Mass loss and nutrient release during litter decay in peatland: The role of microbial adaptability to litter chemistry

Bragazza, Luca; Siffi, Chiara; Iacumin, Paola; Gerdol, Renato

doi:10.1016/j.soilbio.2006.07.014

Cited by 127 publications

(98 citation statements)

References 59 publications

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“…The lowest emissions at our sites occurred where the residual peat was either of Cyperaceous (IP3) or Sphagnum/cyperaceous (IP5) origin. However, while the slow decomposition rate of Sphagnum litter in comparison to other plant litter has been well documented (Verhoeven and Toth, 1995;Bragazza et al, 2007), there is insufficient data from our study sites to determine whether the limited relationship observed here between peat type and CO 2 -C emissions at our study sites is coincidental rather than causal.…”

Section: Wilson Et Al: Derivation Of Greenhouse Gas Emission Factmentioning

confidence: 70%

Derivation of greenhouse gas emission factors for peatlands managed for extraction in the Republic of Ireland and the United Kingdom

Wilson¹,

Dixon

Artz

et al. 2015

Biogeosciences

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Abstract. Drained peatlands are significant hotspots of carbon dioxide (CO 2 ) emissions and may also be more vulnerable to fire with its associated gaseous emissions. Under the United Nations Framework Convention on Climate Change (UNFCCC) and the Kyoto Protocol, greenhouse gas (GHG) emissions from peatlands managed for extraction are reported on an annual basis. However, the Tier 1 (default) emission factors (EFs) provided in the IPCC 2013 Wetlands Supplement for this land use category may not be representative in all cases and countries are encouraged to move to highertier reporting levels with reduced uncertainty levels based on country-or regional-specific data. In this study, we quantified (1) CO 2 -C emissions from nine peat extraction sites in the Republic of Ireland and the United Kingdom, which were initially disaggregated by land use type (industrial versus domestic peat extraction), and (2) a range of GHGs that are released to the atmosphere with the burning of peat. Drainagerelated methane (CH 4 ) and nitrous oxide (N 2 O) emissions as well as CO 2 -C emissions associated with the off-site decomposition of horticultural peat were not included here. Our results show that net CO 2 -C emissions were strongly controlled by soil temperature at the industrial sites (bare peat) and by soil temperature and leaf area index at the vegetated domestic sites. Our derived EFs of 1.70 (±0.47) and 1.64 (±0.44) t CO 2 -C ha −1 yr −1 for the industrial and domestic sites respectively are considerably lower than the Tier 1 EF (2.8 ± 1.7 t CO 2 -C ha −1 yr −1 ) provided in the Wetlands Supplement. We propose that the difference between our derived values and the Wetlands Supplement value is due to differences in peat quality and, consequently, decomposition rates. Emissions from burning of the peat (g kg −1 dry fuel burned) were estimated to be approximately 1346 CO 2 , 8.35 methane (CH 4 ), 218 carbon monoxide (CO), 1.53 ethane (C 2 H 6 ), 1.74 ethylene (C 2 H 4 ), 0.60 methanol (CH 3 OH), 2.21 hydrogen cyanide (HCN) and 0.73 ammonia (NH 3 ), and this emphasises the importance of understanding the full suite of trace gas emissions from biomass burning. Our results highlight the importance of generating reliable Tier 2 values for different regions and land use categories. Furthermore, given that the IPCC Tier 1 EF was only based on 20 sites (all from Canada and Fennoscandia), we suggest that data from another 9 sites significantly expand the global data set, as well as adding a new region.

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Section: Wilson Et Al: Derivation Of Greenhouse Gas Emission Factmentioning

confidence: 70%

Derivation of greenhouse gas emission factors for peatlands managed for extraction in the Republic of Ireland and the United Kingdom

Wilson¹,

Dixon

Artz

et al. 2015

Biogeosciences

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“…One possible explanation of this finding is adaptation and specialization of decomposers to plant species characteristic of a given community; a "home field advantage" (Hunt et al, 1988;Gholz et al, 2000;Bragazza et al, 2007;Strickland et al, 2009). Litter types included in common litter represent plant species more typical of bogs, i.e., B. nana and P. sylvestris.…”

Section: Site Effectmentioning

confidence: 99%

Litter type affects the activity of aerobic decomposers in a boreal peatland more than site nutrient and water table regimes

et al. 2011

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Abstract. Peatlands are carbon (C) storage ecosystems sustained by a high water table (WT). High WT creates anoxic conditions that suppress the activity of aerobic decomposers and provide conditions for peat accumulation. Peatland function can be dramatically affected by WT drawdown caused by climate and/or land-use change. Aerobic decomposers are directly affected by WT drawdown through environmental factors such as increased oxygenation and nutrient availability. Additionally, they are indirectly affected via changes in plant community composition and litter quality. We studied the relative importance of direct and indirect effects of WT drawdown on aerobic decomposer activity in plant litter at two stages of decomposition (incubated in the field for 1 or 2 years). We did this by profiling 11 extracellular enzymes involved in the mineralization of organic C, nitrogen (N), phosphorus (P) and sulphur. Our study sites represented a three-stage chronosequence from pristine to shortterm (years) and long-term (decades) WT drawdown conditions under two nutrient regimes (bog and fen). The litter types included reflected the prevalent vegetation: Sphagnum mosses, graminoids, shrubs and trees.Litter type was the main factor shaping microbial activity patterns and explained about 30 % of the variation in enzyme activities and activity allocation. Overall, enzyme activities were higher in vascular plant litters compared to Sphagnum litters, and the allocation of enzyme activities towards C or nutrient acquisition was related to the initial litter quality Correspondence to: P. Straková (petra.strakova@helsinki.fi) (chemical composition). Direct effects of WT regime, site nutrient regime and litter decomposition stage (length of incubation period) summed to only about 40 % of the litter type effect. WT regime alone explained about 5 % of the variation in enzyme activities and activity allocation. Generally, enzyme activity increased following the long-term WT drawdown and the activity allocation turned from P and N acquisition towards C acquisition. This caused an increase in the rate of litter decomposition. The effects of the shortterm WT drawdown were minor compared to those of the long-term WT drawdown: e.g., the increase in the activity of C-acquiring enzymes was up to 120 % (bog) or 320 % (fen) higher after the long-term WT drawdown compared to the short-term WT drawdown. In general, the patterns of microbial activity as well as their responses to WT drawdown depended on peatland type: e.g., the shift in activity allocation to C-acquisition was up to 100 % stronger at the fen compared to the bog.Our results imply that changes in plant community composition in response to persistent WT drawdown will strongly affect the C dynamics of peatlands. The predictions of decomposer activity under changing climate and/or land-use thus cannot be based on the direct effects of the changed environment only, but need to consider the indirect effects of environmental changes: the changes in plant community composition, their dependen...

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“…As the decomposition of Sphagnum is a continuum process, the section 2-4 cm below the capitulum was taken as equivalent to freshly senesced "litter", as in other studies (e.g. Bragazza et al, 2007). Samples were sorted to remove any vegetation not belonging to the target species and then cut to 2 cm length and homogenised.…”

Section: Introductionmentioning

confidence: 99%

The effect of drought on dissolved organic carbon (DOC) release from peatland soil and vegetation sources

et al. 2017

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Abstract. Drought conditions are expected to increase in frequency and severity as the climate changes, representing a threat to carbon sequestered in peat soils. Downstream water treatment works are also at risk of regulatory compliance failures and higher treatment costs due to the increase in riverine dissolved organic carbon (DOC) often observed after droughts. More frequent droughts may also shift dominant vegetation in peatlands from Sphagnum moss to more drought-tolerant species. This paper examines the impact of drought on the production and treatability of DOC from four vegetation litters (Calluna vulgaris, Juncus effusus, Molinia caerulea and Sphagnum spp.) and a peat soil. We found that mild droughts caused a 39.6 % increase in DOC production from peat and that peat DOC that had been exposed to oxygen was harder to remove by conventional water treatment processes (coagulation/flocculation). Drought had no effect on the amount of DOC production from vegetation litters; however large variation was observed between typical peatland species (Sphagnum and Calluna) and drought-tolerant grassland species (Juncus and Molinia), with the latter producing more DOC per unit weight. This would therefore suggest the increase in riverine DOC often observed postdrought is due entirely to soil microbial processes and DOC solubility rather than litter layer effects. Long-term shifts in species diversity may, therefore, be the most important impact of drought on litter layer DOC flux, whereas pulses related to drought may be observed in peat soils and are likely to become more common in the future. These results provide evidence in support of catchment management which increases the resilience of peat soils to drought, such as ditch blocking to raise water tables.

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Mass loss and nutrient release during litter decay in peatland: The role of microbial adaptability to litter chemistry

Cited by 127 publications

References 59 publications

Derivation of greenhouse gas emission factors for peatlands managed for extraction in the Republic of Ireland and the United Kingdom

Derivation of greenhouse gas emission factors for peatlands managed for extraction in the Republic of Ireland and the United Kingdom

Litter type affects the activity of aerobic decomposers in a boreal peatland more than site nutrient and water table regimes

The effect of drought on dissolved organic carbon (DOC) release from peatland soil and vegetation sources

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