Department of Biological Sciences, University of Southern California, Los Angeles, California, USA.
Woods Hole Oceanographic Institution, Marine Chemistry and Geochemistry, Woods Hole, Massachusetts, USA.
Environ Microbiol. 2022 Dec;24(12):6033-6051. doi: 10.1111/1462-2920.16137. Epub 2022 Jul 26.
Protistan algae (phytoplankton) dominate coastal upwelling ecosystems where they form massive blooms that support the world's most important fisheries and constitute an important sink for atmospheric CO . Bloom initiation is well understood, but the biotic and abiotic forces that shape short-term dynamics in community composition are still poorly characterized. Here, high-frequency (daily) changes in relative abundance dynamics of the metabolically active protistan community were followed via expressed 18S V4 rRNA genes (RNA) throughout two algal blooms during the spring of 2018 and 2019 in Santa Monica Bay (central Southern California Bight). A diatom bloom formed after wind-driven, nutrient upwelling events in both years, but different taxa dominated each year. Whereas diatoms bloomed following elevated nutrients and declined after depletion each year, a massive dinoflagellate bloom manifested under relatively low inorganic nitrogen conditions following diatom bloom senescence in 2019 but not 2018. Network analysis revealed associations between diatoms and cercozoan putative parasitic taxa and syndinean parasites during 2019 that may have influenced the demise of the diatoms, and the transition to a dinoflagellate-dominated bloom.
原生藻类（浮游植物）在沿海上升流生态系统中占主导地位，它们形成大规模的水华，支持着世界上最重要的渔业，并构成大气 CO 的重要汇。水华的起始过程已经得到很好的理解，但塑造群落组成短期动态的生物和非生物力量仍未得到很好的描述。在这里，通过表达的 18S V4 rRNA 基因（RNA），对代谢活跃的原生动物群落相对丰度动态的高频（每日）变化进行了跟踪，这是在 2018 年和 2019 年春季圣莫尼卡湾（南加州中部海湾）的两次藻类水华期间进行的。在这两年中，风驱动的营养物质上升事件之后形成了硅藻水华，但每年的优势物种不同。虽然硅藻在营养物质升高后大量繁殖，在耗尽后减少，但在 2019 年硅藻水华衰老后，在相对较低的无机氮条件下出现了大规模的甲藻水华，而 2018 年则没有。网络分析显示，2019 年期间硅藻与肉足类寄生虫类群和 Syndinean 寄生虫之间存在关联，这可能影响了硅藻的消亡，以及向甲藻水华为主的转变。
