Pacific Northwest National Laboratory, Coastal Sciences Division, Marine Sciences Laboratory, Sequim, Washington.
Glob Chang Biol. 2018 Dec;24(12):5961-5971. doi: 10.1111/gcb.14430. Epub 2018 Oct 4.
The physical controlling factors on coastal plant communities are among the most dynamic of known ecosystems, but climate change alters coastal surface and subsurface hydrologic regimes, which makes rapid measurement of greenhouse gas fluxes critical. Greenhouse gas exchange rates in these terrestrial-aquatic ecosystems are highly variable worldwide with climate, soil type, plant community, and weather. Therefore, increasing data collection and availability should be a priority. Here, we demonstrate and validate physical and analytical modifications to automated soil-flux chamber measurement methods for unattended use in tidally driven wetlands, allowing the high-frequency capture of storm surge and day/night dynamics. Winter CO flux from Sarcocornia perennis marsh to the atmosphere was significantly greater during the day (2.8 mmol m hr ) than the night (2.2 mmol m hr ; p < 0.001), while CH was significantly greater during the night (0.16 μmol m hr ) than the day (-0.13 μmol m hr ; p = 0.04). The magnitude of CO flux during the day and the frequency of CH flux were reduced during a surge (p < 0.001). Surge did not significantly affect N O flux, which without non-detects was normally distributed around -24.2 nmol m hr . Analysis with sustained-flux global potentials and increased storm surge frequency scenarios, 2020 to 2100, suggested that the marsh in winter remains an atmospheric CO source. The modeled results showed an increased flux of CO to the atmosphere, while in soil, the uptake of CH increased and N O uptake decreased. We present analytical routines to correctly capture gas flux curves in dynamic overland flooding conditions and to flag data that are below detection limits or from unobserved chamber-malfunction situations. Storm surge is an important phenomenon globally, but event-driven, episodic factors can be poorly estimated by infrequent sampling. Wider deployment of this system would permit inclusion of surge events in greenhouse gas estimates.
海岸植物群落的物理控制因素是已知生态系统中最具动态性的因素之一，但气候变化改变了海岸的地表和地下水文状况，这使得温室气体通量的快速测量变得至关重要。在这些陆地-水域生态系统中，温室气体交换率在全球范围内随气候、土壤类型、植物群落和天气而高度变化。因此，增加数据收集和可用性应该是优先事项。在这里，我们展示并验证了对自动土壤通量室测量方法的物理和分析修改，以便在潮汐驱动的湿地中无人值守使用，从而可以高频捕获风暴潮和昼夜动态。冬季来自盐角草沼泽的 CO 通量到大气中的通量白天（2.8mmol m 小时）明显大于夜间（2.2mmol m 小时；p<0.001），而 CH 在夜间（0.16μmol m 小时）明显大于白天（-0.13μmol m 小时；p=0.04）。在浪涌期间，白天的 CO 通量幅度和 CH 通量的频率降低（p<0.001）。浪涌对 N O通量没有显著影响，无未检出值时，N O通量通常分布在-24.2nmol m 小时左右。根据全球潜在持续通量和增加的风暴潮频率情景（2020 年至 2100 年）的分析表明，冬季沼泽仍然是大气 CO 的来源。模拟结果表明，向大气中 CO 的通量增加，而在土壤中，CH 的吸收增加，N O 的吸收减少。我们提出了分析程序，以正确捕获动态陆地淹没条件下的气体通量曲线，并标记低于检测限或未观察到腔室故障情况的数据。风暴潮是全球范围内的一个重要现象，但偶发事件因素可能因频繁采样而被低估。更广泛地部署该系统将允许在温室气体估计中包括浪涌事件。
