黄海春季贫营养和富营养水域浮游植物对灰霾添加的响应

Response of Phytoplankton in Oligotrophic and Eutrophic Areas of the Yellow Sea to Haze Addition in Spring

本文基于霾天采集的气溶胶样品,于2019年春季在黄海开展了灰霾添加的船基围隔培养实验。在黄海中部贫营养海域采集的海水表现为氮(N)限制,而灰霾添加由于带来了大量的N营养盐,显著促进了总Chl-a浓度的增加。小型浮游植物对总Chl-a的贡献率与水体中NO~-+NO~-浓度呈显著正相关(r=0.94),表明灰霾添加带来的N是促进浮游植物的粒级结构向大粒径转移的重要原因。在黄海南部的富营养海域采集的海水无明显营养盐限制,灰霾添加对总Chl-a浓度影响较小,但浮游植物的粒级结构也发生了向大粒径的转移。具有“高氮(N)低磷(P)”特征的灰霾添加使培养过程中的PO被逐渐耗尽,但灰霾添加组碱性磷酸酶活性(Alkaline Phosphatase Activity, APA)显著高于对照组,表明灰霾添加促进了浮游植物对溶解性有机磷(Dissolved Organic Phosphorus, DOP)的利用。小型浮游植物对总Chl-a的贡献率与APA呈显著正相关(r=0.65),表明小型浮游植物对水体中DOP利用存在优势,这可能是富营养水体中灰霾添加导致浮游植物粒级结构向大粒径转移的重要原因。综上所述,本研究揭示了灰霾添加对贫营养和富营养水域浮游植物粒级结构发生转移的不同作用机制。

In order to explore the influence of atmospheric deposition on size structure of phytoplankton community in oligotrophic and eutrophic waters, we collected aerosol sample in haze weather in 2019, and carried out a series of haze-added onboard incubations in the Yellow Sea in spring. The seawater collected in the middle of the Yellow Sea(oligotrophic area) showed N limitation, and the excessive N brought by haze addition promoted the increase of total Chl-a concentration. The contribution of microsized phytoplankton to total Chl-a was positively correlated with NO+NOconcentration in incubation water(r=0.94), indicated that N in haze particles might be the reason for size structure of phytoplankton community shift to large size. In the southern Yellow Sea(eutrophic area), there was no obvious nutrient restriction. The effect of haze addition on the total Chl-a concentration was insignificant, but the size structure of phytoplankton community also shifted to large size. The haze addition with the characteristic of “high N and low P” gradually depleted POin incubation water, but the alkaline phosphatase activity(APA) of the haze treatment was significantly higher than that of the control, indicated that the haze addition promoted the utilization of dissolved organic phosphorus(DOP) by phytoplankton. The positive correlation between the contribution of microsized phytoplankton to total Chl-a and APA(r=0.65) indicated that microsized phytoplankton had an important contribution to the increase of APA in incubation water, and the improvement of APA indicated that micresized phytoplankton have advantages in the utilization of DOP in seawater, which might the reason why haze addition in the eutrophic water causes the size structure of phytoplankton community shift to large size. In summary, this study reveals the different mechanisms of haze addition on the shift of size structure of phytoplankton community in oligotrophic and eutrophic waters.