Linking Hydrology and Dissolved Organic Matter Characteristics in a Subtropical Wetland: A Long‐Term Study of the Florida Everglades
Linking Hydrology and Dissolved Organic Matter Characteristics in a Subtropical Wetland: A Long‐Term Study of the Florida Everglades
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DOI：
10.1029/2020gb006648
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发表时间：
2020-10
影响因子：
5.2
通讯作者：
P. Regier;L. Larsen;K. Cawley;R. Jaffé
中科院分区：
文献类型：
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作者：
P. Regier;L. Larsen;K. Cawley;R. Jaffé
溶解有机物（DOM）是水生生态系统的重要地球化学成分，控制营养循环，影响水质，并连接陆地和海洋碳库，但长期研究环境驱动因素如何改变其丰度和组成是罕见的。利用全球重要湿地大沼泽地国家公园10年的空间显式数据集，基于广义线性模型和累积和分析，研究了沿着两个对比的沼泽-河口样带DOM质量/数量与水文/气候驱动因子之间的关系。分析显示，不同的空间，季节和年际变化的DOC和光学特性的模式。景观尺度的季节模式显示，相对于雨季，旱季微生物样和蛋白质样DOM富集。虽然有些成分变化与阳历，响应温度和光周期，其他变化与水文日历。独立的水位和排放的影响表明，强大的水文控制DOM质量，两个样带之间的差异，证明其连接到高农业活动的地区的差异。在所有地点，观察到荧光指数的长期显著增加趋势，与降水呈正相关，也与农业投入的潜在变化有关，其他特征与干旱和飓风有关。最后，累积和分析揭示了两个样带之间DOM组成对与30年气候情景相关的水位下降的敏感性的差异，水文动态较小的样带表现出更大的潜在敏感性。
Dissolved organic matter (DOM) acts as an important biogeochemical component of aquatic ecosystems that controls nutrient cycling, influences water quality, and links terrestrial and oceanic carbon pools, yet long‐term studies of how changing environmental drivers alter its abundance and composition are rare. Using a 10‐year, spatially explicit data set from Everglades National Park, a globally significant wetland, we investigated the relationships between DOM quality/quantity and hydrologic/climatic drivers along two contrasting marsh‐estuarine transects based on generalized linear modeling and a cumulative sums analysis. Analyses revealed distinct spatial, seasonal, and interannual patterns in variability of DOC and optical properties. Landscape‐scale seasonal patterns showed an enrichment in microbial‐like and protein‐like DOM during the dry season relative to the wet season. While some compositional constituents varied with the solar calendar, responsive to temperature and photoperiod, others varied with the hydrologic calendar. Independent water level and discharge effects indicated strong hydrologic control on DOM quality that differed between the two transects, evidencing differences in their connectivity to areas of high agricultural activity. Across all sites, a significant long‐term increasing trend in the fluorescence index was observed, associated with a positive correlation with precipitation and also potential changes in agricultural inputs, with other features associated with drought and hurricanes. Lastly, the cumulative sums analysis revealed differences between the two transects in the sensitivity of DOM composition to decreased water levels associated with 30‐year climate scenarios, with the less hydrologically dynamic transect exhibiting greater potential sensitivity.