/10.1007/s002030050567
Krichels AH, Sipic E, Yang WH (2019) Iron redox reactions can drive microtopographic variation in upland soil carbon dioxide and nitrous oxide emissions. Soil Syst 3:16. https://doi.org/10.3390/soilsystems3030060
Kronvang B, Andersen HE, Børgesen C, Dalgaard T, Larsen SE, Bøgestrand J, Blicher-Mathiasen G (2008) Effects of policy measures implemented in Denmark on nitrogen pollution of the aquatic environment. Environ Sci Policy 11:144–152. https://doi.org/10.1016/j.envsci.2007.10.007
Laufer K, Røy H, Jørgensen BB, Kappler A (2016) Evidence for the existence of autotrophic nitrate-reducing Fe(II)-oxidizing bacteria in marine coastal sediment. Appl Environ Microbiol 82:6120–6132. https://doi.org/10.1128/AEM.01570-16
Liu W, Xiong Z, Liu H, Zhang Q, Liu G (2016) Catchment agriculture and local environment affecting the soil denitrification potential and nitrous oxide production of riparian zones in the Han River Basin, China. Agric Ecosyst Environ 216:147–154. https://doi.org/10.1016/j.agee.2015.10.002
Liu T, Chen D, Luo X, Li X, Li F (2019a) Microbially mediated nitrate-reducing Fe(II) oxidation: quantification of chemodenitrification and biological reactions. Geochim Cosmochim Acta 256:97–115. https://doi.org/10.1016/j.gca.2018.06.040
Liu T et al (2019b) Rice root Fe plaque enhances paddy soil N2O emissions via Fe(II) oxidation-coupled denitrification. Soil Biol Biochem 139:8. https://doi.org/10.1016/j.soilbio.2019.107610
Lowrance R (1992) Groundwater nitrate and denitrification in a coastal plain riparian forest. J Environ Qual 21:401–405. https://doi.org/10.2134/jeq1992.00472425002100030017x
McClain ME et al (2003) Biogeochemical hot spots and hot moments at the interface of terrestrial and aquatic ecosystems. Ecosystems 6:301–312. https://doi.org/10.1007/s10021-003-0161-9
Murray WD, Khan AW, van den Berg L (1982) Clostridium saccharolyticum sp. nov., a saccharolytic species from sewage sludge. Int J Syst Evol Microbiol 32:132–135. https://doi.org/10.1099/00207713-32-1-132
Myhre G et al (2013) Anthropogenic and natural radiative forcing. In: Stocker TF et al (eds) Climate Change 2013 – The Physical Science Basis: Working Group I Contribution to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, pp 659–740. https://doi.org/10.1017/CBO9781107415324.018
Paulo AMS et al (2017) Sodium lauryl ether sulfate (SLES) degradation by nitrate-reducing bacteria. Appl Microbiol Biotechnol 101:5163–5173. https://doi.org/10.1007/s00253-017-8212-x
Payne WJ (1984) Influence of acetylene on microbial and enzymatic assays. J Microbiol Methods 2:117–133. https://doi.org/10.1016/0167-7012(84)90001-0
Petersen SO et al (2012) Annual emissions of CH4 and N2O, and ecosystem respiration, from eight organic soils in Western Denmark managed by agriculture. Biogeosciences 9:403–422. https://doi.org/10.5194/bg-9-403-2012
Petersen RJ, Prinds C, Iversen BV, Engesgaard P, Jessen S, Kjaergaard C (2020a) Riparian lowlands in clay till landscapes, Part I: Heterogeneity of flow paths and water balances. Water Resour Res 56. https://doi.org/10.1029/2019WR025808
Petersen RJ, Prinds C, Jessen S, Iversen BV, Kjaergaard C (2020b) Riparian lowlands in clay till landscapes, part II. Nitrogen reduction and release along variable flow paths. Water Resour Res 56. https://doi.org/10.1029/2019WR025810
Prinds C, Petersen RJ, Greve M, Iversen BV (2020) Three-dimensional voxel geological model of a riparian lowland and surrounding catchment using a multi-geophysical approach. J Appl Geophys 174:103965. https://doi.org/10.1016/j.jappgeo.2020.103965
Putz M, Schleusner P, Rütting T, Hallin S (2018) Relative abundance of denitrifying and DNRA bacteria and their activity determine nitrogen retention or loss in agricultural soil. Soil Biol Biochem 123:97–104. https://doi.org/10.1016/j.soilbio.2018.05.006
Ravishankara AR, Daniel JS, Portmann RW (2009) Nitrous oxide (N2O): the dominant ozone-depleting substance emitted in the 21st century. Science 326:123–125. https://doi.org/10.1126/science.1176985
Refsgaard JC et al (2014) Nitrate reduction in geologically heterogeneous catchments: a framework for assessing the scale of predictive capability of hydrological models. Sci Total Environ 468:1278–1288. https://doi.org/10.1016/j.scitotenv.2013.07.042
Refsgaard JC et al (2019) Spatially differentiated regulation: can it save the Baltic Sea from excessive N-loads? Ambio 48:1278–1289. https://doi.org/10.1007/s13280-019-01195-w
Rennert T (2019) Wet-chemical extractions to characterise pedogenic Al and Fe species: a critical review. Soil Res 57:1–16. https://doi.org/10.1071/SR18299
Risgaard-Petersen N, Revsbech NP, Rysgaard S (1995) Combined microdiffusion-hypobromite oxidation method for determining nitrogen-15 isotope in ammonium. Soil Sci Soc Am J 59:1077–1080. https://doi.org/10.2136/sssaj1995.03615995005900040018x
Robertson EK, Roberts KL, Burdorf LDW, Cook P, Thamdrup B (2016) Dissimilatory nitrate reduction to ammonium coupled to Fe(II) oxidation in sediments of a periodically hypoxic estuary. Limnol Oceanogr 61:365–381. https://doi.org/10.1002/lno.10220
Roland FAE, Darchambeau F, Borges AV, Morana C, De Brabandere L, Thamdrup B, Crowe SA (2018) Denitrification, anaerobic ammonium oxidation, and dissimilatory nitrate reduction to ammonium in an East African Great Lake (Lake Kivu). Limnol Oceanogr 63:687–701. https://doi.org/10.1002/lno.10660
Roussel J, Carliell-Marquet C (2016) Significance of vivianite precipitation on the mobility of iron in anaerobically digested sludge. Front Environ Sci. https://doi.org/10.3389/fenvs.2016.00060
Rütting T, Boeckx P, Müller C, Klemedtsson L (2011) Assessment of the importance of dissimilatory nitrate reduction to ammonium for the terrestrial nitrogen cycle. Biogeosciences 8:1779–1791. https://doi.org/10.5194/bg-8-1779-2011
Sander R (2015) Compilation of Henry's law constants (version 4.0) for water as solvent. Atmos Chem Phys 15:4399–4981. https://doi.org/10.5194/acp-15-4399-2015
Schaedler F, Lockwood C, Lueder U, Glombitza C, Kappler A, Schmidt C (2018) Microbially mediated coupling of Fe and N cycles by nitrate-reducing Fe(II)-oxidizing bacteria in littoral freshwater sediments. Appl Environ Microbiol 84:e02013–e2017. https://doi.org/10.1128/aem.02013-17
Schnabel RR, Cornish LF, Stout WL, Shaffer JA (1996) Denitrification in a grassed and a wooded, valley and ridge, riparian ecotone. J Environ Qual 25:1230–1235. https://doi.org/10.2134/jeq1996.00472425002500060009x
Simmons RC, Gold AJ, Groffman PM (1992) Nitrate dynamics in riparian forests: groundwater studies. J Environ Qual 21:659–665. https://doi.org/10.2134/jeq1992.00472425002100040021x
Smith MS, Firestone MK, Tiedje JM (1978) The acetylene inhibition method for short-term measurement of soil denitrification and its evaluation using nitrogen-13. Soil Sci Soc Am J 42:611–615. https://doi.org/10.2136/sssaj1978.03615995004200040015x
Song GD, Liu SM, Kuypers MMM, Lavik G (2016) Application of the isotope pairing technique in sediments where anammox, denitrification, and dissimilatory nitrate reduction to ammonium coexist. Limnol Oceanogr 14:801–815. https://doi.org/10.1002/lom3.10127
Stepanauskas R, Davidsson ET, Leonardson L (1996) Nitrogen transformations in wetland soil cores measured by n isotope pairing and dilution at four infiltration rates. Appl Environ Microbiol 62:2345–2351
Stookey LL (1970) Ferrozine: a new spectrophotometric reagent for iron. Anal Chem 42:779–781. https://doi.org/10.1021/ac60289a016
Stoppe N, Amelung W, Horn R (2015) Chemical extraction of sedimentary iron oxy(hydr)oxides using ammonium oxalate and sodium dithionite revisited: an explanation of processes in coastal sediments. Agro Surf 43:11–17. https://doi.org/10.4206/agrosur.2015.v43n2-03
Straub KL, Rainey FA, Widdel F (1999) Rhodovulum iodosum sp. nov. and Rhodovulum robiginosum sp. nov., two new marine phototrophic ferrous-iron-oxidizing purple bacteria. Int J Syst Evol Microbiol 49:729–735. https://doi.org/10.1099/00207713-49-2-729
Stumm W, Morgan JJ (1996) Aquatic chemistry: chemical equilibria and rates in natural waters, 3rd edn. Wiley, New York
Sørensen J, Nybroe O (2004) Pseudomonas in the Soil Environment. In: Ramos J-L (ed) Pseudomonas. Volume 1: Genomics, life style and molecular architecture. Springer US, Boston, pp 369–401. https://doi.org/10.1007/978-1-4419-9086-0
Taghizadeh-Toosi A, Elsgaard L, Clough TJ, Labouriau R, Ernstsen V, Petersen SO (2019) Regulation of N2O emissions from acid organic soil drained for agriculture. Biogeosciences 16:4555–4575. https://doi.org/10.5194/bg-16-4555-2019
Thamdrup B, Dalsgaard T (2002) Production of N2 through anaerobic ammonium oxidation coupled to nitrate reduction in marine sediments. Appl Environ Microbiol 68:1312–1318. https://doi.org/10.1128/aem.68.3.1312-1318.2002
Thamdrup B, Finster K, Hansen JW, Bak F (1993) Bacterial disproportionation of elemental sulfur coupled to chemical reduction of iron or manganese. Appl Environ Microbiol 59:101–108
van den Berg EM, Boleij M, Kuenen JG, Kleerebezem R, van Loosdrecht MCM (2016) DNRA and denitrification coexist over a broad range of acetate/N-NO3- ratios, in a chemostat enrichment culture. Front Microbiol 7:1842. https://doi.org/10.3389/fmicb.2016.01842
Vought LBM, Dahl J, Pedersen CL, Lacoursiére JO (1994) Nutrient retention in riparian ecotones. Ambio 23:342–348
Walton CR et al (2020) Wetland buffer zones for nitrogen and phosphorus retention: impacts of soil type, hydrology and vegetation. Sci Total Environ. https://doi.org/10.1016/j.scitotenv.2020.138709
Wang M, Hu R, Zhao J, Kuzyakov Y, Liu S (2016) Iron oxidation affects nitrous oxide emissions via donating electrons to denitrification in paddy soils. Geoderma 271:173–180. https://doi.org/10.1016/j.geoderma.2016.02.022
Wang M, Hu RG, Ruser R, Schmidt C, Kappler A (2020) Role of chemodenitrification for N2O emissions from nitrate reduction in rice paddy soils. ACS Earth Space Chem 4:122–132. https://doi.org/10.1021/acsearthspacechem.9b00296
Warembourg FR (1993) Nitrogen fixation in soil and plant systems. In: Knowles R, Blackburn TH (eds) Nitrogen Isotope Techniques. Academic Press, San Diego, pp 127–156. https://doi.org/10.1016/B978-0-08-092407-6.50010-9
Wolfe RS (1971) Microbial formation of methane. In: Rose AH, Wilkinson JF (eds) Advances in Microbial Physiology, vol 6. Academic Press, New York, pp 107–146. https://doi.org/10.1016/S0065-2911(08)60068-5
Wood DE, Salzberg SL (2014) Kraken: ultrafast metagenomic sequence classification using exact alignments. Genome Biol 15:R46. https://doi.org/10.1186/gb-2014-15-3-r46
Yan R et al (2019) Effect of reduced sulfur species on chemolithoautotrophic pyrite oxidation with nitrate. Geomicrobiol J 36:19–29. https://doi.org/10.1080/01490451.2018.1489915
Zhu G, Jetten MSM, Kuschk P, Ettwig KF, Yin C (2010) Potential roles of anaerobic ammonium and methane oxidation in the nitrogen cycle of wetland ecosystems. Appl Microbiol Biotechnol 86:1043–1055. https://doi.org/10.1007/s00253-010-2451-4
Zhu-Barker X, Cavazos AR, Ostrom NE, Horwath WR, Glass JB (2015) The importance of abiotic reactions for nitrous oxide production. Biogeochemistry 126:251–267. https://doi.org/10.1007/s10533-015-0166-4
Acknowledgements
We thank Bodil Stensgaard, Marianne Ahrenfeldt Stevenson, Henrik Nørgaard, Margit Paulsen, Mette Søgaard Ejsing-Duun and Joseph Martin for assistance in the field and in the lab. Thanks also to Rasmus Rasmussen for facilitating field work in Fensholt and to two journal reviewers for helpful comments.
Funding
This project was financially supported by Innovation Fund Denmark, grant no. 4106-00027B (TReNDS). The main author was funded by a PhD scholarship from GSST, Aarhus University.
Author information
Authors and Affiliations
Contributions
RJP, CK and LE designed the field studies; RJP and LE designed the laboratory studies, RJP, CP and LE performed the field studies; RJP, ZL and LE performed the laboratory studies; AJ performed the metagenomic studies; BT, RJP and ZL performed the 15N analyzes; RJP and LE performed the data analyzes with assistance from BT, AJ and ZL; RJP and LE wrote the manuscript; all authors contributed to discussion and revision of the manuscript.
Corresponding author
Ethics declarations
Conflict of interest
None.
Additional information
Responsible Editor: Karsten Kalbitz.
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
About this article
Cite this article
Petersen, R.J., Liang, Z., Prinds, C. et al. Nitrate reduction pathways and interactions with iron in the drainage water infiltration zone of a riparian wetland soil. Biogeochemistry 150, 235–255 (2020). https://doi.org/10.1007/s10533-020-00695-2
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10533-020-00695-2