金门岛北部海域浮游植物的季节变动及与环境的关联

采用2013—2014年四季度月在金门岛北部海域获取的浮游植物及环境因子监测数据, 分析该区浮游植物的群落结构和季节变化及其与温度、盐度、悬浮物、营养盐、叶绿素等的关系, 初步探讨涉海工程建设对浮游植物群落的潜在影响。结果显示, 鉴定出的浮游植物隶属3门43属82种(不含未定种), 群落构成以硅藻为主, 其次是甲藻, 蓝藻仅1种。物种组成的季节差异较大, 3月物种贫乏, 1月次之, 7月和11月最丰富。四季丰度平均为47.09×103 cells/L, 1月丰度最高, 7月次之, 11月最低, 3月高于11月少许。四季优势种均为硅藻, 13个优势种分别为柔弱几内亚藻(Guinardia delicatula)、短角弯角藻(Ecampia zoodicaus)、骨条藻(Skeletonema spp.)、具槽帕拉藻(Paralia sulcata)、微小海链藻(Thalassiosira exigua)、标志星杆藻(Asterionella notula)、旋链角毛藻(Chaetoceros curvisetus)、新月菱形藻(Nitzchia closterium)、派格棍形藻(Bacillaria paxillifera)、异常角毛藻(Chaetoceros abmormis)、小细柱藻(Leptocylindrus minutum)、宽角曲舟藻(Pleurosigma angulatum)和美丽曲舟藻(Pleurosigma formosum)。不同季节优势种有一定程度交错, 仅在单季占优的有6种, 有2/3在3个以上季节出现, 具槽帕拉藻、骨条藻为四季优势种。浮游植物物种多样性和均匀度总体较好, 群落结构稳定。与毗邻海区相比, 本区物种丰富度偏低, 丰度高于毗邻海区, 种类组成相似, 优势种却有较大差别。Pearson相关分析表明, 溶解无机氮及活性磷酸盐仅在1月与丰度存在极显著的正相关, 是促使丰度为四季最高的原因。涉海工程施工产生的悬浮物和冲击波是影响浮游植物群落的主要因素, 大量海洋工程建设案例表明, 施工期造成的浮游植物丰度下降趋势和优势种更替混乱在工程结束后能得以恢复。

SEASONAL DYNAMICS OF PHYTOPLANKTON COMMUNITY AND ITS RELATION WITH ENVIRONMENTAL FACTORS IN SEA WATERS OF THE NORTHERN JINMEN ISLAND

Based on four cruise surveys carried out from 2013 to 2014, we analyzed phytoplankton community struc-ture and seasonal pattern and compared them with those of the adjacent sea area. We also assessed the relationship between phytoplankton and environmental factors and potential influence by the second phase of the Xiamen Airport Project construction on phytoplankton. A total of 82 species (excluding unknown taxa) belonging to 43 genera of 3 classes were identified from 95 samples, in which diatoms were dominant in both the species composition and the abundance. Dinoflagellates was the second-largest group. Cyanobacteria was the least with only one species. Signifi-cant seasonal changes existed for phytoplankton species composition and abundance. Species richness was the lowest in March and the highest in November. The annual average phytoplankton abundance was 47.09×103 cells/L with the peak in January and the minimum in November. The dominant species were diatoms including thirteen species:Guinardia delicatula,Ecampia zoodicaus,Skeletonema spp.,Paralia sulcata,Thalassiosira exigua,Asterionella notula,Chaeto-ceros curvisetus,Nitzchia closterium,Bacillaria paradoxa,Chaetoceros abmormis,Leptocylindrus minutum,Pleuro-sigma angulatum andPleurosigma formosum. In detail,Paralia sulcata andSkeletonema spp. were dominant species in four seasons. Shannon-wiener diversity index and Pielou's evenness index indicated a more integrated and stable state of phytoplankton community. Compared with adjacent sea areas around Xiamen Island, the Northern Jinmen Island had medium level of richness of phytoplankton species, similar species composition but different dominant species and higher abundance. Pearson Correlation Analysis indicated that phytoplankton abundance was remarkably nega-tively associated with water temperature in November and was significantly negatively linked with salinity in January and November. Phytoplankton abundance were correlated positively to suspended substance in January but negatively linked in July. The phosphate and dissolved inorganic nitrogen were significantly positively linked with phytoplankton abundance in January. Chlorophylla content was positively associated with phytoplankton abundance in November and significantly positive in January. Phytoplankton abundance in March was not clearly related to environmental factors. The second phase of Xiamen Airport Project mainly affected phytoplankton by massive suspended substance and shock wave during construction period. Moreover, ocean engineering cases indicated that phytoplankton abundance of investi-gated water began to rise and the disorder of dominants succession gradually recovered to the pre-construction status. More investigations of phytoplankton after completing ocean engineering projects are required to assess ecological af-fect by the second phase of Xiamen Airport Project.