Measurements of dissolved methane were performed in a sequentially connected system of water bodies that form the Pregolya River Estuary: Pregolya River – Kaliningrad Sea Canal – Vistula and Curonian Lagoons – Baltic Straight – Baltic Sea. Methane concentrations were detected on a gas chromatograph with a flame ionization detector, and the fluxes were calculated using a boundary layer gas transfer model. During a study period between 2016 and 2022, the Pregolya River is characterized by the high range of methane concentrations, reaching 8838 nmol/L in the annual maximum in May. This could be result of the “cumulative effect” of the contact of fresh and brackish waters and the inhibition of river flow during the surge events, probably, in combination with episodic release of methane from the bottom sediments. The estuary water was constantly oversaturated in methane, thus, emission from water into the atmosphere reached 1018 μmol/m2/day. The study area was notable source of methane to the atmosphere. In spring and in summer, subsurface maximums in methane were observed in the gas-saturated mud area on the Gdansk Deep slope, which did not seem to be related to the spreading of methane-reach water from the Baltic Straight.

中文翻译：

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普雷戈利亚河河口（波罗的海）的甲烷排放


溶解甲烷的测量是在形成普雷戈利亚河河口的连续连接水体系统中进行的：普雷戈利亚河 - 加里宁格勒运河 - 维斯瓦河和库尔斯泻湖 - 波罗的海海峡 - 波罗的海。在带有火焰离子化检测器的气相色谱仪上检测甲烷浓度，并使用边界层气体传递模型计算通量。在 2016 年至 2022 年的研究期间，Pregolya 河的特点是甲烷浓度范围高，5 月份的年最大值达到 8838 nmol/L。这可能是淡水和咸水接触的“累积效应”以及浪涌事件期间河流流量抑制的结果，这可能是与底部沉积物中甲烷的偶发释放相结合的结果。河口水的甲烷持续过饱和，因此，从水排放到大气中的物质达到 1018 μmol/m2/天。研究区域是大气中甲烷的显着来源。在春季和夏季，在格但斯克深坡的气体饱和泥浆区观察到甲烷的地下最大值，这似乎与波罗的海峡甲烷到达的水的扩散无关。