Nitrous oxide and biogeochemical variables related to Intermediate Waters into Eastern South Pacific Ocean ...

• Main Authors: Farias, Laura, Carrasco, Cristina, Faúndez, Juan
• Format: Dataset
• Language: English
• Published: PANGAEA 2019
• Subjects: Greenhouse gases; nitrate; nitrite; nitrogen cycle; nitrous oxide; oceanography; Salinity; silicate; Temperature; Event label; Cruise/expedition; Station label; Latitude of event; Longitude of event; DATE/TIME; DEPTH, water; Temperature, water; Density, mass density; Oxygen; Nitrous oxide, dissolved; Silicate; Nitrate; Nitrite; Phosphate; CTD/Rosette; CTD-O probe; Dissolved oxygen, automated Winkler Strickland & Parsons, 1972; Headspace Gas Chromatography, Perkin-Elmer; Seawater analysis after Grasshoff et al., 1983 Verlag Chemie GmbH Weinheim; BiG RAPA; BIOSOPE; Galathea 3; KNR182-7; KNR182-9; MOBIO; MR03-K04 Leg1; Melville; L Atalante; HDMS Vaedderen; Knorr; Abate Molina; Mirai; Antarc*; Antarctic
• Online Access: https://dx.doi.org/10.1594/pangaea.906231; https://doi.pangaea.de/10.1594/PANGAEA.906231

Nitrous oxide (N2O) is a powerful greenhouse gas principally produced by nitrification and denitrification in the marine environment. Observations were made in the eastern South Pacific (ESP), between 10º and 60°S, and ~75° to 88°W, from intermediate waters targeting Antarctic Intermediate Water (AAIW) at potential density of 27.0-27.1 kg m-3. Between 60° to 20°S, a gradual equatorward increase of N2O from 8 to 26 nmol L-1 was observed at density 27.0-27.1 kg m-3 where AAIW penetrates. Positive correlations were found between apparent N2O production (∆N2O) and O2 utilization (AOU), and between ∆N2O and NO3-, which suggested that local N2O production is predominantly produced by nitrification. Closer to the equator, between 20° and 10°S at AAIW core, a strong N2O increase up to 75 nmol L-1 was observed. Because negative correlations were found between ∆N2O vs. NO3- and ∆N2O vs. N* (a Nitrogen deficit index) and because ∆N2O and AOU do not follow a linear trend, we suspect that, in addition to nitrification, ... : Seven oceanographic cruises which include the vertical distribution of Nitrous Oxide, Oxygen, Silicate, Nitrate, Nitrite, Phosphate, Temperature, Salinity and estimated variable such as Density and Potential Density, are shared. The cruises cover the South Eastern Pacific Ocean between -9.5 to -60 °S and -70.7 to -91.4 °W and from surface up 2000 meters depth. Nitrous Oxide was analyzed in 20 ml vials with headspace by Gas Chromatography, while the Temperature, Salinity, Pressure and Dissolved Oxygen were determinate using a calibrated CTD-O probe. Nutrients were filtered with 0.45 micras pore size glass filter and determine by colorimetry.Water samples were collected using Niskin bottles attached to rosette sampler, in order to obtain discrete measurements of dissolver oxygen (O2) and nutrients (NO3, NO2, SiO4 and PO43). Discrete samples of DO (in triplicate) were analyzed using the AULOX measurement system, an automatic Winkler method. Samples for all nutrients (15 mL in triplicate) were filtered (using a ...