2000－2013年中国南部近海赤潮发生规律及影响因素研究

利用历年中国海洋环境质量公报、灾害公报、南海海洋环境质量公报以及相关统计数据,以2000-2013年广东省、广西壮族自治区和海南省发生的赤潮事件为对象,研究了中国南部近海赤潮发生的时空动态、赤潮生物的生态演替以及与温度、营养盐、地理水文要素和厄尔尼诺-南方涛动事件(ENSO)的关联。结果表明:(1)时间分布上,赤潮高发期为2月和8月,9月和12月发生频次较低;(2)空间分布上,赤潮集中发生在珠江口以及大鹏湾、大亚湾、深圳湾3个海湾,汕头港、汕尾港、湛江港以及涠洲岛、硇洲岛附近也是赤潮频发海域;(3)引发赤潮的生物共检出31种,包括甲藻20种、硅藻5种、金藻2种、蓝藻2种、黄藻1种、原生动物1种,共检出149次,其中以金藻门的球形棕囊藻(Phaeocystis globosa)、甲藻门的锥状施克里普藻(Scrippsiella trochoidea)、夜光藻(Noctiluca scintillans)、红色赤潮藻(Akashiwo sanguinea)以及硅藻门的中肋骨条藻(Skeletonema costatum)出现次数较多;(4)赤潮生物存在着明显的季节演替现象,温度和营养盐结构对赤潮爆发及其优势种演替起关键作用,高通量的陆源污染物与弱化的水动力相互叠加为诱发赤潮提供了条件,而厄尔尼诺效应强度与赤潮发生面积呈显著正相关(P<0.05)。

Outbreak Frequency and Factors Influencing Red Tides in Nearshore Waters of the South China Sea from 2000 to 2013

Red tide is among the first three pollutants listed for coastal waters worldwide by the United Nations in 1990. Red Tides have serious adverse effects on the marine environment, fish production and human health. In the coastal region of southern China, rapid economic growth and high population density has increased pollutant discharge to nearshore waters of the South China Sea and led to frequently occurring red tides in recent years. In this study, we analyzed the spatial-temporal dynamics and ecological succession of the species responsible for red tides in the South China Sea from 2000 to 2013 using historical statistics of the red tides that occurred in Guangdong Province, Guangxi Zhuang Autonomous Region and Hainan Province. The analysis included the duration and areal extent of red tides, red tide intensity scale, dominant species, economic impact, emission flux of land-sourced pollutants, relevant meteorological and hydrological data and the southern oscillation index (SOI). The correlation of red tide occurrence with temperature, nutrient levels, geographical and hydrological factors and the El Niño-Southern Oscillation (ENSO) was also studied. Our results will help to better understand the occurrence regularity and influencing factors of red tides and provide information to help predict and control the blooms that produce red tide disasters. Results indicate: (1) Red tide frequency peaks in February and August and is lowest in September and December. (2) Spatially, red tides occur most frequently in the Pearl River Estuary and locations nearby Dapeng Bay, Daya Bay and Shenzhen Bay, in waters surrounding three harbors (Shantou, Shanwei, Zhanjiang) and two offshore islands (Weizhou and Naozhou). (3) 31 species were associated with 149 red tides occurring in the South China Sea, including 20 species of Dinoflagellate, 5 species of Diatom, 2 species of Chrysophyte, 2 species of Cyanophyta, and single species of Xanthophyte and Protozoa. Among them, Phaeocystis globosa, Scrippsiella trochoidea, Noctiluca scintillans, Akashiwo sanguinea and Skeletonema costatum occurred much more frequently and red tide organisms displayed obvious seasonal succession. (4) Temperature and nutrient levels were crucial to both red tide formation and seasonal succession of red tide species. High pollutant discharge during times of reduced hydrodynamic force provides favorable conditions for red tide outbreaks and the areal extent of red tides showed a significant positive correlation to El Niño intensity (P<0.05).