Temporal distribution of dissolved CH₄ was analysed in a zone of strong seasonal coastal upwelling off central Chile (36.5°S,73°W). Observations were taken from a twelve-year time series that included monthly sampling of the water at eight depths. CH₄ concentration fluctuated between 1.75 and 100.9 nmol L^-1 (or 67.11% and 3965% of saturation), with the highest levels at bottom waters, which increase as upwelling evolved. Three kind of CH₄ profiles were identified; a classical diffusion–advection distribution, with bottom/surface CH₄ concentration ratio > 2, was predominantly observed in ~ 54% of the all profiles and attributed to high CH₄ production in the sediments during coastal upwelling season (austral spring-summer); a period of higher biological productivity, as well as in hypoxic/anoxic condition. In contrast, relatively homogeneous profiles (CH₄ level ratio between bottom and surface depth < 2) was observed about ~ 46% of all profiles during periods of extreme vertical mixing (such as winter storms). Furthermore, irregular CH₄ profile with superficial peaks occurring between the surface and 15–30 m depth was likely observed. These peaks indicated that local production rates exceed turbulent mixing rates, suggesting a rapid CH₄ cycling due to microbial processes on the surface. Despite the fact that strong seasonality was observed in most oceanographic variables, according to favourable and non-favourable upwelling periods, only a weak seasonality was observed in CH₄ content and its air-sea flux, the latter ranged from 1.27 to 47.02 µmol m⁻² d^-1 (mean ± SD: 10.94 ± 7.48). The annual weighted mean CH₄ effluxes during upwelling (64%) and non-upwelling (36%) periods fluctuated from 1.66 to 6.22 mmol m⁻² (mean ± SD: 3.40 ± 1.43), highlighting the importance of the continental shelf under the influence of coastal upwelling as a significant CH₄ source toward the atmosphere.

在智利中部（36.5°S，73°W）附近强烈季节性沿海上升区分析了溶解的CH _4的时间分布。观测是从十二年的时间序列中进行的，其中包括每月对八个深度的水进行采样。CH ₄浓度在1.75至100.9 nmol L ^-1之间波动（或饱和度的67.11％和3965％），在底部水域最高，随着上升流的增加而增加。鉴定出三种CH ₄分布图；底部/表面CH ₄浓度比> 2的经典扩散-对流分布，主要在约54％的所有剖面中观察到，并归因于高CH ₄沿海上升季节（春季夏季）的沉积物产量；生物生产力较高的时期，以及缺氧/缺氧条件下的时期。相反，在极端垂直混合（例如冬季风暴）期间，观察到相对均匀的剖面（底部和表面深度之间的CH ₄水平比<2）约占所有剖面的〜46％。此外，很可能观察到不规则的CH ₄轮廓，在表面和15–30 m深度之间出现表面峰。这些峰表明，局部生产率超过了湍流混合速率，表明CH ₄迅速由于表面上的微生物过程而循环。尽管在大多数海洋变量观察到强的季节性，根据有利的和非有利涌周期的事实，在CH只观察到微弱的季节性₄内容及其海气通量，后者介于1.27至47.02微摩尔米^{- 2} d ^-1（平均值±SD：10.94±7.48）。上升阶段（64％）和非上升阶段（36％）的年均CH ₄流出量在1.66至6.22 mmol m ^-2之间波动（平均值±SD：3.40±1.43），突显了陆架在大气层下的重要性。海岸上升流作为大气中重要的CH ₄来源的影响。