Episodic disturbances drive nutrient dynamics along freshwater-to-estuary gradients in a subtropical wetland
Episodic disturbances drive nutrient dynamics along freshwater-to-estuary gradients in a subtropical wetland
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间歇性扰动驱动亚热带湿地淡水至河口梯度的营养动态
DOI：
10.1002/ecs2.2296
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发表时间：
2018
期刊：
影响因子：
2.7
通讯作者：
Troxler, Tiffany
中科院分区：
文献类型：
--
作者：
Davis, Stephen E.;Boucek, Ross;Castañeda-Moya, Edward;Dessu, Shimelis;Gaiser, Evelyn;Kominoski, John;Sah, Jay P.;Surratt, Donatto;Troxler, Tiffany
湿地是生态地球化学活跃的生态系统，其中初级生产和呼吸与物理化学条件相互作用，影响时空尺度上的养分可用性。情景干扰对湿地内水质动态的影响是相对未知的，特别是在大型贫营养湿地，如大沼泽地。我们描述了一系列的情景干扰事件及其对大沼泽地地表水总氮（TN）和总磷（TP）浓度的时空动态的影响，以了解其影响和遗产。自2000年以来，沿着两个主要排水系统-泰勒斯劳（TS）和鲨鱼河斯劳（SRS）的水质监测一直在进行，从2005年的飓风威尔玛等高能风暴到2010年创纪录的寒冷事件和大型火灾，各种干扰都有。局部事件包括脉冲降雨、低沼泽阶段和阶段衰退和恢复（即，干旱和随后的干-湿转变）。威尔玛飓风产生的海洋沉积物沉积对应于SRS红树林站点TP的加倍（从0.39到0.84 μmol/L），然后在5-6年后恢复到干扰前的平均值。2010年冷事件发生后一周内TP短暂升高，一个月后TN（>1000 μmol/L）和TN：TP均超过5000。2008年，雨季前SRS上游的一场大火导致下游位置SRS 2、SRS 3和可能的SRS 4出现滞后TP脉冲。TP也变化与深度/阶段在沼泽网站和河口网站的盐度正，反映物理浓度或稀释效应。在TS上部，TP变化根据极端，如高降雨量和低阶段相对于正常条件。虽然在大沼泽地过量的磷通常来自于人为的高地或天然的海洋来源，情节干扰调动内部来源的营养物沿着大沼泽地的淡水河口连续，影响水质从天到年取决于干扰类型和强度。沿海湿地生态系统的恢复能力很高，这些生态系统暴露于高能量热带风暴和其他偶发事件，即使是在高度管理的佛罗里达大沼泽地。
Wetlands are biogeochemically active ecosystems where primary production and respiration interact with physico‐chemical conditions to influence nutrient availability across spatio‐temporal scales. The effect of episodic disturbances on water quality dynamics within wetlands is relatively unknown, especially in large oligotrophic wetlands such as the Everglades. We describe a range of episodic disturbance events and their impacts on the spatio‐temporal dynamics of surface water total N (TN) and total P (TP) concentrations in the Everglades as a means to understand their effect and legacies. Water quality monitoring along the two principal drainages—Taylor Slough (TS) and Shark River Slough (SRS)—has been ongoing since 2000, spanning myriad disturbances ranging from high‐energy storms such as Hurricane Wilma in 2005 to a record cold event in 2010 and large fires. Local events include pulsed rainfall, low marsh stage, and stage recession and recovery (i.e., droughts and subsequent dry‐to‐wet transitions). The deposition of marine‐derived sediment from Hurricane Wilma corresponded with a doubling of TP in SRS mangrove sites (from 0.39 to 0.84 μmol/L) before recovering to pre‐disturbance mean after 5–6 yr. A brief increase in TP within one week of the 2010 cold event was followed by delayed spikes in TN (>1000 μmol/L) and TN:TP exceeding 5000 after one month. In 2008, a large fire in upper SRS prior to the wet season caused a lagged TP pulse at downstream locations SRS2, SRS3, and possibly SRS4. TP also varied negatively with depth/stage in marsh sites and positively with salinity in estuarine sites, reflecting physical concentration or dilution effects. In upper TS, TP varied according to extremes such as high rainfall and low stage relative to normal conditions. Although excess P in the Everglades is generally derived from anthropogenic upland or natural marine sources, episodic disturbance mobilizes internal sources of nutrients along an Everglades freshwater‐to‐estuary continuum, affecting water quality from days to years depending on disturbance type and intensity. The capacity for resilience is high in coastal wetland ecosystems that are exposed to high‐energy tropical storms and other episodic events, even in the highly managed Florida Everglades.