Paerl H W, Bales J D, Ausley L W, Buzzelli C P, Crowder L B, Eby L A, Fear J M, Go M, Peierls B L, Richardson T L, Ramus J S
University of North Carolina at Chapel Hill, Institute of Marine Sciences, Morehead City, NC 28557, USA.
Proc Natl Acad Sci U S A. 2001 May 8;98(10):5655-60. doi: 10.1073/pnas.101097398.
Three sequential hurricanes, Dennis, Floyd, and Irene, affected coastal North Carolina in September and October 1999. These hurricanes inundated the region with up to 1 m of rainfall, causing 50- to 500-year flooding in the watershed of the Pamlico Sound, the largest lagoonal estuary in the United States and a key West Atlantic fisheries nursery. We investigated the ecosystem-level impacts on and responses of the Sound to the floodwater discharge. Floodwaters displaced three-fourths of the volume of the Sound, depressed salinity by a similar amount, and delivered at least half of the typical annual nitrogen load to this nitrogen-sensitive ecosystem. Organic carbon concentrations in floodwaters entering Pamlico Sound via a major tributary (the Neuse River Estuary) were at least 2-fold higher than concentrations under prefloodwater conditions. A cascading set of physical, chemical, and ecological impacts followed, including strong vertical stratification, bottom water hypoxia, a sustained increase in algal biomass, displacement of many marine organisms, and a rise in fish disease. Because of the Sound's long residence time ( approximately 1 year), we hypothesize that the effects of the short-term nutrient enrichment could prove to be multiannual. A predicted increase in the frequency of hurricane activity over the next few decades may cause longer-term biogeochemical and trophic changes in this and other estuarine and coastal habitats.
1999年9月和10月，飓风“丹尼斯”“弗洛伊德”和“艾琳”相继袭击了北卡罗来纳州沿海地区。这些飓风给该地区带来了高达1米的降雨，导致美国最大的泻湖河口、西大西洋重要渔业育苗场——帕姆利科湾流域发生了50至500年一遇的洪水。我们调查了洪水排放对该海湾造成的生态系统层面的影响以及海湾的应对情况。洪水使海湾四分之三的水体被置换，盐度下降了类似幅度，并给这个对氮敏感的生态系统带来了至少一半的典型年氮负荷。通过一条主要支流（纽斯河河口）进入帕姆利科湾的洪水中有机碳浓度至少比洪水前条件下的浓度高出两倍。随后出现了一系列连锁的物理、化学和生态影响，包括强烈的垂直分层、底层水缺氧、藻类生物量持续增加、许多海洋生物被驱离以及鱼类疾病增多。由于该海湾的停留时间较长（约1年），我们推测短期养分富集的影响可能会持续数年。预计在未来几十年里，飓风活动频率的增加可能会导致这个以及其他河口和沿海栖息地发生长期的生物地球化学和营养变化。
