胶州湾夜光藻种群动态及其大量繁殖的生态机制

NOCTILUCA SCINTILLANS BLOOMING IN THE JIAOZHOU BAY: POPULATION DYNAMICS AND ECOLOGICAL MECHANISM

为研究胶州湾夜光藻大量繁殖的生态机制,于2015年逐月对胶州湾12个站位进行了多学科综合调查,获取了温度、盐度、营养盐等环境因子的周年数据,分析了夜光藻种群丰度和结构的时空分布特征,探讨了环境因子对夜光藻种群动态的影响,以及夜光藻种群增长与其繁殖方式的相关关系。结果发现:全年各站位夜光藻丰度范围为0—31.17×10~3ind./m^3,月平均丰度呈现双峰分布;二分裂个体比例介于0—31.25‰,有性繁殖个体比例介于0—29.41‰,两种繁殖方式均呈现出季节差异及空间差异。相关性分析表明,影响夜光藻种群动态的主要因子包括水温、叶绿素a、硝氮及亚硝氮。夜光藻是冷水种,水温与夜光藻种群丰度、两种繁殖个体比例均呈显著负相关;叶绿素a反映夜光藻食物的丰富程度,与夜光藻丰度、两种繁殖个体比例呈显著正相关;亚硝氮和硝氮可能对夜光藻代谢繁殖起调控作用,与夜光藻丰度及有性繁殖个体比例呈负相关。

To investigate the mechanism of Noctiluca scintillans blooms in the Jiaozhou Bay, Shandong, China, water samples were collected in January to December 2015 in 12 stations. Correlation among population, reproductive rate, and environmental factors were studied. The iV. scintillans abundance varied 0--31373.33ind./m3, and the monthly average abundance presented a bimodal distribution pattern. The rate of binary fission was between 0--31.25%o, and the rate of sexual reproduction between 0--29.41%o. No overt season and station variations were observed in ratios of two reproduction strategies. As correlation analysis indicated, water temperature, chlorophyll a, nitrite and nitrate were the key factors on abundance and reproduction of N. scintillans. Water temperature was negatively but chlorophyll a positively correlated with the abundance and the rate of reproductive individuals, as chlorophyll a reflects the abundance of food for N. scintiIlans; and nitrite and nitrate were negatively correlated with the abundance and the rate of sexual reproduction, indicating possible role of play by nitrite and nitrate in regulating the metabolism pathway of reproduction.