Physical and biological controls on trace gas fluxes in semi-arid urban ephemeral waterways

Gallo, E. L.; Lohse, Kathleen A.; Ferlin, C.; Meixner, Thomas; Brooks, P. D.

doi:10.1007/s10533-013-9927-0

Cited by 65 publications

(99 citation statements)

References 65 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These results are in line with studies in wetlands, where increases in CO 2 emissions after drying have been widely reported (Moore and Knowles 1989, Freeman et al 1993, Fenner and Freeman 2011. Moreover, our CO 2 efflux from dry watercourses was generally slightly above values found by Gallo et al (2013) ), in what to our knowledge is the only previous study reporting CO 2 emissions from dry watercourses. This result suggests that, similar to soils, there may be significant regional differences in CO 2 emissions from dry watercourses.…”

Section: Discussionsupporting

confidence: 93%

“…Our intention, however, was not to provide a definitive, unbiased estimate of dry watercourse emissions, but, in a first approach, to attempt to obtain an estimate of their magnitude. We also report emissions using the minimum and maximum CO 2 efflux from dry watercourses found in the compiled dataset (our study and Gallo et al 2013) to highlight the large uncertainty that results from the scarcity of data on the efflux of CO 2 from dry watercourses.…”

Section: Methodsmentioning

confidence: 99%

“…Our understanding of the biogeochemical processes that occur during this dry phase is limited (Larned et al 2010, Steward et al 2012), yet recent studies have shown that biofilms process organic carbon in dry watercourses (Zoppini andMarxsen 2011, Timoner et al 2012), and that CO 2 can be released from these dry systems (Gallo et al 2013). Emissions of CO 2 from dry watercourses should not be considered terrestrial emissions because the carbon processed in dry watercourses has either already left terrestrial ecosystems and entered the river network or has been produced within the river network.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Carbon dioxide emissions from dry watercourses

Schiller

Marcé

Obrador

et al. 2014

View full text Add to dashboard Cite

Temporary watercourses that naturally cease to flow and run dry comprise a notable fraction of the world's river networks, yet estimates of global carbon dioxide (CO 2 ) emissions from watercourses do not consider emissions from these systems when they are dry. Using data from a sampling campaign in a Mediterranean river during the summer drought period, we demonstrate that the CO 2 efflux from dry watercourses can be substantial, comparable to that from adjacent terrestrial soils and higher than from running or stagnant waters. With an up-scaling approach, we show that including emissions from dry watercourses could increase the estimate of CO 2 emissions from watercourses in our study region by 0.6-15%. Moreover, our results tentatively illustrate that emissions from dry watercourses could be especially important in arid regions, increasing the estimate of global CO 2 emissions from watercourses by 0.4-9%. Albeit relatively small, the contribution of dry watercourses could help to constrain the highly uncertain magnitude of the land carbon sink. We foresee that in many areas of the world, the expected increase in the extent of temporary watercourses associated with future global change will increase the relevance of CO 2 emissions from dry watercourses.

show abstract

Section: Discussionsupporting

confidence: 93%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Carbon dioxide emissions from dry watercourses

Schiller

Marcé

Obrador

et al. 2014

View full text Add to dashboard Cite

show abstract

“…In another Tucson study, pervious channel density was associated with decreases in NO 2 − and NH 4 + concentrations but had no relationship with NO 3 − or dissolved organic N concentrations. 24 However, biogeochemical processes that are triggered by rainfall events may be sustained for extended periods of time after events, 19 suggesting that gaseous N losses may be significant between events even if they do not affect concentrations of N in stormwater.…”

Section: Microbially Nitrified Nomentioning

confidence: 99%

Sources and Transport of Nitrogen in Arid Urban Watersheds

Hale

Turnbull

Earl

et al. 2014

Environ. Sci. Technol.

Self Cite

View full text Add to dashboard Cite

Urban watersheds are often sources of nitrogen (N) to downstream systems, contributing to poor water quality. However, it is unknown which components (e.g., land cover and stormwater infrastructure type) of urban watersheds contribute to N export and which may be sites of retention. In this study we investigated which watershed characteristics control N sourcing, biogeochemical processing of nitrate (NO 3 − ) during storms, and the amount of rainfall N that is retained within urban watersheds. We used triple isotopes of NO 3 − (δ 15 N, δ 18 O, and Δ 17 O) to identify sources and transformations of NO 3 − during storms from 10 nested arid urban watersheds that varied in stormwater infrastructure type and drainage area. Stormwater infrastructure and land coverretention basins, pipes, and grass cover dictated the sourcing of NO 3 − in runoff. Urban watersheds were strong sinks or sources of N to stormwater depending on runoff, which in turn was inversely related to retention basin density and positively related to imperviousness and precipitation. Our results suggest that watershed characteristics control the sources and transport of inorganic N in urban stormwater but that retention of inorganic N at the time scale of individual runoff events is controlled by hydrologic, rather than biogeochemical, mechanisms.

show abstract

“…While much of the research on greenhouse gas (GHG) emissions from streams has taken place in agricultural watersheds, urban-impacted river networks receive similar N loads and have also shown elevated GHG concentrations and emissions (e.g., Daniel et al, 2001;Beaulieu et al, 2010Beaulieu et al, , 2011Kaushal et al, 2014a;Gallo et al, 2014). As urban land cover and populations continue to expand, it is critical to understand the impacts on downstream waters, including C and N loading and GHG emissions.…”

Section: Introductionmentioning

confidence: 99%

Influence of infrastructure on water quality and greenhouse gas dynamics in urban streams

et al. 2017

View full text Add to dashboard Cite

Abstract. Streams and rivers are significant sources of nitrous oxide (N 2 O), carbon dioxide (CO 2 ), and methane (CH 4 ) globally, and watershed management can alter greenhouse gas (GHG) emissions from streams. We hypothesized that urban infrastructure significantly alters downstream water quality and contributes to variability in GHG saturation and emissions. We measured gas saturation and estimated emission rates in headwaters of two urban stream networks (Red Run and Dead Run) of the Baltimore Ecosystem Study Long-Term Ecological Research project. We identified four combinations of stormwater and sanitary infrastructure present in these watersheds, including: (1) stream burial, (2) inline stormwater wetlands, (3) riparian/floodplain preservation, and (4) septic systems. We selected two firstorder catchments in each of these categories and measured GHG concentrations, emissions, and dissolved inorganic and organic carbon (DIC and DOC) and nutrient concentrations biweekly for 1 year. From a water quality perspective, the DOC : NO − 3 ratio of streamwater was significantly different across infrastructure categories. Multiple linear regressions including DOC : NO − 3 and other variables (dissolved oxygen, DO; total dissolved nitrogen, TDN; and temperature) explained much of the statistical variation in nitrous oxide (N 2 O, r 2 = 0.78), carbon dioxide (CO 2 , r 2 = 0.78), and methane (CH 4 , r 2 = 0.50) saturation in stream water. We measured N 2 O saturation ratios, which were among the highest reported in the literature for streams, ranging from 1.1 to 47 across all sites and dates. N 2 O saturation ratios were highest in streams draining watersheds with septic systems and strongly correlated with TDN. The CO 2 saturation ratio was highly correlated with the N 2 O saturation ratio across all sites and dates, and the CO 2 saturation ratio ranged from 1.1 to 73. CH 4 was always supersaturated, with saturation ratios ranging from 3.0 to 2157. Longitudinal surveys extending form headwaters to third-order outlets of Red Run and Dead Run took place in spring and fall. Linear regressions of these data yielded significant negative relationships between each gas with increasing watershed size as well as consistent relationships between solutes (TDN or DOC, and DOC : TDN ratio) and gas saturation. Despite a decline in gas saturation between the headwaters and stream outlet, streams remained saturated with GHGs throughout the drainage network, suggesting that urban streams are continuous sources of CO 2 , CH 4 , and N 2 O. Our results suggest that infrastructure decisions can have significant effects on downstream water quality and greenhouse gases, and watershed management strategies may need to consider coupled impacts on urban water and air quality.

show abstract

Physical and biological controls on trace gas fluxes in semi-arid urban ephemeral waterways

Cited by 65 publications

References 65 publications

Carbon dioxide emissions from dry watercourses

Carbon dioxide emissions from dry watercourses

Sources and Transport of Nitrogen in Arid Urban Watersheds

Influence of infrastructure on water quality and greenhouse gas dynamics in urban streams

Contact Info

Product

Resources

About