Nitrous oxide measurements in the Benguela Upwelling System during METEOR cruise M157
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| Sprache: | en |
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PANGAEA
2023
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| author | Dangl, Gabriela Frey, Claudia Hassenrück, Christiane Sabbaghzadeh, Bita Wäge-Recchioni, Janine Lehmann, Moritz F Ley, Martin Rehder, Gregor Jürgens, Klaus |
| author_facet | Dangl, Gabriela Frey, Claudia Hassenrück, Christiane Sabbaghzadeh, Bita Wäge-Recchioni, Janine Lehmann, Moritz F Ley, Martin Rehder, Gregor Jürgens, Klaus |
| collection | Datos científicos de ciencias marinas y ambientales |
| contents | Upwelling systems are significant sources of atmospheric nitrous oxide (N₂O). The Benguela Upwelling System is one of the most productive regions worldwide and a temporally variable source of N₂O. Strong O₂ depletions above the shelf are favoring periodically OMZ formations. We aimed to assess underlying N₂O production and consumption processes on different temporal and spatial scales during austral winter in the Benguela Upwelling System, when O₂⁻deficiency in the water column is relatively low. The fieldwork took place during the cruise M157 (August 4ᵗʰ – September 16ᵗʰ 2019) onboard the R/V METEOR. This expedition included four close-coastal regions around Walvis Bay at 23°S, which presented the lowest O₂ concentrations near the seafloor and thus may provide hotspots of N₂O production. Seawater was collected in 10 L free-flow bottles by using a rosette system equipped with conductivity-temperature-depth (CTD) sensors (SBE 911plus, Seabird-electronics, USA).Seawater samples were collected from 10 L free-flow bottles bubble-free, filled into 200 mL serum bottles and immediately fixed with saturated mercury chloride (HgCl₂). Concentrations of dissolved N₂O were measured by a purge and trap system using a dynamic headspace (Sabbaghzadeh et al., 2021). The N₂O gas saturation (N₂Oₛₐₜ in %) was calculated from the concentration ratio between the seawater sample and seawater equilibrated with the atmosphere. ∆N₂O (N₂O saturation disequilibrium in nmol L⁻¹) was calculated as the difference between the measured N₂O concentration and the atmospheric equilibrium N₂O concentration using Bunsen solubility coefficient (Weiss and Price, 1980). AOU (apparent oxygen utilization in µmol L⁻¹) expresses the O₂ consumption by microbial respiration and was calculated as the difference between the equilibrated O₂ and observed O₂ concentration with the same physico-chemical properties (Weiss and Price, 1980). |
| format | Dataset Open Access |
| id | pangaea_https___doi_org_10_1594_PANGAEA_955991 |
| institution | PANGAEA |
| language | en |
| publishDate | 2023 |
| publisher | PANGAEA |
| record_format | pangaea |
| spellingShingle | Nitrous oxide measurements in the Benguela Upwelling System during METEOR cruise M157 Dangl, Gabriela Frey, Claudia Hassenrück, Christiane Sabbaghzadeh, Bita Wäge-Recchioni, Janine Lehmann, Moritz F Ley, Martin Rehder, Gregor Jürgens, Klaus apparent oxygen utilization; Benguela Upwelling System; BUSUC 1; Calculated according to Weiss and Price (1980); CTD, Sea-Bird SBE 911plus; CTD/Rosette; CTD-RO; DATE/TIME; DEPTH, water; Event label; Field observation; Gas chromatography, Agilent 7820B, coupled with a flame ionization detector and an Electron Capture Detector; LATITUDE; LONGITUDE; M157; M157_14-2; M157_16-3; M157_17-2; M157_2-8; Measured according to Sabbaghzadeh et al. (2021); Meteor (1986); Namibia; Nitrous oxide; Nitrous oxide, dissolved; Nitrous oxide, dissolved, disequilibrium; Nitrous oxide, dry air; Nitrous oxide saturation; Oxygen, apparent utilization; Oxygen minimum zone; Partial pressure of nitrous oxide in wet air; Sample code/label; Station label Upwelling systems are significant sources of atmospheric nitrous oxide (N₂O). The Benguela Upwelling System is one of the most productive regions worldwide and a temporally variable source of N₂O. Strong O₂ depletions above the shelf are favoring periodically OMZ formations. We aimed to assess underlying N₂O production and consumption processes on different temporal and spatial scales during austral winter in the Benguela Upwelling System, when O₂⁻deficiency in the water column is relatively low. The fieldwork took place during the cruise M157 (August 4ᵗʰ – September 16ᵗʰ 2019) onboard the R/V METEOR. This expedition included four close-coastal regions around Walvis Bay at 23°S, which presented the lowest O₂ concentrations near the seafloor and thus may provide hotspots of N₂O production. Seawater was collected in 10 L free-flow bottles by using a rosette system equipped with conductivity-temperature-depth (CTD) sensors (SBE 911plus, Seabird-electronics, USA).Seawater samples were collected from 10 L free-flow bottles bubble-free, filled into 200 mL serum bottles and immediately fixed with saturated mercury chloride (HgCl₂). Concentrations of dissolved N₂O were measured by a purge and trap system using a dynamic headspace (Sabbaghzadeh et al., 2021). The N₂O gas saturation (N₂Oₛₐₜ in %) was calculated from the concentration ratio between the seawater sample and seawater equilibrated with the atmosphere. ∆N₂O (N₂O saturation disequilibrium in nmol L⁻¹) was calculated as the difference between the measured N₂O concentration and the atmospheric equilibrium N₂O concentration using Bunsen solubility coefficient (Weiss and Price, 1980). AOU (apparent oxygen utilization in µmol L⁻¹) expresses the O₂ consumption by microbial respiration and was calculated as the difference between the equilibrated O₂ and observed O₂ concentration with the same physico-chemical properties (Weiss and Price, 1980). |
| title | Nitrous oxide measurements in the Benguela Upwelling System during METEOR cruise M157 |
| topic | apparent oxygen utilization; Benguela Upwelling System; BUSUC 1; Calculated according to Weiss and Price (1980); CTD, Sea-Bird SBE 911plus; CTD/Rosette; CTD-RO; DATE/TIME; DEPTH, water; Event label; Field observation; Gas chromatography, Agilent 7820B, coupled with a flame ionization detector and an Electron Capture Detector; LATITUDE; LONGITUDE; M157; M157_14-2; M157_16-3; M157_17-2; M157_2-8; Measured according to Sabbaghzadeh et al. (2021); Meteor (1986); Namibia; Nitrous oxide; Nitrous oxide, dissolved; Nitrous oxide, dissolved, disequilibrium; Nitrous oxide, dry air; Nitrous oxide saturation; Oxygen, apparent utilization; Oxygen minimum zone; Partial pressure of nitrous oxide in wet air; Sample code/label; Station label |
| url | https://doi.org/10.1594/PANGAEA.955991 |