2019年秦皇岛海域海洋卡盾藻赤潮与理化因子关系研究

Studies on the relationship between Chattonella marina blooms and physicochemical parameters in Qinhuangdao coastal area in 2019

2019年7月23日至7月29日,河北秦皇岛海域暴发了一次小规模的海洋卡盾藻(Chattonella marina)赤潮(最高浓度达2.22×106 cell/L)。本文对该次赤潮进行了监测,同时选取当期海域浮标在线监测数据(表层海水温度、降雨量、盐度、浊度、pH、溶解氧、叶绿素a和营养盐等)进行了海洋卡盾藻赤潮与环境要素变化规律的分析。分析结果表明,7月23日的强降雨是此次海洋卡盾藻赤潮的关键诱因,降雨带来的陆源营养盐使海水中营养盐的浓度与组成比例发生变化,表现在NO3-N、NO2-N和DIP含量增高,NO3-N在DIN中占比提高,为海洋卡盾藻赤潮的形成提供了良好的营养基础。海洋卡盾藻的密度变化与溶解氧和pH两项浮标数据变化的趋势呈正相关(相关系数r分别为0.85和0.77,0.01<p<0.05),验证了浮标在线监测理化数据在赤潮跟踪预警中的有效性。此次海洋卡盾藻赤潮期间,调查站位的浮游植物优势种群经历了丹麦细柱藻(Leptocylindrus danicus)、双突角毛藻(Chaetoceros didymus)——丹麦细柱藻、海洋卡盾藻——海洋卡盾藻3个阶段的演替过程,卡盾藻不同于硅藻的营养吸收策略和生殖策略可能是其在浮游植物群落中获得竞争优势,形成赤潮的原因。

From July 23rd to July 29th,2019,a Chattonella marina-dominated algae bloom was detected in the Qinhuangdao coastal area.We investigated the relationship between C.marina abundance and environmental parameters such as rainfall,water temperature,salinity,turbidity,pH,dissolved oxygen(DO),chlorophyll a,and dissolved inorganic nutrients in this study.The data revealed that rainfall on July 23rd was the most important component for the bloom's formation.Inflows changed the concentration and structure of nutrients significantly after the rain.Inflows enhanced the concentrations of NO_(3)-N,NO_(2)-N,dissolved phosphate,and the ratio of NO_(3)-N to total dissolved nitrogen in the seawater,allowing C.marina to proliferate.Furthermore,Spearman rank correlation analysis revealed that the abundance of C.marina was positively correlated with DO(r=0.85)and pH(r=0.77),significantly(0.01<p<0.05).The results indicated that using environmental elements sensed by buoys to monitor algal blooms is a viable option.The dominating species of phytoplankton communities during the bloom changed from Leptocylindrus danicus and Chaetoceros didymus to Leptocylindrus danicus and C.marina,and subsequently to C.marina.We hypothesized that the distinct reproductive and nutrient assimilation strategies between C.marina and diatoms facilitated the bloom of C.marina.