两种涡鞭毛藻的周日垂直迁移特性研究

DIURNAL VERTICAL MIGRATIONS OF TWO DINOFLAGELLATES

Alexandriumlusitanicum于1987年采自葡萄牙沿海，Y－100于1989年采自德国湾。在暗室中用一根柱长150cm、内径3．4cm的玻璃柱对两种涡鞭毛藻的垂直迁移特性进行研究。结果表明，两种藻均进行有规律的周日垂直迁移，且均在光照开始前2h开始向上迁移，光照结束前3h开始向下迁移。A．lusitanicum向上迁移速度约为240μm／s向下约为850μm／s；Y－100向上迁移速度约为280μm／s，向下约为1400μm／s，二者都属能够高速迁移的藻类。Y－100呈很规则的周日阶段性分裂现象，分裂频率高峰出现在光照前1h左右。这两种涡鞭毛漠的周日垂直迁移特性有利于它们更多地获取光能和营养盐从而在其他条件也合适时迅速增殖并聚集在水体表层而引起赤潮。

Clear patterns of diurnal vertical migration of two dinoflagellates, Alexandriumlusitanicum and Y-100 were observed using a 150cm long and 3.4cm diameter glasstube in a dark room. The results show that both algae started to move upwardswith speeds of 240μm/s and 280μm/s, respectively, 2 hours before light on and began to swim downwards 3 hours before light off with speeds of 850μm/s and1 400μm/s, respectively. The growth of Y-100 showed distinctly phased division.The peak of division frequency appeared 1 hour before light on with division frequencies of 13%-17% while the division frequencies at other times were less than3%. Vertical migration enables the algae to assimilate sun energy at the top layerand to take up nutrients at the bottom, hence to growth quickly under other suitable conditions to form red tides.