Phosphorus (P) is frequently considered the limiting nutrient for marine phytoplankton growth and primary production in oceans. To explore P utilization by phytoplankton during spring blooms, field observations and incubation experiments were conducted during a cruise in the Yellow Sea (YS). In particular, phytoplankton cell-associated P pools were identified as intracellular P pool (P_{intracellular}) and cell surface-adsorbed P pool (P_surface). Both P_{intracellular} and P_surface varied in a wide range of 9.0–125.7 and 0.5–93.3 μmol g⁻¹, respectively, in the YS. P_{intracellular} was frequently dominant in the total cellular P pool (contributing to 46–96%). Variation in the cell-associated P content was observed at different bloom stages, probably depending on phytoplankton species and seawater parameters. Cell-associated P enrichment was associated with a decrease in phosphate and increase in chlorophyll a, suggesting that the phytoplankton assimilated phosphate from the seawater and stored P in both cell interior and surface. This process supported the rapid biomass accumulation during the spring blooms. Incubation experiments further indicated that the accumulation rate of P_{intracellular} and P_surface was positively correlated with the phosphate removal rate in the seawater. Phytoplankton luxury P consumption could enhance both P_{intracellular} and P_surface mass content. P_surface, as a bioavailable P pool on the cell surface, could be internalized by the phytoplankton during active growth. Our study on the P assimilation mechanism involved in cell surface adsorption and intracellular accumulation enhanced the understanding of the dynamics of spring bloom.

磷（P）通常被认为是海洋浮游植物生长和海洋初级生产的限制性营养素。为了探索春季开花期间浮游植物对磷的利用，在黄海（YS）航行期间进行了野外观察和孵化实验。特别是，浮游植物细胞相关的P池被确定为细胞内P池（P _{intracellular}）和细胞表面吸附的P池（P _surface）。在YS中，P_细胞内和P_表面的变化范围分别为9.0-125.7和0.5-93.3μmolg ^-1。P_胞内在细胞总磷库中经常占主导地位（占46–96％）。在不同的开花阶段观察到了与细胞相关的磷含量的变化，这可能取决于浮游植物的种类和海水参数。细胞相关磷的富集与磷酸盐的减少和叶绿素a的增加有关，这表明浮游植物吸收了海水中的磷酸盐，并在细胞内部和表面均吸收了磷。这一过程支持了春季开花期间生物量的快速积累。孵化实验进一步表明，磷在_细胞内和磷_表面的积累速率与海水中磷的去除速率呈正相关。浮游植物奢侈磷的消费可同时提高磷含量_细胞内和磷_表面质量含量。磷_表面作为细胞表面上可生物利用的磷库，在活跃的生长过程中可能会被浮游植物内在化。我们对参与细胞表面吸附和细胞内积累的P同化机制的研究增强了对春天开花动态的理解。