Are Phragmites-dominated wetlands a net source or net sink of greenhouse gases?

Brix, Hans; Sorrell, Brian K.; Lorenzen, Bent

doi:10.1016/s0304-3770(01)00145-0

Cited by 256 publications

(157 citation statements)

References 23 publications

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“…1). Because introduced Phragmites australis exhibits tremendous genotypic variation (McCormick et al 2010;Kettenring and Mock 2012), and given the broad geographic extent of introduced Phragmites invasion (Chambers et al 1999;, our data argue for field studies that consider the consequences of genotypic variation for important ecosystem services such as carbon sequestration (Brix et al 2001). …”

Section: Discussionmentioning

confidence: 87%

Increased Methane Emissions by an Introduced Phragmites australis Lineage under Global Change

Mozdzer

Megonigal

2013

Wetlands

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North American wetlands have been invaded by an introduced lineage of the common reed, Phragmites australis. Native lineages occur in North America, but many populations have been extirpated by the introduced conspecific lineage. Little is known about how subtle changes in plant lineage may affect methane (CH 4 ) emissions. Native and introduced Phragmites were grown under current and predicted future levels of atmospheric CO 2 and nitrogen(N) pollution in order to understand how CH 4 emissions may vary between conspecific lineages. We found introduced Phragmites emitted more CH 4 than native Phragmites, and that CH 4 emissions increased significantly in both with CO 2 +N treatment. There was no significant difference in CH 4 production potentials, but CH 4 oxidation potentials were higher in soils from the introduced lineage. Intraspecific plant responses to resource availability changed CH 4 emissions, with plant density, root mass, and leaf area being significantly positively correlated with higher emissions. The absence of CO 2 -only or N-only effects highlights a limitation on the generalization that CH 4 emissions are proportional to plant productivity. Our data suggest that intraspecific changes in plant community composition have important implications for greenhouse emissions. Furthermore, global change-enhanced invasion by introduced Phragmites may increase CH 4 emissions unless these factors cause a compensatory increase in carbon sequestration.

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Section: Discussionmentioning

confidence: 87%

Increased Methane Emissions by an Introduced Phragmites australis Lineage under Global Change

Mozdzer

Megonigal

2013

Wetlands

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“…Since methane's potential to absorb infrared radiation in the atmosphere (IPCC, 2007). If considered the contribution of Phragmites australis to C balance coupled with different physical features of the two gases (CO 2 and CH 4 ), wetlands can increase the greenhouse effect on a short time scale basis because of methane emission (Brix et al, 2001). However, such ecosystems also work as a greenhouse gas sink, forcing the gases to attenuate it if they are evaluated over longer time scales.…”

Section: Discussionmentioning

confidence: 99%

The role played by aquatic macrophytes regarding CO2 balance in a tropical coastal lagoon (Cabiúnas Lagoon, Macaé, RJ)

Gripp¹,

Marinho²,

Sanches³

et al. 2013

Acta Limnol. Bras.

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The role played by aquatic macrophytes regarding CO 2 balance in a tropical coastal lagoon (Cabiúnas Lagoon, Macaé, RJ)O papel desempenhado pelas macrófitas aquáticas em relação ao balanço de CO 2 em uma lagoa costeira tropical (Lagoa Cabiúnas, Macaé, RJ) 2 ) is an important atmospheric trace gas that is involved in both the biological carbon cycle and global warming. Inland waters -mainly lakes -contribute to C cycling and have been considered a large source of atmospheric CO 2 . However, scientific studies usually neglect lake morphometry and the presence of aquatic macrophytes in littoral zones, which have a great potential for CO 2 absorption and for C storage. This study aimed to evaluate the importance of the littoral region on the CO 2 balance in the Cabiúnas Lagoon, while also considering the contribution of the limnetic region and of Typha domingensis and Eichhornia azurea, prominent species in the area. Methods: CO 2 flux was estimated by a linear integration of CO 2 concentrations measured in the internal atmospheric of a single-component static closed chambers at the studied sites. The distribution of macrophyte stands throughout lagoon surface was taken into account to evaluate the effects of macrophytes on CO 2 supersaturation. Other factors were also measured throughout the sampling process to evaluate their relationship with CO 2 flux data by means of Akaike model selection criterion. The area covered by aquatic macrophytes at the Cabiúnas lagoon was estimated by profiles and transects. Results and discussion: CO 2 flux through the water surface ranged from -7.39 to 17.56 mgCO2m -2 h -1 . An emission pattern predominated, suggesting that water columns are CO 2 supersaturated at all sampling sites. Rates were similar among all the sampling sites, suggesting that aquatic macrophytes do not influence CO 2 saturation in the water column at Cabiúnas lagoon. On the other hand, CO 2 fluxes from macrophyte tissues showed a clear assimilation pattern. Influxes were higher in T. domingensis (-229.1 ± 320.9 mg CO2.m -2 .h -1 ) than in E. azurea stands (-43.8 ± 39.5 mg CO2.m -2 .h -1 ). Once these macrophytes covered a considerable area of the lagoon and CO 2 absorption strongly overwhelmed the emission processes, then we were able to extrapolate data from the total estimated area of the evaluated sites (75% of the Cabiúnas lagoon), which resulted in a net influx of 46.6 mg CO2.m -2 .h -1 . The strong Typha domingensis contribution to CO 2 absorption and other C cycling processes indicate that it is one of the most important species to Carbon cycling in the studied ecosystem. Thus, it is worth considering C cycling in lake littoral zones as a key process when estimating C balance in shallow aquatic ecosystems.

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“…local emissions from most types of natural wetlands can vary by a few orders of magnitude over a few metres (IPCC 2001;Pavel 2009). Although wetlands act as a source of CH 4 , most may also act as a CO 2 sink due to photosynthesis and sequestration of organic matter in wetland soils or sediments (Brix et al 2001). In this study, benthic releases of methane were measured to follow up on the remineralisation of organic biomass in lake sediments.…”

Section: Background Aim and Scopementioning

confidence: 99%