Low-inflow estuaries (LIEs) in Mediterranean climates located within regions of wind-driven coastal upwelling have seasonally minimal freshwater inflow, are supplied by nutrient-rich upwelled water, and often used for sustainable shellfish mariculture supported by a rich pelagic food web. They likely support endemic estuarine phytoplankton supplemented during the upwelling season with phytoplankton supplied from the ocean. There are few descriptions of LIE algal assemblages. This study characterizes the spatio-temporal phytoplankton community dynamics in a low-inflow estuary located along the northern California coast with high frequency sampling to assess seasonal influences on functional groups, blooms, and endemic populations. Phytoplankton biomass and community composition were measured in Drakes Estero monthly from June 2016 to November 2017. We predicted blooms with diatoms in summer and dinoflagellates in fall but had no prediction for non-bloom situations and what phytoplankton would occur year-round. Flagellates were ubiquitous throughout the Estero at all times. Two summer blooms occurred with diatoms characteristic of upwelling (Chaetoceros, Skeletonema, Asterionellopsis, Thalassiosira) and two blooms in fall with dinoflagellates dominated by Prorocentrum and high densities of the raphidophyte Heterosigma. Harmful algal bloom (HAB) taxa were observed, some at levels reported to have negative effects. Non-metric multi-dimensional scaling analyses showed the diatoms to be associated with upwelling, cooler temperatures and high nitrate, and the dinoflagellates and flagellates associated with warmer temperatures and reduced upwelling. Dinoflagellate and flagellate communities, especially HAB taxa, might be promoted with warmer temperatures or longer warm seasons accompanying climate change; an important consideration for managers of LIEs, especially those containing mariculture facilities.

地中海风的低流入河口位于风力驱动的沿海上升流区域，季节性淡水流入最少，由营养丰富的上升流提供，通常用于有丰富的中上层食物网的可持续贝类海水养殖。他们可能会支持在上升流季节补充海洋提供的浮游植物的地方性河口浮游植物。LIE藻类组合的描述很少。这项研究通过高频采样来表征加利福尼亚北部海岸低流入河口的时空浮游植物群落动态，以评估对功能群，水华和地方性种群的季节性影响。从2016年6月至2017年11月，每月在Drakes Estero中测量浮游植物的生物量和群落组成。我们预测夏季会有硅藻盛开，秋季有硅藻鞭毛，但没有非开花情况以及全年会发生什么浮游植物的预测。鞭毛虫在任何时候都无处不在。发生了两次夏季开花，其硅藻具有上升的特征（Chaetoceros，Skeletonema，Asterionellopsis，Thalassiosira）和秋天的两次绽放，以鞭毛藻和杂草高密度的杂​​草藻为主。观察到有害的藻华（HAB）类群，据报导有一些有害作用。非度量多维标度分析显示，硅藻与上升流，温度降低和硝酸盐含量高有关，而硅藻和鞭毛与温度升高和上升流减少有关。随着气候变化，气温升高或温暖季节延长，可能会促进鞭毛和鞭毛群落，特别是HAB种类。LIE管理者的重要考虑因素，尤其是那些拥有海水养殖设施的管理者。