Dissolved organic nutrients at the interface of fresh and marine waters: flow regime changes, biogeochemical cascades and picocyanobacterial blooms—the example of Florida Bay, USA
Dissolved organic nutrients at the interface of fresh and marine waters: flow regime changes, biogeochemical cascades and picocyanobacterial blooms—the example of Florida Bay, USA
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DOI：
10.1007/s10533-021-00760-4
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发表时间：
2021-02
期刊：
影响因子：
4
通讯作者：
P. Glibert;C. Heil;C. Madden;S. Kelly
中科院分区：
文献类型：
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作者：
P. Glibert;C. Heil;C. Madden;S. Kelly
各种自然和人类活动以及与气候有关的变化正在改变溶解的无机和有机营养物的可获得性及其在淡水到海洋连续体中的沿着转化。亚热带中部和东部佛罗里达湾，位于佛罗里达半岛的南端，通常被认为具有高于雷德菲尔德比率的无机营养条件，以及高水平的有机和化学还原形式的氮。然而，盐度，pH值和营养物质，有机和无机，随着流入海湾的淡水的变化而变化。在这里，使用2009年至2019年的水质和物理化学条件的时间序列，探讨了管理流量，干旱，厄尔尼诺相关降水增加以及强烈风暴和飓风的明显变化对水质变化和由此产生的生态系统影响的影响，重点是了解为什么微蓝细菌水华形成时，他们这样做。干旱造成高盐度条件，导致海草大量死亡。几年后，由于强风暴和飓风导致的降水增加与有机营养物的高负荷有关，pH值下降，可能是由于高有机酸输入和腐烂的有机物质，共同导致生理上有利的条件下生长的picocyanobacterium，集球藻属。这些条件，包括非常高浓度的NH4+，可能抑制海草恢复和竞争浮游植物或其食草动物的生长。考虑到预测的未来气候条件，以及预期的干旱和强风暴周期，未来海草死亡和微蓝细菌大量繁殖的可能性很高。
The availability of dissolved inorganic and organic nutrients and their transformations along the fresh to marine continuum are being modified by various natural and anthropogenic activities and climate-related changes. Subtropical central and eastern Florida Bay, located at the southern end of the Florida peninsula, is classically considered to have inorganic nutrient conditions that are in higher-than-Redfield ratio proportions, and high levels of organic and chemically-reduced forms of nitrogen. However, salinity, pH and nutrients, both organic and inorganic, change with changes in freshwater flows to the bay. Here, using a time series of water quality and physico-chemical conditions from 2009 to 2019, the impacts of distinct changes in managed flow, drought, El Niño-related increases in precipitation, and intensive storms and hurricanes are explored with respect to changes in water quality and resulting ecosystem effects, with a focus on understanding why picocyanobacterial blooms formed when they did. Drought produced hyper-salinity conditions that were associated with a seagrass die-off. Years later, increases in precipitation resulting from intensive storms and a hurricane were associated with high loads of organic nutrients, and declines in pH, likely due to high organic acid input and decaying organic matter, collectively leading to physiologically favorable conditions for growth of the picocyanobacterium,Synechococcusspp. These conditions, including very high concentrations of NH4+, were likely inhibiting for seagrass recovery and for growth of competing phytoplankton or their grazers. Given projected future climate conditions, and anticipated cycles of drought and intensive storms, the likelihood of future seagrass die-offs and picocyanobacterial blooms is high.