Southeast Environmental Research Center, Institute of Environment, Florida International University, Miami, FL 33199;
Department of Oceanography and Coastal Sciences, College of the Coast and Environment, Louisiana State University, Baton Rouge, LA 70803.
Proc Natl Acad Sci U S A. 2020 Mar 3;117(9):4831-4841. doi: 10.1073/pnas.1908597117. Epub 2020 Feb 18.
Hurricanes are recurring high-energy disturbances in coastal regions that change community structure and function of mangrove wetlands. However, most of the studies assessing hurricane impacts on mangroves have focused on negative effects without considering the positive influence of hurricane-induced sediment deposition and associated nutrient fertilization on mangrove productivity and resilience. Here, we quantified how Hurricane Irma influenced soil nutrient pools, vertical accretion, and plant phosphorus (P) uptake after its passage across the Florida Coastal Everglades in September 2017. Vertical accretion from Irma's deposits was 6.7 to 14.4 times greater than the long-term (100 y) annual accretion rate (0.27 ± 0.04 cm y). Storm deposits extended up to 10-km inland from the Gulf of Mexico. Total P (TP) inputs were highest at the mouth of estuaries, with P concentration double that of underlying surface (top 10 cm) soils (0.19 ± 0.02 mg cm). This P deposition contributed 49 to 98% to the soil nutrient pool. As a result, all mangrove species showed a significant increase in litter foliar TP and soil porewater inorganic P concentrations in early 2018, 3 mo after Irma's impact, thus underscoring the interspecies differences in nutrient uptake. Mean TP loading rates were five times greater in southwestern (94 ± 13 kg ha d) mangrove-dominated estuaries compared to the southeastern region, highlighting the positive role of hurricanes as a natural fertilization mechanism influencing forest productivity. P-rich, mineral sediments deposited by hurricanes create legacies that facilitate rapid forest recovery, stimulation of peat soil development, and resilience to sea-level rise.
飓风是沿海地区反复出现的高能干扰，会改变红树林湿地的群落结构和功能。然而，大多数评估飓风对红树林影响的研究都集中在负面影响上，而没有考虑飓风引起的沉积物沉积和相关养分施肥对红树林生产力和恢复力的积极影响。在这里，我们量化了 2017 年 9 月飓风“艾尔玛”（Irma）穿过佛罗里达州沿海大沼泽地（Florida Coastal Everglades）后，如何影响土壤养分库、垂直堆积和植物磷（P）吸收。Irma 沉积物的垂直堆积量是长期（100 年）年堆积率（0.27 ± 0.04 cm y）的 6.7 至 14.4 倍。风暴沉积物从墨西哥湾延伸到内陆 10 公里处。总磷（TP）输入量在河口处最高，磷浓度是底层表面（顶部 10 cm）土壤的两倍（0.19 ± 0.02 mg cm）。这种磷沉积对土壤养分库的贡献为 49%至 98%。因此，所有红树林物种的叶片总磷（foliar TP）和土壤孔隙水无机磷浓度在 Irma 影响后的 3 个月（2018 年初）都显著增加，这突显了物种间养分吸收的差异。西南（94 ± 13 kg ha d）以红树林为主的河口的平均 TP 加载率是东南部地区的五倍，突出了飓风作为一种自然施肥机制影响森林生产力的积极作用。飓风带来的富含磷的矿物质沉积物会留下遗产，促进森林的快速恢复、刺激泥炭土的发展以及对海平面上升的恢复力。
