Denitrification at two nitrogen-polluted, ombrotrophic Sphagnum bogs in Central Europe: Insights from porewater N2O-isotope profiles

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F60076658%3A12310%2F15%3A43888738" target="_blank" >RIV/60076658:12310/15:43888738 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/67985556:_____/15:00439538 RIV/00025798:_____/15:00000020

Výsledek na webu

<a href="http://www.sciencedirect.com/science/article/pii/S003807171400368X" target="_blank" >http://www.sciencedirect.com/science/article/pii/S003807171400368X</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.soilbio.2014.10.021" target="_blank" >10.1016/j.soilbio.2014.10.021</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Denitrification at two nitrogen-polluted, ombrotrophic Sphagnum bogs in Central Europe: Insights from porewater N2O-isotope profiles

Popis výsledku v původním jazyce

Measurements of nitrogen isotope ratios (delta N-15) along vertical porewater profiles are instrumental in localizing sources and sinks of nitrous oxide (N2O) in wetland ecosystems. We present the first N2O concentration and isotope data for porewaters of ombrotrophic, mountain-top bogs. Our two study sites, situated in the Czech Republic at elevations higher than 1000 m, have been affected by atmospheric N pollution for more than 100 years. In recent decades, the northeastern site KB received over 30 kg N ha(-1) yr(-1) via atmospheric deposition, the southwestern site BS was 3 times less polluted. Both peat bogs were surrounded by defoliated, dead spruce stands. We hypothesized that elevated nitrate (NO3-) inputs in rain-fed bogs may cause sizeable N2O emissions. Porewater N2O concentrations in the studied ombrotrophic bogs were 400-800 times higher, compared to fens in nearby Bavaria (Germany). The highest N2O concentrations and the lowest delta N-15-N2O values were found at the bottom of the sampled porewater profiles, 40-60 cm below surface. Low delta N-15-N2O values resulted from a N isotope fractionation associated with denitrification. The site with the lower historical N pollution, BS, exhibited up to 7 times higher porewater N2O concentrations than KB, possibly due to a higher denitrification potential determined as abundance of nirK and nirS genes. Upcore, N2O abundance decreased and delta N-15 -N2O increased, indicating N2O reduction. Processes of N2O formation and consumption at different depths were integrated by measuring N2O fluxes across the peat - atmosphere interface. These fluxes were minute (<0.02 mu mol N2O m(-2) h(-1)). We even observed scavenging of air-borne N2O by the bog substrate. Nitrogen pollution of ombrotrophic bogs led to vigorous N cycling, manifested by extremely high peat porewater N2O concentrations. However, effective in-situ consumption of the produced N2O greatly reduced its warming potential.

Název v anglickém jazyce

Denitrification at two nitrogen-polluted, ombrotrophic Sphagnum bogs in Central Europe: Insights from porewater N2O-isotope profiles

Popis výsledku anglicky

Measurements of nitrogen isotope ratios (delta N-15) along vertical porewater profiles are instrumental in localizing sources and sinks of nitrous oxide (N2O) in wetland ecosystems. We present the first N2O concentration and isotope data for porewaters of ombrotrophic, mountain-top bogs. Our two study sites, situated in the Czech Republic at elevations higher than 1000 m, have been affected by atmospheric N pollution for more than 100 years. In recent decades, the northeastern site KB received over 30 kg N ha(-1) yr(-1) via atmospheric deposition, the southwestern site BS was 3 times less polluted. Both peat bogs were surrounded by defoliated, dead spruce stands. We hypothesized that elevated nitrate (NO3-) inputs in rain-fed bogs may cause sizeable N2O emissions. Porewater N2O concentrations in the studied ombrotrophic bogs were 400-800 times higher, compared to fens in nearby Bavaria (Germany). The highest N2O concentrations and the lowest delta N-15-N2O values were found at the bottom of the sampled porewater profiles, 40-60 cm below surface. Low delta N-15-N2O values resulted from a N isotope fractionation associated with denitrification. The site with the lower historical N pollution, BS, exhibited up to 7 times higher porewater N2O concentrations than KB, possibly due to a higher denitrification potential determined as abundance of nirK and nirS genes. Upcore, N2O abundance decreased and delta N-15 -N2O increased, indicating N2O reduction. Processes of N2O formation and consumption at different depths were integrated by measuring N2O fluxes across the peat - atmosphere interface. These fluxes were minute (<0.02 mu mol N2O m(-2) h(-1)). We even observed scavenging of air-borne N2O by the bog substrate. Nitrogen pollution of ombrotrophic bogs led to vigorous N cycling, manifested by extremely high peat porewater N2O concentrations. However, effective in-situ consumption of the produced N2O greatly reduced its warming potential.

Druh

J_x - Nezařazeno - Článek v odborném periodiku (Jimp, Jsc a Jost)

CEP obor

DD - Geochemie

OECD FORD obor

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Projekt

<a href="/cs/project/GAP504%2F12%2F1782" target="_blank" >GAP504/12/1782: Vztah mezi atmosférickou depozicí dusíku a akumulací dusíku v ombrotrofních mokřadech: Izotopová studie za užití 210Pb a 15N</a><br>

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2015

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Soil Biology &amp; Biochemistry

ISSN

0038-0717

e-ISSN

—

Svazek periodika

81

Číslo periodika v rámci svazku

FEB 2015

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

10

Strana od-do

48-57

Kód UT WoS článku

000350524700006

EID výsledku v databázi Scopus

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