Peat bogs have historically represented exceptional carbon (C) sinks because of their extremely low decomposition rates and consequent accumulation of plant remnants as peat. Among the factors favoring that peat accumulation, a major role is played by the chemical quality of plant litter itself, which is poor in nutrients and characterized by polyphenols with a strong inhibitory effect on microbial breakdown. Because bogs receive their nutrient supply solely from atmospheric deposition, the global increase of atmospheric nitrogen (N) inputs as a consequence of human activities could potentially alter the litter chemistry with impor- tant, but still unknown, effects on their C balance. Herewe present data showing the decomposition rates of recently formed litter peat samples collected in nine European countries under a natural gradient of atmospheric N deposition from 0.2 to 2 g m 2 yr 1. We found that enhanced decomposition rates for material accu- mulated under higher atmospheric N supplies resulted in higher carbon dioxide (CO2) emissions and dissolved organic carbon release. The increased N availability favored microbial decompo- sition (i) by removing N constraints on microbial metabolism and (ii) through a chemical amelioration of litter peat quality with a positive feedback on microbial enzymatic activity. Although some uncertainty remains aboutwhether decay-resistant Sphagnumwill continue to dominate litter peat, our data indicate that, even without such changes, increased N deposition poses a serious risk to our valuable peatland C sinks.

Atmospheric nitrogen deposition promotes carbon loss from peat bogs / BRAGAZZA L; FREEMAN C; JONES T; RYDIN H; LIMPENS J; HELLIS T; FENNER N; GERDOL R; HAJEK M; HAJEK T; IACUMIN P.; KUTNAR L; TAHVANAINEN T; TOBERMAN H. - In: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA. - ISSN 1091-6490. - 103:(2006), pp. 19386-19389.

Atmospheric nitrogen deposition promotes carbon loss from peat bogs

IACUMIN, Paola;
2006

Abstract

Peat bogs have historically represented exceptional carbon (C) sinks because of their extremely low decomposition rates and consequent accumulation of plant remnants as peat. Among the factors favoring that peat accumulation, a major role is played by the chemical quality of plant litter itself, which is poor in nutrients and characterized by polyphenols with a strong inhibitory effect on microbial breakdown. Because bogs receive their nutrient supply solely from atmospheric deposition, the global increase of atmospheric nitrogen (N) inputs as a consequence of human activities could potentially alter the litter chemistry with impor- tant, but still unknown, effects on their C balance. Herewe present data showing the decomposition rates of recently formed litter peat samples collected in nine European countries under a natural gradient of atmospheric N deposition from 0.2 to 2 g m 2 yr 1. We found that enhanced decomposition rates for material accu- mulated under higher atmospheric N supplies resulted in higher carbon dioxide (CO2) emissions and dissolved organic carbon release. The increased N availability favored microbial decompo- sition (i) by removing N constraints on microbial metabolism and (ii) through a chemical amelioration of litter peat quality with a positive feedback on microbial enzymatic activity. Although some uncertainty remains aboutwhether decay-resistant Sphagnumwill continue to dominate litter peat, our data indicate that, even without such changes, increased N deposition poses a serious risk to our valuable peatland C sinks.
Atmospheric nitrogen deposition promotes carbon loss from peat bogs / BRAGAZZA L; FREEMAN C; JONES T; RYDIN H; LIMPENS J; HELLIS T; FENNER N; GERDOL R; HAJEK M; HAJEK T; IACUMIN P.; KUTNAR L; TAHVANAINEN T; TOBERMAN H. - In: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA. - ISSN 1091-6490. - 103:(2006), pp. 19386-19389.
File in questo prodotto:
File Dimensione Formato  
PNAS_2006[1].pdf

non disponibili

Tipologia: Documento in Post-print
Licenza: Creative commons
Dimensione 484.74 kB
Formato Adobe PDF
484.74 kB Adobe PDF   Visualizza/Apri   Richiedi una copia
Abstract PNAS 2006.doc

non disponibili

Tipologia: Abstract
Licenza: Creative commons
Dimensione 21.5 kB
Formato Microsoft Word
21.5 kB Microsoft Word   Visualizza/Apri   Richiedi una copia

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11381/1485531
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 338
  • ???jsp.display-item.citation.isi??? 319
social impact