Time series off Concepcion (Chile) was initiated on half 2002 by Concepción University (Chile) in order to characterize the main scales of temporal variability of main biogeochemical carbon (C )and nitrogen (N) cycling at a single location and relate them to physical processes (i.e. El Niño-Southern Oscillation, ENSO). The central area off Chile has the widest continental shelf of Chile, extended about 40 km offshore. This system presents other important features: it is under the influence of wind-driven coastal upwelling with a strong seasonal pattern and it is certainly one of most productive regions in the ocean and also is characterized by a semi-permanent (fluctuating in extension) oxygen minimum zone (OMZ) extending from ca. 30 m depth down to depth, which bath the shelf sediments. Its hydrographic structure is strongly affected by runoff from the Itata and Bio Bio river (up to 3000 m3 s-1) with maximum discharges during winter. This data report was focussed on nitrous oxide (N2O) measurements and ancillary variables at monthly frequency to determine how changes in the nutricline, oxycline and others control N2O distribution. Starting on July 2002 the time series was initiated with a single station located off Dichato, corresponding to Station 18, located at 36º30,8' S - 73º07,7' W, with a depth of 90 m depth. At this station, a CTD with oxygen sensor (CTDO) was deployed from surface to near the bottom and water samples was obtained with 10L Niskin bottles, at the following discrete depth: surface, 5, 10, 15, 20, 30, 50, 65, 80 m depth. Nitrate and N2O (a greenhouse gas) was included in the measurement using methodology delineated by Farías et al. (2015). This dataset includes data that was collected with the research vessel KAY KAY II between 2016 and 2020.

Further information on methods: Nitrate & Nitrite: filtered 45 µm , colorimetric determination, Seal Autoanalyzer Nitrous oxide: headspace technique, gas chromatography, ECD detectorT (according to Wilson et al. 2018)