浮游植物多样性与表观增氧量的关系及其在赤潮预警中的应用

The correlation between phytoplankton diversity and apparent oxygen increment to the prewarning of red tide events

近年来应用微型围隔生态实验探讨了浮游植物多样性与表观增氧量(AOI)的关系及其在赤潮预警与评价中的应用。结果显示,在赤潮发生过程中,浮游植物多样性与生物量(以AOI计)存在显著的相关关系。多样性指数H′与AOI呈密切的负相关关系,优势度D2呈密切的指数正相关关系。该研究以赤潮预警与评价的AOI参考指标为依据,利用H′和D2与AOI的相关模式,提出了赤潮预警与评价的H′和D2的指标值,赤潮预警的H′和D2指标分别为0.72和0.36,赤潮判别的H′和D2指标分别为0.66和0.51。

The recent years have witnessed the continual expansion of red tides in the coastal waters of the world and its serious damage to marine fishery industries and threats to human health. For mitigation and prevention of red tide disasters, researchers have attached great attention to the studies on the prewarning and forecasting of red tide events. Based on the microsm experiments this paper discusses the correlation between phytoplankton diversity and apparent oxygen increment （AOI） and its application to the prewarning of red tide events. The water samples for the experiment were collected at surface waters respectively from the stations near Baozhu Islet at the inner bay and Qingyu Islet at the outer bay of Xiamen. Each water sample was subsampled into five boron-silicate glass bottles each of 500 cm^3 in the filed and shipped back to land. Two groups of subsamples were then put into a open pond of 1 m deep and let the phyto- plankton in the subsamples to grow naturally under the natural sunlight and water temperature. During the experimental period, one subsample was taken from each group for the identification and counting of phytoplankton and the determination of physical and chemical parameters. The experiment results indicate that in the formation process of a red tide event, phytoplankton diversity index H＇ decreased greatly while dominancy D2 increased remarkably. The paper takes Apparent Oxygen Increment （AOI, the differences between field concentration of dissolved oxygen and the saturated oxygen concentration under field temperature and salinity conditions） as the measurement index for phytoplankton biomass during the red tide event in the study on the correlation between H＇ and D2 and phytoplankton biomass. The results indicated that H＇and AOI were highly negatively correlated and D2 and AOI highly exponentially. The correlation implies that during the red tide formation process, there is a cause and effect relationship between phyto- plankton diversity and biomass. Based on the correlation modes between H＇ and D2 and AOI and by taking AOI index in red tide assessment as the reference, the paper proposes the index values for both H＇ and D2 for red tide assessment. The test by field monitoring data indicated that these two indexes can be used as the supplementary indexes in the assessment of red tide strength.