Prairie-pothole wetlands are an important freshwater resource in the Northern Great Plains of North America and play a crucial role in providing vital ecosystem services. Changes in water levels, water stable isotopes, and water chemistry of these wetlands are a function of processes including evaporation, precipitation, groundwater exchange, and surface-water flows. Understanding mechanisms influencing chemical changes under highly variable meteorological and complicated hydrological conditions is important for predicting changes in wetland ecosystem services in response to future climate change. We examined changes in stable isotopes and chemistry in the water of two adjacent, but hydrologically different (closed-basin vs open-basin), prairie-pothole wetlands over two years at the Cottonwood Lake Study Area, North Dakota. Our goals were to: (1) characterize the effects of meteorological variation (normal vs wet) and basin differences on wetland hydrological processes; and (2) identify patterns in water chemical changes and main drivers of identified changes between closed-basin and open-basin prairie-pothole wetlands. Our results indicated that meteorological variations and basin morphology had noticeable effects on hydrological processes and chemical conditions in our study wetlands. The water of the closed-basin wetland was enriched in heavy isotopes and multiple dissolved ions due to higher evaporation and lack of losses to surface flows compared to the open-basin wetland. In both wetlands studied, higher phosphorus concentrations were mostly related to the catchment runoff as rainfall increased. This study highlights the importance of considering the heterogenous hydrological conditions of prairie-pothole wetlands when studying their responses to future changes in climate.

中文翻译：

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气象变率对两个水文不同的草原坑洼湿地化学变化的影响


草原坑洼湿地是北美北部大平原的重要淡水资源，在提供重要的生态系统服务方面发挥着至关重要的作用。这些湿地的水位、水稳定同位素和水化学的变化是蒸发、降水、地下水交换和地表水流动等过程的函数。了解在高度变化的气象和复杂水文条件下影响化学变化的机制对于预测湿地生态系统服务的变化以应对未来气候变化具有重要意义。我们在北达科他州卡顿伍德湖研究区检查了两个相邻但水文不同（封闭盆地与开放盆地）草原坑洼湿地两年内水中稳定同位素和化学的变化。我们的目标是：（1） 描述气象变化（正常与潮湿）和流域差异对湿地水文过程的影响;（2） 确定封闭盆地和开放盆地草原坑洼湿地之间水化学变化的模式和确定变化的主要驱动因素。我们的结果表明，气象变化和盆地形态对我们研究湿地的水文过程和化学条件有显着影响。与开阔流域湿地相比，由于蒸发量较高且没有对地表流的损失，封闭盆地湿地的水富含重同位素和多种溶解离子。在研究的两个湿地中，随着降雨量的增加，较高的磷浓度主要与集水区径流有关。 本研究强调了在研究草原坑洼湿地对未来气候变化的响应时考虑其异质性水文条件的重要性。