Despite the rising interest in understanding how climate change could affect the emissions of greenhouse gases (GHGs) from river systems, including floodplains, we still lack a mechanistic understanding of how changing environmental conditions, such as moisture and nutrient availability, limit the temperature responses of GHG production in floodplain sediments. To examine the environmental co-limitations on the temperature responses of three major GHGs (CO₂, CH₄, and N₂O) produced in floodplain sediments, sediments from a constructed wetland on the floodplain of the lower Han River were incubated for 24 d at four temperatures spanning 4–28 ℃, under three conditions (closed, open/wetting, and open/drying). The net production of all three GHGs exhibited nonlinear temperature responses with gas-specific patterns and magnitudes of response varying over the incubation period. During the later incubation phase, positive temperature responses were weakened for the net production of CO₂ and CH₄ in the dried treatments, whereas a similar weakening occurred for N₂O production in the wet treatments. This, combined with incubation-induced changes in dissolved organic carbon and its fluorescence components, indicated the lack or excess of moisture and associated changes in O₂ and organic carbon availability as critical co-limiting factors for the temperature responses of GHG production. Warming decreased δ¹³C in the CH₄ emitted from wet and hypoxic sediments, implying a stronger warming effect on CH₄ production over oxidation. Unlike many studies assuming a consistent relationship between temperature and GHG production in sediments irrespective of other environmental conditions, our results suggest that warming effects on the GHG emissions from floodplain sediments would depend on the balance between gas production and consumption under the prevailing constraints of moisture, O₂, and labile carbon availability.

尽管人们越来越有兴趣了解气候变化如何影响河流系统（包括洪泛区）的温室气体（GHG）排放，但我们仍然缺乏对不断变化的环境条件（例如水分和养分可用性）如何限制温度响应的机制理解。洪泛区沉积物中的温室气体产生。为了研究洪泛区沉积物中产生的三种主要温室气体（CO ₂ 、CH ₄和 N ₂ O）对温度响应的环境共同限制，对汉江下游洪泛区人工湿地的沉积物进行了 24 d 的培养。在 4–28 ℃ 的四种温度下，在三种条件下（封闭、开放/湿润和开放/干燥）。所有三种温室气体的净产生量均表现出非线性温度响应，其气体特定模式和响应幅度在潜伏期内发生变化。在孵化后期，干燥处理中CO ₂和CH ₄净产量的正温度响应减弱，而湿处理中N ₂ O 产量也出现类似的减弱。这与孵化引起的溶解有机碳及其荧光成分的变化相结合，表明水分的缺乏或过量以及 O ₂和有机碳可用性的相关变化是温室气体产生的温度响应的关键共同限制因素。变暖降低了潮湿和缺氧沉积物排放的CH ₄中的δ ¹³ C，这意味着变暖对CH ₄产生的影响比氧化更强。 与许多研究假设温度和沉积物中的温室气体产生之间存在一致的关系（无论其他环境条件如何）不同，我们的结果表明，变暖对洪泛区沉积物温室气体排放的影响将取决于在普遍的水分约束下气体产生和消耗之间的平衡， O ₂和活性碳的可用性。