Cyanobacterial blooms are predicted to become more prominent in the future as a result of increasing seawater temperatures and the continued addition of nutrients to coastal waters. Many benthic marine cyanobacteria have potent chemical defenses that protect them from top down pressures and contribute to the persistence of blooms. Blooms of benthic cyanobacteria have been observed along the coast of Florida and within the Indian River Lagoon (IRL), a biodiverse estuary system that spans 250 km along Florida’s east coast. In this study, the cyanobacterial bloom progression at three sites within the central IRL was monitored over the course of two summers. The blooms consisted of four unique cyanobacterial species, including the recently described Okeania erythroflocculosa. The cyanobacteria produced a range of known bioactive compounds including malyngolide, lyngbyoic acid, microcolins A–B, and desacetylmicrocolin B. Ecologically-relevant assays showed that malyngolide inhibited the growth of marine fungi (Dendryphiella salina and Lindra thalassiae); microcolins A–B and desacetylmicrocolin B inhibited feeding by a generalist herbivore, the sea urchin Lytechinus variegatus; and lyngbyoic acid inhibited fungal growth and herbivore feeding. These chemical defenses likely contribute to the persistence of cyanobacterial blooms in the IRL during the summer growing period.

预计由于海水温度升高和向沿海水域不断添加营养，蓝藻水华将在未来变得更加突出。许多底栖海洋蓝细菌具有有效的化学防御作用，可保护它们免受自上而下的压力，并有助于持续开花。在佛罗里达海岸和印度河泻湖（IRL）内已观察到底栖蓝细菌的花朵，印度河泻湖（IRL）是一个生物多样性的河口系统，沿佛罗里达东海岸横跨250公里。在这项研究中，在两个夏季的过程中对中央IRL内三个位置的蓝细菌水华进行了监测。花朵由四个独特的蓝细菌种类组成，包括最近描述的Okeania erythroflocculosa。蓝藻生产的范围已知的生物活性化合物包括malyngolide，lyngbyoic酸，microcolins A-B的，并desacetylmicrocolin B.生态相关的实验表明，malyngolide抑制海洋真菌（生长Dendryphiella藻和Lindra thalassiae）; microcolins A–B和desacetylmicrocolin B抑制了通才草食动物海胆Lytechinus variegatus的摄食；lyngbyoic acid抑制真菌生长和草食动物摄食。这些化学防御作用可能导致IRL在夏季生长期持续存在蓝细菌。