嵊泗海域浮游植物数量分布与优势种

Horizontal Distribution and Dominant Species of Phytoplankton in the Shengsi Sea Area

摘要: 通过2016~2017年嵊泗海域(30 ^˚ 30 ' ~31 ^˚ N、121 ^˚ 30 ' ~122 ^˚ 42 ' E) 4个季节现场调查，研究了嵊泗海域浮游植物丰度时空分布和变化动力学机制及嵊泗海域浮游植物优势种的生态学特征。结果表明：嵊泗海域浮游植物丰度的季节变化明显，春(96.00 × 10 ³ cell∙m ⁻³ ) > 秋季(51.72 × 10 ³ cell∙m ⁻³) > 夏季(38.23 × 10 ³ cell∙m ⁻³ ) > 冬季(20.04 ×10 ³ cell∙m ⁻³ )，丰度年平均为51.50 × 10 ³ cell∙m ⁻³ 。冬季嵊泗海域近海高于外海，其他季节外海高于近海。全年共同优势种(优势度Y ≥ 0.02)有2种，为虹彩圆筛藻和琼氏圆筛藻，中肋骨条藻在春、夏和秋季为优势种。聚集性分析表明嵊泗海域浮游植物有明显的聚集现象。通过浮游植物丰度与环境因子的相关分析表明，冬季影响浮游植物丰度分布的主要因素是温度和溶解氧，其他季节浮游植物丰度与环境因子相关性不显著。浮游植物优势种适应性分析表明，虹彩圆筛藻和琼氏圆筛藻的适温性(7.5℃~32℃)比中肋骨条藻的适温性(16℃~32℃)强，在高丰度分布区，虹彩圆筛藻和琼氏圆筛藻温度和盐度适应范围比中肋骨条藻广，但春、夏季丰度比中肋骨条藻低。

Abstract: This article discusses the phytoplankton horizontal distribution and dominant species in Shengsi Sea Area. The ecological characteristics of phytoplankton and their adaptability to the environment were also considered. Oceanographic investigation was carried out in the Shengsi Sea Area (30 ^˚ 30 ' ~31 ^˚ N and 121 ^˚ 30 ' ~122 ^˚ 42 ' E) in four seasons from 2016 to 2017. It was found that the total abundance showed obviously seasonal variations. It peaked in spring with a mean value of 96.00 ×10 ³ cell∙m ⁻³ , followed by autumn (51.72 × 10 ³ cell∙m ⁻³ ). The lowest abundance occurred in winter (20.04 × 10 ³ cell∙m ⁻³ ). The mean density of phytoplankton was 51.50 × 10 ³ cell∙m ⁻³ . For the horizontal distribution, abundance in winter was higher in the near shore than in the off shore, and other seasons were higher in offshore than in nearshore areas. The aggregation characteristics of phytoplankton were obvious from multivariate regression analysis. Over the whole year, phytoplankton abundance showed a significant correlation with the water temperature. Three dominant species were observed in 4 investigated seasons, in which Skeletonema costatum dominated in winter, Coscinodiscus oculus-iridis and Coscinodiscus jonesianus in spring, summer, autumn and winter. Temperature and DO were found to be major influencing factors to winter phytoplankton abundance, while in other seasons the relationship between the environment and the phytoplankton abundance was not obvious. Comparing their adaptability, Coscinodiscus oculus-iridis and Coscinodiscus jonesianus can survive in a wider temperature range (7.5˚C ~32˚C), which enabled them to dominate in spring, summer and winter, while Skeletonema costatum survived in a relatively narrow temperature range (16˚C~32˚C). Coscinodiscus oculus-iridis and Coscinodiscus jonesianus had the wider suitable temperature and salinity zone than the Skeletonema costatum, while the later had the higher abundance in winter.