Ecological features of phytoplankton in red tide outburst area in the Xiamen Harbor

The results from the 38 cruises of phytoplankton surveys in the red tide outburst area in the Xiamen Harbor in 1987 indicate 41 species of red tide organisms among 110 species of phytoplankton identified.Species tomposition was dominant by eurytopic species and warm water species.Species diversity apparently changed with (cold and warm) seasons.There was a high diversity in warm seasons, 63 species in August.Average annual number of phytoplankton reached 1 119×10³ ind./dm³ which was 2 to 2.6 times that in 2 control monitoring stations.The number of phytoplankton in horizonal distribution displayed an obvious increasing tendency from the harbour mouth to the inner harbor.The phytoplankton number always changed with time, but with 3 peak values in the year round.The daily change of the phytoplankton number with tide exhibited a negative relativity.Moreover phytoplankton species and their number showed a vertical movement during day and night.Futhermore, 10 predominant species changed with seasons was noted in the present paper.