Alexandrium catenella is a harmful algal bloom (HAB)-forming dinoflagellate that causes significant damage to the cultivation and harvest of shellfish due to its synthesis of paralytic shellfish toxins. To evaluate the potential for macroalgae aquaculture to mitigate A. catenella blooms, we determined the effects of three cultivable macroalgae - Saccharina latissima (sugar kelp), Chondrus crispus (Irish moss), and Ulva spp. - on A. catenella in culture- and field-based experiments. Co-culture growth assays of A. catenella exposed to environmentally realistic concentrations of each macroalgae showed that all species except low levels of C. crispus caused cell lysis and significant reductions in A. catenella densities relative to control treatments of 17-74% in 2-3 days and 42-96% in ~one week (p<0.05 for all assays). In a toxin accumulation experiment, S. latissima significantly lessened (p<0.05) saxitoxin (STX) accumulation in blue mussels (Mytilus edulis), keeping levels (71.80±1.98 µg STX 100 g-1) below US closure limits (80 µg STX 100 g-1) compared to the untreated control (93.47±8.11 µg STX 100 g-1). Bottle incubations of field-collected, bloom populations of A. catenella experienced significant reductions in cell densities of up to 95% when exposed to aquaculture concentrations of all three macroalgae (p<0.005 for all). The stocking of aquacultured S. latissima within mesocosms containing a bloom population of A. catenella (initial density: 3.2 × 104 cells L-1) reduced the population of A. catenella by 73% over 48 h (p<0.005) while Ulva addition caused a 54% reduction in A. catenella over 96 h (p<0.01). Among the three seaweeds, their ordered ability to inhibit A. catenella was S. latissima > Ulva spp. > C. crispus. Seaweeds' primary anti-A. catenella activity were allelopathic, while nutrient competition, pH elevation, and macroalgae-attached bacteria may have played a contributory role in some experiments. Collectively, these results suggest that the integration of macroalgae with shellfish-centric aquaculture establishments should be considered as a non-invasive, environmentally friendly, and potentially profit-generating measure to mitigate A. catenella-caused damage to the shellfish aquaculture industry.

中文翻译：

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使用可培养的海藻减轻由链状亚历山大藻引起的有害藻华，并减少双壳类动物的石房蛤毒素积累。

链状亚历山大藻是一种有害的藻华（HAB）形成的甲藻，由于其合成麻痹性贝类毒素，对贝类的养殖和收获造成重大损害。为了评估大型藻类水产养殖减轻链状链球菌大量繁殖的潜力，我们确定了三种可培养的大型藻类 - Saccharina latissima（糖海带）、Chondrus discus（爱尔兰苔藓）和 Ulva spp。- 在基于培养和实地的实验中对链状链球菌进行研究。暴露于环境现实浓度的每种大型藻类的 A. catenella 的共培养生长测定表明，除了低水平的 C.crispus 外，所有物种都会导致细胞裂解，并且相对于对照处理，A. catenella 密度显着降低 2 -3 天，约一周内达到 42-96%（所有检测 p<0.05）。在毒素积累实验中，阔叶贻贝显着减少（p<0.05）石房蛤毒素 (STX) 在蓝贻贝（Mytilus edulis）中的积累，将水平 (71.80±1.98 µg STX 100 g-1) 保持在美国关闭限制 (80 µg STX) 以下100 g-1) 与未处理的对照 (93.47±8.11 µg STX 100 g-1) 相比。当暴露于所有三种大型藻类的水产养殖浓度时，田间收集的 A. catenella 盛开种群的瓶中孵化经历了细胞密度显着降低高达 95%（所有 p<0.005）。将水产养殖的 S. latissima 放养在包含 A. catenella 大量繁殖（初始密度：3.2 × 104 个细胞 L-1）的中层中，在 48 小时内将 A. catenella 的数量减少了 73%（p<0.005），同时添加石莼在 96 小时内导致链状链球菌减少 54%（p<0.01）。在三种海藻中，它们抑制链状链球菌的有序能力是 S. latissima > Ulva spp。> C. 脆皮。海藻的主要抗A。链球菌的活性是化感作用的，而营养竞争、pH 值升高和大型藻类附着的细菌可能在一些实验中起到了促进作用。总的来说，这些结果表明，大型藻类与以贝类为中心的水产养殖设施的整合应被视为一种非侵入性、环境友好且可能产生利润的措施，以减轻链状链球菌对贝类水产养殖业的损害。和大型藻类附着的细菌可能在一些实验中起到了促进作用。总的来说，这些结果表明，大型藻类与以贝类为中心的水产养殖设施的整合应被视为一种非侵入性、环境友好且可能产生利润的措施，以减轻链状链球菌对贝类水产养殖业的损害。和大型藻类附着的细菌可能在一些实验中起到了促进作用。总的来说，这些结果表明，大型藻类与以贝类为中心的水产养殖设施的整合应被视为一种非侵入性、环境友好且可能产生利润的措施，以减轻链状链球菌对贝类水产养殖业的损害。