| Macao Wetland Reservation, including 15 hectare of Taipa-Coloane Wetland Reservation and 45 hectare of Lotus Flower Bridge Wetland Reservation, is the largest Wetland in Macao. Temporal and spatial variations of plankton and water quality in this Wetland were yearly investigated in the present study. The aim of this research was to analyze the environmental situation of the Wetland Reservation as well as anticipate its ecological change in the future by observing the change of the water quality, and to provide scientific data for local government to take measures to protect this Wetland Reservation.The water temperature of the Wetland Reservation, ranging from 18.7℃ to 31.7℃, was varied in different seasons. The values of pH in the whole year were stably between 7.61 and 8.74. Salinity was low in summer and high in winter, ranging from 2.0 to 13.8.The total inorganic nitrogen and total nitrogen in brackish lake were high in summer and autumn, and low in winter and spring, but those in coastal wetland were high in spring and low in other seasons. Phosphate levels hit an all-time high in November 2002 in brackish lake and in March 2003 in coastal wetland, and an all-time low in these two wetlands in September 2003. Total phosphorus concentrations in brackish lake were higher in spring and autumn as compared to winter and summer, but in coastal wetland the highest and the lowest levels were in winter and summer, respectively. The yearly average value of COD in Wetland Reservation was 16.31 mg/L, the average COD level from July to September 2003 was less than 2 mg/L, and the mean in October was 8.6 mg/L, and the average value in other months was higher than 18 mg/L.Phytoplankton in the Wetland Reservation water was comprised by diatom, green alga, and blue alga. The richness of phytoplankton in Wetland Reservation had the positive relation with water temperature. Due to the effect of nutrient and location, the phytoplankton richness in brackish lake reached only a peak with about 8.38×10~6 individuals/L in September 2003. However, the density of phytoplankton in coastal wetland had two peaks, 1.39×10~6 individuals/L in January 2003 and 1.05×10~6 individuals/L in July 2003.Zooplankton composition and richness were mainly influenced by water temperature and phytoplankton. Zooplankton richness peaked twice in the whole year. In brackish lake, the peak values were in October 2002 with thedensity of 723.13 individual/L and May 2003 with the density of 331.25 individual/L, and the valley value was in March 2003 with the density of 10.81 individual/L. In coastal wetland, the two peaks and the valley of zooplankton density were 235.95 individuals/L in October 2002, 75.93 individuals/L in July 2003, and 10.01 in individuals/L in May 2003, respectively.The temperature, pH and COD in coastal wetland were lower than those of brackish lake, but the contents of nitrogen and phosphorus in coastal wetland were higher. The plankton population in coastal wetland was lower than that in brackish lake in summer. The differences between these two wetlands were closely related to their locations.Wetland Reservation water had less plankton species and low biodiversity. The survey result showed the water quality parameters had surpassed the IV-Seawater-Quality standard, which indicated the water had been seriously polluted.
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