In 2011, the Indian River Lagoon, a biodiverse estuary in eastern Florida (USA), experienced an intense microalgal bloom with disastrous ecological consequences. The bloom included a mix of microalgae with unresolved taxonomy and lasted for 7 months with a maximum concentration of 130 μg chlorophyll a L⁻¹. In 2012, brown tide Aureoumbra lagunensis also bloomed in portions of this estuary, with reoccurrences in 2016 and 2018. To identify and understand the role of grazer pressure (top-down control) on bloom formation, we coupled DNA sequencing with bivalve feeding assays using three microalgae isolated from the 2011 bloom and maintained in culture. Feeding experiments were conducted on widely distributed bivalve species in the lagoon, including eastern oysters (Crassostrea virginica), hooked mussels (Ischadium recurvum), charru mussels (Mytella charruana), green mussels (Perna viridis), Atlantic rangia (Rangia cuneata), and hard clams (Mercenaria mercenaria), which were exposed to 3 × 10⁴ cells mL⁻¹ of five species of microalgae consisting of A. lagunensis and the three species clarified herein, the picocyanobacteria Crocosphaera sp. and ‘Synechococcus’ sp., and the picochlorophyte Picochlorum sp., as well as Nannochloropsis oculata used as a control. To ensure clearance rates were indicative of consumption and assimilation, the microalgae were isotopically (¹⁵N) labeled prior to feeding experiments. Clearance rates differed among bivalve and microalgal species, but enriched ¹⁵N values in bivalve tissue suggest that algal bloom species were assimilated by the bivalves. These results expand our understanding of the important ecosystem services that healthy, biodiverse filter feeder communities provide.

中文翻译：

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双壳类动物对印度河泻湖微藻开花物种的摄食反应：自上而下控制的潜力

2011年，印度佛罗里达州东部（美国）的一个生物多样性河口印度河泻湖经历了强烈的微藻繁殖，造成了灾难性的生态后果。大花包括微藻与未解决的分类学的混合物，并持续7个月，最大浓度为130μg叶绿素a  L ^-1。在2012年，棕色潮Aureoumbra lagunensis在该河口部分也盛放，并于2016年和2018年再次发生。为鉴定和了解放牧压力（自上而下的控制）在盛开形成中的作用，我们使用从2011年盛开中分离出的三种微藻，将DNA测序与双壳类进食分析相结合并保持文化。对泻湖中分布广泛的双壳类鱼类进行了饲喂实验，包括东部牡蛎（Crassostrea virginica），钩贻贝（Ischadium recurvum），夏鲁贻贝（Mytella charruana），青口贻贝（Perna viridis），大西洋朗格（Rangia cuneata）和硬蛤（Mercenaria mercenaria），暴露于3×10 ⁴细胞mL^-1的五种组成的微藻A. lagunensis和三个物种本文阐明，所述picocyanobacteria Crocosphaera藻。和“ Synechococcus ” sp。，和皮绿藻Picochlorum sp。，以及Nannochloropsis oculata用作对照。为确保清除率指示食用和同化作用，在饲喂实验前对微藻进行同位素标记（¹⁵ N）。双壳类和微藻类的清除率不同，但丰富了¹⁵双壳类动物组织中的N值表明，双壳类动物吸收了藻华物种。这些结果扩大了我们对健康，生物多样的滤池饲养者社区提供的重要生态系统服务的理解。