广东汕头南澳岛近岸海域浮游植物群落结构与环境特征

Phytoplankton community and environmental characteristics in the coastal waters of Nanao Island, Shantou, Guangdong

浮游植物是海洋生态系统的主要生产者,其群落结构与水质密切相关.为揭示汕头南澳岛环境特征,于2018年1月(冬季)和4月(春季)在环南澳岛近岸海域设置12个采样站位,开展浮游植物群落结构和水环境调查.冬季共发现浮游植物74种,以硅藻为主,优势种为具槽帕拉藻(Paralia sulcate),浮游植物丰度平均值为(3.45±1.59)×104 cells/L;春季共发现浮游植物80种,以硅藻和甲藻为主,优势种为新月菱形藻(Nitzschia closterium),浮游植物丰度平均值为(5.23±6.02)×104 cells/L.春季浮游植物丰度和物种数较冬季高,优势种季节变化明显.冬季和春季浮游植物丰度均以青澳湾S11最高,该站位受到人类活动影响严重;深澳湾龙须菜栽培区S7浮游植物密度相对较低,说明龙须菜规模栽培对浮游植物生长抑制效应明显.冗余分析表明,冬季影响浮游植物群落结构的主要环境因子为总氮(TN)和水温(WT),春季为活性磷酸盐(PO43--P)、亚硝酸盐(NO2--N)和铵盐(NH4+-N).上述结果表明南澳岛近岸海域浮游植物群落结构与环境因子的时空分布差异显著,且浮游植物分布特征与水体营养盐关系密切,其中个别样点受人类活动影响较大,水质指标和浮游植物丰度都较高,呈现富营养化趋势;因此,应加强海岛环境和旅游业管理,控制陆源生活污水排放,保护海岛近海环境.

Phytoplankton is a major producer in marine ecosystems and its community structure is closely related to water quality.An investigation of the phytoplankton community and the water environment in the coastal waters of Nanao Island,was performed in January(winter) and April(spring),2018.Seventy-four species of phytoplankton were identified in winter;these were mainly diatoms.The dominant species was Paralia sulcata The average density of phytoplankton was(3.45±1.59)×10^4 cells/L.Eighty species of phytoplankton were identified in spring;these were mainly diatoms and dinoflagellates.The dominant species was Nitzschia closterium.The average density of phytoplankton was(5.23±6.02)×10^4 cells/L.The density and species composition of phytoplankton in spring was higher than that in winter,and there was a clear seasonal variation in the dominant species.The density of phytoplankton was the highest in Qingao Bay(S11) in winter and spring,whereas the cultivation area of Gracilaria lemaneiformis(S7) had a relatively low density.S11 was seriously affected by human activity.G.lemaneiformis cultivation had an obvious inhibitory effect on phytoplankton growth.Redundancy analysis revealed that the main environmental factors affecting the phytoplankton community structure in the coastal waters of Nanao Island were total nitrogen(TN) and water temperature(WT) in winter and reactive phosphate(PO43--P),nitrite(NO2--N),and ammonium(NH4+-N) in spring.This study showed that the phytoplankton community structure and environmental factors in the coastal waters of Nanao Island are significantly different depending on the season and region.The distribution characteristics of phytoplankton were closely related to the nutrient content of the coastal waters.Some of the sampling sites were affected by human activity.Water quality indicators and phytoplankton abundance were high,showing a trend of eutrophication.Therefore,it is necessary to strengthen the island environment,improve tourism management,control the discharge of domestic sewage,and protect the offshore environment of the island.