Fujian Provincial Key Laboratory for Coastal Ecology and Environmental Studies/State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361005, China; Key Laboratory of Marine Biological Resources Protection and Utilization, Guangxi University for Nationalities, Nanning 530006, China.
Research Center of Harmful Algae and Marine Biology, and Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, Jinan University, Guangzhou 510632, China.
Sci Total Environ. 2020 Aug 20;731:139192. doi: 10.1016/j.scitotenv.2020.139192. Epub 2020 May 5.
Phosphorus (P) is a potential limiting nutrient for primary production in the East China Sea (ECS). Four cruises over four seasons were conducted during 2009-2011 to evaluate the dynamics of alkaline phosphatase (AP) activity (APA) and the P status of phytoplankton in the ECS. Sampling for bulk and single-cell APA assays was performed across the ECS, which included the Changjiang River diluted water (CDW), the mid-shelf surface water (MSW), and the Kuroshio surface water (KSW) masses. The results showed that the distribution patterns of APA varied between water masses and with season. Higher APA was normally observed in the CDW, which was influenced by the Changjiang River plume. In the CDW, phytoplankton were P-stressed during the late spring with an average bulk APA of 20.4 ± 19.5 nmol h L, which strengthened during the late summer (average APA maximizing at 106.2 ± 133.3 nmol h L) and remained severe during the late autumn (average APA of 48.7 ± 34.1 nmol h L) until reducing during the winter (average APA of 9.1 ± 13.6 nmol h L). The variation patterns of APA and the P status of phytoplankton in the MSW were similar but with slight variations. In the KSW, a certain amount of APA occurred during the late spring and late autumn (averages of 18.7 ± 19.8 and 23.1 ± 18.7 nmol h L, respectively). Single-cell APA coincided with the bulk APA to exhibit the temporal and spatial P-stress status of the dominant micro-phytoplankton. Phytoplankton were the main AP producers in the CDW, especially during the late summer, while pico-plankton contributed most to AP in the MSW and KSW. Our results suggest that phytoplankton suffer P-stress in most seasons, and emphasize the importance of AP in the recycling of organic P to support primary production in the P-deficient ECS.
磷（P）是东海（ECS）初级生产力的潜在限制营养物质。2009-2011 年期间进行了四次四季巡航，以评估东海碱性磷酸酶（AP）活性（APA）和浮游植物磷状况的动态。在整个东海进行了批量和单细胞 APA 测定的采样，包括长江稀释水（CDW）、中架表层水（MSW）和黑潮表层水（KSW）。结果表明，APA 的分布模式在水团之间和季节之间有所不同。在受长江羽流影响的 CDW 中通常观察到较高的 APA。在 CDW 中，浮游植物在春末受到磷胁迫，平均批量 APA 为 20.4±19.5 nmol h L，在夏末增强（平均 APA 最大值为 106.2±133.3 nmol h L），并在秋末仍然严重（平均 APA 为 48.7±34.1 nmol h L），直到冬季减少（平均 APA 为 9.1±13.6 nmol h L）。MSW 中 APA 和浮游植物磷状况的变化模式相似，但略有不同。在 KSW 中，春末和秋末出现一定量的 APA（平均值分别为 18.7±19.8 和 23.1±18.7 nmol h L）。单细胞 APA 与批量 APA 一致，表现出优势微浮游植物的时间和空间磷胁迫状态。浮游植物是 CDW 中主要的 AP 生产者，尤其是在夏末，而微微型浮游生物对 MSW 和 KSW 中的 AP 贡献最大。我们的结果表明，浮游植物在大多数季节都受到磷胁迫，强调了 AP 在有机磷再循环中的重要性，以支持磷缺乏的东海的初级生产力。
