High nitrogen deposition alters the decomposition of bog plant litter and reduces carbon accumulation

Bragazza, Luca; Buttler, Alexandre; Habermacher, Jonathan; Brancaleoni, Lisa; Gerdol, Renato; Fritze, Hannu; Hanajík, Peter; Laiho, Raija; Johnson, David

doi:10.1111/j.1365-2486.2011.02585.x

Cited by 118 publications

(86 citation statements)

References 50 publications

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“…Intermittent flooding typically enhances the decay of litter at the soil surface in ecosystems with mostly aerobic soil surfaces such as riparian forests, prairie wetlands, and freshwater marshes (Brinson, 1977;Day, 1979;Ewel and Odum, 1978;Maltby, 1988;Mendelssohn et al, 1999;Neckles and Neill, 1994). In these ecosystems, flooding may accelerate the leaching and microbial decomposition phases of organic matter decay by providing moisture and nutrients to microbial and fungal communities (Bragazza et al, 2012;Neckles and Neill, 1994). However, decomposition generally occurs more rapidly in aerobic soils than anaerobic soils, and positive relationships between flooding and decay rate observed near the soil surface tend to disappear with soil depth (e.g.…”

Section: Discussionmentioning

confidence: 99%

The impact of sea-level rise on organic matter decay rates in Chesapeake Bay brackish tidal marshes

et al. 2013

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The balance between organic matter production and decay determines how fast coastal wetlands accumulate soil organic matter. Despite the importance of soil organic matter accumulation rates in influencing marsh elevation and resistance to sea-level rise, relatively little is known about how decomposition rates will respond to sea-level rise. Here, we estimate the sensitivity of decomposition to flooding by measuring rates of decay in 87 bags filled with milled sedge peat, including soil organic matter, roots and rhizomes. Experiments were located in field-based mesocosms along 3 mesohaline tributaries of the Chesapeake Bay. Mesocosm elevations were manipulated to influence the duration of tidal inundation. Although we found no significant influence of inundation on decay rate when bags from all study sites were analyzed together, decay rates at two of the sites increased with greater flooding. These findings suggest that flooding may enhance organic matter decay rates even in water-logged soils, but that the overall influence of flooding is minor. Our experiments suggest that sea-level rise will not accelerate rates of peat accumulation by slowing the rate of soil organic matter decay. Consequently, marshes will require enhanced organic matter productivity or mineral sediment deposition to survive accelerating sea-level rise

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Section: Discussionmentioning

confidence: 99%

The impact of sea-level rise on organic matter decay rates in Chesapeake Bay brackish tidal marshes

et al. 2013

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“…Sphagnum mosses are effective at utilizing available nutrients and restricting mineralization, limiting the ability of vascular plants to compete (Malmer and Wallen, 2004). However, high nitrogen deposition can remove nutrient limitations on the growth of vascular plants allowing them to successfully compete with Sphagnum, resulting in increased decay rates (Bragazza et al, 2006(Bragazza et al, , 2012. Nitrogen content in peat reflects a combination of dominant source plant material, nutrient status and atmospheric nitrogen deposition.…”

Section: Introductionmentioning

confidence: 99%

Drivers of Holocene peatland carbon accumulation across a climate gradient in northeastern North America

Charman

Amesbury

Hinchliffe

et al. 2015

Quaternary Science Reviews

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a b s t r a c tPeatlands are an important component of the Holocene global carbon (C) cycle and the rate of C sequestration and storage is driven by the balance between net primary productivity and decay. A number of studies now suggest that climate is a key driver of peatland C accumulation at large spatial scales and over long timescales, with warmer conditions associated with higher rates of C accumulation. However, other factors are also likely to play a significant role in determining local carbon accumulation rates and these may modify past, present and future peatland carbon sequestration. Here, we test the importance of climate as a driver of C accumulation, compared with hydrological change, fire, nitrogen content and vegetation type, from records of C accumulation at three sites in northeastern North America, across the NeS climate gradient of raised bog distribution. Radiocarbon age models, bulk density values and %C measurements from each site are used to construct C accumulation histories commencing between 11,200 and 8000 cal. years BP. The relationship between C accumulation and environmental variables (past water table depth, fire, peat forming vegetation and nitrogen content) is assessed with linear and multivariate regression analyses. Differences in long-term rates of carbon accumulation between sites support the contention that a warmer climate with longer growing seasons results in faster rates of long-term carbon accumulation. However, mid-late Holocene accumulation rates show divergent trends, decreasing in the north but rising in the south. We hypothesise that sites close to the moisture threshold for raised bog distribution increased their growth rate in response to a cooler climate with lower evapotranspiration in the late Holocene, but net primary productivity declined over the same period in northern areas causing a decrease in C accumulation. There was no clear relationship between C accumulation and hydrological change, vegetation, nitrogen content or fire, but early successional stages of peatland growth had faster rates of C accumulation even though temperatures were probably lower at the time. We conclude that climate is the most important driver of peatland accumulation rates over millennial timescales, but that successional vegetation change is a significant additional influence. Whilst the majority of northern peatlands are likely to increase C accumulation rates under future warmer climates, those at the southern limit of distribution may show reduced rates. However, early succession peatlands that develop under future warming at the northern limits of peatland distribution are likely to have high rates of C accumulation and will compensate for some of the losses elsewhere.

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“…For these normally nutrient-limited ecosystems, eutrophication is a major threat, as demonstrated in several long-term fertilization experiments. A decade of fertilizer applications to bogs in Canada (Mer Bleue), in the UK (Whim bog), and in Sweden (Degerö Stormyr) and 7 years of high nitrogen deposition to a bog in the Italian Alps caused a loss of mosses and an increase in vascular plant biomass (Bubier et al, 2007;Wang et al, 2016;Sheppard et al, 2013;Wiedermann et al, 2007;Bragazza et al, 2012). In the Mer Bleue bog, nutrient addition mostly increased the abundance of shrubs, whereas at Whim bog, Degerö Stormyr, and an Italian mire, both shrub and graminoid cover increased.…”

Section: Introductionmentioning

confidence: 99%

Differential response of carbon cycling to long-term nutrient input and altered hydrological conditions in a continental Canadian peatland

et al. 2018

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Abstract. Peatlands play an important role in global carbon cycling, but their responses to long-term anthropogenically changed hydrologic conditions and nutrient infiltration are not well known. While experimental manipulation studies, e.g., fertilization or water table manipulations, exist on the plot scale, only few studies have addressed such factors under in situ conditions. Therefore, an ecological gradient from the center to the periphery of a continental Canadian peatland bordering a eutrophic water reservoir, as reflected by increasing nutrient input, enhanced water level fluctuations, and increasing coverage of vascular plants, was used for a case study of carbon cycling along a sequence of four differently altered sites. We monitored carbon dioxide (CO 2 ) and methane (CH 4 ) surface fluxes and dissolved inorganic carbon (DIC) and CH 4 concentrations in peat profiles from April 2014 through September 2015. Moreover, we studied bulk peat and pore-water quality and we applied δ 13 C-CH 4 and δ 13 C-CO 2 stable isotope abundance analyses to examine dominant CH 4 production and emission pathways during the growing season of 2015. We observed differential responses of carbon cycling at the four sites, presumably driven by abundances of plant functional types and vicinity to the reservoir. A shrub-dominated site in close vicinity to the reservoir was a comparably weak sink for CO 2 (in 1.5 years: −1093 ± 794, in 1 year: +135 ± 281 g CO 2 m −2 ; a net release) as compared to two graminoid-moss-dominated sites and a moss-dominated site (in 1.5 years: −1552 to −2260 g CO 2 m −2 , in 1 year: −896 to −1282 g CO 2 m −2 ). Also, the shrub-dominated site featured notably low DIC pore-water concentrations and comparably 13 C-enriched CH 4 (δ 13 C-CH 4 : −57.81 ± 7.03 ‰) and depleted CO 2 (δ 13 C-CO 2 : −15.85 ± 3.61 ‰) in a more decomposed peat, suggesting a higher share of CH 4 oxidation and differences in predominant methanogenic pathways. In comparison to all other sites, the graminoid-mossdominated site in closer vicinity to the reservoir featured a ∼ 30 % higher CH 4 emission (in 1.5 years: +61.4 ± 32, in 1 year: +39.86 ± 16.81 g CH 4 m −2 ). Low δ 13 C-CH 4 signatures (−62.30 ± 5.54 ‰) indicated only low mitigation of CH 4 emissions by methanotrophic activity here. Pathways of methanogenesis and methanotrophy appeared to be related to the vicinity to the water reservoir: the importance of acetoclastic CH 4 production apparently increased toward the reservoir, whereas the importance of CH 4 oxidation increased toward the peatland center. Plant-mediated transport was the prevailing CH 4 emission pathway at all sites even where graminoids were rare. Our study thus illustrates accelerated carbon cycling in a strongly altered peatland with consequences for CO 2 and CH 4 budgets. However, our results suggest that long-term excess nutrient input does not necessarily lead to a loss of the peatland carbon sink function.

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High nitrogen deposition alters the decomposition of bog plant litter and reduces carbon accumulation

Cited by 118 publications

References 50 publications

The impact of sea-level rise on organic matter decay rates in Chesapeake Bay brackish tidal marshes

The impact of sea-level rise on organic matter decay rates in Chesapeake Bay brackish tidal marshes

Drivers of Holocene peatland carbon accumulation across a climate gradient in northeastern North America

Differential response of carbon cycling to long-term nutrient input and altered hydrological conditions in a continental Canadian peatland

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