Distribution of N 2 O in the eastern shelf of the Gulf of Cadiz (SW Iberian Peninsula)

Sierra, A.; Jiménez-López, D.; Ortega, T.; Ponce, R.; Bellanco, M.J.; Sánchez-Leal, R.F.; Gómez-Parra, Abelardo; Forja, Jesús M.

doi:10.1016/j.scitotenv.2017.03.189

Cited by 19 publications

(10 citation statements)

References 78 publications

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“…We stored these samples in the dark at controlled temperature (25 C) until analysis. We measured dissolved N 2 O using headspace equilibration in a 50 mL airtight glass syringe (Agilent P/N 5190-1547; Sierra et al 2017). We obtained two replicates for each 125 mL Winkler bottle and three replicates for each 250 mL Winkler bottle.…”

Section: Dissolved N 2 O In the Water Columnmentioning

confidence: 99%

P inputs determine denitrifier abundance explaining dissolved nitrous oxide in reservoirs

León‐Palmero

Morales‐Baquero

Reche

2023

Limnology & Oceanography

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Reservoirs are important sites for nitrogen processing, especially those located in agricultural and urban watersheds. Nitrogen inputs promote N2O production and emission, but the microbial pathways controlling N2O have been seldom studied in reservoir water columns. We determined N2O concentration in the water column of 12 reservoirs during the summer stratification and winter mixing. We explored the potential microbial sources and sinks of N2O by quantifying key genes involved in ammonia oxidation (bacterial and archaeal amoA) and denitrification (nirS and nosZ). Dissolved N2O varied up to three orders of magnitude (4.7–2441.2 nmol L−1) across systems, from undersaturated to supersaturated values (37%–24,174%) depending on reservoirs and depths. N2O concentration depended on nitrogen and oxygen availabilities, with the lowest and highest N2O values at suboxic conditions. Ammonia‐oxidizing archaea dominated over ammonia‐oxidizing bacteria but were not related to the dissolved N2O. In contrast, the abundance of the nirS gene was significantly related to N2O concentration, and three orders of magnitude higher than amoA abundance. Denitrifying bacteria appeared consistently in the water column of all reservoirs. The nirS and nosZ genes appeared in oxic and suboxic waters, but they were more abundant in suboxic waters. The nitrate concentration, and nirS and nosZ relative abundances explained the dissolved N2O. Besides, nirS abundance was related positively with total phosphorus and cumulative chlorophyll a, a proxy for fresh organic matter. Therefore, P inputs, not just N inputs, promoted N2O production by denitrification in the water column of reservoirs.

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Section: Dissolved N 2 O In the Water Columnmentioning

confidence: 99%

P inputs determine denitrifier abundance explaining dissolved nitrous oxide in reservoirs

León‐Palmero

Morales‐Baquero

Reche

2023

Limnology & Oceanography

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“…We acidified with phosphoric acid (final pH<2) the samples for DOC, total dissolved nitrogen (TDN), and total nitrogen (TN). We measured DOC, dissolved inorganic carbon (DIC), TN, and TDN by high-temperature catalytic oxidation using a Shimadzu total organic carbon (TOC) analyzer (Model TOC-V CSH) coupled to nitrogen analyzer (TNM-1) (Álvarez-Salgado and Miller 1998 We also measured dissolved CH 4 and N 2 O by headspace equilibration in a 50 ml air-tight glass syringe by duplicate in the water column (Sierra et al 2017a(Sierra et al , 2017b. We analyzed simultaneously the concentration of dissolved CH 4 and N 2 O using gas chromatography (more details in supplementary methods).…”

Section: C N and P Analysis In The Water Columnmentioning

confidence: 99%

Greenhouse gas fluxes from reservoirs determined by watershed lithology, morphometry, and anthropogenic pressure

León‐Palmero

Morales‐Baquero

Reche

2020

Environ. Res. Lett.

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Human population growth has increased the demand for water and clean energy, leading to the massive construction of reservoirs. Reservoirs can emit greenhouse gases (GHG) affecting the atmospheric radiative budget. The radiative forcing due to CO 2 , CH 4 , and N 2 O emissions and the relative contribution of each GHG in terms of CO 2 equivalents to the total forcing is practically unknown. We determined simultaneously the CO 2 , CH 4 , and N 2 O fluxes in reservoirs from diverse watersheds and under variable human pressure to cover the vast idiosyncrasy of temperate Mediterranean reservoirs. We obtained that GHG fluxes ranged more than three orders of magnitude. The reservoirs were sources of CO 2 and N 2 O when the watershed lithology was mostly calcareous, and the crops and the urban areas dominated the landscape. By contrast, reservoirs were sinks of CO 2 and N 2 O when the watershed lithology was predominantly siliceous, and the landscape had more than 40% of forestal coverage. All reservoirs were sources of CH 4 , and emissions were determined mostly by reservoir mean depth and water temperature. The radiative forcing was substantially higher during the stratification than during the mixing. During the stratification the radiative forcings ranged from 125 mg CO 2 equivalents m −2 d −1 to 31 884 mg CO 2 equivalents m −2 d −1 and were dominated by the CH 4 emissions; whereas during the mixing the radiative forcings ranged from 29 mg CO 2 equivalents m −2 d −1 to 722 mg CO 2 equivalents m −2 d −1 and were dominated by CO 2 emissions. The N 2 O contribution to the radiative forcing was minor except in one reservoir with a landscape dominated by crops and urban areas. Future construction of reservoirs should consider that siliceous bedrocks, forestal landscapes, and deep canyons could minimize their radiative forcings.

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“…For example, at some stations, this activity could take up to 8 hours due to the sampling of zooplankton where a bongo and neuston net and/or multinet was used. Studies such as those of Sierra et al (2017aSierra et al ( , 2017b, González-García et al (2018) are examples of these cruises and the other activities carried out here. This sentence is now clarified in the text: Line 239-241: "In Fig.…”

Section: Discussion Papermentioning

confidence: 92%

Author comments_Factors controlling pCO2 variability in the eastern Gulf of Cádiz (SW Iberian Península)

López¹

2019

Preprint

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The authors are very grateful for your constructive comments and suggestions on the previous version. We think that the manuscript has been significantly improved thanks to all the contributions made. Below you will find the comments you made and our comments as authors (marked AC) on each point. In response to all the comments the manuscript has been modified, resulting in changes to line numbers. Therefore, we have included the new line numbers (whenever applicable) so that you can refer to either the current or (former) version if you wish.

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Distribution of N 2 O in the eastern shelf of the Gulf of Cadiz (SW Iberian Peninsula)

Cited by 19 publications

References 78 publications

P inputs determine denitrifier abundance explaining dissolved nitrous oxide in reservoirs

P inputs determine denitrifier abundance explaining dissolved nitrous oxide in reservoirs

Greenhouse gas fluxes from reservoirs determined by watershed lithology, morphometry, and anthropogenic pressure

Author comments_Factors controlling pCO2 variability in the eastern Gulf of Cádiz (SW Iberian Península)

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