Modelling photodegradation in the global carbon cycle

Foereid, Bente; Rivero, Marı́a J.; Primo, Óscar; Ortiz, Inmaculada

doi:10.1016/j.soilbio.2011.03.004

Cited by 37 publications

(40 citation statements)

References 19 publications

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“…The mechanistic model for photopriming outlined here suggests that this process can be of importance in many highly productive terrestrial ecosystems where senescent plant material may be exposed to solar radiation for some period during the year, including tundra, grasslands, savannah, agroecosystems, droughtdeciduous forests, and alpine ecosystems. This implication challenges the estimation of a modest contribution of photodegradation to the global carbon cycle (25). The full nature of the interactions between photodegradation, subsequent microbial decomposition, and climate controls has yet to be determined although it seems that the way in which photodegradation affects the enzymatic accessibility to carbohydrates in plant cell walls, and thus litter decomposability, is an underestimated factor determining plant carbon turnover in a wide range of terrestrial ecosystems.…”

Section: Discussionmentioning

confidence: 99%

“…Recent studies have demonstrated stimulation of litter decomposition and respiration with prior exposure to ultraviolet (UV) (22,23) or full solar radiation (24) in dry Mediterranean ecosystems. Nevertheless, the quantitative significance of photodegradation in terrestrial ecosystems that support greater microbial activity than arid-land ecosystems is generally considered to be minimal (25).…”

Section: Uv Radiationmentioning

confidence: 99%

See 1 more Smart Citation

Photodegradation alleviates the lignin bottleneck for carbon turnover in terrestrial ecosystems

Austin

Méndez

Ballaré

2016

Proc. Natl. Acad. Sci. U.S.A.

163

211

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A mechanistic understanding of the controls on carbon storage and losses is essential for our capacity to predict and mitigate human impacts on the global carbon cycle. Plant litter decomposition is an important first step for carbon and nutrient turnover, and litter inputs and losses are essential in determining soil organic matter pools and the carbon balance in terrestrial ecosystems. Photodegradation, the photochemical mineralization of organic matter, has been recently identified as a mechanism for previously unexplained high rates of litter mass loss in arid lands; however, the global significance of this process as a control on carbon cycling in terrestrial ecosystems is not known. Here we show that, across a wide range of plant species, photodegradation enhanced subsequent biotic degradation of leaf litter. Moreover, we demonstrate that the mechanism for this enhancement involves increased accessibility to plant litter carbohydrates for microbial enzymes. Photodegradation of plant litter, driven by UV radiation, and especially visible (blue-green) light, reduced the structural and chemical bottleneck imposed by lignin in secondary cell walls. In leaf litter from woody species, specific interactions with UV radiation obscured facilitative effects of solar radiation on biotic decomposition. The generalized effect of sunlight exposure on subsequent microbial activity, mediated by increased accessibility to cell wall polysaccharides, suggests that photodegradation is quantitatively important in determining rates of mass loss, nutrient release, and the carbon balance in a broad range of terrestrial ecosystems.carbon cycle | plant litter decomposition | photodegradation | lignin |

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Section: Discussionmentioning

confidence: 99%

Section: Uv Radiationmentioning

confidence: 99%

Photodegradation alleviates the lignin bottleneck for carbon turnover in terrestrial ecosystems

Austin

Méndez

Ballaré

2016

Proc. Natl. Acad. Sci. U.S.A.

163

211

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“…If radiation was completely blocked, decomposition was reduced by 60%, if only UV-B radiation was blocked, there was already a reduction of decomposition by 33%. Photodegradation, especially degradation due to UV radiation, may play a particularly prominent role in arid and semi-arid ecosystems (e.g., [47]), but there is evidence that this mechanism is also important for a wider range of grasslands, including more mesic sites [48], [49]. Our experiment was not designed to determine the mechanism behind these effects, but assuming photodegradation plays a significant role in our system, it is conceivable that decomposition was sensitive to the roof artifacts through changes in radiation.…”

Section: Discussionmentioning

confidence: 99%

Separating Drought Effects from Roof Artifacts on Ecosystem Processes in a Grassland Drought Experiment

et al. 2013

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1Given the predictions of increased drought probabilities under various climate change scenarios, there have been numerous experimental field studies simulating drought using transparent roofs in different ecosystems and regions. Such roofs may, however, have unknown side effects, called artifacts, on the measured variables potentially confounding the experimental results. A roofed control allows the quantification of potential artifacts, which is lacking in most experiments.2We conducted a drought experiment in experimental grasslands to study artifacts of transparent roofs and the resulting effects of artifacts on ecosystems relative to drought on three response variables (aboveground biomass, litter decomposition and plant metabolite profiles). We established three drought treatments, using (1) transparent roofs to exclude rainfall, (2) an unroofed control treatment receiving natural rainfall and (3) a roofed control, nested in the drought treatment but with rain water reapplied according to ambient conditions.3Roofs had a slight impact on air (+0.14°C during night) and soil temperatures (−0.45°C on warm days, +0.25°C on cold nights), while photosynthetically active radiation was decreased significantly (−16%). Aboveground plant community biomass was reduced in the drought treatment (−41%), but there was no significant difference between the roofed and unroofed control, i.e., there were no measurable roof artifact effects.4Compared to the unroofed control, litter decomposition was decreased significantly both in the drought treatment (−26%) and in the roofed control treatment (−18%), suggesting artifact effects of the transparent roofs. Moreover, aboveground metabolite profiles in the model plant species Medicago x varia were different from the unroofed control in both the drought and roofed control treatments, and roof artifact effects were of comparable magnitude as drought effects.5Our results stress the need for roofed control treatments when using transparent roofs for studying drought effects, because roofs can cause significant side effects.

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“…If a simple relationship between amount of radiation received and nutrient release rate can be found, the optimal exposure time only needs to be tested in a few sites and predictions can be made for other sites. Previous work has shown that a fairly consistent relationship between radiation exposure and carbon mineralization can be developed [9]. There is also evidence that the effect of photo-exposure depends on lignin content [13], meaning that it may also be possible to generalize between litter types.…”

Section: Introductionmentioning

confidence: 83%

“…Several recent studies have indicated that photodegradation, enhancement of decomposition rate caused by exposure to light, may play an important role in plant residue decomposition and in the carbon cycle in semi-arid ecosystems where other climatic factors appear less important [3][4][5][6][7][8][9]. These environments are characterized by high radiation levels coinciding with low vegetation cover for at least part of the year, meaning that the degrading litter on the soil surface will be exposed to high radiation.…”

Section: Introductionmentioning

confidence: 99%

Photodegradation for Nutrient Management in the Dry Tropics

Foereid

2012

OJSS

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Nutrient limitation in agriculture is a big problem in many tropical areas. Much research has focused on the optimal use of crop residues in agriculture. Recent work indicates that plant residue decomposition rates, including nutrient release rates can be increased by pre-exposure to sunlight. This has potential as a technology to manipulate nutrient release from residues to match crop demands. The possible development and use of this technology is discussed. There is some evidence that this could increase emissions of trace gases, but the increase is thought to be small. Research needs are discussed.

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Modelling photodegradation in the global carbon cycle

Cited by 37 publications

References 19 publications

Photodegradation alleviates the lignin bottleneck for carbon turnover in terrestrial ecosystems

Photodegradation alleviates the lignin bottleneck for carbon turnover in terrestrial ecosystems

Separating Drought Effects from Roof Artifacts on Ecosystem Processes in a Grassland Drought Experiment

Photodegradation for Nutrient Management in the Dry Tropics

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