Figure 10. Meridional-Seasonal relationship between N₂O concentration and in-situ oxygen in the BUS. Colour code represents the sum of NO₃^- and NO₂^- concentrations (in µmol L^-1). In the summer season, the samples were marked with black circles. The best fitted model, accompanied by the corresponding r-squared value (r²) and the total number of samples (n) are also presented.

Our depth-cross section plots also reveal the potential consumption of N₂O in the inner shelf of Lüderitz in summer campaign (Figure 5). This, in conjunction with nutrient depletion, points towards a possible denitrification process, leading to a breakdown in correlation.

Overall, there is a more heterogeneous distribution of N₂O in the water column during summer, indicating a potential small-scale variability compared to the homogenous distribution observed in winter (Figures 3, 4, 5, and 9).

Our extended investigations into the primary factors influencing seasonal-spatial outgassing in the nBUS have revealed that the drivers of F CO₂ and F N₂O exhibit similarity within the BUS. Factor 1 accounts for approximately 60% of the total variance for both gases during the winter season. Despite oxygen displaying a negative correlation with various parameters such as wind speed, ΔCO₂, ΔN₂O, F CO₂and F N₂O, we propose that, particularly in winter, biological processes associated with oxygen depletion significantly contribute to the emissions of CO₂ and N₂O. This contribution becomes notably pronounced, particularly in conjunction with upwelling events, in regions adjacent to the coast in Kunene and Walvis Bay, where the highestp CO₂ values were also observed (Figure 11).