Carbon Dioxide and Methane Emissions from a Temperate Salt Marsh Tidal Creek

Trifunovic, Branimir; Vázquez‐Lule, Alma; Capooci, Margaret; Seyfferth, Angelia L.; Moffat, Carlos; Vargas, Rodrigo

doi:10.1002/essoar.10504497.1

Cited by 3 publications

(4 citation statements)

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“…Numerous statistical methods with known strengths and weaknesses have been used to describe and model FCH4, ranging from simple correlation analysis to more complex machine learning algorithms (Genuer et al, 2010; Kim et al, 2020; Peltola et al, 2019). By implementing and comparing multiple statistical approaches, it is possible to evaluate how our understanding of the complex interactions between controls on FCH4 is influenced by the choice of statistical analysis (Trifunovic et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

Identifying dominant environmental predictors of freshwater wetland methane fluxes across diurnal to seasonal time scales

Knox

Bansal

McNicol

et al. 2021

Global Change Biology

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While wetlands are the largest natural source of methane (CH4) to the atmosphere, they represent a large source of uncertainty in the global CH4 budget due to the complex biogeochemical controls on CH4 dynamics. Here we present, to our knowledge, the first multi‐site synthesis of how predictors of CH4 fluxes (FCH4) in freshwater wetlands vary across wetland types at diel, multiday (synoptic), and seasonal time scales. We used several statistical approaches (correlation analysis, generalized additive modeling, mutual information, and random forests) in a wavelet‐based multi‐resolution framework to assess the importance of environmental predictors, nonlinearities and lags on FCH4 across 23 eddy covariance sites. Seasonally, soil and air temperature were dominant predictors of FCH4 at sites with smaller seasonal variation in water table depth (WTD). In contrast, WTD was the dominant predictor for wetlands with smaller variations in temperature (e.g., seasonal tropical/subtropical wetlands). Changes in seasonal FCH4 lagged fluctuations in WTD by ~17 ± 11 days, and lagged air and soil temperature by median values of 8 ± 16 and 5 ± 15 days, respectively. Temperature and WTD were also dominant predictors at the multiday scale. Atmospheric pressure (PA) was another important multiday scale predictor for peat‐dominated sites, with drops in PA coinciding with synchronous releases of CH4. At the diel scale, synchronous relationships with latent heat flux and vapor pressure deficit suggest that physical processes controlling evaporation and boundary layer mixing exert similar controls on CH4 volatilization, and suggest the influence of pressurized ventilation in aerenchymatous vegetation. In addition, 1‐ to 4‐h lagged relationships with ecosystem photosynthesis indicate recent carbon substrates, such as root exudates, may also control FCH4. By addressing issues of scale, asynchrony, and nonlinearity, this work improves understanding of the predictors and timing of wetland FCH4 that can inform future studies and models, and help constrain wetland CH4 emissions.

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Section: Introductionmentioning

confidence: 99%

Identifying dominant environmental predictors of freshwater wetland methane fluxes across diurnal to seasonal time scales

Knox

Bansal

McNicol

et al. 2021

Global Change Biology

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“…Additionally, the regular tidal exchange of marine and fresh water in coastal ecosystems can affect CH 4 production and consumption processes. For example, CH 4 fluxes in mangrove and tidal marsh waters have been shown to follow a typical tidal pattern with lower fluxes at high tide and higher fluxes at low tide, driven by a mechanism termed ‘tidal pumping’ (Ovalle et al., 1990; Stieglitz et al., 2013), which describes the tidally mediated exchange of groundwater or interstitial pore water (high in CH 4 ) with coastal surface water (Call et al., 2015, 2019; Maher et al., 2013; Trifunovic et al., 2020). In high salinity marshes, CH 4 fluxes via submarine groundwater discharge (SGD) have been shown to almost double total CH 4 fluxes, suggesting the combined export pathways (i.e., CH 4 marsh emissions and SGD fluxes) increase the potential to offset climate benefits of carbon burial in saltmarshes (Schutte et al., 2020).…”

Section: Introductionmentioning

confidence: 99%

Methane and Nitrous Oxide Emissions Complicate Coastal Blue Carbon Assessments

Rosentreter

Al‐Haj

Fulweiler

et al. 2021

Global Biogeochemical Cycles

125

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The role of coastal wetlands as natural ‘blue carbon’ sinks may be counter‐acted by emissions of methane (CH4) and nitrous oxide (N2O). Site‐specific fluxes of these two potent greenhouse gases from coastal wetlands show high spatial and temporal variability , making global estimates sensitive to statistical assumptions and uncertainties. Here, we review the magnitude of CH4 and N2O fluxes from mangroves, saltmarshes and seagrasses and identify direct and indirect drivers that can control production and consumption pathways. Significant research is required to better quantify fluxes and to understand factors causing flux variability from different transport pathways before restoration of coastal blue carbon ecosystems can be reliably used for climate mitigation.

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“…Based operationally on past vegetation surveys conducted at the DNERR, peak biomass occurs between Mid‐July through Mid‐August. A PhenoCam affixed to the EC tower shows that tidal marsh vegetation in 2018 began to grow at the end of April and reached a peak around Mid‐July (Trifunovic et al., 2020).…”

Section: Resultsmentioning

confidence: 99%

“…Instruments were deployed over the marsh from the edge of a small wooden boardwalk (1.7 m width) adjacent to an existing AmeriFlux site (US‐StJ) hosted by the University of Delaware (Trifunovic et al., 2020). AmeriFlux is a network of sites that measure carbon dioxide (CO 2 ), water, and energy fluxes in different ecosystems across the USA and include sites across the Americas (Hargrove et al., 2003).…”

Section: Methodsmentioning

confidence: 99%

Atmospheric Ammonia Measurements Over a Coastal Salt Marsh Ecosystem Along the Mid‐Atlantic U.S.

et al. 2021

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Terrestrial-aquatic interfaces such as salt marshes, mangroves, and similar coastal wetlands occupy only a small fraction of the Earth's surface but account for at least 50% of the total carbon sequestration to ocean ecosystems (Duarte et al., 2005). Carbon sequestered and stored in coastal ecosystems and oceans is known as blue carbon (Mcleod et al., 2011) and there is a need to improve Earth system models across such coastal interfaces (Ward et al., 2020). These ecosystems are carbon-rich and play important roles in greenhouse gas biogeochemistry and the cycling of nutrients, including nitrogen (N) and phosphorus (Mcleod et al., 2011). The rapid loss (1%-3%/yr) of these coastal ecosystems, due to a variety of natural and anthropogenic disturbances, results in substantial impacts on carbon sequestration, carbon storage capacity, and nutrient cycling Abstract Measurements of atmospheric ammonia (NH 3 ) concentrations and fluxes are limited in coastal regions in the eastern U.S. In this study, continuous and high temporal resolution measurements (5s) of atmospheric NH 3 concentrations were recorded using a cavity ring-down spectrometer in a temperate tidal salt marsh at the St Jones Reserve (Dover, DE). Micrometeorological variables were measured using an eddy covariance system which is part of the AmeriFlux network (US-StJ). Soil, plant, and water chemistry were also analyzed to characterize the sources and sinks of atmospheric NH 3 . A new analytical methodology was used to estimate the average ecosystem-scale diurnal cycle of NH 3 fluxes by replicating the characteristics of a chamber experiment. This virtual chamber approach estimates positive surface fluxes in continuing strongly stable conditions when mixing with the air above is minimal. Our findings show that tidal water level may have a significant impact on NH 3 emissions from the marsh. The largest fluxes were observed at low tide when more soil was exposed. While it is expected that NH 3 fluxes will peak when the air temperature maximizes, high tide occurred concurrently with midday peaks in solar irradiance led to a decrease in NH 3 fluxes. Furthermore, soil, plant, and water chemistry measurements underpinning the NH 3 concentrations and fluxes lead us to conclude that this coastal wetland ecosystem can act as either a sink or a source of NH 3 . Such measurements provide novel data on which we can base reliable parameterizations to simulate NH 3 emissions from coastal salt marsh ecosystems using surface-atmosphere transfer models. Plain Language SummaryCoastal wetlands such as salt marshes, mangroves, and seagrasses provide a natural environment for the sequestration and long-term storage of carbon dioxide (CO 2 ) from the atmosphere. As a fertilizer, nitrogen (N) increases the vegetative growth and thus more CO 2 may be fixed in plants as biomass representing the short-term storage pool of carbon, therefore reducing its atmospheric level. Salt marshes, in particular, have been identified as being highly effective at carbon sequestration as well as a...

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Carbon Dioxide and Methane Emissions from a Temperate Salt Marsh Tidal Creek

Cited by 3 publications

References 43 publications

Identifying dominant environmental predictors of freshwater wetland methane fluxes across diurnal to seasonal time scales

Identifying dominant environmental predictors of freshwater wetland methane fluxes across diurnal to seasonal time scales

Methane and Nitrous Oxide Emissions Complicate Coastal Blue Carbon Assessments

Atmospheric Ammonia Measurements Over a Coastal Salt Marsh Ecosystem Along the Mid‐Atlantic U.S.

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