渤海湾天津近岸海域初级生产力及网采浮游植物种类组成

于2012至2013年调查了渤海湾天津近岸海域的初级生产力和网采浮游植物种类组成。2012—2013年春季调查海域初级生产力为2.20～23.18 mgC/(m²·d),平均值为9.54 mgC/(m²·d),高值区主要分布在塘沽附近海域;夏季初级生产力为6.37～138.37 mgC/(m²·d),平均值为44.13 mgC/(m²·d),高值区主要分布在北塘和汉沽附近海域。与1982—1983年和1992—1993年同期调查结果相比,近30 a来渤海湾初级生产力呈下降趋势。网采浮游植物经初步分析发现2门59种(包括未定名种),其中硅藻49种,占种类组成的83.1%;甲藻10种,占种类组成的16.9%;优势种主要为柔弱根管藻Rhizosolenia delicatula、布氏双尾藻Ditylum brightwellii、中华盒形藻Bidduiphia sinensis、中肋骨条藻Skeletonema costatum、旋链角毛藻Chaetoceros curvisetus、尖刺菱形藻Nitzschia pungens、丹麦细柱藻Leptocylindrus danicus和浮动弯角藻Eucampia zoodiacus。调查海域春季浮游植物细胞丰度为3.32×10³～3.85×10⁷ cell/m³,夏季为2.48×10⁶～4.65×10⁹ cell/m³,夏季明显高于春季;从分布上看,北部和南部的浮游植物细胞丰度高于中部,主要是由天津近岸海域河流分布造成。浮游植物多样性指数在春季和夏季的均值分别为1.865和1.560。2012—2013年浮游植物细胞丰度及其分布主要与水深、化学需氧量、pH值、溶解氧和无机磷相关性较大。

Primary productivity and net-phytoplankton composition in the Tianjin nearshore waters of Bohai Bay from 2012 to 2013

Primary productivities and features of the phytoplankton composition in the nearshore waters of Tianjin from 2012 to 2013 were studied. In spring, the primary productivities were 2.20 to 23.18 mgC/(m²·d), and the average value was 9.54 mgC/(m²·d), while in summer, the primary productivities were 6.37 to 138.37 mgC/(m²·d), and the average value was 44.13 mgC/(m²·d), which were lower than those from 1982 to 1983 and from 1992 to 1993. The horizontal distribution of primary productivities in Tanggu was higher in spring, while those in Beitang and Hangu were higher in summer. Total 2 phyla including 59 species of phytoplankton were commonly found in the survey area, in which 83.1% were diatoms and 16.9% were dinoflagellates. The dominant species were Rhizosolenia delicatula, Ditylum brightwellii, Bidduiphia sinensis, Skeletonema costatum, Chaetoceros curvisetus, Nitzschia pungens, Leptocylindrus danicus and Eucampia zoodiacus. Phytoplankton cell abundance from 2012 to 2013 was from 3.32×10³ to 3.85×10⁷ cell/m³ in spring and 2.48×10⁶ to 4.65×10⁹ cell/m³ in summer, which was higher than that in spring clearly. The horizontal distribution of phytoplankton cell abundance in north and south of Tianjin nearshore waters was higher than that in the middle, which was due to the river distribution. Shannon-Wiener index of phytoplankton community average value was 1.865 in spring and 1.560 in summer. Features of the phytoplankton community form 2012 to 2013 were mainly influenced by depth, COD, pH, DO and phosphorus.