大亚湾大鹏澳网箱养殖水域的浮游植物生态特征研究

Ecological Characteristics of Phytoplankton in Caged Culturing Waters of Dapengao in Daya Bay

采用现场采样及观察、计数、分析等方法,对大亚湾大鹏澳网箱养殖区及附近海域浮游植物生态特征进行研究。结果显示,养殖区与对照区种类组成基本一致,优势种发生一定变化,主要优势种为菱形海线藻、伏氏海毛藻、细弱海链藻、中肋骨条藻、尖刺菱形藻等。养殖区及附近水域浮游植物栖息密度范围为6.2￣2010×104·m-3,平均235.2×104·m-3,养殖区与对照区平均密度分别为141.8和328.6×104·m-3。比较显示,密度均值除冬季养殖区约低于后者2.4倍外,其他季节2个区域基本接近,差异不明显。多样性指数在0.97￣4.08范围内变化,养殖区和对照区四季均值分别为3.12和3.15,两者差异不明显。种类组成均匀度变化范围为0.19￣0.94,养殖区与对照区无明显差异。多样性阈值在0.23￣3.64范围变化,多样性处于Ⅱ￣Ⅳ级,即多样性差￣多样性非常丰富水平,养殖区和对照区均值分别为2.22和2.20,平均处于Ⅲ级,即多样性较好水平。季节变化均以冬季最低,均值分别为0.79和0.83,夏季最高,均值分别为2.83和3.05。

According to the data obtained from 2001 to 2002, the ecological characteristics of phytoplankton were studied around the waters of caged culturing area in Dapengao of Daya Bay. The species composition in the culturing area were the same as that in the control area, and the dominant species changed to a certainty in both of the two areas with the main Thalassionerna nitzschioides, Thalassionthrix frauenfeldii, Thalassiosira subtilis, Skeletonerna costatum, Nitzschia pungens. Around the waters of the culturing area, the density of phytoplankton ranged from 6.2×10^4 cells·m^-3 to 2010×10^4cells·m^-3 with the average of 235.2×10^4cells·m^-3. In the culturing area and the control area, the average densities were 141.8×10^4cells·m^-3 and 328.6×10^4cells·m^-3, respectively. The biodiversity index ranged from 0.97 to 4.08, and the averages were 3.12 and 3.15 in the culturing area and in the control area, respectively. The evenness of the species composition ranged from 0.19 to 0.94 and showed no difference between the two areas. The biodiversity threshold value varied from 0.23～3.64, and the average in the two areas were 2.22 and 2.20, respectively, which showed the better diversity level. In the seasonal variation, the threshold value in winter was the lowest in both of the areas with the average of 0.79 and 0.83, respectively, while that in summer was the highest with the average of 2.83 and 3.05, respectively.