Liangming Huang*, Kedong Yin, Xiaoping Huang, Jianqiang Yin, Yehui Tan, Xingyu Song, Weijun Jian, Pingping Shen, Sheng Liu, South China Sea Institute of Oceanography, Chinese Academic of Sciences, Guangzhou, 510301 China

Abstract

Based on the data investigated above 10 years last, this paper present the changes of the composing of main red-tide organisms and relevant some ecological factors in the Pearl River estuary and its adjacent waters including Daya Bay, Dapeng Bay, Lingdingyang and Hong Kong waters. The result indicated that there are more than 40 species of red tide organisms recorded in the researched waters. Principal species ever caused red tides have Noctiluca scintillans, Skeletonema costatum, Chattonella marina, Rhizosolenia alata f. gracillima, Gonyaulax polygramma, Pseudonitzschia pungens, Chaetoceros affinis, Thalassiosira subtilis, Scrippsiella trochoidea, Protocentrum sigmoides, Gymnodinium mikimotoi etc. Red tides could be caused by various factors, such as a close correlation with the weather conditions, water dynamics, nutrients and changes of the biological environment. In Pear River estuary, the high concentration of inorganic nitrogen quicken up phytoplankton grow and occurred in eutrophication. Season succession of phytoplankton and swilling fresh-water flow into the waters, the high ratio of N:P (>200) and significant correlation between phytoplankton and PO₄ indicated that P and turbidity were an important factors influencing phytoplankton grow. However, the relationship between the occurrence of red tides and their environmental conditions has not been well known, say nothing of what is the key stimulating factors and the shaping mechanisms of red tides, especially ecological and oceanographic regulation. All mentioned above make difficult to take pertinently to monitor, forecast, prevent and cure for red tides. Therefore, more spot monitoring and researches are especially requested for comprehensive father and preventing occurrence of red tides. Which would be useful for performing an integrated management and protect of the coastal environment, and to make a sustainable development.

Key words: Pearl River estuary, red tide organism, environmental factors, monitor research