强壮前沟藻(Amphidinium carterae Hulburt)形态特征及其生长特性研究

MORPHOLOGICAL FEATURES AND GROWTH CHARACTERISTICS OF THE DINOFLAGELLATE AMPHIDINIUM CARTERAE HULBURT

采用实验室内单种分离培养方法 ,对强壮前沟藻AmphidiniumcarteraeHulburt进行光学显微镜和扫描电镜观察、鉴定 ,描述其形态特征。采用多因子影响强壮前沟藻生长的方法 ,在不同温度 ( 1 8℃、2 3℃、2 8℃ )、不同盐度 ( 1 0、1 7、2 4、30、35 )和不同的光照条件下 ( 380 0lx、2 4 0 0lx)的生长情况 ,以及各种条件组合的相互作用关系 ,进行了环境因子对该藻生长特性影响的研究。结果表明 ,细胞最大生长率的最适温度、光照、盐度条件分别为 1 8℃、380 0lx、30。根据强壮前沟藻的生长特性 ,初步探讨了温度、光照。

Harmful algae are microscopic, single celled plants that live in the sea. Most species of algae or phytoplankton are not harmful and serve as the energy producers at the base of the food web, without which higher life on this planet would not exist. Unfortunately, a small number of species produce potent toxins that can be transferred through the food web where they affect and even kill the higher forms of life such as zooplankton, shellfish, fish, birds, marine mammals, and even humans that live either directly or indirectly on them. Species of the genus Amphidinium have been thought as one of the toxin producing Harmful Algae Bloom dinoflagellates. Genus Amphidinium belongs to the Gymnodiniidae family. Differences can be observed between Amphidinium and Gymnodinium in position of the annulus of girdle. In Gymnodinium , the girdle is located in the center, while in Amphidinium , it is located at the anterior end. A. carterae Hulburt is a cosmopolitan shallow water species in temperate and tropical zones. Some species of the genus Amphidinium have been linked to red tides and discolouration of sand in subtidal areas. Toxin production has also been reported. Cells of A. carterae were toxic to fish and mice. Crude extracts of the organism also had a significant effect on molluscan, crustacean, amphibian heart activity and caused contractions in the intestines of mice. Furthermore, the seasonal blooms of A. carterae coincided with increasing levels of fish mortality. In Chinese waters, A. carterae mainly distributed in south Hainan coastal regions, north of the South China Sea. This is the first recording of A. carterae in Jiaozhou Bay, China. Unialgal cultures were developed in Guillard's medium of enriched sea water (30 salinity). 300ml of culture was maintained under standard growth conditions: (18±1)℃ and 12h∶12h light∶dark illumination with cool white daylight lamp irradiance (3000lx). Morphological features of A. carterae isolated from shrimp ponds in Jiaozhou Bay was observed by optical microscopes and scanning electron microscope. Growth of the alga was studied in unialgal batch cultures under different conditions. Controlled experiments were conducted on cell density under 30 different conditions of varying temperature (18℃, 23℃, 28℃), salinity(10, 17, 24, 30, 35) and light (3800lx, 2400lx). Effects of variable environmental factors on cells' density were measured by Turner Design Fluorometer every 24 hours. Maximum growth rate of A. carterae (0 36 divisions/d) was obtained in ambient of 18℃, 30 salinity and 3800lx. Demonstrated by ANOVA analysis, salinity and temperature light interaction have a significant impact on the growth. Based on physiological characteristics, the dinoflagellate may become potential outbreaks of red tide in future.