School of Earth and Environmental Sciences, Queens College, 65-30 Kissena Blvd, 11367 Queens, NY, USA; Advanced Science Research Center at the Graduate Center, 85 St Nicholas Terrace, 10031 New York, NY, USA.
Yokogawa Fluid Imaging Technologies, Inc., 200 Enterprise Dr, 04074 Scarborough, ME, USA.
Harmful Algae. 2023 Jun;125:102423. doi: 10.1016/j.hal.2023.102423. Epub 2023 Mar 12.
Light microscopy, FlowCam, and sandwich hybridization assay (SHA) are three approaches that facilitate the monitoring of harmful algal bloom (HAB) forming phytoplankton. Yet, cross-comparisons among these techniques have not been conducted. This study addressed that gap using the saxitoxin-producing 'red tide' dinoflagellate Alexandrium catenella, a species responsible for blooms and paralytic shellfish poisoning worldwide. To achieve this goal, the dynamic ranges of each technique were compared using A. catenella cultures spanning low (pre-bloom), moderate (bloom), and high (dense bloom) levels. To assess field detection, water samples containing very low (<3 cells mL) A. catenella levels were collected from Long Island Sound, USA (Jun-Aug 2021) and evaluated using each method. Field samples were also spiked with A. catenella to high (160 cells mL) or low (40 cells mL) concentrations. In general, microscopy, FlowCam, and SHA returned comparable A. catenella cell concentrations for all tests. Mean cell concentrations from laboratory intercalibration experiments were not significantly different for any method or concentration (ANOVA, p > 0.05). However, relative to microscopy at times SHA produced non-detect signals <2 cells mL in field samples and the FlowCam slightly underestimated cell concentrations when A. catenella abundances were high in laboratory and field samples. Mean cell concentrations of spike experiments were not significantly different for any test date, sampling location, or method, despite variability among methods within the high concentration treatment (ANOVA, p > 0.05 for all treatments). Findings are relevant to HAB researchers, managers, and public health officials because they help reconcile disparate cell abundance datasets that inform numerical models and enhance HAB monitoring and prediction. Results are also likely broadly applicable to several HAB species.
显微镜检查、FlowCam 和夹心杂交检测（SHA）是三种有助于监测有害藻华（HAB）形成浮游植物的方法。然而，这些技术之间的交叉比较尚未进行。本研究使用产石房蛤毒素的“赤潮”甲藻亚历山大藻（Alexandrium catenella）来解决这一差距，该物种是全球赤潮和麻痹性贝类中毒的罪魁祸首。为了实现这一目标，使用跨越低（前赤潮）、中（赤潮）和高（密集赤潮）水平的 A. catenella 培养物比较了每种技术的动态范围。为了评估现场检测，从美国长岛海峡（2021 年 6 月至 8 月）采集了含有极低（<3 个细胞 mL）A. catenella 水平的水样，并使用每种方法进行了评估。现场样品还被 A. catenella 污染至高（160 个细胞 mL）或低（40 个细胞 mL）浓度。一般来说，显微镜检查、FlowCam 和 SHA 对所有测试的 A. catenella 细胞浓度返回了可比的结果。实验室内部校准实验的平均细胞浓度在任何方法或浓度下都没有显着差异（ANOVA，p > 0.05）。然而，与显微镜检查相比，有时 SHA 在现场样品中产生低于 2 个细胞 mL 的不可检测信号，并且当 A. catenella 在实验室和现场样品中的丰度较高时，FlowCam 略微低估了细胞浓度。尽管在高浓度处理中方法之间存在变异性，但任何测试日期、采样地点或方法的 Spike 实验的平均细胞浓度均无显着差异（ANOVA，所有处理的 p > 0.05）。研究结果与 HAB 研究人员、管理者和公共卫生官员有关，因为它们有助于协调不一致的细胞丰度数据集，为数值模型提供信息，并增强 HAB 监测和预测。结果也可能广泛适用于几种 HAB 物种。
