Intermittently closed and open lakes and lagoons (ICOLLs) are coastal lakes that intermittently exchange water with the sea and experience saline intrusions. Understanding effects of seawater exchange on local biota is important to preserve ecosystem functioning and ecological integrity. Coastal dune lakes of northwest Florida are an understudied group of ICOLLs in close geographic proximity and with entrance regimes operating along a frequency continuum. We exploited this natural continuum and corresponding water chemistry gradient to determine effects of water chemistry on resident submersed aquatic vegetation (SAV) distributions in these ecosystems. SAV distribution decreased with increases in salinity, but was unaffected by variation in nitrogen, phosphorous, and turbidity. Salinity perturbations corresponding with water exchange with the Gulf of Mexico were associated with reductions in SAV in coastal dune lakes. Potential impacts associated with changes in global climate may increase the frequency of seawater exchange across all coastal dune lakes and potentially reduce the distribution of oligohaline macrophytes among these ecosystems.

间歇性关闭和开放的湖泊和泻湖 (ICOLL) 是沿海湖泊，它们间歇性地与海洋交换水并经历盐水入侵。了解海水交换对当地生物群的影响对于保护生态系统功能和生态完整性非常重要。佛罗里达州西北部的沿海沙丘湖是一组未充分研究的 ICOLL，它们在地理上很接近，入口制度沿频率连续体运行。我们利用这种自然连续体和相应的水化学梯度来确定水化学对这些生态系统中常驻沉没水生植被 (SAV) 分布的影响。SAV 分布随着盐度的增加而下降，但不受氮、磷和浊度变化的影响。与墨西哥湾的水交换相应的盐度扰动与沿海沙丘湖中 SAV 的减少有关。与全球气候变化相关的潜在影响可能会增加所有沿海沙丘湖的海水交换频率，并可能减少这些生态系统中寡盐型大型植物的分布。