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首页> 外文学位 >Effects of water-level fluctuations on phosphorus dynamics of two subtropical wetlands in Doana National Park, Spain, and the Everglades, Florida, United States.
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Effects of water-level fluctuations on phosphorus dynamics of two subtropical wetlands in Doana National Park, Spain, and the Everglades, Florida, United States.

机译：水位波动对西班牙多纳国家公园和美国佛罗里达大沼泽地两个亚热带湿地磷动力学的影响。

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Water-level fluctuations in wetlands result in alternate flooding and draining of soils, which greatly influences the processes regulating phosphorus retention and release to water. Drawdown can degrade or improve water quality in wetlands depending on soil conditions. It can enhance organic matter decomposition and mineralization due to increased microbial and photolytic activity in aerobic soils, promoting release of labile P to the water upon reflooding. It can also reduce P flux from soils by consolidating newly accreted soil, favoring precipitation reactions, and decimating bacterial populations.; Phosphorus dynamics were compared for two subtropical wetland ecosystems. A temporary pond in Doñana and a treatment wetland in Everglades were chosen to illustrate processes in each ecosystem. Doñana wetlands are hypereutrophic, have mineral soils, and are frequently exposed to drawdown. Everglades wetlands are oligotrophic, have organic soils, and are usually flooded. Constructed wetlands treat agricultural runoff by remaining flooded.; Phosphorus release and retention were investigated in soils exposed to varying flooding conditions. Phosphorus flux experiments showed how phosphorus release processes varied along a natural gradient of increasing drawdown exposure in Doñana ponds. In the Everglades treatment wetland, experiments evaluated the effectiveness of short-term drawdown for reducing phosphorus flux from soils.; In Doñana ponds, drawdown increased release of labile P to water upon flooding. In contrast, a 30-day drawdown of Everglades treatment-wetland soils markedly reduced P flux to the water. Mechanisms regulating P dynamics in Doñana ponds are release and uptake from phytoplankton in pond basins and rooted macrophytes-epiphytes in littoral and floodplains; complexation with iron/aluminum, calcium, and humic substances; and high organic matter decomposition rates. In the Everglades marsh, they are macrophyte-epiphyte removal and leaching, precipitation with calcium, and peat accretion.; The warm subtropical climate stimulates growth of aquatic biota, promoting high organic matter deposition. The functioning of Doñana ponds is characterized by erratic pulses of water and nutrients followed by explosive biological production, and high loss of organic matter via mineralization. Everglades marshes exhibit slower and more constant ecosystem processes under prevalent flooding, marked by limited linkage to watershed hydrodynamics, sustained high macrophyte-based production, slow detritus decomposition, and long-term accumulation of organic matter.
机译：湿地中的水位波动导致土壤交替泛滥和排水，这极大地影响了调节磷保持和释放到水中的过程。根据土壤条件，水位下降会降低或改善湿地的水质。由于需氧土壤中微生物和光解活性的增加，它可以增强有机物的分解和矿化作用，从而促进再灌注时不稳定磷向水中的释放。通过巩固新积聚的土壤，促进降水反应，减少细菌种群，还可以减少土壤中的磷通量。比较了两个亚热带湿地生态系统的磷动力学。选择了多纳纳的一个临时池塘和大沼泽地的一个处理湿地来说明每个生态系统的过程。多纳纳（Doñana）湿地是富营养化的，具有矿质土壤，并且经常遭受压降。大沼泽地的湿地是贫营养的，有有机土壤，通常被淹。人工湿地通过保持洪水来处理农业径流。在暴露于不同洪水条件下的土壤中研究了磷的释放和保留。磷通量实验表明，在Doñana池塘中，磷的释放过程如何沿着水位下降的自然梯度变化。在大沼泽地湿地中，实验评估了短期回落减少土壤磷流的有效性。在多纳纳（Doñana）池塘中，水位下降导致洪水时不稳定的磷向水中的释放增加。相比之下，沼泽地处理湿地土壤30天的下降显着降低了向水中的P通量。调节多纳纳（Doñana）池塘磷动力学的机制是池塘盆地浮游植物的释放和吸收以及沿海和洪泛区生根的大型植物-表生植物；与铁/铝，钙和腐殖质络合；和高有机物分解率。在大沼泽地沼泽中，它们是大型植物-表生植物的去除和浸出，钙的沉淀以及泥炭的堆积。亚热带温暖的气候刺激了水生生物的生长，促进了高有机质的沉积。 Doñana池塘的功能特点是水和养分的脉冲不稳定，随后产生爆炸性生物，并且由于矿化作用而使有机物大量流失。在普遍的洪水下，大沼泽地沼泽地的生态系统过程缓慢而持续，其特征是与流域水动力的联系有限，基于大型植物的持续高产，碎屑分解缓慢以及有机物质的长期积累。

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