Phytoplankton blooms in nearshore waters are difficult to predict using only biogeochemical factors known to control phytoplankton growth, yet the need to understand these events continues to grow with expanding harmful algal bloom (HAB) events. The present study investigated the spatial and temporal dynamics of phytoplankton blooms and their drivers in King Harbor, a harbor in Santa Monica Bay in the Southern California Bight. High-frequency sensor measurements of environmental variables and biomass and discrete sampling of phytoplankton community composition and nutrients over an annual cycle were obtained. Eleven distinct bloom events, nine of which were numerically dominated by dinoflagellates, were identified over the study period. Results from both regression-based and time series analyses show that these blooms were correlated with increased temperature, changes in nutrient concentrations, and decreased tidally driven mixing, revealing an opportunity for bloom initiation close to neap tides. Predictors of chlorophyll biomass and environmental factors that explained differences in microplankton community structure differed between the two basins of King Harbor, despite their close and connected nature. Biomass and HAB taxa abundances in the harbor were significantly correlated with those in Santa Monica Bay with a 1-week lag in the harbor data, suggesting possible onshore transport of organisms into the harbor. The results of this study quantify the significant influence of tidal cycle as a physical process operating locally and at timescales of hours to days and provide evidence for a high degree of spatial heterogeneity in bloom dynamics in nearshore environments.

中文翻译：

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物理和生物地球化学因素驱动美国圣塔莫尼卡湾近岸水域浮游植物异质性空间扩散

仅使用已知的控制浮游植物生长的生物地球化学因素很难预测近海浮游植物的开花，但是随着有害藻华（HAB）事件的扩大，对这些事件的理解仍在继续增长。本研究调查了南加利福尼亚湾圣塔莫尼卡湾的金港（King Harbor）浮游植物开花及其驱动因素的时空动态。获得了环境变量和生物量的高频传感器测量值，以及一年周期内浮游植物群落组成和养分的离散采样。在研究期间，确定了11个不同的开花事件，其中9个在数字上以鞭毛鞭毛虫为主。来自回归分析和时间序列分析的结果均表明，这些开花与温度升高，养分浓度变化以及潮汐驱动的混合减少有关，揭示了在潮汐接近潮汐时出现开花的机会。叶绿素生物量和环境因素的预测因子解释了金港两个盆地之间的微浮游生物群落结构的差异，尽管它们具有密切而联系的性质。港口数据中生物量和HAB分类单元的丰度与圣莫尼卡湾的生物量和丰度显着相关，港口数据滞后了1周，表明可能将生物体陆上运输到港口。