海南岛西部海域球形棕囊藻赤潮过程环境因子变化特征及影响因素分析

Analysis on the variation characteristics of environmental factors and influencing factors in the process of Phaeocystis globosa bloom in the western waters of Hainan Island

通过2022年3月10-15日在海南岛西部昌江昌化沿岸海域开展为期6 d的现场跟踪调查,结合水文气象资料分析了本次球形棕囊藻(Phaeocystis globosa)赤潮生消过程环境因子变化特征及影响因素。本次赤潮高峰期球形棕囊藻丰度及COD_(Mn)分别高达3.10×10^(8) cells/L及35 mg/L,远高于其他海域报道记录。赤潮暴发前降雨及风浪扰动促进了陆源输入及沉积营养盐释放,为赤潮暴发提供物质条件。气温骤升诱导赤潮发生,更大潮差及较低风速为囊体沿岸聚集创造了有利的外部条件。赤潮消亡过程中,DIN、PO_(4)-P、DO、COD_(Mn)及Mn浓度显著下降,其中DIN及PO_(4)-P是本次赤潮消亡的限制因子,DO、COD_(Mn)及Mn为本次赤潮消亡的重要特征因子。黄色囊体出现破碎后,Chlorophyll a及SiO_(3)-Si浓度也迅速下降,随后缓慢上升甚至高于高峰期浓度水平,此时以旋链角毛藻(Chaetoceros curvisetus)等代表的硅藻丰度逐渐增加。研究还初步探索了本次赤潮的基本生消过程,为进一步揭示本区域球形棕囊藻赤潮爆发机理提供重要参考依据。

Combined with hydrometeorological data,a six-day tracking survey was carried out in the coastal waters of Changhua Town,Changjiang County,western Hainan Island on March 10 to 15,2022.And this study analyzed the variation characteristics of environmental factors and influencing factors in the process of Phaeocystis globose bloom.During the peak of the bloom,the abundance of Phaeocystis globosa and CODMn were as high as 3.10×10^(8) cells/L and 35 mg/L,which were much higher than those reported in other areas.The rainfall and wind wave dis-turbance before the bloom promoted the terrestrial runoff and the release of sedimentary nutrients,which provided material conditions for the bloom.The sudden rise of temperature induces the bloom,and the larger tidal range and lower wind speed create favorable external conditions for the accumulation along the colony.During the elimina-tion of the bloom,the concentrations of DIN,PO_(4)-P,DO,CODMn and Mn decreased significantly,in which DIN and PO_(4)-P were the limiting factors,and DO,CODMn and Mn were important characteristic factors.After the yellow colony broken,the concentrations of Chl a and SiO_(3)-Si also decreased rapidly,and then slowly increased or even higher than the peak concentration level,when the diatom abundance represented by Chaetoceros curvisetus gradu-ally increased.The study also preliminarily explores the basic generation and elimination process of the bloom,which provides an important reference for the further study of the bloom mechanism of P.globosa in this area.