中国赤潮新记录种──球形棕囊藻(Phaeocystis　globosa)

A report of Phaeocystis globosa bloom in coastal water of Southeast China

报道１９９７年１０月～１９９８年２月在中国东南沿海首次暴发的Ｐｈａｅｏｃｙｓｔｉｓ赤潮．对现场状况、受灾情况进行了调查．赤潮生物主要以群体形式出现，显微镜下观察，成千上万个细胞包埋在凝胶状的基质中形成中空的球形群体，直径从几十微米到３ｃｍ．自由单细胞近圆形，具双鞭毛和一根短的定鞭毛（ｈａｐｔｏｎｅｍａ）．结合本次发生赤潮的Ｐｈａｅｏｃｙｓｔｉｓ的形态特征、环境条件（水温、生物地理等），认为本次赤潮种为：球形棕囊藻（Ｐｈａｅｏｃｙｓｔｉｓ ｇｌｏｂｏｓａ Ｓｃｈｅｒｆｆｅｌ）．分析网箱养殖密集区（Ｓ１、Ｓ２）和近外海（Ｓ３、Ｓ４）水样的结果表明：Ｓ１、Ｓ２的叶绿素ａ和总磷浓度明显高于Ｓ３、Ｓ４，总氮浓度则低于后者；氮磷比浓度明显低于后者；Ｓ１站氮磷比浓度与叶绿素ａ含量明显相关．氮磷比浓度与赤潮发生有密切关系．

A bloom of foe planktonic algae Phaeocystis globosa was observed to occur for the first timein the coastal water of Southeast China during Nov. 1997 to Feb. 1998. Many fishes were killed and local aquaculture was heavily destroyed. Two morphological forms(gelatinous colony and free-living cell) ofPhaeocystis globosa were observed. The colonies - composed of thousands of cells embedded in a mucilaginous matrix - varied in form from small (20 um) to large (30 mm ) in diameter. The other was anearly spherical motile cell, which has two flagella and a short haptonema. It's difficult on identificationof Phaeocystis because of complex life cycle and practical difficulties of observation at the ultrastructurallevel. With the structure of the bloom species and the environment features (water temperature、geography), we think it is Phaeocystis globosa. DIN, DIP, chl a water temperature and DO between aquaculture area(S1, S2) and offshore (S3,S4) during the red tide period were compared. The results showed,DIN and DIP in aquaculture area were up to 160. 4 ug/L and 26. 3 ug/L respectively. N: P ratio (atomic) in aquaculture area was obviously lower than that offshore. There was a negative relationship betweenN: P ratio and the concentration of chl a in S1 station. So the marked decline in N: P ratio could possiblyhe used as a dangerous sign for predicting red tide.