Contrasting potential for biological N2 fixation at three polluted central European Sphagnum peat bogs: combining the 15N2-tracer and natural-abundance isotope approaches

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00025798%3A_____%2F23%3A10169036" target="_blank" >RIV/00025798:_____/23:10169036 - isvavai.cz</a>

Result on the web

<a href="https://doi.org/10.5194/soil-9-623-2023" target="_blank" >https://doi.org/10.5194/soil-9-623-2023</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.5194/soil-9-623-2023" target="_blank" >10.5194/soil-9-623-2023</a>

Result language

angličtina

Original language name

Contrasting potential for biological N2 fixation at three polluted central European Sphagnum peat bogs: combining the 15N2-tracer and natural-abundance isotope approaches

Original language description

Availability of reactive nitrogen (Nr) is a key control on carbon (C) sequestration in wetlands. To complement the metabolic demands of Sphagnum in pristine rain-fed bogs, diazotrophs supply additional Nr via biological nitrogen fixation (BNF). As breaking the triple bond of atmospheric N2 is energy-intensive, it is reasonable to assume that increasing inputs of pollutant Nr will lead to BNF downregulation. However, recent studies have also documented measurable BNF rates in Sphagnum-dominated bogs in polluted regions, indicating the adaptation of N2 fixers to changing N deposition. Our aim was to quantify BNF in high-elevation peatlands located in industrialized central Europe. A 15N2-tracer experiment was combined with a natural-abundance N-isotope study at three Sphagnum-dominated peat bogs in the northern Czech Republic in an attempt to assess the roles of individual BNF drivers. High short-term BNF rates (8.2 +- 4.6 g N m2 d-1) were observed at Malé mechové jezírko, which receives TILDE OPERATOR+D91 17 kg Nr ha-1 yr-1. The remaining two peat bogs, whose recent atmospheric Nr inputs differed from Malé mechové jezírko by only 1-2 kg ha-1 yr-1 (Uhlirska and Brumist), showed zero BNF. The following parameters were investigated to elucidate the BNF difference: the NH4+-N / NO3 - N ratio, temperature, wetness, Sphagnum species, organic-N availability, possible P limitation, possible molybdenum (Mo) limitation, SO42- deposition, and pH. At Malé mechové jezírko and Uhlířská, the same moss species (S. girgensohnii) was used for the 15N2 experiment; therefore, the host identity could not explain the difference in BNF at these sites. Temperature and moisture were also identical in all incubations and could not explain the between-site differences in BNF. The N : P stoichiometry in peat and bog water indicated that Brumišta may have lacked BNF due to P limitation, whereas non-detectable BNF at Uhlířská may have been related to the 70-fold higher SO42- concentration in bog water. Across the sites, the mean natural-abundance I 15N values increased in the following order: atmospheric deposition (-5.3 +- 0.3 %o) &lt; Sphagnum (-4.3 +- 0.1 %o) &lt; bog water (-3.9 +- 0.4 %o) &lt; atmospheric N2 (0.0 %o). Only at Brumišta was N in Sphagnum significantly isotopically heavier than in atmospheric deposition, possibly indicating a longer-term BNF effect. Collectively, our data highlight spatial heterogeneity in BNF rates under high Nr inputs as well as the importance of environmental parameters other than atmospheric Nr pollution in regulating BNF.

Czech name

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Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

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OECD FORD branch

10505 - Geology

Project

—

Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2023

Confidentiality

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

Name of the periodical

SOIL

ISSN

2199-398X

e-ISSN

2199-398X

Volume of the periodical

9

Issue of the periodical within the volume

2

Country of publishing house

DE - GERMANY

Number of pages

18

Pages from-to

623-640

UT code for WoS article

001170599600001

EID of the result in the Scopus database

2-s2.0-85182993350